Ion exchange membrane, membrane electrode assembly, unit for redox flow battery, and redox flow battery

Abstract

An ion exchange membrane includes a resin composition containing a side chain heteroaromatic resin having a structural unit represented by general formula 1, and a cation exchange resin. (In the formula, R1, R2, and R3 may be the same or different and each represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1-10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6-10 carbon atoms, R4 represents a directly bonded, substituted or unsubstituted divalent aliphatic hydrocarbon group having 1-10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6-10 carbon atoms, and R3 represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1-10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6-10 carbon atoms. Hc represents a substituted or unsubstituted heteroaromatic group having 4-30 carbon atoms, said heteroaromatic group having at least one nitrogen atom in a heteroaromatic ring structure and comprising a 5-membered ring and / or a 6-membered ring structure. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an ion exchange membrane, a membrane electrode assembly, a cell for a redox flow battery, and a redox flow battery. Background Art

[0002] Redox flow batteries are secondary batteries that store and release electricity, and are suitable for large fixed batteries used to balance electricity consumption. Redox flow batteries have a structure in which a positive electrode electrolyte (positive electrode unit) containing a positive electrode and a positive electrode redox active substance and a negative electrode electrolyte (negative electrode unit) containing a negative electrode and a negative electrode redox active substance are separated by a diaphragm, and charge and discharge are performed using the redox reaction of the two redox active substances. By allowing the electrolyte containing the two redox active substances to flow from the storage tank to the electrolytic cell, a large capacity can be achieved.

[0003] As the redox active material contained in the electrolyte, for example, iron / chromium, chromium / bromine, zinc / bromine, vanadium using charge difference, etc. can be used. In particular, vanadium redox flow batteries have advantages such as high electromotive force, fast electrode reaction of vanadium ions, small amount of hydrogen generated as a side reaction, and high output, and therefore are being actively developed.

[0004] In vanadium redox flow batteries, the divalent vanadium (V 2+ ) / 3 valence (V 3+ ) and the tetravalent vanadium (V 4+ ) / 5 valence (V 5+ ) redox reaction. In this way, the redox active material contained in the electrolyte of the positive electrode unit and the negative electrode unit is the same kind of vanadium ion, so even if the electrolyte passes through the diaphragm and mixes, it can be regenerated by an electrical process, which is excellent from the perspective of being able to be used for a long time. However, if the redox active material passes through, the accumulated charge is neutralized and the current efficiency is reduced, so it is desirable that the diaphragm suppresses the penetration of the redox active material as much as possible. On the other hand, the protons contained in the electrolyte can easily and fully penetrate the diaphragm, thereby reducing the resistance of the battery and improving the voltage efficiency, so it is desirable that the diaphragm does not hinder the penetration of protons as much as possible. That is, a diaphragm that can achieve both high current efficiency and high voltage efficiency, that is, high power efficiency (power efficiency is the product of current efficiency and voltage efficiency) is required.

[0005] It is disclosed that an ion exchange membrane is processed in order to suppress the permeation of redox active substances and achieve high power efficiency (Patent Documents 1 to 3).

[0006] Patent Document 1 discloses that the initial power efficiency is excellent by alternately laminating cation exchange base layers and anion exchange base layers.

[0007] Patent Document 2 discloses that the use of a membrane containing a sulfonated polymer and a heterocyclic molecule containing a plurality of nitrogen atoms allows for a low proton area resistivity and excellent vanadium ion permeation selectivity.

[0008] Patent Document 3 discloses that at least one of discharge capacity, current efficiency, voltage efficiency, and power efficiency can be improved by using a polymer electrolyte membrane having an anti-crossover layer which is a metal layer formed by reducing a cationic metal.

[0009] Patent Document 4 discloses that curling is suppressed and power efficiency is excellent by using a redox flow battery separator including a first ion exchange resin layer, an anion exchange resin layer containing an anion exchange compound, and a second ion exchange resin layer in this order.

[0010] Patent Document 5 discloses a 5 mass % solution obtained by dissolving a fluororesin having an acidic group in a solvent having ethanol and water in a mass ratio of 50:50.

[0011] Patent Document 6 discloses that a thin film having high strength, good adhesion to a substrate, and good chemical resistance can be obtained by using a polymer electrolyte solution obtained by dissolving a fluororesin having an acidic group in a solvent containing a hydrophilic polar solvent having a high boiling point.

[0012] Patent Document 7 and Non-Patent Document 1 disclose that it is difficult to sufficiently increase the molecular weight of the polymer and produce a polymer electrolyte membrane having sufficient mechanical strength when attempting to produce a polymer having a large sulfonic acid group ratio in a fluororesin having a specific acidic group.

[0013] Patent Document 8 discloses that by coextruding a perfluorosulfonic acid polymer precursor and an incompatible polymer, a multilayer film having a perfluorosulfonic acid polymer precursor layer with reduced thickness supported by an incompatible polymer layer can be formed, and a proton exchange membrane with reduced thickness can be obtained.

[0014] Prior art literature

[0015] Patent Literature

[0016] Patent Document 1: Japanese Patent Application Laid-Open No. 11-260390

[0017] Patent Document 2: International Patent Application Publication No. 2017 / 155648

[0018] Patent Document 3: International Patent Application Publication No. 2016 / 163773

[0019] Patent Document 4: International Patent Application Publication No. 2021 / 215126

[0020] Patent Document 5: Japanese Patent Application Laid-Open No. 07-296634

[0021] Patent Document 6: Japanese Patent Application Publication No. 2004-164854

[0022] Patent Document 7: International Patent Application Publication No. 2008 / 090990

[0023] Patent Document 8: International Patent Application Publication No. 2013 / 091073

[0024] Non-patent literature

[0025] Non-patent document 1: W. Vielstich, HA Gasteiger, A. Lamm, eds., "Handbook of Fuel Cells, vol. 3", John Wiley & Sons, Ltd., USA, 2003, Chapter 30, p. 351-352 Summary of the invention

[0026] The embodiments of the present invention are as follows.

[0027] <1>

[0028] An ion exchange membrane comprises a resin composition, wherein the resin composition comprises:

[0029] A side chain heteroaromatic resin having a structural unit represented by the following general formula 1, and a cation exchange resin.

[0030]

[0031] (Where,

[0032] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0033] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0034] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure.

[0035] <2>

[0036] The ion exchange membrane according to <1>, wherein the weight ratio of the aforementioned side chain heteroaromatic resin to the aforementioned cation exchange resin is 1:100 to 100:1.

[0037] <3>

[0038] The ion exchange membrane according to <1> or <2>, wherein the aforementioned cation exchange resin is a fluororesin.

[0039] <4>

[0040] The ion exchange membrane according to <3>, wherein the aforementioned fluororesin has a structural unit represented by the following general formula G1,

[0041]

[0042] (In the formula,

[0043] X 5 、X 6 、X 7 、and X 8 are each independently optionally the same or different and are a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms. The aforementioned halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. X 5 and X 6 、or X 5 and X 7 are optionally bonded to each other to form a cyclic structure,

[0044] R 5 and R 6 are each independently optionally the same or different and are a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms. The aforementioned halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0045] X 9 is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ. Z is at least one selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, and amines. Optionally, the fluororesins are crosslinked with each other via X 9 by ionic crosslinking,

[0046] h and p represent the molar ratios in all the structural units contained in the resin and are numbers satisfying 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1,

[0047] i is an integer from 0 to 8,

[0048] j is 0 or 1,

[0049] k, l and m are each optionally the same or different and are integers of 0 to 6. When k, l and m are all 0, X 9 CF(CF2X 10 )2,X 10 is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, and Z is the same as described above. )

[0050] <5>

[0051] according to <1> ~ <4> The ion exchange membrane described in any one of the preceding claims has at least one layer (L) comprising the resin composition and at least one layer (M) comprising a fluororesin alternately, wherein the fluororesin has a structural unit represented by the following general formula G1.

[0052]

[0053] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0054] <6>

[0055] according to <5> The ion exchange membrane comprises one layer of the layer (L) and one layer of the layer (M).

[0056] <7>

[0057] according to <5> or <6> The ion exchange membrane comprises the aforementioned layer (L), the aforementioned layer (M) and the aforementioned layer (L) in sequence.

[0058] <8>

[0059] An ion exchange membrane comprises: a side chain heteroaromatic resin having a structural unit represented by the following general formula 2.

[0060]

[0061] (Where,

[0062] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0063] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0064] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure,

[0065] Rf is an aliphatic hydrocarbon group substituted with at least one fluorine atom,

[0066] X - is the counter anion.)

[0067] <9>

[0068] according to <8> The ion exchange membrane comprises at least one layer (L) containing the side chain heteroaromatic resin and at least one layer (M) containing a fluororesin alternately, wherein the fluororesin has a structural unit represented by the following general formula G1.

[0069]

[0070] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0071] <10>

[0072] according to <9> The ion exchange membrane comprises one layer of the layer (L) and one layer of the layer (M).

[0073] <11>

[0074] according to <9> The ion exchange membrane comprises the aforementioned layer (L), the aforementioned layer (M) and the aforementioned layer (L) in sequence.

[0075] <12>

[0076] according to <9> ~ <11> The ion exchange membrane described in any one of the preceding claims, wherein the layer (L) further comprises a cation exchange resin.

[0077] <13>

[0078] according to <12> The ion exchange membrane, wherein the weight ratio of the side chain heteroaromatic resin to the cation exchange resin is 1:100 to 100:1.

[0079] <14>

[0080] according to <12> or <13> The ion exchange membrane, wherein the cation exchange resin is a fluororesin.

[0081] <15>

[0082] according to <14> The ion exchange membrane, wherein the fluororesin has a structural unit represented by the following general formula G1.

[0083]

[0084] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0085] <16>

[0086] according to <1> In the ion exchange membrane, the side chain heteroaromatic resin further has a structural unit represented by the following general formula 2.

[0087]

[0088] (Where,

[0089] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0090] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0091] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure,

[0092] Rf is an aliphatic hydrocarbon group substituted with at least one fluorine atom,

[0093] X - is the counter anion.)

[0094] <17>

[0095] according to <16> The ion exchange membrane, wherein the molar ratio of the structural unit represented by the general formula 1 to the structural unit represented by the general formula 2 is 1:100 to 100:1.

[0096] <18>

[0097] according to <16> or <17> The ion exchange membrane, wherein the weight ratio of the side chain heteroaromatic resin to the cation exchange resin is 1:100 to 100:1.

[0098] <19>

[0099] according to <16> ~ <18> The ion exchange membrane according to any one of the preceding claims, wherein the cation exchange resin is a fluororesin.

[0100] <20>

[0101] according to <16> ~ <19> The ion exchange membrane described in any one of the preceding claims, wherein the fluororesin has a structural unit represented by the following general formula G1.

[0102]

[0103] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0104] <21>

[0105] according to <20> The ion exchange membrane comprises at least one layer (L) comprising the resin composition and at least one layer (M) comprising a fluororesin alternately, wherein the fluororesin has a structural unit represented by the following general formula G1.

[0106]

[0107] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0108] <22>

[0109] according to <21> The ion exchange membrane comprises one layer of the layer (L) and one layer of the layer (M).

[0110] <23>

[0111] according to <21> The ion exchange membrane comprises the aforementioned layer (L), the aforementioned layer (M) and the aforementioned layer (L) in sequence.

[0112] <24>

[0113] An ion exchange membrane comprising a layer (L1) and a layer (M1),

[0114] The layer (L1) comprises: a fluororesin containing a heteroaromatic structure having a structural unit represented by the following general formula A1, a saponified product thereof, or a salt thereof;

[0115] The layer (M1) comprises a fluororesin (G1) having a structural unit represented by the following general formula G1.

[0116]

[0117] (Where,

[0118] X 1 , X 2 , X 3 and X 4Each independently and optionally the same or different, is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, and the aforementioned halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, X 1 and X 2 , or X 1 and X 3 optionally bond to each other to form a cyclic structure,

[0119] R 1 , R 2 Each independently and optionally the same or different, is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, and the aforementioned halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0120] R 3 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0121] R 4 is a linking group between NR 3 and Hc, and is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0122] X 10 is a divalent group represented by the chemical formula -CO2- or -SO2-,

[0123] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the heteroaromatic group contains at least one nitrogen atom, and includes a 5-membered ring and / or a 6-membered ring structure,

[0124] a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1,

[0125] b is an integer from 0 to 8,

[0126] c is 0 or 1,

[0127] d, e, and f each independently and optionally the same or different, are integers from 0 to 6. Among them, d, e, and f are not simultaneously 0.)

[0128]

[0129] (In the formula, the definitions of each substituent are the same as the meanings in the aforementioned general formula G1.)

[0130] <25>

[0131] according to <24> The ion exchange membrane has three or more layers of the layer (L1) and the layer (M1) alternately.

[0132] <26>

[0133] according to <24> or <25> The ion exchange membrane, wherein the thickness of the layer (L1) is 10 μm or less.

[0134] <27>

[0135] according to <24> ~ <26> The ion exchange membrane according to any one of the preceding claims, wherein the thickness of the ion exchange membrane is 200 μm or less.

[0136] <28>

[0137] An ion exchange membrane comprising a layer (L3) and a layer (M3),

[0138] The layer (L3) comprises: a fluororesin containing side chain nitrogen atoms having a structural unit represented by the following general formula A3, a saponified product thereof, or a salt thereof;

[0139] The layer (M3) comprises a fluororesin (G1) having a structural unit represented by the following general formula G1.

[0140]

[0141] (Where,

[0142] X 20 , X 21 , X 22 and X 23 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 20 With X 21 , or X 20 With X 22 Optionally forming a ring structure,

[0143] R 20 and R 21 each of which is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0144] R 22 and R 24 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0145] R 26 and R 27 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, R 26 and R 27 at least one of which is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms,

[0146] R 23 and R 25 each independently and optionally the same or different, is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, and when h is 2 or more, the repeating R 23 each independently and optionally the same or different,

[0147] X 24 is a divalent group represented by -CO2- or -SO2-,

[0148] a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1,

[0149] b is an integer from 0 to 8,

[0150] c is 0 or 1,

[0151] d, e, f, and h each independently and optionally the same or different, are integers from 0 to 6. Among them, d, e, and f are not simultaneously 0.)

[0152]

[0153] (In the formula, the definitions of each substituent are the same as the meaning of the aforementioned general formula G1.)

[0154] <29>

[0155] The ion exchange membrane according to <28>, which alternately has three or more of the aforementioned layer (L3) and the aforementioned layer (M3).

[0156] <30>

[0157] The ion exchange membrane according to <28> or <29>, wherein the thickness of the aforementioned layer (L3) is 10 μm or less.

[0158] <31>

[0159] The ion exchange membrane according to any one of <28> to <30>, wherein the thickness of the aforementioned ion exchange membrane is 200 μm or less.

[0160] <32>

[0161] according to <1> ~ <31> The ion exchange membrane described above is used in a redox flow battery.

[0162] <33>

[0163] A membrane electrode assembly, wherein: <1> ~ <31> The ion exchange membrane described in any one of the above aspects is joined to at least one electrode.

[0164] <34>

[0165] according to <33> The membrane electrode assembly is used in a redox flow battery.

[0166] <35>

[0167] A cell for a redox flow battery, comprising:

[0168] a first electrolyte solution containing a first redox active material,

[0169] a second electrolyte solution containing a second redox active material,

[0170] a first electrode in contact with the first electrolyte,

[0171] a second electrode in contact with the second electrolyte, and

[0172] a separator disposed between the first electrolyte and the second electrolyte,

[0173] The aforementioned diaphragm is <1> ~ <31> The ion exchange membrane described above.

[0174] <36>

[0175] according to <35> The redox flow battery cell is a membrane electrode assembly in which a diaphragm is joined to at least one electrode.

[0176] <37>

[0177] according to <35> or <36> In the redox flow battery cell, at least one of the first electrode and the second electrode is a carbon electrode.

[0178] <38>

[0179] according to <35> ~ <37> The redox flow battery cell according to any one of the preceding claims, wherein at least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials.

[0180] <39>

[0181] A redox flow battery having a plurality of layers <35> ~ <38> The redox flow battery cell according to any one of the above.

[0182] <40>

[0183] A cell for a redox flow battery, comprising:

[0184] a first electrolyte solution containing a first redox active material,

[0185] a second electrolyte solution containing a second redox active material,

[0186] a first electrode in contact with the first electrolyte,

[0187] a second electrode in contact with the second electrolyte, and

[0188] a separator disposed between the first electrolyte and the second electrolyte,

[0189] The separator comprises at least a first cation exchange resin layer and an anion exchange resin layer.

[0190] The equivalent weight of the above-mentioned separator is 1150 g / eq or less,

[0191] The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm.

[0192] The anion exchange resin layer of the separator is disposed on the electrode side functioning as the negative electrode.

[0193] <41>

[0194] according to <40> In the redox flow battery cell, the first cation exchange resin layer is disposed closer to the electrode functioning as a positive electrode than the anion exchange resin layer.

[0195] <42>

[0196] according to <40> or <41> The redox flow battery cell, wherein the distance D between the anion exchange resin layer of the separator and the electrode functioning as the negative electrode is neg The distance D between the anion exchange resin layer of the separator and the electrode functioning as the positive electrode is pos The following relationships are shown.

[0197] D neg / D pos <1

[0198] <43>

[0199] according to <40> ~ <42> The redox flow battery cell according to any one of the preceding claims, wherein the first cation exchange resin layer has a thickness of 1 μm to 150 μm.

[0200] <44>

[0201] according to <40> ~ <43> The redox flow battery cell according to any one of the preceding claims, wherein the first cation exchange resin layer contains a fluororesin.

[0202] <45>

[0203] according to <40> ~ <44> The redox flow battery cell according to any one of the preceding claims, wherein the first cation exchange resin layer has at least one functional group selected from the group consisting of a sulfonic group, a carboxyl group, and a phosphoric acid group.

[0204] <46>

[0205] according to <40> ~ <45> The redox flow battery cell according to any one of the preceding claims, wherein the first cation exchange resin layer comprises a fluororesin having a structural unit represented by the following general formula G1.

[0206]

[0207] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0208] <47>

[0209] according to <40> ~ <46> The redox flow battery cell according to any one of the preceding claims, wherein the anion exchange resin layer comprises at least one selected from the group consisting of the following structures:

[0210] Primary amino group;

[0211] Secondary amino group;

[0212] Tertiary amino group;

[0213] An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound;

[0214] Heterocyclic structures containing nitrogen atoms;

[0215] A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; and

[0216] Quaternary ammonium group.

[0217] <48>

[0218] according to <40> ~ <47> The redox flow battery cell according to any one of the preceding claims, wherein:

[0219] The aforementioned diaphragm comprises:

[0220] the first cation exchange resin layer,

[0221] The anion exchange resin layer, and

[0222] The second cation exchange resin layer,

[0223] The thickness of the first cation exchange resin layer is greater than the thickness of the second cation exchange resin layer.

[0224] <49>

[0225] according to <48> In the redox flow battery cell, the first cation exchange resin layer is disposed closer to an electrode functioning as a positive electrode than the anion exchange resin layer.

[0226] <50>

[0227] according to <48> or <49> The redox flow battery cell, wherein the distance D between the anion exchange resin layer of the separator and the electrode functioning as the negative electrode is neg The distance D between the anion exchange resin layer of the separator and the electrode functioning as the positive electrode is pos The following relationships are shown.

[0228] D neg / D pos <1

[0229] <51>

[0230] according to <48> ~ <50> The redox flow battery cell according to any one of the preceding claims, wherein the second cation exchange resin layer contains a fluororesin.

[0231] <52>

[0232] according to <48> ~ <51> The redox flow battery cell according to any one of the preceding claims, wherein the second cation exchange resin layer has a thickness of 0.01 μm or more and less than 150 μm.

[0233] <53>

[0234] according to <48> ~ <52> The redox flow battery cell according to any one of the preceding claims, wherein a value obtained by dividing the thickness of the second ion exchange resin layer by the thickness of the first cation exchange resin layer is less than 0.7.

[0235] <54>

[0236] according to <40> ~ <53> The redox flow battery cell according to any one of the preceding claims, wherein at least one of the first electrode and the second electrode is a carbon electrode.

[0237] <55>

[0238] according to <40> ~ <54> The redox flow battery cell according to any one of the preceding claims, wherein at least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials.

[0239] <56>

[0240] according to <40> ~ <55> The redox flow battery cell described in any one of the above is a separator-electrode assembly in which at least one of the first electrode and the second electrode is bonded to a separator.

[0241] <57>

[0242] A redox flow battery having a plurality of layers <40> ~ <56> The redox flow battery cell according to any one of the above.

[0243] <58>

[0244] A method for producing a diaphragm, wherein the diaphragm comprises at least a first cation exchange resin layer and an anion exchange resin layer,

[0245] The equivalent weight of the above-mentioned separator is 1150 g / eq or less,

[0246] The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm.

[0247] The manufacturing method comprises:

[0248] a step of forming the first cation exchange resin layer, and

[0249] A step of forming the anion exchange resin layer.

[0250] <59>

[0251] according to <58> The method for manufacturing the diaphragm comprises:

[0252] a step of reacting a fluororesin precursor layer as a precursor of the first cation exchange resin layer, the fluororesin precursor layer containing at least one selected from the group consisting of a halogenated sulfonyl group, an acyl halide group, and a halogenated phosphoric acid group, with a modifying compound having at least two nitrogen atom-containing groups; and

[0253] After the above step, a step of converting at least one selected from the group consisting of halogenated sulfonyl groups, acyl halide groups and halogenated phosphoric acid groups contained in the fluororesin precursor layer into at least one selected from the group consisting of sulfonic groups, carboxyl groups and phosphoric acid groups,

[0254] The nitrogen atom-containing group comprises at least one selected from the group consisting of the following structures:

[0255] Primary amino group;

[0256] Secondary amino group;

[0257] Tertiary amino group;

[0258] An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound;

[0259] Heterocyclic structures containing nitrogen atoms;

[0260] A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; and

[0261] Quaternary ammonium group.

[0262] <60>

[0263] according to <58> The manufacturing method of the diaphragm, the diaphragm comprises:

[0264] the first cation exchange resin layer,

[0265] The anion exchange resin layer, and

[0266] The second cation exchange resin layer,

[0267] The thickness of the first cation exchange resin layer is greater than the thickness of the second cation exchange resin layer, and the manufacturing method comprises:

[0268] a step of forming the first cation exchange resin layer,

[0269] a step of forming the anion exchange resin layer, and

[0270] A step of forming the second cation exchange resin layer.

[0271] <61>

[0272] according to <60> The method for producing the separator includes the step of stacking the anion exchange resin layers of the membranes having the first cation exchange resin layer and the anion exchange resin layer.

[0273] <62>

[0274] A polymer electrolyte solution comprising:

[0275] A fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq; and

[0276] A solvent comprising water, an aliphatic alcohol and an aliphatic carboxylic acid,

[0277] The mass ratio of the total amount of the aliphatic carboxylic acid and the reaction product thereof to the total mass of the solvent is 100:1 to 100:50.

[0278]

[0279] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0280] <63>

[0281] according to <62> In the polymer electrolyte solution, the mass ratio of the aliphatic carboxylic acid to the aliphatic alcohol is 100:1 to 1:100.

[0282] <64>

[0283] An ion exchange membrane comprising a fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq,

[0284] The number of broken spots per unit area of ​​the ion exchange membrane is less than 10 / m 2 .

[0285]

[0286] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0287] <65>

[0288] according to <64> The ion exchange membrane has an orientation ratio OR in the membrane surface direction measured by X-ray scattering measurement of 1.0 or more and less than 1.1.

[0289] <66>

[0290] according to <64> or <65> The ion exchange membrane has an average membrane thickness of less than 75 μm.

[0291] <67>

[0292] according to <64> ~ <66> The ion exchange membrane described above has an average film thickness of 25 μm or more.

[0293] <68>

[0294] according to <64> ~ <67> The ion exchange membrane described in any one of the preceding claims, wherein the minimum film thickness is 90% or more of the average film thickness and the maximum film thickness is 110% or less of the average film thickness.

[0295] <69>

[0296] A wound body, wherein <64> ~ <68> The ion exchange membrane described above is wound and configured.

[0297] <70>

[0298] according to <68> In the wound body, the ion exchange membrane has a width of 50 mm to 5,000 mm.

[0299] <71>

[0300] according to <69> or <70> In the wound body, the length of the ion exchange membrane is greater than 100 mm.

[0301] <72>

[0302] A membrane electrode assembly, wherein: <64> ~ <68> The ion exchange membrane described in any one of the above aspects is joined to at least one electrode.

[0303] <73>

[0304] according to <64> ~ <68> The ion exchange membrane described above is used in a redox flow battery.

[0305] <74>

[0306] according to <72> The membrane electrode assembly is used in a redox flow battery.

[0307] <75>

[0308] A cell for a redox flow battery, comprising:

[0309] a first electrolyte solution containing a first redox active material,

[0310] a second electrolyte solution containing a second redox active material,

[0311] a first electrode in contact with the first electrolyte,

[0312] a second electrode in contact with the second electrolyte, and

[0313] a separator disposed between the first electrolyte and the second electrolyte,

[0314] The aforementioned diaphragm is <64> ~ <68> The ion exchange membrane described above.

[0315] <76>

[0316] according to <75> In the redox flow battery cell, the separator is joined to at least one electrode.

[0317] <77>

[0318] according to <75> or <76> In the redox flow battery cell, at least one of the first electrode and the second electrode is a carbon electrode.

[0319] <78>

[0320] according to <75> ~ <77> The redox flow battery cell according to any one of the preceding claims, wherein at least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials.

[0321] <79>

[0322] A redox flow battery having a plurality of layers <75> ~ <78> The redox flow battery cell according to any one of the above.

[0323] <80>

[0324] A method for manufacturing an ion exchange membrane, comprising: <62> or <63> The polymer electrolyte solution coating and drying process,

[0325] The ion exchange membrane comprises a fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq, and the number of cracks per unit area of ​​the ion exchange membrane is less than 10 / m 2 .

[0326]

[0327] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.) BRIEF DESCRIPTION OF THE DRAWINGS

[0328] Figure 1 This is an example of a schematic diagram showing a redox flow battery using the redox flow battery separator according to the present embodiment. DETAILED DESCRIPTION

[0329] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description, and various modifications can be made within the scope of the gist thereof.

[0330] [First embodiment]

[0331] First, the first embodiment will be described.

[0332] Patent Document 1 discloses that, in order to improve current efficiency and power efficiency, an aromatic polysulfone-based polymer is used as an anion exchange substrate, and although the current efficiency is excellent, the battery resistance increases and the voltage efficiency decreases. Therefore, an anion exchange substrate having excellent current efficiency, voltage efficiency, and current efficiency is required to be well balanced.

[0333] In Patent Document 2, in order to suppress the increase of proton surface resistance and improve the vanadium ion permeation selectivity, Nafion (registered trademark) 117 reacted with some heterocyclic molecules is disclosed. However, when the proton surface resistance is to be reduced, the vanadium ion permeation selectivity becomes low. On the other hand, when the vanadium ion permeation selectivity is to be improved, the proton surface resistance becomes high, and there are still problems in terms of balancing. In addition, no evaluation as a redox flow battery is performed in the embodiments, and the current efficiency, voltage efficiency and power efficiency are still unclear. However, in the embodiments, the proton surface resistance is a value higher than that of Nafion (registered trademark) 117, from which it can be inferred that the voltage efficiency is lower than that of Nafion (registered trademark) 117. In summary, a material with excellent current efficiency, voltage efficiency and current efficiency is required to be well balanced.

[0334] Patent Document 3 discloses that a metal layer, namely, an anti-crossing layer, formed by reducing a cationic metal is provided inside a polymer electrolyte membrane in order to improve at least one of the characteristics of discharge capacity, current efficiency, voltage efficiency, and power efficiency, but higher characteristics are required.

[0335] Patent Document 4 discloses that some polymer compounds are used as an anion exchange resin layer in order to achieve high power efficiency. However, when the anion exchange resin layer is not located between the anion exchange resin layer, although high power efficiency can be obtained as an initial characteristic, it is shown that high power efficiency cannot be obtained after 100 cycles. Therefore, the anion exchange compound contained in the anion exchange resin layer used in Patent Document 4 is required to have higher characteristics.

[0336] The present invention relates to a side chain heteroaromatic resin, a resin composition, an ion exchange membrane, a membrane electrode assembly, a redox flow battery cell and a redox flow battery using the same, which can provide a redox battery cell having excellent current efficiency and voltage efficiency in a good balance and high power efficiency.

[0337] The present inventors have conducted intensive studies on the above-mentioned problems and have found that by using a side chain heteroaromatic resin having a specific structural unit as a separator of a redox flow battery cell, current efficiency and voltage efficiency are well balanced and excellent, and high power efficiency can be obtained.

[0338] The ion exchange membrane of the first embodiment includes the following resin composition. That is, the resin composition includes:

[0339] A side chain heteroaromatic resin having a structural unit represented by the following general formula 1, and a cation exchange resin.

[0340]

[0341] (Where,

[0342] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0343] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0344] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure.

[0345] According to the present embodiment, a novel side chain heteroaromatic resin having a specific structural unit can be provided. In addition, according to the present embodiment, a side chain heteroaromatic resin, a resin composition, an ion exchange membrane, a membrane electrode assembly, a redox flow battery cell and a redox flow battery using the same can be provided, which can obtain a redox flow battery cell having a good balance between current efficiency and voltage efficiency and high power efficiency.

[0346] In addition, the ion exchange membrane of the first embodiment contains a side chain heteroaromatic resin having a structural unit represented by the following general formula 2.

[0347]

[0348] (Where,

[0349] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0350] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0351] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure,

[0352] Rf is an aliphatic hydrocarbon group substituted with at least one fluorine atom,

[0353] X - is the counter anion.)

[0354] <Side chain heteroaromatic resin>

[0355] The side chain heteroaromatic resin in the first embodiment has a structural unit represented by the following general formula 1.

[0356]

[0357] (Where,

[0358] R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0359] R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0360] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure.

[0361] R in the above general formula 1 1 , R 2 and R 3Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0362] In the case of a substituted aliphatic hydrocarbon group or a substituted aromatic hydrocarbon group, the substituent is not particularly limited, and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, nitrile groups (-CN), alkoxy groups (-OR a ), alkyl carbonate group (-OCO2R a ), alkyl ester group (-CO2R a ), acyl (-COR a ), sulfide group (-SR a ), sulfoxide (-SOR a ), sulfo (-SO2R a ) and carbamate groups (-NHCO2R a ) etc. a It is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. It should be noted that when it is an aliphatic hydrocarbon group, the substituent may be an aromatic hydrocarbon group having 6 to 10 carbon atoms, and when it is an aromatic hydrocarbon group, the substituent may be an aliphatic hydrocarbon group having 1 to 10 carbon atoms. When it has a substituent, the substituent may be a single type or multiple types.

[0363] As R 1 , R 2 and R 3 , from the aspect that the raw material compound when manufacturing the side chain heteroaromatic resin is easy to obtain, preferably a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, more preferably a hydrogen atom, an unsubstituted aliphatic hydrocarbon group. From the aspect that the raw material compound when manufacturing the side chain heteroaromatic resin has high reactivity and tends to be able to suppress the manufacturing cost, a hydrogen atom is further preferred.

[0364] The substituted or unsubstituted aliphatic hydrocarbon group has 1 to 10 carbon atoms. The carbon atoms are preferably 1 to 6, more preferably 1 to 4, further preferably 1 or 2, and further preferably 1, from the viewpoint of easy availability of raw material compounds when producing the side chain heteroaromatic resin.

[0365] The substituted or unsubstituted aromatic hydrocarbon group has a carbon number of 6 to 10. The carbon number is preferably 6 to 10, more preferably 6 to 8, and even more preferably 6, from the viewpoint of easy availability of raw material compounds when producing a side chain heteroaromatic resin.

[0366] R in the above general formula 1 4 It is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms. The substituents here are the same as the substituents described above.

[0367] Here, direct bonding means that Hc in the structural unit represented by the general formula 1 and R 3 The carbon atom of the main chain to which the bonding occurs is directly bonded. 4 The same meaning is expressed in the records of .)

[0368] The substituted or unsubstituted divalent aliphatic hydrocarbon group has 1 to 10 carbon atoms. The carbon atoms are preferably 1 to 6, more preferably 1 to 4, further preferably 1 or 2, and further preferably 1, from the viewpoint of easy availability of raw material compounds when producing the side chain heteroaromatic resin.

[0369] The substituted or unsubstituted divalent aromatic hydrocarbon group has a carbon number of 6 to 10. The carbon number is preferably 6 to 10, more preferably 6 to 8, and even more preferably 6, from the viewpoint of easy availability of raw material compounds when producing a side chain heteroaromatic resin.

[0370] As R of the above general formula 1 4 From the perspective of easy availability of raw material compounds when manufacturing side chain heteroaromatic resins, direct bonding or substituted or unsubstituted aliphatic hydrocarbon groups are preferred, and direct bonding and unsubstituted aliphatic hydrocarbon groups are more preferred. From the perspective of high reactivity of raw material compounds when manufacturing side chain heteroaromatic resins and a tendency to suppress manufacturing costs, direct bonding is further preferred. 4 In the case of direct bonding, the structural unit represented by the general formula 1 is represented by the following general formula 1-2. The substituents here are the same as the above-mentioned substituents.

[0371]

[0372] (In the formula, the definitions of the substituents are the same as those in the above general formula 1.)

[0373] Hc in the above general formula 1 is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group has at least one nitrogen atom in the heteroaromatic ring structure and contains a 5-membered ring and / or a 6-membered ring structure.

[0374] The 5-membered ring and / or 6-membered ring structure in Hc of the general formula 1 is not particularly limited, and examples thereof include an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a pyridazine structure, a pyrimidine structure, a cinnoline structure, a quinazoline structure, a phthalazine structure, a quinoxaline structure, a pteridine structure, a purine structure, a 2,2'-bipyridine structure, a 2,3'-bipyridine structure, a 2,4'-bipyridine structure, a 1,7-phenanthroline structure, a 1,10-phenanthroline structure, and a 2,2':6',2"-terpyridine structure. The structure of Hc exemplified above may be a single structure or may have a plurality of structures.

[0375] Since Hc has at least one nitrogen atom in the heteroaromatic ring structure, among the above-mentioned 5-membered ring and / or 6-membered ring structure, it is preferred to have an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a 2,2'-bipyridine structure, a 2,3'-bipyridine structure, a 2,4'-bipyridine structure, a 1,7-phenanthroline structure, and a 1,10-phenanthroline structure; it is more preferred to have an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a 2,2'-bipyridine structure, and a 1,10-phenanthroline structure; from the perspective of the tendency for the durability to be improved when the side chain heteroaromatic resin is used for a redox flow battery unit, it is further preferred to have an imidazole structure, a benzimidazole structure, an imidazopyridine structure, and a pyridine structure; and it is particularly preferred to have an imidazole structure and a pyridine structure.

[0376] H C The substituents in are the same as the above-mentioned substituents.

[0377] Examples of Hc include imidazolyl, benzimidazolyl, imidazopyridyl, pyridyl, oxazolyl, thiazolyl, pyridazinyl, pyrimidinyl, cinnolinyl, quinazolinyl, phthalazinyl, quinoxalinyl, pteridinyl, purinyl, 2,2′-bipyridyl, 2,3′-bipyridyl, 2,4′-bipyridyl, 1,7-phenanthrolinyl, 1,10-phenanthrolinyl, and 2,2′:6′,2″-terpyridyl. Among these, imidazolyl and pyridyl are preferred.

[0378] When Hc is an imidazole group, the structural unit represented by the general formula 1 is a structural unit represented by the following general formula 1-3.

[0379]

[0380] When Hc is a pyridyl group, the structural unit represented by the general formula 1 is a structural unit represented by the following general formula 1-4.

[0381]

[0382] The structural unit represented by the above-mentioned general formula 1 is preferably a structural unit represented by the following general formula 1-5 or the following general formula 1-6.

[0383]

[0384] The side chain heteroaromatic resin preferably further has a structural unit represented by the following general formula 2.

[0385]

[0386] (Where R 1 , R 2 , R 3 , R4 , Hc and n are the same as those in Formula 1, Rf is an aliphatic hydrocarbon group substituted with at least one fluorine atom, X - is the counter anion.)

[0387] When the side chain heteroaromatic resin further has a structural unit represented by Formula 2, water resistance, chemical resistance, acid resistance, and alkali resistance tend to be improved.

[0388] The aliphatic hydrocarbon group in Rf preferably has 1 to 20 carbon atoms, more preferably 3 to 16 carbon atoms, further preferably 3 to 11 carbon atoms, and further preferably 3 to 9 carbon atoms.

[0389] The number of fluorine atoms substituting in the aliphatic hydrocarbon group in Rf is preferably 1-41, more preferably 3-25, further preferably 5-18.

[0390] As Rf, preferably the formula: -(CH2) o -(CF2) p A group represented by -CF3 (wherein o+p is 1 to 19 and o is 0 to 19).

[0391] o and p may be integers. o+p is preferably 1 to 19, more preferably 2 to 15, further preferably 2 to 10, further preferably 2 to 8. From the same viewpoint, o is preferably 0 to 19, more preferably 1 to 10, and from the viewpoint of further improving the water resistance and chemical resistance of the side chain heteroaromatic resin, it is further preferably 2 to 4, further preferably 2. From the viewpoint that the compound that becomes the precursor of Rf is easy to obtain and the manufacturing cost of the side chain heteroaromatic resin can be suppressed, p is preferably 0 to 19, more preferably 2 to 10, further preferably 3 to 7, further preferably 4 to 6.

[0392] More specifically, for example, Rf includes -(CH2)2(CF2)3CF3, -(CH2)2(CF2)4CF3, and -(CH2)2(CF2)6CF3.

[0393] As X - , we can list F - , Cl - Br - ,I - 、HSO4 - 、(SO4 2- ) 1 / 2 、NO3 - OH - .

[0394] The structural unit represented by the general formula 2 is preferably a structural unit represented by the following general formula 2-2.

[0395]

[0396] The structural unit represented by the general formula 2 is preferably a structural unit represented by the following general formula 2-3 or the following general formula 2-4.

[0397]

[0398] As the structural unit represented by the general formula 2, more preferably, there can be mentioned a structure represented by the following general formula 2-5 or the following general formula 2-6.

[0399]

[0400] The side chain heteroaromatic resin preferably has a structural unit represented by Formula 2, and more preferably has a structural unit represented by Formula 1 and a structural unit represented by Formula 2.

[0401] <Cation Exchange Resin>

[0402] The resin composition of the present embodiment preferably contains a cation exchange resin.

[0403] The cation exchange resin refers to a resin having an ion exchange capacity for cations (hereinafter also referred to as "Cation").

[0404] The cation exchange resin is not particularly limited and may be a hydrocarbon resin or a fluororesin. For applications requiring reduction in manufacturing costs, hydrocarbon resins are preferred, and for applications requiring long-term durability, fluororesins are preferred. Hydrocarbon resins and fluororesins may be used alone or in combination.

[0405] The cation exchange resin preferably contains a functional group having ion exchange capacity. The functional group having ion exchange capacity is not particularly limited, and examples thereof include sulfonic group (SO3H), carboxyl group (CO2H), phenolic hydroxyl group (OH), phosphate group (PO3H2), thiol group (SH), and alkali metal salts, alkaline earth metal salts, or transition metal salts of these functional groups. The functional group having ion exchange capacity may be a single type or multiple functional groups.

[0406] Among the functional groups having ion exchange ability, at least one selected from a sulfo group, a carboxyl group and a phosphoric acid group is preferred, at least one selected from a sulfo group and a carboxyl group is more preferred, and a sulfo group is particularly preferred because it tends to have excellent ion exchange ability.

[0407] The hydrocarbon resin is not particularly limited, and examples thereof include resins containing functional groups having the aforementioned ion exchange capacity, such as polystyrene, polyphenylene ether, polybenzimidazole, polyetheretherketone, polyimide, polyetherimide, polyaryletherketone, polysulfone, polyethersulfone, polyphenylene sulfide, and polyphenylsulfone. The hydrocarbon cation exchange resin may be cross-linked or may form a copolymer, and may have various substituents (e.g., halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms; aliphatic hydrocarbon groups such as nitrile groups, methyl groups, ethyl groups, vinyl groups, allyl groups, 1-methylvinyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, and tert-butyl groups; aromatic hydrocarbon groups such as benzyl groups, phenyl groups, and nitrile-substituted phenyl groups; amino groups; nitro groups; hydroxyl groups; silyl groups, etc.). The hydrocarbon resin may be used alone or in combination.

[0408] The fluororesin is not particularly limited, and examples thereof include partially fluorinated resins and perfluorinated resins containing the aforementioned functional group having ion exchange ability. Examples of partially fluorinated resins and perfluorinated resins include resins in which not all hydrogen atoms on carbon contained in the aforementioned hydrocarbon-based cation exchange resin are replaced by fluorine atoms, but at least one hydrogen atom, and resins in which all hydrogen atoms on carbon are replaced by fluorine atoms.

[0409] The fluororesin is preferably a fluororesin having a structural unit represented by the following general formula G1 (hereinafter also referred to as “fluororesin G1”).

[0410]

[0411] (Where,

[0412] X 5 , X 6 , X 7 , and X 8 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 5 With X 6 , or X 5 With X 7 optionally bonded to each other to form a ring structure,

[0413] R 5 and R 6 each of which is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0414] X 9Groups represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, where Z is at least one selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, and amines. Optionally, fluororesins are crosslinked with each other via X 9 are crosslinked by ionic crosslinking

[0415] h and p represent the molar ratios in all the structural units contained in the resin, and are numbers that satisfy 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1

[0416] i is an integer from 0 to 8

[0417] j is 0 or 1

[0418] k, l, and m are each independently optionally the same or different and are integers from 0 to 6. Among them, when k, l, and m are all 0, X 9 is CF(CF2X 10 )2, and X 10 is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, where Z is the same as described above.)

[0419] X 5 、X 6 、X 7 and X 8 are each independently optionally the same or different and are a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms. The aforementioned halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. X 5 and X 6 、or X 5 and X 7 are optionally bonded to each other to form a cyclic structure

[0420] The carbon number of the perfluoroalkyl group is preferably 1 to 8, more preferably 1 to 6, and further preferably 1 to 3. The perfluoroalkyl group can be linear or branched. Examples of the perfluoroalkyl group include a trifluoromethyl group and a pentafluoroethyl group, etc.

[0421] The carbon number of the cyclic perfluoroalkyl group is preferably 6 to 8. Examples of the cyclic perfluoroalkyl group include a perfluorocyclohexyl group, etc.

[0422] As X 5 、X 6 、X 7 and X 8 , from the viewpoint of easy availability of raw materials and a tendency to suppress the manufacturing cost of the fluororesin, a fluorine atom and an unsubstituted perfluoroalkyl group having 1 to 3 carbon atoms are preferred. Furthermore, from the viewpoint of a tendency to improve the chemical stability such as the oxidation resistance deterioration of the fluororesin, a fluorine atom and a trifluoromethyl group are more preferred, and a fluorine atom is further preferred.

[0423] X 5 With X 6 , or X 5 With X 7 When they are bonded to each other to form a cyclic structure, the cyclic structure may be, for example, a substituted or unsubstituted cyclic perfluoroalkyl structure having 5 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroether structure having 4 to 9 carbon atoms.

[0424] R 5 and R 6 Each of them may be the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 5 , R 6 , from the viewpoint of easy acquisition of raw materials and the tendency to suppress the production cost of the fluororesin, preferably a fluorine atom and an unsubstituted perfluoroalkyl group having 1 to 3 carbon atoms. Furthermore, from the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin, more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

[0425] X 9 is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, Z is at least one selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkaline earth metal atom and an amine, and the fluororesins are optionally bonded to each other via X 9 The crosslinking is performed by ionic crosslinking.

[0426] The alkali metal atom is not particularly limited, and includes lithium atom, sodium atom, potassium atom, rubidium atom, cesium atom, and francium atom. Among these, lithium atom, sodium atom, and potassium atom are preferred from the viewpoint of easy acquisition of raw materials and the tendency to suppress the manufacturing cost of the fluororesin, and sodium atom and potassium atom are more preferred from the same viewpoint.

[0427] The alkaline earth metal atom is not particularly limited, and examples thereof include beryllium, magnesium, calcium, strontium, barium, and radium atoms. Of these, magnesium and calcium atoms are preferred from the viewpoint of easy availability of raw materials and the tendency to reduce the production cost of the fluororesin G1.

[0428] The amines are not particularly limited, and examples thereof include NH4, NH3R 30 NH2R 30 R 31 、NHR 30 R 31 R 32 NR 30 R 31R 32 R 33 The structure of R 30 R 31 R 32 R 33 are optionally the same or different and are a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms. Among these, from the viewpoints of easy availability of raw materials and a tendency to be able to suppress the manufacturing cost of the fluororesin, an unsubstituted aliphatic hydrocarbon group having 1 to 6 carbon atoms and a phenyl group are preferred, an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms is more preferred, and a methyl group or an ethyl group is further preferred. When the fluororesins are crosslinked by ionic crosslinking via X 9 , Z is an alkaline earth metal atom.

[0429] h and p are numbers satisfying 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1. i is an integer from 0 to 8. j is 0 or 1. k, l, and m are each optionally the same or different and are integers from 0 to 6 (wherein when k, l, and m are simultaneously 0, X 9 is CF(CF2X 10 ), X 10 is a monovalent group represented by the chemical formula -COOZ, -SO3Z, -PO3Z2, -PO3HZ, and Z is the same as described above. It should be noted that the substituents in the case of "substituted" are the same as the substituents exemplified in General Formula 1.

[0430] In the fluororesin G1, from the viewpoints of a tendency to improve the chemical stability such as oxidation degradation resistance of the fluororesin and a tendency to be able to suppress the manufacturing cost of the fluororesin, it preferably contains a structural unit represented by the following General Formula G2 and at least one selected from the structural units represented by the following General Formula G3, the structural unit represented by the following General Formula G4, and the structural unit represented by the following General Formula G5.

[0431] -(CF2-CF2)-[G2]

[0432] -(CF2-CF(-O-(CF2CFXO) N -A))-[G3]

[0433] (In the formula, X is F or a perfluoroalkyl group having 1 to 3 carbon atoms, N is an integer from 0 to 5, A is (CF2) M -SO3H (M represents an integer from 0 to 6. Among them, N and M are not simultaneously 0.))

[0434] -(CF2-CF(-O-(CF2) P -CFX(-O-(CF2) K -SO3H)))-[G4]

[0435] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms, P represents an integer of 0 to 12, and K represents an integer of 1 to 5. Here, P and K are not both 0.)

[0436] -(CF2-CF(-O-(CF2) Q -CFX(-(CF2) L -O-(CF2) o -SO3H)))-[G5]

[0437] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms, Q represents an integer of 0 to 12, L represents an integer of 1 to 5, and o represents an integer of 0 to 6. Here, Q and O are not both 0.)

[0438] The fluororesin G1 preferably contains a structural unit represented by the general formula G2 and at least one selected from the structural units represented by the general formula G3, the structural unit represented by the general formula G4, and the structural unit represented by the general formula G5. More preferably, it contains the structural unit represented by the general formula G2 and the structural unit represented by the general formula G3 (where X is F or trifluoromethyl, N is an integer of 0 to 2, and M is an integer of 1 to 4). Even more preferably, it contains the structural unit represented by the general formula G2 and the structural unit represented by the general formula G3 (where X is F or trifluoromethyl, N is 0 or 1, and M is an integer of 2 to 4).

[0439] The structural unit represented by the general formula G1 in the fluororesin G1 is preferably the structural unit represented by the following general formula G1-2, and more preferably the structural unit represented by the following general formula G1-3.

[0440]

[0441] (In the formula, h and p represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1. i is 0 or 1.)

[0442]

[0443] (In the formula, h and p represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1.)

[0444] It is also possible to directly or indirectly perform a partial crosslinking reaction between some molecules of the functional groups having ion exchange ability contained in the fluororesin G1. The aforementioned partial crosslinking has a tendency to suppress solubility in the electrolyte and suppress excessive swelling property, and thus is sometimes preferred.

[0445] When the fluororesin G1 has a high melt flow index (hereinafter also referred to as "MFI", measured according to ASTM: D1238 (measurement conditions: temperature 270°C, load 2160 g)) (when it has a low molecular weight), the aforementioned partial crosslinking can also increase the entanglement between molecules and reduce solubility and excessive swelling.

[0446] As the aforementioned partial cross-linking reaction, for example, there can be listed: the reaction of the functional group having ion exchange ability with the functional group or main chain of other molecules, or the reaction of the functional groups having ion exchange ability with each other, the cross-linking reaction (covalent bonding) by means of low molecular weight compounds, oligomers or polymer substances with excellent oxidation resistance, etc., and depending on the circumstances, it can also be a reaction with a salt-forming (including ionic bonds with functional groups having ion exchange ability) substance. As low molecular weight compounds, oligomers, or polymer substances with excellent oxidation resistance, for example, there can be listed polyols and organic diamines.

[0447] The equivalent weight of the fluororesin G1 is not particularly limited, but is preferably 2000 g / eq or less, more preferably 1500 g / eq or less, and further preferably 1100 g / eq or less from the viewpoint of the tendency to have excellent ion exchange capacity. For applications where the fluororesin G1 is formed into a film and the property of cation migration in the film is utilized, it is further preferably 1050 g / eq or less, and further preferably 1000 g / eq or less from the viewpoint of the tendency to reduce the migration resistance of the cations. For applications where the fluororesin G1 is formed into a film and utilized, it is further preferably 500 g / eq or more, and further preferably 700 g / eq or more from the viewpoint of the tendency to further improve the water resistance and chemical resistance of the fluororesin. For applications where the fluororesin is formed into a film and utilized, it is further preferably 800 g / eq or more, and further preferably 880 g / eq or more from the viewpoint of the tendency to improve the mechanical strength of the film.

[0448] It should be noted that the equivalent weight refers to the dry mass grams of the ion exchange resin relative to each 1 equivalent of the ion exchange group having the ion exchange capacity in the ion exchange resin as a resin having the ion exchange capacity, and refers to the dry mass grams of the fluororesin relative to each 1 equivalent of the ion exchange group possessed by the fluororesin in the fluororesin. Hereinafter, in the present embodiment, the expression of equivalent weight is appropriately used. In addition, in the determination of equivalent weight, the following method can be used: salt replacement is performed on the fluororesin, and the solution is back-titrated using an alkaline solution. The equivalent weight can be appropriately adjusted by the copolymerization ratio of the monomers used as the raw materials of the fluororesin G1, the selection of the monomer types, etc.

[0449] <Method for producing fluororesin G1>

[0450] The method for producing the fluororesin G1 is not particularly limited, and an example thereof is a method in which a copolymer comprising a fluoroolefin monomer represented by the following general formula G8 and a fluorovinyl ether compound represented by at least one selected from the following general formula G9, the following general formula G10, and the following general formula G11 is used as a fluororesin G1 precursor and subjected to the hydrolysis treatment and acid treatment described below.

[0451] C F Z 1 =CZ 2 Z 3 [G8]

[0452] (Where Z 1 , Z 2 , Z 3 Each of them may be the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a cyclic perfluoroalkyl group, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0453] CF2=CF-O-(CF2CFXO) N -A [G9]

[0454] (wherein, X is F or a perfluoroalkyl group having 1 to 3 carbon atoms, N is an integer of 0 to 5, and A is (CF2) M -W (M is an integer of 0 to 6, N and M are not 0 at the same time), W is a functional group that can be converted into a -SO3H group by hydrolysis treatment and acid treatment. )

[0455] CF2=CF-O-(CF2) P -CFX(-O-(CF2) K -W)[G10]

[0456] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms, P represents an integer of 0 to 12, K represents an integer of 1 to 5 (wherein P and K are not simultaneously 0), and W is a functional group that can be converted into a -SO3H group by hydrolysis treatment and acid treatment.)

[0457] CF2=CF-O-(CF2) Q -CFX(-(CF2) L -O-(CF2) m -W)

[11]

[0458] (In the formula, X is a perfluoroalkyl group having 1 to 3 carbon atoms, Q is an integer of 0 to 12, L is an integer of 1 to 5 (wherein Q and L are not simultaneously 0), m is an integer of 0 to 6 (Q, L and m are not simultaneously 0), and W can be converted into a functional group of -SO3H group by hydrolysis treatment and acid treatment.)

[0459] As a method for producing the fluororesin G1, a method is preferably a method in which a copolymer formed of a fluoroolefin monomer represented by the general formula G8 and a fluorovinyl ether compound represented by at least one selected from the group consisting of the general formula G9, the general formula G10 and the general formula G11 is used as a precursor of the fluororesin G1 and subjected to hydrolysis treatment and acid treatment. From the viewpoint that the chemical stability of the fluororesin G1, such as the resistance to oxidative degradation, tends to be improved and the production cost of the fluororesin G1 tends to be reduced, a method of using a copolymer of the general formula G8 (wherein Z 1 , Z 2 and Z 3 The fluoroolefin monomer represented by the general formula G9 (wherein X is F or trifluoromethyl, N is an integer of 0 to 2, and M is an integer of 1 to 4) is preferably formed by the fluorovinyl ether compound represented by the general formula G8 (wherein Z 1 , Z 2 and Z 3 The fluoroolefin monomer represented by the general formula G9 (wherein X is F or trifluoromethyl, N is 0 or 1, and M is an integer of 2 to 4) is preferably formed. Furthermore, the fluorovinyl ether compound represented by the general formula G8 (wherein Z 1 , Z 2 and Z 3 The fluororesin G1 precursor is formed by a fluoroolefin monomer represented by F) and a fluorovinyl ether compound represented by the general formula G9 (wherein X is a trifluoromethyl group, N is 1, and M is 2).

[0460] The fluoroolefin monomer represented by the general formula G8 is preferably a fluoroolefin monomer represented by the following general formula G12, more preferably a fluoroolefin monomer represented by the following general formula G13, and still more preferably a fluoroolefin monomer represented by the following general formula G14.

[0461] CF2=CFZ[G12]

[0462] (In the formula, Z is H, Cl, F, a perfluoroalkyl group having 1 to 10 carbon atoms, or a cyclic perfluoroalkyl group which may contain oxygen as a ring atom.)

[0463] CF2=CFZ[G13]

[0464] (In the formula, Z is F or a perfluoroalkyl group having 1 to 3 carbon atoms.)

[0465] CF2=CF2[G14]

[0466] The fluorinated vinyl ether compound represented by at least one selected from the group consisting of General Formula G9, General Formula G10, and General Formula G11 is preferably a fluorinated vinyl ether compound represented by the following General Formula G15, and more preferably a fluorinated vinyl ether compound represented by the following General Formula G16.

[0467] CF2=CF-O-(CF2CFXO) n -A[G15]

[0468] (wherein, X is F, trifluoromethyl, n is 0 or 1, and A is (CF2) m -W (m is an integer of 2 to 4, n and m are not 0 at the same time), W is a functional group that can be converted into a -SO3H group by hydrolysis treatment and acid treatment. )

[0469] CF2=CF-O-(CF2CFXO) n -A[G16]

[0470] (wherein X is trifluoromethyl, n is 1, and A is (CF2) m -W (m is 2), W is a functional group that can be converted into a -SO3H group by hydrolysis treatment and acid treatment. )

[0471] In the above general formulae G9 to G11, G15 and G16, W, which is a functional group that can be converted into a -SO3H group by hydrolysis and acid treatment, is not particularly limited, and examples thereof include SO2F, SO2Cl, SO2Br, etc., preferably SO2F and SO2Cl, and more preferably SO2F.

[0472] The fluororesin G1 precursor in this embodiment can be produced by known means. For example, it can be produced by polymerizing a mixture of a fluoroolefin monomer represented by the general formula G8 and at least one fluorovinyl ether compound represented by the group consisting of the general formula G9, the general formula G10 and the general formula G11 in the presence of a free radical generator such as a peroxide. The above-mentioned polymerization method is not particularly limited, and for example, the following methods can be used: a method of polymerizing by filling and dissolving the gas of the above-mentioned fluoroolefin monomer and the fluorovinyl ether compound in a polymerization solvent such as fluorine-containing hydrocarbons and reacting them (solution polymerization); a method of polymerizing by using the fluorovinyl ether compound as a polymerization solvent instead of the fluorine-containing hydrocarbon solvent (bulk polymerization); a method of polymerizing the gas of the above-mentioned fluoroolefin monomer and the fluorovinyl ether compound using an aqueous solution of a surfactant as a medium (emulsion polymerization); a method of emulsifying and polymerizing the gas of the above-mentioned fluoroolefin monomer and the fluorovinyl ether compound using an aqueous solution of a surfactant and an emulsifier such as an alcohol as a medium (emulsion polymerization); and a method of polymerizing by suspending and reacting the gas of the above-mentioned fluoroolefin monomer and the fluorovinyl ether compound using an aqueous solution of a suspension stabilizer as a medium (suspension polymerization).

[0473] The fluororesin G1 precursor in the present embodiment may be one prepared by any of the above-mentioned polymerization methods. Alternatively, a bulk or tapered polymer obtained by adjusting polymerization conditions such as the amount of fluoroolefin monomer supplied may be used as the fluororesin G1 precursor.

[0474] The fluororesin G1 precursor can be fluorinated by treating the impurity terminals and structurally easily oxidized portions (CO groups, H-bonded portions, etc.) generated in the resin molecular structure during the polymerization reaction under fluorine gas by a known method.

[0475] A part of the ion exchange group precursor group (eg, -SO2F group) of the fluororesin G1 precursor may be partially (including intermolecularly) imidized (alkyl imidized or the like).

[0476] The molecular weight of the fluororesin G1 precursor is not particularly limited, but the melt flow index (MFI) value measured according to ASTM: D1238 (measurement conditions: temperature 270° C., load 2160 g) is preferably 0.05 g / 10 minutes or more, more preferably 0.1 g / 10 minutes or more, and further preferably 0.5 g / 10 minutes or more. The MFI value is preferably 100 g / 10 minutes or less, more preferably 80 g / 10 minutes or less, and further preferably 60 g / 10 minutes or less.

[0477] The shape of the fluororesin G1 precursor is not particularly limited, but is preferably 0.5 cm 3 The following granular form, dispersion form, powder granule form are used. Among them, the powder form after polymerization is more preferably used. From the viewpoint of cost, the fluororesin G1 precursor in the form of a film formed by extrusion can also be used.

[0478] The method for producing the fluororesin G1 in the present embodiment from the fluororesin G1 precursor is not particularly limited, and for example, there are the following methods: after melt-kneading the fluororesin G1 precursor, the fluororesin G1 precursor is extruded by using an extruder using a nozzle or a die, and then subjected to the hydrolysis treatment described below; or the state of the output when the fluororesin G1 precursor is polymerized is maintained, that is, after being made into a dispersion liquid or a powdery substance that has been precipitated and filtered, the hydrolysis treatment described below is performed. Through these hydrolysis treatments, a fluororesin G1 in which Z in the general formula G1 is an alkali metal atom or an alkaline earth metal atom can be obtained. By subjecting the fluororesin G1 (Z = alkali metal atom, alkaline earth metal atom) to an acid treatment, a fluororesin G1 in which Z in the general formula G1 is a hydrogen atom can be obtained. Furthermore, by reacting the fluororesin G1 (Z = hydrogen atom) with amines, a fluororesin G1 in which Z in the general formula G1 is an amine can be obtained.

[0479] Specifically, the fluororesin G1 precursor obtained as described above and molded as needed can continue to be immersed in the alkaline reaction liquid and provided for hydrolysis treatment. As the alkaline reaction liquid used in the hydrolysis treatment, there is no particular limitation, and for example, aqueous solutions of amine compounds such as dimethylamine, diethylamine, monomethylamine and monoethylamine, and aqueous solutions of hydroxides of alkali metals or alkaline earth metals can be listed. Among these, an aqueous solution of sodium hydroxide or potassium hydroxide is preferred. In the case of using hydroxides of alkali metals or alkaline earth metals, its content is not particularly limited, and is preferably 10% by mass or more and 30% by mass or less relative to the alkaline reaction liquid as a whole. The alkaline reaction liquid more preferably further contains swelling organic compounds such as methanol, ethanol, acetone and dimethyl sulfoxide. The content of the swelling organic compound is preferably 1% by mass or more and 60% by mass or less relative to the alkaline reaction liquid as a whole.

[0480] After the fluororesin G1 precursor is subjected to a hydrolysis treatment in an alkaline reaction liquid, it is washed with warm water or the like as needed, and then subjected to an acid treatment, thereby being able to produce a fluororesin having a structural unit in which Z in the above-mentioned general formula G1 is a hydrogen atom. The acid used in the acid treatment is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; and organic acids such as oxalic acid, acetic acid, formic acid, and trifluoroacetic acid, preferably a mixture of the aforementioned acids and water. In addition, the aforementioned acids may be used alone or in combination. In addition, the alkaline reaction liquid used in the hydrolysis treatment may be removed in advance before the acid treatment by treating it with a cation exchange resin or the like.

[0481] The fluororesin G1 subjected to the above-mentioned hydrolysis and acid treatment may be dispersed or dissolved in a protic organic solvent, water, or a mixed solvent thereof, and may be in the form of a suspension or a solution.

[0482] Fluororesin G1 can sometimes improve mechanical strength, and therefore, it is sometimes preferable to use a fluororesin composition of two or more fluororesins having different raw material structures constituting fluororesin G1. By mixing two or more fluororesins, it is sometimes possible to exhibit excellent characteristics obtained by integrating the functions of each fluororesin. From the viewpoint of improving crystallinity and mechanical strength, when mixing two or more fluororesins, it is preferable to make the ratio of the fluororesin having a larger equivalent weight greater than 50% by mass, more preferably greater than 55% by mass, and further preferably greater than 60% by mass.

[0483] <Resin composition>

[0484] The resin composition of the present embodiment contains a side chain heteroaromatic resin and a cation exchange resin.

[0485] The weight ratio of the side chain heteroaromatic resin to the cation exchange resin in the resin composition is not particularly limited, but is preferably 1:100 to 100:1. Although it varies depending on the use of the resin composition of the present embodiment, when used as a diaphragm for a redox flow battery, from the viewpoint of suppressing the elution of the side chain heteroaromatic resin into the electrolyte, the weight ratio of the side chain heteroaromatic resin to the cation exchange resin is preferably 10:90 or more, more preferably 20:80 or more, and further preferably 30:70 or more. Although it varies depending on the use of the above-mentioned mixture, when used as a diaphragm for a redox flow battery, from the viewpoint of the tendency to improve power efficiency by using the side chain heteroaromatic resin, the weight ratio of the side chain heteroaromatic resin is preferably 90:10 or less, more preferably 80:20 or less, and further preferably 70:30 or less.

[0486] The resin composition of the present embodiment is preferably a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a polyetheretherketone resin, a polysulfone resin, a polyethersulfone resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a polyphenylene ether resin, a polyphenylene sulfide resin, a syndiotactic polystyrene resin, a polyetherimide, a siloxane-modified polyetherimide resin, a polyamideimide resin, a cycloolefin resin, a cycloolefin copolymer, a polyetherketoneetherketoneketone resin, a polyallyletherketone resin, and a perfluororesin, and may further include a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a syndiotactic polystyrene resin, a cycloolefin resin, and a cycloolefin copolymer. The resin optionally included in the resin composition of the present embodiment may be used alone or in combination.

[0487] <Ion exchange membrane>

[0488] The ion exchange membrane of the present embodiment includes a side chain heteroaromatic resin having a structural unit represented by Formula 1, a side chain heteroaromatic resin having a structural unit represented by Formula 2, or the resin composition of the present embodiment.

[0489] When the side chain heteroaromatic resin having the structural unit represented by the general formula 1, the side chain heteroaromatic resin having the structural unit represented by the general formula 2, or the resin composition of the present embodiment is formed into a film, the forming method is not particularly limited, and examples thereof include: a method of processing a material containing the side chain heteroaromatic resin or the resin composition of the present embodiment into a film-like state by extruding it using an extruder, using a nozzle or a die head, etc.; a method of processing a side chain heteroaromatic resin or the resin composition of the present embodiment into a solution state, applying it to a substrate using a die head, a gravure roll, a doctor blade, or a sprayer and drying it, thereby processing it into a film-like state. Hereinafter, the film of the obtained side chain heteroaromatic resin or the resin composition of the present embodiment is also referred to as a side chain heteroaromatic resin film.

[0490] The solvent that can be used when the side chain heteroaromatic resin or the resin composition is made into a solution is not particularly limited, and examples thereof include saturated hydrocarbon compounds such as n-pentane, n-hexane, n-octane, n-decane, cyclopentane, cyclohexane and cyclooctane; aromatic hydrocarbon compounds such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbon compounds such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, cyclohexanol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone and cyclohexanone; and ethyl acetate. Esters such as butyl acetate and methyl benzoate; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, etc.; polymers of polyols such as ethylene glycol, propylene glycol, glycerol, and compounds having two hydroxyl groups in the polyols, and polyols; esterified compounds of the aforementioned polymers, nitriles such as acrylonitrile and benzonitrile; nitromethane; N,N-dimethylformamide; dimethyl sulfoxide; hexamethylphosphoric triamide; carbon disulfide; fluorine compounds (such as Novec (trademark) manufactured by 3M Company, Asahi Clean manufactured by Asahi Glass Co., Ltd., etc.). These solvents may be used alone or in combination of multiple types.

[0491] When the side chain heteroaromatic resin of the present embodiment or the resin composition of the present embodiment is formed into a film, a substrate may also be used. By using a substrate, a film of the side chain heteroaromatic resin of the present embodiment or the resin composition of the present embodiment can sometimes be manufactured more stably.

[0492] The material used for the substrate is not particularly limited, and examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, cycloolefin polymers, polycarbonate, polyamide, polyimide, polyamideimide, polyvinyl chloride, polystyrene, polyphenylene oxide, polyetheretherketone, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyetherimide, polyimide resin, polyetherketoneetherketoneketone, polyallyletherketone, etc. The aforementioned material may be modified, and one kind may be used alone, or a plurality of kinds may be used in combination.

[0493] The ion exchange membrane of the present embodiment has at least one layer (L) composed of the resin composition and one layer (M) composed of a fluororesin having a structural unit represented by the following general formula G1, alternately.

[0494]

[0495] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0496] As layer (M), by using a film containing a fluororesin (hereinafter also referred to as a fluororesin film) as a substrate, an ion exchange membrane having a fluororesin film (layer (M)) and a side chain heteroaromatic resin film (layer (L)) can be prepared. It should be noted that the side chain heteroaromatic resin may not be contained in the layer (M).

[0497] The ion exchange resin of this embodiment may have one layer (L) and one layer (M) (a membrane having one layer (M) and one layer (L) is also referred to as a "bipolar membrane"). By using a laminated membrane, an ion exchange membrane having the characteristics of both a fluororesin membrane and a side chain heteroaromatic resin membrane can be prepared. It should be noted that, hereinafter, in the laminated state, a fluororesin membrane is also referred to as a fluororesin layer, and a side chain heteroaromatic resin membrane is also referred to as a side chain heteroaromatic resin layer.

[0498] It should be noted that, regarding the interface between the layer (L) containing the side chain heteroaromatic resin and the layer (M) containing the fluororesin having the structural unit represented by the general formula G1 contained in the ion exchange membrane, the presence or absence of the interface is determined based on the value at which the maximum signal intensity of the characteristic peak of the side chain heteroaromatic resin measured by a time-of-flight secondary ion mass spectrometer becomes 1 / 10, with reference to JIS K 0146: 2002. The region where the maximum signal intensity of the characteristic peak of the side chain heteroaromatic resin shows 1 / 10 or more is defined as the layer (L), and the region where the maximum signal intensity of the characteristic peak of the side chain heteroaromatic resin shows less than 1 / 10 is defined as the layer (M).

[0499] The method for manufacturing the fluororesin film (layer (M)) is not particularly limited, and can be obtained by processing a resin composition containing a fluororesin G1 into a film, or by processing a resin composition containing a fluororesin G1 precursor having a functional group having ion exchange capacity by hydrolysis into a film and subjecting it to the aforementioned hydrolysis treatment and acid treatment. For example, the following method can be cited: melt-kneading the resin composition containing the fluororesin, and then using an extruder and using a nozzle or a die to perform extrusion molding, thereby processing it into a film. Another method can be cited: melt-kneading the resin composition containing the fluororesin G1 precursor, and then using an extruder and using a nozzle or a die to perform extrusion molding, thereby forming a film, and then performing hydrolysis treatment and acid treatment to form ion exchange groups. In addition, it is also possible to disperse the substance containing the fluororesin in a solvent and then perform film casting on a substrate to process it into a film.

[0500] The layer (L) can be produced by a method of forming the side chain heteroaromatic resin having a structural unit represented by Formula 1, the side chain heteroaromatic resin having a structural unit represented by Formula 2, or the resin composition of the present embodiment into a film.

[0501] By repeatedly applying the method for producing a side chain heteroaromatic resin film and the method for producing a fluororesin film to the laminated film, a film in which a plurality of side chain heteroaromatic resin films and fluororesin films are laminated can be produced.

[0502] A multi-layered membrane can be manufactured by alternately stacking the side chain heteroaromatic resin membrane and the fluororesin membrane of the bipolar membrane and pressing the membranes together by applying pressure. Also, a three-layered membrane can be manufactured by attaching two bipolar membrane side chain heteroaromatic resin membranes or fluororesin membranes together and pressing the membranes together by applying pressure.

[0503] The side chain heteroaromatic resin film of the present embodiment and the ion exchange membrane with the side chain heteroaromatic resin film and the fluororesin film (the ion exchange membrane is not particularly limited as long as it has more than 2 layers, and the same is true in the following description) can be used for various purposes. If the above-mentioned uses are exemplified, redox flow batteries, fuel cells, salt electrolysis, alkaline water electrolysis, carbon dioxide reduction electrolysis, etc. can be listed, among which, cells for redox flow batteries and redox flow batteries can be suitably exemplified. By being used for redox flow batteries and redox flow batteries, there is a tendency for excellent power efficiency relative to the diaphragms used in the past.

[0504] The total thickness of the ion exchange membrane of the present embodiment is not particularly limited. In the redox flow battery unit and the redox flow battery exemplified as suitable uses, it is preferably 0.01 μm or more and 200 μm or less. From the perspective of the tendency of improving the handling properties and mechanical strength of the membrane, it is more preferably 1 μm or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is further preferably 10 μm or more, and particularly preferably 20 μm or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and tending to improve power efficiency, the total thickness of the ion exchange membrane of the present embodiment is more preferably 150 μm or less, more preferably 130 μm or less, and particularly preferably 100 μm or less.

[0505] The thickness of the layer (L) (side chain heteroaromatic resin membrane) in the ion exchange membrane of the present embodiment is not particularly limited. In the redox flow battery cell and the redox flow battery exemplified as suitable applications, it is preferably 0.01 μm or more and 10 μm or less. From the perspective of being able to further suppress the redox active material from penetrating the membrane when used in the redox flow battery cell and the redox flow battery, it is more preferably 0.1 μm or more, and more preferably 0.2 μm or more. In the case where the side chain heteroaromatic resin membrane has large pulsation and high mechanical strength is required, the thickness of the layer (L) (side chain heteroaromatic resin membrane) is particularly preferably 0.3 μm or more, and more preferably 0.4 μm or more. From the perspective of suppressing the resistance during operation of the redox flow battery cell and the redox flow battery and having a tendency to improve power efficiency, it is more preferably 7 μm or less, more preferably 5 μm or less, particularly preferably 3 μm or less, and more particularly preferably 2 μm or less.

[0506] The equivalent weight of the ion exchange membrane is not particularly limited, but is preferably 500 g / eq or more and 2000 g / eq or less. From the perspective of improving the handling properties and mechanical strength of the membrane, it is more preferably 700 g / eq or more, and further preferably 800 g / eq or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is particularly preferably 880 g / eq or more, and further particularly preferably 900 g / eq or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and improving the power efficiency, the equivalent weight of the ion exchange membrane is more preferably 1500 g / eq or less, further preferably 1400 g / eq or less, further preferably 1200 g / eq or less, and further particularly preferably 1150 g / eq or less.

[0507] [Second embodiment]

[0508] Next, a second embodiment will be described.

[0509] Patent Document 1 discloses that, in order to improve current efficiency and power efficiency, an aromatic polysulfone-based polymer is used as an anion exchange substrate, and although the current efficiency is excellent, the battery resistance increases and the voltage efficiency decreases. Therefore, an anion exchange substrate having excellent current efficiency, voltage efficiency, and current efficiency is required to be well balanced.

[0510] In Patent Document 2, in order to suppress the increase of proton surface resistance and improve the vanadium ion permeation selectivity, Nafion (registered trademark) 117 reacted with some heterocyclic molecules is disclosed. However, when the proton surface resistance is to be reduced, the vanadium ion permeation selectivity becomes low. On the other hand, when the vanadium ion permeation selectivity is to be improved, the proton surface resistance becomes high, and there are still problems in terms of balancing. In addition, no evaluation as a redox flow battery is performed in the embodiments, and the current efficiency, voltage efficiency and power efficiency are still unclear. However, in the embodiments, the proton surface resistance is a value higher than that of Nafion (registered trademark) 117, from which it can be inferred that the voltage efficiency is lower than that of Nafion (registered trademark) 117. In summary, a material with excellent current efficiency, voltage efficiency and current efficiency is required to be well balanced.

[0511] Patent Document 3 discloses that a metal layer, namely, an anti-crossing layer, formed by reducing a cationic metal is provided inside a polymer electrolyte membrane in order to improve at least one of the characteristics of discharge capacity, current efficiency, voltage efficiency, and power efficiency, but higher characteristics are required.

[0512] Patent Document 4 discloses that some polymer compounds are used as an anion exchange resin layer in order to achieve high power efficiency. However, when the anion exchange resin layer is not located between the anion exchange resin layer, although high power efficiency can be obtained as an initial characteristic, it is shown that high power efficiency cannot be obtained after 100 cycles. Therefore, the anion exchange compound contained in the anion exchange resin layer used in Patent Document 4 is required to have higher characteristics.

[0513] The subject of the present embodiment relates to an ion exchange membrane, a membrane electrode assembly, a redox flow battery cell, and a redox flow battery that can provide a redox battery cell having excellent current efficiency and voltage efficiency in a good balance and high power efficiency.

[0514] The present inventors have conducted intensive studies on the above-mentioned problems and have found that by using a fluororesin containing a heteroaromatic structure having a specific structural unit, a saponified product thereof or a salt thereof as an ion exchange membrane, a redox battery cell having an excellent balance between current efficiency and voltage efficiency and high power efficiency can be provided.

[0515] <Ion Exchange Membrane of Second Embodiment>

[0516] The ion exchange membrane of the second embodiment comprises a layer (L1) and a layer (M1).

[0517] The layer (L1) comprises: a fluororesin containing a heteroaromatic structure having a structural unit represented by the following general formula A1, a saponified product thereof, or a salt thereof;

[0518] The layer (M1) comprises a fluororesin (G1) having a structural unit represented by the following general formula G1.

[0519]

[0520] (Where,

[0521] X 1 , X 2 , X 3 and X 4 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 1 With X 2 , or X 1 With X 3 optionally bonded to each other to form a ring structure,

[0522] R 1 , R 2 each of which may be the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0523] R 3 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 1 to 10 carbon atoms,

[0524] R 4 NR 3 The connecting group to Hc is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0525] X 10 A divalent group represented by the chemical formula of -CO2- or -SO2-,

[0526] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group contains at least one nitrogen atom and has a 5-membered ring and / or a 6-membered ring structure,

[0527] a and g represent the molar ratios in all the structural units contained in the resin, and are numbers that satisfy 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1.

[0528] b is an integer from 0 to 8.

[0529] c is 0 or 1.

[0530] d, e, and f are each independently an integer from 0 to 6, which may be the same or different. Among them, d, e, and f are not simultaneously 0.)

[0531] According to the present embodiment, it is possible to provide an ion exchange membrane, a membrane electrode assembly, a unit for a redox flow battery, and a redox flow battery for a redox flow battery that can achieve excellent balance between current efficiency and voltage efficiency and have high power efficiency.

[0532] <Fluororesin containing a heteroaromatic structure>

[0533] The fluororesin containing a heteroaromatic structure of the present embodiment has a structural unit represented by the following general formula A1.

[0534]

[0535] X 1 , X 2 , X 3 and X 4 are each independently a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms. The halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. X 1 and X 2 , or X 1 and X 3 optionally bond to each other to form a cyclic structure. As X 1 , X 2 , X 3 and X 4 , from the viewpoint of easy availability of raw materials and a tendency to suppress the manufacturing cost of the fluororesin containing a heteroaromatic structure, fluorine atoms and unsubstituted perfluoroalkyl groups having 1 to 3 carbon atoms are preferred. Further, from the viewpoint of a tendency to improve the chemical stability such as oxidation degradation resistance of the fluororesin containing a heteroaromatic structure, fluorine atoms and trifluoromethyl groups are more preferred, and fluorine atoms are particularly preferred.

[0536] R 1 and R 2Each of them may be the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 1 and R 2 , from the viewpoint of easy acquisition of raw materials and the tendency to suppress the production cost of the fluororesin containing a heteroaromatic structure, a fluorine atom or an unsubstituted perfluoroalkyl group having 1 to 3 carbon atoms is preferred. Furthermore, from the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin containing a heteroaromatic structure, a fluorine atom or a trifluoromethyl group is more preferred, and a fluorine atom is particularly preferred.

[0537] In addition, the substituent in the case of "substituted" is the same as the substituent exemplified in General Formula 1.

[0538] R 3 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms. 3 , from the viewpoint of easy acquisition of raw materials and the tendency to suppress the production cost of the fluororesin containing a heteroaromatic structure, preferably a hydrogen atom or an aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms. From the viewpoint of further suppressing the production cost of the fluororesin containing a heteroaromatic structure, a hydrogen atom is more preferred, and from the viewpoint of improving the stability of the fluororesin containing a heteroaromatic structure under alkaline conditions, an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms is more preferred. It should be noted that the substituent in the case of "substituted" is the same as the substituent exemplified in Formula 1.

[0539] R 4 NR 3 The linking group to Hc is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms. 4 From the viewpoint of easy acquisition of raw materials and the tendency to suppress the manufacturing cost of the fluororesin containing a heteroaromatic structure, it is preferably an unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably an unsubstituted aliphatic hydrocarbon group having 1 to 6 carbon atoms, and further preferably an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms. From the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin containing a heteroaromatic structure, it is particularly preferred to be an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms, and further preferably an unsubstituted aliphatic hydrocarbon group having 1 carbon atoms. It should be noted that the substituent in the case of "substituted" is the same as the substituent exemplified in Formula 1.

[0540] X 10It is a divalent group represented by the chemical formula of -CO2- or -SO2-. From the viewpoint that the chemical stability such as the resistance to oxidative degradation of the heteroaromatic structure-containing fluororesin tends to be improved, a divalent group represented by the chemical formula of -SO2- is preferred.

[0541] Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, wherein the heteroaromatic group contains at least one nitrogen atom and has a 5-membered ring and / or a 6-membered ring structure.

[0542] The 5-membered ring and / or 6-membered ring structure in Hc is not particularly limited, and examples thereof include an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a pyridazine structure, a pyrimidine structure, a cinnoline structure, a quinazoline structure, a phthalazine structure, a quinoxaline structure, a pteridine structure, a purine structure, a 2,2'-bipyridine structure, a 2,3'-bipyridine structure, a 2,4'-bipyridine structure, a 1,7-phenanthroline structure, a 1,10-phenanthroline structure, and a 2,2':6',2"-terpyridine structure. The structure of Hc exemplified above may be either a single structure or a plurality of structures. The structure of Hc exemplified above may be either a single structure or a plurality of structures may be used in combination.

[0543] Since Hc has at least one nitrogen atom in the heteroaromatic ring structure, among the above-mentioned 5-membered ring and / or 6-membered ring structure, an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a 2,2'-bipyridine structure, a 2,3'-bipyridine structure, a 2,4'-bipyridine structure, a 1,7-phenanthroline structure, and a 1,10-phenanthroline structure are preferred, and an imidazole structure, a benzimidazole structure, an imidazopyridine structure, a pyridine structure, an oxazole structure, a thiazole structure, a 2,2'-bipyridine structure, and a 1,10-phenanthroline structure are more preferred. From the perspective that when a fluororesin containing a heteroaromatic structure is used for a unit for a redox flow battery, the durability tends to be improved, and an imidazole structure, a benzimidazole structure, an imidazopyridine structure, and a pyridine structure are further preferred, and an imidazole structure and a pyridine structure are particularly preferred.

[0544] H C The substituents in are the same as the substituents exemplified in Formula 1.

[0545] Examples of Hc include imidazolyl, benzimidazolyl, imidazopyridyl, pyridyl, oxazolyl, thiazolyl, pyridazinyl, pyrimidinyl, cinnolinyl, quinazolinyl, phthalazinyl, quinoxalinyl, pteridinyl, purinyl, 2,2′-bipyridyl, 2,3′-bipyridyl, 2,4′-bipyridyl, 1,7-phenanthrolinyl, 1,10-phenanthrolinyl, and 2,2′:6′,2″-terpyridyl. Among these, imidazolyl and pyridyl are preferred.

[0546] Among the above-mentioned fluororesins containing heteroaromatic structures, from the viewpoint of the tendency that the chemical stability of the fluororesins containing heteroaromatic structures, such as the resistance to oxidative degradation, is improved, and from the viewpoint that the manufacturing cost of the fluororesins containing heteroaromatic structures and the manufacturing cost of the units for redox flow batteries can be suppressed, it is preferred that the fluororesins contain at least one structural unit represented by the general formula A2 and a structural unit selected from the group consisting of the structural unit represented by the following general formula A4, the structural unit represented by the following general formula A5 and the structural unit represented by the following general formula A6.

[0547] -(CF2-CF2)-[A2]

[0548] -(CF2-CF(-O-(CF2CFXO) N -Ag))-[A4]

[0549] (wherein, X represents F or a perfluoroalkyl group having 1 to 3 carbon atoms. Ag represents (CF2) in the above general formula A1) f -X 10 -NR 3 -R 4 -Hc. N represents an integer from 0 to 5. )

[0550] -(CF2-CF(-O-(CF2) P -CFX(-O-(CF2) K -SO2NX 41 Ax)))-[A5]

[0551] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. 41 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -R in the above general formula A1 4 -Hc. P represents an integer of 0 to 12, and K represents an integer of 1 to 5. Wherein, P and K are not 0 at the same time.)

[0552] -(CF2-CF(-O-(CF2) Q -CFX(-(CF2) L -O-(CF2) o -SO2NX 41 Ax)))-[A6]

[0553] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. 41 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -R in the above general formula A1 4-Hc. Q represents an integer from 0 to 12, L represents an integer from 1 to 5, and o represents an integer from 0 to 6. Among them, Q and O are not 0 at the same time).

[0554] The fluororesin containing a heteroaromatic structure more preferably contains a structural unit represented by the general formula A2 and at least one selected from the group consisting of a structural unit represented by the general formula A4, a structural unit represented by the general formula A5, and a structural unit represented by the general formula A6, and further preferably contains a structural unit represented by the general formula A2 and a structural unit represented by the general formula A4 (wherein X is F or trifluoromethyl, N is an integer from 0 to 2, and f is an integer from 1 to 4), and particularly preferably contains a structural unit represented by the general formula A2 and a structural unit represented by the general formula A4 (wherein X is F or trifluoromethyl, N is 0 or 1, and f is an integer from 2 to 4).

[0555] The fluororesin containing a heteroaromatic structure more preferably contains a structural unit represented by the following general formula A1-1, and further preferably contains a structural unit represented by the following general formula A1-2.

[0556] -[CF2CF2] a -[CF2-CF((-O-CF2-(CF(CF3))) b -O-(CF2)2-SO2NX 41 Ax)] g -[A1-1]

[0557] (In the formula, X 41 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -R in the above general formula A1 4 -Hc. a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1. b is 0 or 1.)

[0558] -[CF2CF2] a -[CF2-CF((-O-CF2-(CF(CF3)))-O-(CF2)2-SO2NX 41 Ax)] g -[A1-2]

[0559] (In the formula, X 41 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -R in the above general formula A1 4 -Hc. a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1.)

[0560] In the above general formulae A5, A6, A1-1 and A1-2, X is easily available as a raw material and tends to be able to reduce the production cost of the heteroaromatic structure-containing fluororesin. 41 A hydrogen atom or an aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferred, and a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms is more preferred. From the viewpoint of being able to further reduce the production cost of the heteroaromatic structure-containing fluororesin, a hydrogen atom is more preferred, and from the viewpoint of improving the stability of the heteroaromatic structure-containing fluororesin under alkaline conditions, an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms is more preferred.

[0561] The method for producing the heteroaromatic structure-containing fluororesin is not particularly limited, and an example thereof includes a method of reacting a fluororesin precursor described below with a modifying compound.

[0562] The aforementioned modified compound has at least two nitrogen-containing groups. Among the aforementioned nitrogen-containing groups, at least one nitrogen-containing group is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, and the heteroaromatic group contains at least one nitrogen atom and includes a 5-membered ring and / or a 6-membered ring structure (equivalent to Hc). In addition, among the aforementioned nitrogen-containing groups, at least one nitrogen-containing group is a primary amino group or a secondary amino group. From the viewpoint of improving the reactivity of the modified compound with the fluororesin precursor, the primary amino group is preferred, and from the viewpoint of improving the stability of the fluororesin containing a heteroaromatic structure, the secondary amino group is preferred. In addition to these, the nitrogen-containing groups optionally included in the modified compound include:

[0563] An amino salt structure of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group and at least one amino group selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound;

[0564] A salt structure of a nitrogen atom-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound; and a quaternary ammonium group.

[0565] Here, the quaternary ammonium group is a quaternary ammonium group different from the aforementioned amino salt structure and the aforementioned salt structure.

[0566] More specifically, examples of the modified compound include 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(ethylaminomethyl)pyridine, 4-(4-piperidinyl)pyridine, 2-methyltryptamine, 5-methoxytryptamine, 6-methoxytryptamine, necrostatin-1, alosetron, sulfamethoxypyridazine, 1- (3-Chloroanilino)-4-phenylphthalazine, 4-amino-5-aminomethyl-2-methylpyrimidine, 2-(aminomethyl)-5-methylpyrazine, 2-(4-piperidinyl)benzimidazole, 2-(4-aminophenyl)benzimidazole, 5-amino-2-(4-aminophenyl)benzimidazole, 6-(aminomethyl)quinoline, 2-methyl-7-[phenyl(phenylamino)methyl]-8-hydroxyquinoline, 1-(2-amino-1-naphthyl)isoquinoline. These modified compounds may be used alone or in combination of two or more.

[0567] From the viewpoint that the modified compound is easily available and the production cost of the fluororesin containing a heteroaromatic structure tends to be suppressed, it is preferably selected from 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(ethylaminomethyl)pyridine, 4-(2-aminoethyl)pyridine, 4-(4-piperidinyl)pyridine, 2-(4-piperidinyl)benzimidazole, 2-(4-aminophenyl)benzimidazole, 5-amino-2 -At least one selected from the group consisting of 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(4-piperidinyl)pyridine, and 2-(4-aminophenyl)benzimidazole, and further preferably at least one selected from the group consisting of 1-(3-aminopropyl)imidazole, 4-aminomethylpyridine, and 4-(2-aminoethyl)pyridine.

[0568] The fluororesin containing heteroaromatic structure in the present embodiment has a sulfonamide bond (-SO2NR-) (it should be noted that in the aforementioned chemical formula representing sulfonamide, R is not particularly limited). The sulfonamide bond of the fluororesin containing heteroaromatic structure can be analyzed by a conventional analytical method, and as an analytical device, for example, FT-IR, TOF-SIMS, etc. can be used.

[0569] The heteroaromatic structure-containing fluororesin in the present embodiment may be a saponified product thereof or a salt thereof.

[0570] The saponified product of the fluororesin containing a heteroaromatic structure is a saponified product obtained by reacting the fluororesin containing a heteroaromatic structure with an alkaline substance. Examples of the alkaline substance include amine compounds such as dimethylamine, diethylamine, monomethylamine, and monoethylamine; alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and alkaline earth metal hydroxides. Among these, sodium hydroxide or potassium hydroxide is preferred.

[0571] The salt of the fluororesin containing a heteroaromatic structure is a salt of the fluororesin containing a heteroaromatic structure and an acidic substance. Examples of the acidic substance include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as oxalic acid, acetic acid, formic acid, and trifluoroacetic acid.

[0572] <Fluororesin G1>

[0573] The heteroaromatic structure-containing fluororesin in the present embodiment may be used in the form of a resin composition mixed with other resins.

[0574] The resin composition may contain the heteroaromatic structure-containing fluororesin in the present embodiment and the fluororesin G1.

[0575] In the present embodiment, a mixture of fluororesins such as a composition containing a heteroaromatic structure-containing fluororesin and fluororesin G1 is referred to as a resin composition.

[0576] The fluororesin G1 is a fluororesin having an ion exchange capacity for cations (hereinafter also referred to as "Cation").

[0577] The fluororesin G1 has a structural unit represented by the following general formula G1.

[0578]

[0579] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0580] The preferred fluororesin G1 is the same as described above.

[0581] The weight ratio of the fluororesin containing a heteroaromatic structure to the fluororesin G1 in the resin composition is not particularly limited, but is preferably 1:100 to 100:1. Although it varies depending on the use of the resin composition of the present embodiment, when used as a diaphragm for a redox flow battery, from the viewpoint of suppressing the elution of the fluororesin containing a heteroaromatic structure into the electrolyte, the weight ratio of the fluororesin containing a heteroaromatic structure to the fluororesin G1 is preferably 5:95 or more, more preferably 10:90 or more, and further preferably 15:85 or more. Although it varies depending on the use of the above-mentioned mixture, when used as a diaphragm for a redox flow battery, from the viewpoint of the tendency to improve the power efficiency by using the fluororesin containing a heteroaromatic structure, the weight ratio of the fluororesin containing a heteroaromatic structure is preferably 90:10 or less, more preferably 80:20 or less, and further preferably 70:30 or less.

[0582] The content of the fluororesin containing a heteroaromatic structure in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. Although it varies depending on the purpose of using the above-mentioned mixture, when it is used as a diaphragm for a redox flow battery, the content of the fluororesin containing a heteroaromatic structure in the resin composition is preferably 90% or less, more preferably 80% or less, and further preferably 70% or less, from the perspective of the tendency to improve power efficiency by using the fluororesin containing a heteroaromatic structure.

[0583] When a heteroaromatic structure-containing fluororesin having a structural unit represented by the general formula A1 is used, the ratio of each resin is exemplified as follows.

[0584] The weight ratio of the fluororesin containing side chain nitrogen atoms to the fluororesin G1 in the resin composition is not particularly limited, but is preferably 1:100 to 100:1. Although it varies depending on the application of the resin composition of the present embodiment, when used as a diaphragm for a redox flow battery, from the viewpoint of suppressing the elution of the fluororesin containing a heteroaromatic structure into the electrolyte, the weight ratio of the fluororesin containing side chain nitrogen atoms to the fluororesin G1 is preferably 10:90 or more, more preferably 20:80 or more, and further preferably 30:70 or more. Although it varies depending on the application of the above-mentioned mixture, when used as a diaphragm for a redox flow battery, from the viewpoint of the tendency of using the fluororesin containing side chain nitrogen atoms to improve power efficiency, the weight ratio of the fluororesin containing side chain nitrogen atoms is preferably 90:10 or less, more preferably 80:20 or less, and further preferably 70:30 or less.

[0585] The content of the fluororesin containing side chain nitrogen atoms in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more. Although it varies depending on the purpose of using the above-mentioned mixture, when it is used as a separator for a redox flow battery, the content of the fluororesin containing side chain nitrogen atoms in the resin composition is preferably 90% or less, more preferably 80% or less, and further preferably 70% or less, from the perspective of the tendency to improve power efficiency by using the fluororesin containing side chain nitrogen atoms.

[0586] The resin composition of the present embodiment is preferably a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a polyetheretherketone resin, a polysulfone resin, a polyethersulfone resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a polyphenylene ether resin, a polyphenylene sulfide resin, a syndiotactic polystyrene resin, a polyetherimide, a siloxane-modified polyetherimide resin, a polyamideimide resin, a cycloolefin resin, a cycloolefin copolymer, a polyetherketoneetherketoneketone resin, a polyallyletherketone resin, and a fluororesin, and may further include a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a syndiotactic polystyrene resin, a cycloolefin resin, and a cycloolefin copolymer. The resin optionally included in the resin composition of the present embodiment may be used alone or in combination.

[0587] <Ion exchange membrane>

[0588] The ion exchange membrane of the present embodiment contains a fluororesin containing a heteroaromatic structure or the resin composition of the present embodiment.

[0589] When the resin composition containing the fluororesin containing a heteroaromatic structure is formed into a film, the forming method is not particularly limited, and examples thereof include: a method of processing the resin composition containing the fluororesin containing a heteroaromatic structure into a film by making the resin composition containing the heteroaromatic structure into a molten state, using an extruder, extruding the molten state using a nozzle or a die head, etc., and processing the molten state into a film; a method of processing the resin composition containing the fluororesin containing a heteroaromatic structure into a solution state, applying the solution to a substrate using a die head, a gravure roll, a doctor blade, or a sprayer, and drying the solution. Hereinafter, the obtained film of the fluororesin containing a heteroaromatic structure is also referred to as a fluororesin film containing a heteroaromatic structure.

[0590] The solvent that can be used when the fluororesin containing a heteroaromatic structure is made into a solution is not particularly limited, and examples thereof include saturated hydrocarbon compounds such as n-pentane, n-hexane, n-octane, n-decane, cyclopentane, cyclohexane and cyclooctane; aromatic hydrocarbon compounds such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbon compounds such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, cyclohexanol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone and cyclohexanone; and ethyl acetate. , butyl acetate and methyl benzoate; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, etc.; polymers of polyols such as ethylene glycol, propylene glycol, glycerol and compounds having two hydroxyl groups in the polyols, and polyols; esterified compounds of the aforementioned polymers, nitriles such as acrylonitrile and benzonitrile; nitromethane; N,N-dimethylformamide; dimethyl sulfoxide; hexamethylphosphoric triamide; carbon disulfide; fluorine compounds (such as Novec (trademark) manufactured by 3M Company, Asahi Clean manufactured by Asahi Glass Co., Ltd., etc.). The solvent may be used alone or in combination of multiple types.

[0591] When the composition containing a heteroaromatic structure-containing fluororesin is formed into a film, a substrate may be used. By using a substrate, a film of the composition containing a heteroaromatic structure-containing fluororesin may be produced more stably.

[0592] The material used for the substrate is not particularly limited, and examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, cycloolefin polymers, polycarbonate, polyamide, polyimide, polyamideimide, polyvinyl chloride, polystyrene, polyphenylene oxide, polyetheretherketone, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyetherimide, polyimide resin, polyetherketoneetherketoneketone, polyallyletherketone, etc. The material used for the substrate may be modified, and one kind may be used alone, or a plurality of kinds may be used in combination.

[0593] The ion exchange membrane of the present embodiment has at least one layer (L1) containing the above-mentioned heteroaromatic structure-containing fluororesin and one layer (M1) containing a fluororesin having a structural unit represented by the following general formula G1, alternately.

[0594]

[0595] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0596] By using a film containing fluororesin G1 (hereinafter also referred to as fluororesin film) as a substrate as layer (M1), an ion exchange membrane having fluororesin film (M1) and fluororesin film (L1) containing heteroaromatic structure can be prepared. It should be noted that layer (M1) does not need to contain fluororesin containing heteroaromatic structure.

[0597] The ion exchange resin of this embodiment may have one layer (L1) and one layer (M1) (an ion exchange membrane having one layer (L1) and one layer (M1) is also referred to as a "bipolar membrane"). By using a laminated membrane, an ion exchange membrane having the characteristics of both the fluororesin G1 and the fluororesin containing a heteroaromatic structure can be produced. It should be noted that, hereinafter, in the laminated state, the fluororesin membrane is also referred to as a fluororesin layer, and the fluororesin membrane containing a heteroaromatic structure is also referred to as a fluororesin layer containing a heteroaromatic structure.

[0598] It should be noted that, regarding the interface between the layer (L1) containing a fluororesin containing a heteroaromatic structure and the layer (M1) containing a fluororesin having a structural unit represented by the general formula G1 contained in the ion exchange membrane, the presence or absence of the interface is determined based on the value at which the maximum signal intensity of NSO2 (m / z 78, two peaks detected, the low mass side is used) measured by a time-of-flight secondary ion mass spectrometer becomes 1 / 10, with reference to JIS K 0146: 2002. The region where the maximum signal intensity of the peak of NSO2 shows 1 / 10 or more is defined as the layer (L), and the region where the maximum signal intensity of the peak of NSO2 shows less than 1 / 10 is defined as the layer (M).

[0599] The method for producing the fluororesin film is as described above.

[0600] As a method for forming a fluororesin containing heteroaromatic structures into a film, it is also possible to manufacture a fluororesin film containing heteroaromatic structures by hydrolysis treatment after reacting a fluororesin G1 precursor film with a modifying compound. Furthermore, it is also possible to carry out an acid treatment. That is, by hydrolysis treatment, a saponification product of a fluororesin film containing heteroaromatic structures can be formed, and further, by acid treatment, a salt of a fluororesin film containing heteroaromatic structures can be formed. It should be noted that the hydrolysis treatment and the acid treatment are the same as the general formula G1. When using this method, by controlling the reaction of the fluororesin G1 precursor with the modifying compound, a film in which a fluororesin film containing heteroaromatic structures and a fluororesin film are integrated can be formed, and when it is desired to improve the adhesion of the fluororesin film containing heteroaromatic structures and the fluororesin film, a suitable film becomes. It should be noted that, for the film obtained by utilizing this method, by controlling the reaction of the fluororesin precursor with the modifying compound, the distribution in the film of the fluororesin containing heteroaromatic structures can also be controlled. Specifically, since the reaction proceeds from the portion where the fluororesin G1 precursor film contacts the modifying compound, a film can be formed in which the concentration of the heteroaromatic structure-containing fluororesin has a gradient from the contact portion.

[0601] The ion exchange membrane containing the fluororesin membrane containing the heteroaromatic structure of the present embodiment, and the ion exchange membrane containing the fluororesin membrane containing the heteroaromatic structure and the fluororesin membrane (the ion exchange membrane is not particularly limited as long as it has more than 2 layers, and the same applies to the following description) can be used for various purposes. If the above-mentioned uses are exemplified, redox flow batteries, fuel cells, salt electrolysis, alkaline water electrolysis, carbon dioxide reduction electrolysis, etc. can be listed, among which, cells for redox flow batteries and redox flow batteries can be appropriately exemplified. By being used for redox flow batteries and redox flow batteries, there is a tendency to have excellent power efficiency relative to the diaphragms used in the past.

[0602] The total thickness of the ion exchange membrane of the present embodiment is not particularly limited. In the redox flow battery unit and the redox flow battery exemplified as suitable uses, it is preferably 0.01 μm or more and 200 μm or less. From the perspective of the tendency of improving the handleability and mechanical strength of the membrane, it is more preferably 1 μm or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is more preferably 10 μm or more, and particularly preferably 20 μm or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and tending to improve power efficiency, it is more preferably 150 μm or less, more preferably 130 μm or less, and particularly preferably 100 μm or less.

[0603] The thickness of the layer (L1) (fluororesin membrane containing a heteroaromatic structure) in the ion exchange membrane of the present embodiment is not particularly limited, and in the redox flow battery unit and the redox flow battery exemplified as suitable uses, it is preferably 0.001 μm or more and 10 μm or less. From the perspective of being able to further suppress the redox active material from penetrating the membrane when used in the redox flow battery unit and the redox flow battery, the thickness of the layer (L1) is more preferably 0.01 μm or more, and more preferably 0.1 μm or more. In the case where the pulsation of the fluororesin membrane containing a heteroaromatic structure is large and high mechanical strength is required, it is particularly preferably 0.2 μm or more, and more particularly preferably 0.3 μm or more. From the perspective of suppressing the resistance during operation of the redox flow battery unit and the redox flow battery and having a tendency to improve power efficiency, the thickness of the layer (L1) is more preferably 7 μm or less, more preferably 5 μm or less, particularly preferably 3 μm or less, and more particularly preferably 1 μm or less.

[0604] The equivalent weight of the ion exchange membrane of the present embodiment is not particularly limited, but is preferably 500 g / eq or more and 2000 g / eq or less. From the perspective of the tendency of improving the handling property and mechanical strength of the membrane, it is more preferably 700 g / eq or more, and further preferably 800 g / eq or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is particularly preferably 880 g / eq or more, and further particularly preferably 900 g / eq or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and improving the power efficiency, the equivalent weight of the ion exchange membrane of the present embodiment is more preferably 1500 g / eq or less, further preferably 1400 g / eq or less, further preferably 1200 g / eq or less, and further particularly preferably 1150 g / eq or less.

[0605] The ion exchange membrane of the second embodiment according to another embodiment includes a layer (L3) and a layer (M3).

[0606] The layer (L3) comprises: a fluororesin containing side chain nitrogen atoms having a structural unit represented by the following general formula A3, a saponified product thereof, or a salt thereof;

[0607] The layer (M3) comprises a fluororesin (G1) having a structural unit represented by the following general formula G1.

[0608]

[0609] (Where,

[0610] X 20 , X 21 , X 22 and X 23 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 20 With X 21 , or X 20 With X 22 optionally bonded to each other to form a ring structure,

[0611] R 20 and R 21 each of which may be the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom,

[0612] R 22 and R 24is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms,

[0613] R 26 and R 27 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, R 26 and R 27 at least one of which is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms,

[0614] R 23 and R 25 each independently optionally the same or different, is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, and when h is 2 or more, the repeating R 23 each independently optionally the same or different,

[0615] X 24 is a divalent group represented by -CO2- or -SO2-,

[0616] a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1,

[0617] b is an integer from 0 to 8,

[0618] c is 0 or 1,

[0619] d, e, f, and h each independently optionally the same or different, are integers from 0 to 6. Among them, d, e, and f are not simultaneously 0.)

[0620]

[0621] (In the formula, the definition of each substituent is the same as the meaning of the aforementioned general formula G1.)

[0622] <Fluororesin A3 with a side-chain nitrogen atom>

[0623] The fluororesin A3 with a side-chain nitrogen atom has a structural unit represented by the following general formula A3. It should be noted that hereinafter, the fluororesin with a side-chain nitrogen atom having the structural unit represented by the above general formula A3 will also be referred to as "fluororesin A3 with a side-chain nitrogen atom".

[0624]

[0625] X 20 、X 21 、X 22 和X 23Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 20 With X 21 , or X 20 With X 22 They are optionally bonded to each other to form a ring structure. 20 , X 21 , X 22 and X 23 , from the viewpoint of easy acquisition of raw materials and the tendency to suppress the production cost of the fluororesin containing side chain nitrogen atoms, fluorine atoms and unsubstituted perfluoroalkyl groups having 1 to 3 carbon atoms are preferred. Furthermore, from the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin containing side chain nitrogen atoms, fluorine atoms and trifluoromethyl groups are more preferred, and fluorine atoms are particularly preferred.

[0626] R 20 and R 21 Each of them may be the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 20 and R 21 , from the viewpoint of easy availability of raw materials and the tendency to suppress the production cost of the fluororesin containing side chain nitrogen atoms, preferably a fluorine atom and an unsubstituted perfluoroalkyl group having 1 to 3 carbon atoms. Furthermore, from the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin containing side chain nitrogen atoms, more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

[0627] R 22 and R 24 Each of R may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms. 22 and R 24 , from the viewpoint of easy availability of raw materials and the tendency to reduce the production cost of the fluororesin containing a side chain nitrogen atom, preferably a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms. From the same viewpoint, R 24 More preferably, it is a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms, and particularly preferably a hydrogen atom. From the viewpoint of being able to further reduce the production cost of the fluororesin containing a side chain nitrogen atom, R 22A hydrogen atom is more preferred, and from the viewpoint of improving the stability of the fluororesin containing a side chain nitrogen atom under alkaline conditions, an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms is further preferred.

[0628] R 26 and R 27 is a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms. 26 and R 27 At least one of is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, and thus when used in a redox flow battery cell or a redox flow battery, there is a tendency for the current efficiency, voltage efficiency, and power efficiency to be well balanced. From the same viewpoint, R 26 and R 27 More preferably, they are both substituted or unsubstituted aliphatic hydrocarbon groups having 1 to 10 carbon atoms. When used in a redox flow battery cell or a redox flow battery, the current efficiency, voltage efficiency, and power efficiency tend to be well-balanced and excellent. 26 and R 27 It is preferably an unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably an unsubstituted aliphatic hydrocarbon group having 1 to 6 carbon atoms, and still more preferably an unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms.

[0629] R 23 and R 25 Each of them may be the same or different and is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms. 23 can be the same or different. 23 , R 25 From the viewpoint of easy acquisition of raw materials and the tendency to suppress the manufacturing cost of the fluororesin containing side chain nitrogen atoms, it is preferably an unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably an unsubstituted aliphatic hydrocarbon group having 2 to 6 carbon atoms, further preferably an unsubstituted aliphatic hydrocarbon group having 2 to 4 carbon atoms, and particularly preferably an unsubstituted aliphatic hydrocarbon group having 2 to 3 carbon atoms.

[0630] In addition, the substituent in the case of "substituted" is the same as the substituent exemplified in General Formula 1.

[0631] X 24 It is a divalent group represented by the chemical formula of -CO2- or -SO2-. From the viewpoint that the chemical stability such as the resistance to oxidative degradation of the fluororesin containing a side chain nitrogen atom tends to be improved, a divalent group represented by the chemical formula of -SO2- is preferred.

[0632] Among the above-mentioned fluororesins containing side chain nitrogen atoms, from the viewpoint of the tendency that the chemical stability such as the resistance to oxidative degradation of the fluororesins containing side chain nitrogen atoms is improved, and from the viewpoint that the manufacturing cost of the fluororesins containing side chain nitrogen atoms and the manufacturing cost of the units for redox flow batteries can be suppressed, it is preferred that the fluororesins contain a structural unit represented by the general formula A2, and at least one selected from the group consisting of the structural unit represented by the following general formula A17, the structural unit represented by the following general formula A18 and the structural unit represented by the following general formula A19.

[0633] -(CF2-CF2)-[A2]

[0634] -(CF2-CF(-O-(CF2CFXO) N -Bg))-[A17]

[0635] (wherein X represents F or a perfluoroalkyl group having 1 to 3 carbon atoms. Ag represents ((CF2)) f -X 24 -NR 22 -(R 23 -NR 24 ) h -R 25 -NR 26 R 27 ). N represents an integer from 0 to 5. )

[0636] -(CF2-CF(-O-(CF2) P -CFX(-O-(CF2) K -SO2NX 51 Bx)))-[A18]

[0637] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. 51 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Bx represents -(R 23 -NR 24 ) h -R 25 -NR 26 R 27 ). P represents an integer of 0 to 12, and K represents an integer of 1 to 5. Wherein, P and K are not 0 at the same time. )

[0638] -(CF2-CF(-O-(CF2) Q -CFX(-(CF2) L -O-(CF2) o -SO2NX 51 Bx)))-[A19]

[0639] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. X 41 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -(R in the above general formula A3 23 -NR 24 ). h -R 25 -NR 26 R 27 ). Q represents an integer from 0 to 12, L represents an integer from 1 to 5, and o represents an integer from 0 to 6. Among them, Q and O are not 0 at the same time).

[0640] The fluororesin containing a side-chain nitrogen atom more preferably contains a structural unit represented by the general formula A2 and at least one selected from the group consisting of a structural unit represented by the general formula A17, a structural unit represented by the general formula A18, and a structural unit represented by the general formula A19. From the same viewpoint, it is further preferred to contain a structural unit represented by the general formula A2 and a structural unit represented by the general formula A17 (wherein X is F or trifluoromethyl, n is an integer from 0 to 2, and m is an integer from 1 to 4), and particularly preferably contains a structural unit represented by the general formula A2 and a structural unit represented by the general formula A17 (wherein X is F or trifluoromethyl, n is 0 or 1, and m is an integer from 2 to 4).

[0641] The fluororesin containing a side-chain nitrogen atom more preferably has a structural unit represented by the following general formula A20, and further preferably has a structural unit represented by the following general formula A21.

[0642] -[CF2CF2] a -[CF2-CF((-O-CF2-(CF(CF3))) b -O-(CF2)2-SO2NX 51 Bx)] g -[A20]

[0643] (In the formula, X 51 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -(R in the above general formula A3 23 -NR 24 ). h -R 25 -NR 26 R 27 ). a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1. b is 0 or 1.).

[0644] -[CF2CF2] a-[CF2-CF((-O-CF2-(CF(CF3)))-O-(CF2)2-SO2NX 51 Bx)] g -[A21]

[0645] (In the formula, X 51 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax represents -(R 23 -NR 24 ) h -R 25 -NR 26 R 27 ) in the above general formula A3. a and g represent the molar ratios in all structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1.)

[0646] The method for producing the fluororesin containing a side-chain nitrogen atom is not particularly limited, and examples thereof include a method of reacting the above fluororesin G1 precursor with a modifying compound described later.

[0647] As the modifying compound, it has at least two nitrogen atoms. Among the aforementioned nitrogen atoms, the functional group containing the first nitrogen atom is a primary amino group or a secondary amino group. From the viewpoint of improving the reactivity between the modifying compound and the fluororesin precursor containing a side-chain nitrogen atom, a primary amino group is preferred, and from the viewpoint of improving the stability of the fluororesin containing a side-chain nitrogen atom, a secondary amino group is preferred. Among the at least two nitrogen atoms contained in the modifying compound, the functional group containing the second nitrogen atom is at least one functional group selected from the group consisting of a secondary amino group, a tertiary amino group, and a group formed by the aforementioned amino group and an acidic substance. In the reaction between the acidic fluororesin precursor and the modifying compound, when it is required to suppress side reactions, a secondary amino group or a tertiary amino group is preferred, and a tertiary amino group is more preferred.

[0648] Examples of the modified compound include N-methylethylenediamine, N-ethylethylenediamine, N,N-dimethylethylenediamine, N,N'-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N-diethylethylenediamine, N-benzylethylenediamine, N,N-dibutylethylenediamine, 1,2-diphenylethylenediamine, N,N-dicyclohexyl-1,2-ethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldipropylenetriamine, N,N-dibutylethylenediamine, Propylenetriamine, N,N-diethyl-1,3-propylenediamine, N,N-dimethyl-1,4-butanediamine, N,N-diethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, N,N-dimethyl-1,4-cyclohexanediamine, 3-aminopiperidine, isophoronediamine, 4-(aminomethyl)piperidine, 3-aminopyrrolidine, 4-aminopiperidine, 3-aminopyrrolidine, N,N-dimethyltrimethylenediamine, N,N-dibutyltrimethylenediamine, etc. The modifying compound may be used alone or in combination of two or more.

[0649] Among the modified compounds, N-methylethylenediamine, N-ethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldipropylenetriamine, N,N-dibutyldipropylenetriamine, N,N-diethyl-1,3-propylenediamine, N,N-dimethyl-1,4-butanediamine, N,N-diethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, N,N-dimethyl-1,4-cyclohexanediamine, N,N-dimethyltrimethylenediamine, and N,N-dibutyltrimethylenediamine are more preferred because the modified compounds are easily available and there is a tendency that the production cost of the redox flow battery containing the fluororesin containing a side chain nitrogen atom can be suppressed.

[0650] Among the modified compounds, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldipropylenetriamine, N,N-dibutyldipropylenetriamine, N,N-dimethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, and N,N-dimethyltrimethylenediamine are particularly preferred because they tend to be excellent in a good balance when the ion exchange membrane for redox flow battery containing the fluororesin containing side chain nitrogen atoms is used as a redox flow battery cell and a separator of a redox flow battery, and when used for a redox flow battery cell and a redox flow battery.

[0651] From the same viewpoint, N,N-dimethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyldipropylenetriamine, and N,N-dimethyltrimethylenediamine are particularly preferred.

[0652] The fluororesin containing a side chain nitrogen atom in the present embodiment has a sulfonamide bond (-SO2NR-) (it should be noted that in the aforementioned chemical formula representing sulfonamide, R is not particularly limited). The sulfonamide bond of the fluororesin containing a heteroaromatic structure can be analyzed by a conventional analytical method, and as an analytical device, for example, FT-IR, TOF-SIMS, etc. can be used.

[0653] The fluororesin containing a side chain nitrogen atom in the present embodiment may be a saponified product thereof or a salt thereof.

[0654] The saponified product of the fluororesin containing a side chain nitrogen atom is a saponified product obtained by reacting the fluororesin containing a side chain nitrogen atom with an alkaline substance. Examples of the alkaline substance include amine compounds such as dimethylamine, diethylamine, monomethylamine, and monoethylamine; hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; and hydroxides of alkaline earth metals. Among these, sodium hydroxide or potassium hydroxide is preferred.

[0655] The salt of the fluororesin containing a side chain nitrogen atom is a salt of the fluororesin containing a side chain nitrogen atom and an acidic substance. Examples of the acidic substance include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as oxalic acid, acetic acid, formic acid and trifluoroacetic acid.

[0656] <Fluororesin G1>

[0657] The side chain nitrogen atom-containing fluororesin in the present embodiment may be used in the form of a resin composition mixed with other resins.

[0658] The resin composition may contain the side chain nitrogen atom-containing fluororesin in the present embodiment and the fluororesin G1.

[0659] In the present embodiment, a mixture of fluororesins such as a composition containing a fluororesin having a side chain nitrogen atom and the fluororesin G1 is referred to as a fluororesin composition.

[0660] The fluororesin G1 is a fluororesin having an ion exchange capacity for cations (hereinafter also referred to as "Cation").

[0661] The fluororesin G1 has a structural unit represented by the following general formula G1.

[0662]

[0663] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0664] The preferred fluororesin G1 is the same as described above.

[0665] When a side chain nitrogen atom-containing fluororesin having a structural unit represented by the general formula A3 is used, the ratio of each resin is exemplified as follows.

[0666] The weight ratio of the fluororesin containing side chain nitrogen atoms to the fluororesin G1 in the resin composition is not particularly limited, but is preferably 1:100 to 100:1. Although it varies depending on the application of the resin composition of the present embodiment, when used as a diaphragm for a redox flow battery, from the viewpoint of suppressing the elution of the fluororesin containing side chain nitrogen atoms into the electrolyte, the weight ratio of the fluororesin containing side chain nitrogen atoms to the fluororesin G1 is preferably 5:95 or more, more preferably 10:90 or more, and further preferably 15:85 or more. Although it varies depending on the application of the above-mentioned mixture, when used as a diaphragm for a redox flow battery, from the viewpoint of the tendency of using the fluororesin containing side chain nitrogen atoms to improve power efficiency, the weight ratio of the fluororesin containing side chain nitrogen atoms is preferably 90:10 or less, more preferably 70:30 or less, and further preferably 60:40 or less.

[0667] The content of the fluororesin containing side chain nitrogen atoms in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. Although it varies depending on the purpose of using the above-mentioned mixture, when it is used as a separator for a redox flow battery, the content of the fluororesin containing side chain nitrogen atoms in the resin composition is preferably 90% or less, more preferably 70% or less, and further preferably 60% or less, from the perspective of the tendency to improve power efficiency by using the fluororesin containing side chain nitrogen atoms.

[0668] The resin composition of the present embodiment is preferably a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a polyetheretherketone resin, a polysulfone resin, a polyethersulfone resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a polyphenylene ether resin, a polyphenylene sulfide resin, a syndiotactic polystyrene resin, a polyetherimide, a siloxane-modified polyetherimide resin, a polyamideimide resin, a cycloolefin resin, a cycloolefin copolymer, a polyetherketoneetherketoneketone resin, a polyallyletherketone resin, and a fluororesin, and may further include a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a syndiotactic polystyrene resin, a cycloolefin resin, and a cycloolefin copolymer. The resin optionally included in the resin composition of the present embodiment may be used alone or in combination.

[0669] <Ion exchange membrane>

[0670] The ion exchange membrane of the present embodiment contains a fluororesin containing side chain nitrogen atoms or the resin composition of the present embodiment.

[0671] When the resin composition containing the fluororesin containing the side chain nitrogen atom is formed into a film, the forming method is not particularly limited, and examples thereof include: a method of processing the resin composition containing the fluororesin containing the side chain nitrogen atom into a film by making the resin composition containing the fluororesin containing the side chain nitrogen atom into a molten state and extruding it using an extruder, a nozzle or a die head, etc.; a method of processing the resin composition containing the fluororesin containing the side chain nitrogen atom into a solution state, applying it to a substrate using a die head, a gravure roll, a doctor blade, or a sprayer, and drying it, thereby processing it into a film. Hereinafter, the obtained film of the fluororesin containing the side chain nitrogen atom is also referred to as a fluororesin film containing the side chain nitrogen atom.

[0672] The solvent that can be used when the fluororesin containing side chain nitrogen atoms is made into a solution is not particularly limited, and examples thereof include saturated hydrocarbon compounds such as n-pentane, n-hexane, n-octane, n-decane, cyclopentane, cyclohexane and cyclooctane; aromatic hydrocarbon compounds such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbon compounds such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, cyclohexanol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone and cyclohexanone; and ethyl acetate, ethyl acetate and ethyl acetate. Esters such as butyl ester and methyl benzoate; ethers such as diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, etc.; polymers of polyols such as ethylene glycol, propylene glycol, glycerol, and compounds having two hydroxyl groups in the polyols, and polyols; esterified compounds of the aforementioned polymers, nitriles such as acrylonitrile and benzonitrile; nitromethane; N,N-dimethylformamide; dimethyl sulfoxide; hexamethylphosphoric triamide; carbon disulfide; fluorine compounds (such as Novec (trademark) manufactured by 3M Company, Asahi Clean manufactured by Asahi Glass Co., Ltd., etc.). The solvent may be used alone or in combination of multiple types.

[0673] When the composition containing a fluororesin having a side chain nitrogen atom is formed into a film, a substrate may be used. By using a substrate, a film of the composition containing a fluororesin having a side chain nitrogen atom may be produced more stably.

[0674] The material used for the substrate is not particularly limited, and examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, cycloolefin polymers, polycarbonate, polyamide, polyimide, polyamideimide, polyvinyl chloride, polystyrene, polyphenylene oxide, polyetheretherketone, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyetherimide, polyimide resin, polyetherketoneetherketoneketone, polyallyletherketone, etc. The material used for the substrate may be modified, and one kind may be used alone, or a plurality of kinds may be used in combination.

[0675] The ion exchange membrane of the present embodiment has at least one layer (L3) containing the above-mentioned fluororesin containing side chain nitrogen atoms and one layer (M3) containing a fluororesin having a structural unit represented by the following general formula G1, alternately.

[0676]

[0677] (In the formula, the definition of each substituent is the same as that of the aforementioned general formula G1.)

[0678] As layer (M3), by using a film containing fluororesin G1 (hereinafter also referred to as fluororesin film) as a substrate, an ion exchange membrane having a fluororesin film (M3) and a fluororesin film (L3) containing side chain nitrogen atoms can be prepared. It should be noted that layer (M3) does not need to contain a fluororesin containing a heteroaromatic structure.

[0679] The ion exchange resin of this embodiment may have one layer (L3) and one layer (M3) (the ion exchange membrane having one layer (L3) and one layer (M3) is also referred to as a "bipolar membrane"). By using the laminated membrane, an ion exchange membrane having the characteristics of both the fluororesin G1 and the fluororesin containing a heteroaromatic structure can be prepared. It should be noted that, hereinafter, in the laminated state, the fluororesin membrane is also referred to as a fluororesin layer, and the fluororesin membrane containing side chain nitrogen atoms is also referred to as a fluororesin layer containing side chain nitrogen atoms.

[0680] It should be noted that, regarding the interface between the layer (L3) containing the fluororesin containing the side chain nitrogen atom and the layer (M3) containing the fluororesin having the structural unit represented by the general formula G1 contained in the ion exchange membrane, the presence or absence of the interface is determined based on the value at which the maximum signal intensity of NSO2 (m / z 78, 2 peaks detected, using the low mass side) measured by a time-of-flight secondary ion mass spectrometer becomes 1 / 10, with reference to JIS K 0146: 2002. The region where the maximum signal intensity of the peak of NSO2 shows 1 / 10 or more is defined as the layer (L), and the region where the maximum signal intensity of the peak of NSO2 shows less than 1 / 10 is defined as the layer (M).

[0681] The method for producing the fluororesin film is as described above.

[0682] As a method for forming a fluororesin containing side chain nitrogen atoms into a film, it is also possible to manufacture a fluororesin film containing side chain nitrogen atoms by hydrolysis after reacting a fluororesin G1 precursor film with a modified compound. Furthermore, it is also possible to carry out an acid treatment. That is, by hydrolysis, a saponification product of a fluororesin film containing a heteroaromatic structure can be formed, and then, by acid treatment, a salt of a fluororesin film containing a heteroaromatic structure can be formed. It should be noted that the hydrolysis and acid treatment are the same as the general formula G1. When using this method, by controlling the reaction of the fluororesin G1 precursor with the modified compound, a film formed by integrating a fluororesin film containing side chain nitrogen atoms and a fluororesin film can be formed, and when it is desired to improve the adhesion of the fluororesin film containing side chain nitrogen atoms with the fluororesin film, a suitable film becomes. It should be noted that, for the film obtained by utilizing this method, by controlling the reaction of the fluororesin precursor with the modified compound, the distribution in the film of the fluororesin containing side chain nitrogen atoms can also be controlled. Specifically, since the reaction proceeds from the portion where the fluororesin G1 precursor film and the modifying compound come into contact, a film can be formed in which the concentration of the fluororesin containing side chain nitrogen atoms has a gradient from the contact portion.

[0683] The ion exchange membrane of the present embodiment having a fluororesin membrane containing a side chain nitrogen atom, and the ion exchange membrane containing a fluororesin membrane containing a side chain nitrogen atom and a fluororesin membrane (the ion exchange membrane is not particularly limited as long as it has more than 2 layers, and the same applies to the following description) can be used for various purposes. If the above-mentioned uses are exemplified, redox flow batteries, fuel cells, salt electrolysis, alkaline water electrolysis, carbon dioxide reduction electrolysis, etc. can be listed, among which, cells for redox flow batteries and redox flow batteries can be appropriately exemplified. By being used for redox flow batteries and redox flow batteries, there is a tendency for excellent power efficiency relative to the diaphragms used in the past.

[0684] The total thickness of the ion exchange membrane of the present embodiment is not particularly limited. In the redox flow battery unit and the redox flow battery exemplified as suitable uses, it is preferably 0.01 μm or more and 200 μm or less. From the perspective of the tendency of improving the handleability and mechanical strength of the membrane, it is more preferably 1 μm or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is more preferably 10 μm or more, and particularly preferably 20 μm or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and tending to improve power efficiency, it is more preferably 150 μm or less, more preferably 130 μm or less, and particularly preferably 100 μm or less.

[0685] The thickness of the layer (L3) (fluororesin membrane containing side chain nitrogen atoms) in the ion exchange membrane of the present embodiment is not particularly limited, and in the redox flow battery cell and the redox flow battery exemplified as suitable uses, it is preferably 0.001 μm or more and 10 μm or less. From the perspective of being able to further suppress the redox active material from penetrating the membrane when used in the redox flow battery cell and the redox flow battery, the thickness of the layer (L3) is more preferably 0.003 μm or more, and more preferably 0.005 μm or more. In the case where the pulsation of the fluororesin membrane containing side chain nitrogen atoms is large and high mechanical strength is required, it is particularly preferably 0.01 μm or more, and more particularly preferably 0.04 μm or more. From the perspective of suppressing the resistance during operation of the redox flow battery cell and the redox flow battery and having a tendency to improve power efficiency, the thickness of the layer (L3) is more preferably 7 μm or less, more preferably 5 μm or less, particularly preferably 3 μm or less, and more particularly preferably 1.5 μm or less.

[0686] The equivalent weight of the ion exchange membrane of the present embodiment is not particularly limited, but is preferably 500 g / eq or more and 2000 g / eq or less. From the perspective of the tendency of improving the handling property and mechanical strength of the membrane, it is more preferably 700 g / eq or more, and further preferably 800 g / eq or more. In particular, when the membrane has large pulsation and requires high mechanical strength, it is particularly preferably 880 g / eq or more, and further particularly preferably 900 g / eq or more. From the perspective of suppressing the resistance of the redox flow battery unit and the redox flow battery during operation and improving the power efficiency, the equivalent weight of the ion exchange membrane of the present embodiment is more preferably 1500 g / eq or less, further preferably 1400 g / eq or less, further preferably 1200 g / eq or less, and further particularly preferably 1150 g / eq or less.

[0687] <Cell for redox flow battery>

[0688] The redox flow battery unit exemplified as a suitable use of the ion exchange membrane of the present embodiment comprises: a first electrolyte containing a first redox active substance, a second electrolyte containing a second redox active substance, a first electrode in contact with the first electrolyte, a second electrode in contact with the second electrolyte, and a diaphragm disposed between the first electrolyte and the second electrolyte, thereby constituting. It should be noted that it may also include elements other than the aforementioned constituent elements commonly used by those skilled in the art, and elements known from known information such as known literature and patents related to the redox flow battery unit. If the aforementioned elements are exemplified, bipolar plates, frames, compressible seals, conductive additives, balancing cells, etc. may be listed.

[0689] Figure 1 An example of a schematic diagram of the redox flow battery unit is shown. The redox flow battery unit 10 includes an electrolytic cell 6, wherein the electrolytic cell 6 includes an electrode 1 ( Figure 1 The positive electrode is a cell 2, and an electrode 3 ( Figure 1 The present invention relates to a cell chamber 4 (a negative electrode in the cell chamber), and a diaphragm 5 as a diaphragm that separates the cell chamber 2 from the cell chamber 4. The cell chamber 2 and the cell chamber 4 contain an electrolyte containing a redox active substance. The electrolyte containing the redox active substance is stored in, for example, an electrolyte tank 7 and a tank 8, respectively, and is supplied to each cell chamber by a pump or the like. In addition, the current generated by the redox flow battery cell can be converted from DC to AC via an AC / DC conversion device 9, or from AC to DC via an AC / DC conversion device 9, to charge the redox flow battery cell. The redox flow battery cell of this embodiment is preferably a redox flow secondary battery cell.

[0690] <Redox Flow Battery>

[0691] The redox flow battery can be manufactured by stacking the redox flow battery cells. When stacking, electricity can be conducted between the redox flow battery cells via the bipolar plates.

[0692] The material of the bipolar plate is not particularly limited, and examples thereof include carbon, graphite, and metal. In addition, the aforementioned material may be dispersed with carbon particles, carbon fibers, metal particles, metal fibers, graphene, and carbon nanotubes.

[0693] One type may be used alone or two or more types may be used in combination.

[0694] From the perspective of sometimes being able to improve the contact between the electrode and the electrolyte, the bipolar plate may also have various flow paths. The flow paths are not particularly limited, and examples thereof include Serpentine, Interdigitated, Parallel, Multi-parallel, Discontinuous, and a combination of the aforementioned flow paths.

[0695] <Electrolyte>

[0696] The electrolytic solution in the present embodiment is a liquid containing a redox active material and a solvent.

[0697] The redox active material refers to a material having a redox activity directly related to the electromotive force in the redox flow battery unit. The redox active material used in the present embodiment is not particularly limited, and metal redox active materials, non-metal redox active materials, organic redox active materials, etc. can be listed, and they can be neutral compounds or ionic compounds.

[0698] The metal redox active material is a material comprising at least one metal atom, and may comprise a plurality of metal atoms of the same kind, or may comprise a plurality of metals of different kinds. The metal atom used in the metal redox active material is not particularly limited, and may include aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin, lead and cerium, among which titanium, vanadium, chromium, manganese, iron and cerium are preferred. In addition, from the viewpoint that the first redox active material and the second redox active material can be the same kind, vanadium, iron, copper and tin are preferred, vanadium and iron are further preferred, and vanadium is particularly preferred.

[0699] The metal-based redox-active material may have a commonly used active material ligand. Examples of the ligand include cyanide ion, acetylacetone, ethylenediamine, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, carbon monoxide, bipyridine, bipyrazine, ethylene glycol, propylene glycol, ethanedithiol, butanedithiol, terpyridine, diethylenetriamine, triazacyclononane, tris(hydroxymethyl)aminomethane, ascorbic acid, citric acid, glycolic acid, gluconic acid, acetic acid, formic acid, benzoic acid, malic acid, maleic acid, phthalic acid, sarcosine, salicylic acid, oxalic acid, urea, aminophenol salts, and lactic acid.

[0700] The active material ligand may be used alone or in combination of two or more.

[0701] The substance used for the non-metallic redox active material is not particularly limited, and examples thereof include chlorine, bromine, sulfur, and polysulfide.

[0702] The organic redox-active substances are not particularly limited, and examples thereof include viologen, its derivatives and compounds having a viologen structure in a polymer side chain; 2,2,6,6-tetramethyl-1-piperidinyloxy free radical, its derivatives and compounds having a 2,2,6,6-tetramethyl-1-piperidinyloxy free radical structure in a polymer side chain; ferrocene, its derivatives and compounds having a ferrocene structure in a polymer side chain; quinone, its derivatives and compounds having a quinone structure in a polymer side chain; anthraquinone, its derivatives and compounds having an anthraquinone structure in a polymer side chain; quinoxaline, its derivatives and compounds having a quinoxaline structure in a polymer side chain, etc.

[0703] The redox active material may be used alone or in combination of two or more.

[0704] When the aforementioned redox active material is used for a redox flow battery cell, the redox active material used in the electrolyte of the positive electrode and the redox active material used in the electrolyte of the negative electrode can be used in combination according to the desired characteristics. As a combination of redox active materials, it is not particularly limited, and combinations such as vanadium / vanadium, iron / iron, lead / lead, copper / copper, iron / chromium, chromium / bromine, zinc / bromine, polysulfide / bromine, zinc / cerium, zinc / nickel, zinc / cerium, zinc / iodine, titanium / manganese, vanadium / cerium, and vanadium / manganese can be listed. Among these, from the aspect of obtaining high electromotive force and excellent stability in charge and discharge, preferably vanadium / vanadium, iron / iron, iron / chromium, chromium / bromine, zinc / bromine, titanium / manganese, more preferably vanadium / vanadium, iron / iron, zinc / bromine, particularly preferably vanadium / vanadium.

[0705] When the redox active materials of the positive electrode and the negative electrode are both vanadium, it is also expressed as a vanadium redox flow battery cell or a vanadium redox flow battery. In addition, when the redox active materials of the positive electrode and the negative electrode are both vanadium, by using VO 2+ / VO2 + , use V in the negative electrode 2+ / V 3+ The redox pair is charged and discharged by redox reaction. During charging, the protons (H+) in the positive electrode cell become excessive due to the redox reaction, while the protons (H+) in the negative electrode cell are insufficient. The separator selectively moves the excess protons in the positive electrode cell to the negative electrode cell to maintain electrical neutrality. During discharge, the opposite reaction occurs to maintain electrical neutrality.

[0706] The solvent used in the electrolyte is not particularly limited, and examples thereof include water, alcohols, nitriles, esters, ketones, ethers, aliphatic hydrocarbons, aromatic hydrocarbons, etc. Among these, water is preferred from the viewpoint of improving the safety of the redox flow battery cell during operation.

[0707] If the above-mentioned solvents are given as specific examples, they include alcohols such as methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, and glycerol; nitriles such as acetonitrile, propionitrile, and benzonitrile; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as diethyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, ethylene glycol diethyl ether, and diethylene glycol dimethyl ether; aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, octane, chloroform, dichloromethane, and tetrachloromethane; aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, phenol, and cresol, etc.

[0708] The solvent used in the electrolyte may be a single type or a combination of two or more types.

[0709] An electrolyte may be further used in the electrolyte. The electrolyte is a substance that dissociates into ions in the electrolyte and improves the conductivity of the electrolyte. The electrolyte is not particularly limited, and examples thereof include sulfuric acid, hydrochloric acid, nitric acid, acetic acid, phosphoric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium acetate, and the like.

[0710] The electrolyte used in the electrolytic solution may be a single type or a combination of two or more types.

[0711] Additives can be added to the electrolyte according to the desired characteristics of the electrolyte. As additives, there are no particular limitations, and ethylene glycol, diethylene glycol, polyethylene glycol, glycerol, mannitol, sorbitol, pentaerythritol, tris (hydroxymethyl) aminomethane, corn starch, corn syrup, gelatin, glycerol, guar gum, pectin, surfactants, etc. can be listed.

[0712] The additives used in the electrolyte may be a single type or a combination of two or more types.

[0713] <Electrode>

[0714] The electrode of this embodiment is not particularly limited. Examples of the electrode include metal electrodes and carbon electrodes.

[0715] The material of the metal electrode is not particularly limited, and examples thereof include aluminum, gold, silver, copper, chromium, molybdenum, nickel, thallium, titanium, iridium, zinc, tin, and composites of the aforementioned metals. The shape of the metal electrode is not particularly limited, and examples thereof include plate-like, lattice-like, mesh-like (diamond-like, tortoise-shell-like), linear, and rod-like.

[0716] As a carbon electrode, there is no particular limitation, and examples thereof include a glassy carbon electrode, a pyrolytic carbon electrode, a carbon felt electrode, a carbon paper electrode, a carbon foam electrode, a carbon cloth electrode, a carbon knitted electrode, a carbon nanofiber sheet electrode, an activated carbon fiber sheet electrode, and the like. Among the aforementioned electrodes, in the use of allowing liquid or gas to circulate inside the electrode, it is preferred to have a continuous void, and a porous body having a continuous void is more preferred. As a carbon electrode having a continuous void, examples thereof include a carbon felt electrode, a carbon paper electrode, a carbon foam electrode, a carbon cloth electrode, a carbon knitted electrode, a carbon nanofiber sheet electrode, an activated carbon fiber sheet electrode, and the like. Among these, from the viewpoint of being able to reduce resistance due to high flexibility and a large surface area, carbon felt, carbon paper, and carbon foam are preferred, and carbon foam is more preferred. Carbon foam preferably has a structure in which the carbon portion is three-dimensionally continuous. From the aspect of being able to achieve high flexibility and a high surface area, the carbon foam preferably has a linear portion and a bonding portion that bonds the aforementioned linear portion.

[0717] Specific examples of carbon felt and carbon paper include SIGRACET (registered trademark) KFD series, GFA series, GFD series, SGL series and SIGRACET (registered trademark) series manufactured by SGL CARBON, carbon felt (e.g., XF30A, BW-309) manufactured by Toyobo Co., Ltd., CARBORON (registered trademark) GF series (e.g., GF-20, GF-3F) manufactured by Nippon Carbon Co., Ltd., TORAYCA (trademark) TGP series manufactured by Toray Industries, Ltd., PYROFIL (trademark) series, GRAFIL (trademark) series manufactured by Mitsubishi Chemical Corporation, VGCF (registered trademark) sheet manufactured by Showa Denko K.K., carbon felt and graphite felt manufactured by MERSEN, etc. These may be subjected to activation treatment such as oxidation as needed.

[0718] Carbon foam can be produced by a known method (International Patent Application Publication No. 2018 / 096895, International Patent Application Publication No. 2018 / 168741, and International Patent Application Publication No. 2020 / 045645).

[0719] The electrodes may be used alone or in combination of two or more.

[0720] <Membrane Electrode Assembly>

[0721] The membrane electrode assembly in the present embodiment is a structure in which an ion exchange membrane (hereinafter also referred to as a membrane for an assembly) is joined to at least one electrode. The joining means that the assembly membrane is connected to at least one electrode, and by joining, the assembly membrane and at least one electrode can be integrated. For example, in a diaphragm electrode assembly having an assembly membrane and two electrodes, when assembling a redox flow battery unit, it is not necessary to sequentially assemble the electrode, the assembly membrane, and the electrode, and it can be set as one process, which has a tendency to suppress manufacturing costs, and is therefore sometimes preferably used.

[0722] The method of joining the film for a joined body to at least one electrode is not particularly limited, and examples thereof include a method using heat pressing and / or heat roll pressing.

[0723] The temperature during the bonding is not particularly limited. If the bonding between the bonding body film and the electrode is insufficient, the elastic modulus of the bonding body film will decrease. From the perspective of the tendency to improve the bonding between the bonding body film and the electrode, it is preferably set to be above room temperature. From the perspective of the tendency to suppress the deterioration of the bonding body film, the temperature during the bonding is preferably 250°C or less, more preferably 200°C or less, further preferably 170°C or less, and particularly preferably 150°C or less.

[0724] The pressure during the bonding is not particularly limited, and is a pressure greater than 0 MPa. From the perspective of the tendency of the bonding of the bonded body film to the electrode to be improved, it is preferably more than 0.01 MPa, more preferably more than 0.05 MPa, further preferably more than 0.08 MPa, and particularly preferably more than 0.1 MPa. From the perspective of the tendency to suppress the deterioration of the electrode, it is preferably less than 100 MPa, more preferably less than 50 MPa, further preferably less than 20 MPa, and particularly preferably less than 10 MPa.

[0725] The time for joining is not particularly limited, and is a time greater than 0 seconds. From the perspective of improving the joining of the membrane for the joint body and the electrode, it is preferably 0.01 seconds or more, more preferably 0.1 seconds or more, further preferably 0.5 seconds or more, and particularly preferably 1 second or more. From the perspective of being able to reduce the cost when manufacturing the membrane electrode assembly, it is preferably 10 hours or less, more preferably 5 hours or less, further preferably 2 hours or less, and particularly preferably 1 hour or less.

[0726] The atmosphere during bonding is not particularly limited, and examples thereof include air, nitrogen, and argon. Air and nitrogen are preferred, and air is more preferred, from the viewpoint of the tendency to reduce the cost of manufacturing the membrane electrode assembly.

[0727] The membrane electrode assembly of this embodiment can be used for various purposes, and can be preferably used for a redox flow battery unit and a redox flow battery. By using a redox flow battery unit and a redox flow battery, there is a tendency to have excellent power efficiency compared to the combination of a diaphragm and an electrode used in the past.

[0728] In the redox flow battery unit and the redox flow battery of the present embodiment, when the separator uses a side chain heteroaromatic resin film, a fluororesin film containing a heteroaromatic structure, and a fluororesin film containing a side chain nitrogen atom, when the current efficiency and voltage efficiency are well balanced and high power efficiency is required, it is preferred that the side chain heteroaromatic resin layer, the fluororesin film containing a heteroaromatic structure, and the fluororesin film containing a side chain nitrogen atom are arranged on the electrode side that functions as the negative electrode, and preferably arranged in a proximal position on the electrode side. Proximal position means that the distance of the side chain heteroaromatic resin layer, the fluororesin film containing a heteroaromatic structure, and the fluororesin film containing a side chain nitrogen atom relative to the electrode that functions as the negative electrode is smaller than the distance relative to the electrode that functions as the positive electrode. The reason why the above-mentioned special effect is obtained by arranging the side chain heteroaromatic resin layer, the fluororesin film containing heteroaromatic structure and the fluororesin film containing side chain nitrogen atoms near the electrode side that functions as the negative electrode is not yet clear, but it is speculated that the amount of redox active material moving from the positive electrode to the negative electrode is different from the amount of redox active material moving from the negative electrode to the positive electrode. Compared with any redox active material that moves more, the side chain heteroaromatic resin layer, the fluororesin layer containing heteroaromatic structure and the fluororesin layer containing side chain nitrogen atoms function more effectively. In addition, when higher current efficiency is required, it is preferred to arrange the side chain heteroaromatic resin layer on both sides of the separator.

[0729] By using the redox flow battery unit and the redox flow battery of the present embodiment, it is possible to provide a mechanism for smoothing the supply / demand of electricity and stabilizing the variable electricity obtained from renewable energy sources such as solar energy and wind energy. If illustrated more specifically, it is possible to provide the merging of electricity obtained from renewable energy sources, peak load shifting of electricity, stabilization of the transmission and distribution network, base load power, energy arbitrage, support for weak transmission and distribution networks, frequency adjustment, and any combination of the foregoing. In addition, it can also be used as a power source for remote camping, front-line combat bases, transmission and distribution telecommunications, remote sensors, etc. that do not utilize the transmission and distribution network.

[0730] The redox flow battery cell and the redox flow battery of the present embodiment may include a control system and a power adjustment unit.

[0731] By using a control system, the actions of various valves, pumps, circulation loops, sensors, mitigation devices, other electronic / hardware control devices, safety protection devices, etc. can be controlled.

[0732] By using the power conditioning unit, the voltage and current of the input power can be converted into a form that is most suitable for the redox flow battery unit and / or the redox flow battery, and the voltage and current of the output power can be converted into a form that is most suitable for any purpose. For example, when the redox flow battery unit and / or the redox flow battery is connected to the power transmission and distribution network, in the charging cycle, the power conditioning unit can convert the input AC power into DC power of a suitable voltage and current. In addition, in the discharge cycle, the redox flow battery unit and / or the redox flow battery generates DC power, and the power conditioning unit can convert the aforementioned DC power into AC power of a voltage and frequency suitable for transmission to the power transmission and distribution network.

[0733] [Third Embodiment]

[0734] Next, a third embodiment will be described.

[0735] Patent document 1 discloses that: in order to improve the initial power efficiency, the cation exchange base layer and the anion exchange base layer are alternately stacked, but there is no disclosure about the thickness of the cation exchange base layer and the anion exchange base layer except for the examples. In addition, although the preferred range of the ion exchange capacity of the ion exchange membrane composed of an ion exchange layer having ion exchange groups and a porous support layer not having ion exchange groups is disclosed, there is no record about the reasons for the preferred range and the preferred embodiments. It should be noted that in the embodiments, there is no disclosure about the ion exchange capacity of the copolymer having structural formula (1) in patent document 1. In addition, it is disclosed that the cation exchange base layer in the ion exchange base layer can be arranged on the cathode liquid side, which can increase the life of the ion exchange base layer, but there is no disclosure about the arrangement of the anion exchange base layer.

[0736] Patent document 2 discloses the modification of Nafion (registered trademark) 117 using heterocyclic molecules containing multiple nitrogens, but the membrane thickness of Nafion (registered trademark) 117 is large, so even if it has the same proton area resistivity, it is required to be a lower proton area resistivity when actually used in redox flow batteries. In addition, although it is also disclosed to use a support body for thin filming, the proton area resistivity of Nafion (registered trademark) 117 becomes larger, and when it is actually used in redox flow batteries, it is required to be a lower proton area resistivity as described above. It should be noted that there is no disclosure about the use of the disclosed membrane to make the redox flow battery work. In addition, although it is disclosed that one side of the heterocyclic molecule containing multiple nitrogens is optionally located near the negative half-cell of the battery to improve the performance of the membrane, there is no record of what kind of performance is improved, and it is not disclosed in the examples. It should be noted that there is no disclosure about the thickness of the heterocyclic molecule containing multiple nitrogens in the membrane.

[0737] Patent document 3 discloses that in order to improve at least one of the characteristics of discharge capacity, current efficiency, voltage efficiency, and power efficiency, a metal layer, i.e., an anti-crossing layer, is provided inside the polymer electrolyte membrane by reducing a cationic metal, but higher characteristics are required. In addition, regarding the thickness of the formed metal layer, it is disclosed that the preferred range is greater than 10 μm and less than 50 μm. There is no disclosure about the preferred range of the equivalent weight (Equivalent Weight, hereinafter also referred to as "EW") of the polymer electrolyte membrane. Regarding the position of the anti-crossing layer inside the polymer electrolyte membrane, it is disclosed that it is located at a distance of more than 10% and less than 90% of the thickness of the electrolyte membrane from the surface of the polymer electrolyte membrane. However, it is not disclosed whether the anti-crossing layer faces the positive electrode or the negative electrode when a flow battery is made.

[0738] Patent Document 4 discloses that in order to suppress curling, the value obtained by dividing the thickness of the first ion exchange resin layer by the thickness of the second ion exchange resin layer is set to be greater than 0.7 and less than 1.3, indicating that the thickness of the first ion exchange resin layer is equal to that of the second ion exchange resin layer, that is, the anion exchange resin layer is located in the center of the thickness direction of the entire membrane. In addition, even if the thickness of the first ion exchange resin layer is different from that of the second ion exchange resin layer, it is not disclosed at all whether the anion exchange resin layer is arranged on the positive electrode or the negative electrode in the redox flow battery unit.

[0739] The subject of the present embodiment relates to a method for producing a redox battery cell, a redox flow battery, and a separator having high power efficiency.

[0740] The present inventors have conducted intensive research on the above-mentioned subject, and as a result, found that when the diaphragm constituting the redox flow battery cell includes at least a first cation exchange resin layer and an anion exchange resin layer, and the anion exchange resin layer is located on the electrode side that functions as the negative electrode, surprisingly, higher power efficiency can be obtained compared to the case where the anion exchange resin layer is located on the electrode side that functions as the positive electrode. Furthermore, it was found that particularly high power efficiency can be obtained by setting the equivalent weight of the diaphragm and the thickness of the anion exchange resin layer within a specific range.

[0741] The redox flow battery cell of this embodiment includes:

[0742] a first electrolyte solution containing a first redox active material,

[0743] a second electrolyte solution containing a second redox active material,

[0744] a first electrode in contact with the first electrolyte,

[0745] a second electrode in contact with the second electrolyte, and

[0746] a separator disposed between the first electrolyte and the second electrolyte,

[0747] The separator comprises at least a first cation exchange resin layer and an anion exchange resin layer.

[0748] The equivalent weight of the above-mentioned separator is 1150 g / eq or less,

[0749] The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm.

[0750] The anion exchange resin layer of the separator is disposed on the electrode side functioning as the negative electrode.

[0751] According to the present embodiment, it is possible to provide a redox battery cell, a redox flow battery, and a method for manufacturing a separator having high power efficiency.

[0752] <Cell for redox flow battery>

[0753] The redox flow battery unit of the present embodiment comprises: a first electrolyte containing a first redox active substance, a second electrolyte containing a second redox active substance, a first electrode in contact with the first electrolyte, a second electrode in contact with the second electrolyte, and a diaphragm disposed between the first electrolyte and the second electrolyte. It should be noted that it may also include elements other than the aforementioned constituent elements commonly used by those skilled in the art, as well as elements known from known information such as known literature and patents related to the redox flow battery unit. If the aforementioned elements are exemplified, bipolar plates, frames, compressible seals, conductive additives, balancing units, etc. may be listed.

[0754] Figure 1 An example of a schematic diagram of a redox flow battery cell according to the present embodiment is shown. The redox flow battery cell 10 according to the present embodiment includes an electrolytic cell 6, wherein the electrolytic cell 6 includes an electrode 1 ( Figure 1 The positive electrode is a cell 2, and an electrode 3 ( Figure 1The present invention relates to a cell chamber 4 (a negative electrode in the cell chamber), and a diaphragm 5 as a diaphragm that separates the cell chamber 2 from the cell chamber 4. The cell chamber 2 and the cell chamber 4 contain an electrolyte containing a redox active substance. The electrolyte containing the redox active substance is stored in, for example, an electrolyte tank 7 and a tank 8, respectively, and is supplied to each cell chamber by a pump or the like. In addition, the current generated by the redox flow battery cell can be converted from DC to AC via an AC / DC conversion device 9, or from AC to DC via an AC / DC conversion device 9, to charge the redox flow battery cell. The redox flow battery cell of this embodiment is preferably a redox flow secondary battery cell.

[0755] <Electrolyte>

[0756] The electrolytic solution in the present embodiment is a liquid containing a redox active material and a solvent.

[0757] The redox active material refers to a material having a redox activity directly related to the electromotive force in the redox flow battery unit. The redox active material used in the present embodiment is not particularly limited, and metal redox active materials, non-metal redox active materials, organic redox active materials, etc. can be listed, and they can be neutral compounds or ionic compounds.

[0758] The metal redox active material is a material comprising at least one metal atom, and may comprise a plurality of metal atoms of the same kind, or may comprise a plurality of metals of different kinds. The metal atom used in the metal redox active material is not particularly limited, and may include aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin, lead and cerium, among which titanium, vanadium, chromium, manganese, iron and cerium are preferred. In addition, from the viewpoint that the first redox active material and the second redox active material can be the same kind, vanadium, iron, copper and tin are preferred, vanadium and iron are further preferred, and vanadium is particularly preferred.

[0759] The metal redox active material may have a commonly used active material ligand, and if the ligand is exemplified, cyanide ion, acetylacetone, ethylenediamine, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, carbon monoxide, bipyridine, bipyrazine, ethylene glycol, propylene glycol, ethanedithiol, butanedithiol, terpyridine, diethylenetriamine, triazacyclononane, tris(hydroxymethyl)aminomethane, ascorbic acid, citric acid, glycolic acid, gluconic acid, acetic acid, formic acid, benzoic acid, malic acid, maleic acid, phthalic acid, sarcosine, salicylic acid, oxalic acid, urea, aminophenol salts, and lactic acid, etc. The active material ligand may be used alone or in combination.

[0760] The substance used for the non-metallic redox active material is not particularly limited, and examples thereof include chlorine, bromine, sulfur, and polysulfide.

[0761] The organic redox active material is not particularly limited, and examples thereof include viologen, its derivatives, and compounds having a viologen structure in a polymer side chain; 2,2,6,6-tetramethyl-1-piperidinyloxy free radical, its derivatives, and compounds having a 2,2,6,6-tetramethyl-1-piperidinyloxy free radical structure in a polymer side chain; ferrocene, its derivatives, and compounds having a ferrocene structure in a polymer side chain; quinone, its derivatives, and compounds having a quinone structure in a polymer side chain; anthraquinone, its derivatives, and compounds having an anthraquinone structure in a polymer side chain; quinoxaline, its derivatives, and compounds having a quinoxaline structure in a polymer side chain, etc. The redox active material may be used alone or in combination of multiple types.

[0762] When the aforementioned redox active material is used for a redox flow battery cell, the redox active material used in the electrolyte of the positive electrode and the redox active material used in the electrolyte of the negative electrode can be used in combination according to the desired characteristics. As a combination of redox active materials, it is not particularly limited, and combinations such as vanadium / vanadium, iron / iron, lead / lead, copper / copper, iron / chromium, chromium / bromine, zinc / bromine, polysulfide / bromine, zinc / cerium, zinc / nickel, zinc / cerium, zinc / iodine, titanium / manganese, vanadium / cerium, and vanadium / manganese can be listed. Among these, from the aspect of obtaining high electromotive force and excellent stability in charge and discharge, preferably vanadium / vanadium, iron / iron, iron / chromium, chromium / bromine, zinc / bromine, titanium / manganese, more preferably vanadium / vanadium, iron / iron, zinc / bromine, particularly preferably vanadium / vanadium.

[0763] When the redox active materials of the positive electrode and the negative electrode are both vanadium, it is also expressed as a vanadium redox flow battery cell or a vanadium redox flow battery. In addition, when the redox active materials of the positive electrode and the negative electrode are both vanadium, by using VO 2+ / VO2 + , use V in the negative electrode 2+ / V 3+ The redox pair is charged and discharged by redox reaction. During charging, the protons (H+) in the positive electrode cell become excessive due to the redox reaction, while the protons (H+) in the negative electrode cell are insufficient. The separator selectively moves the excess protons in the positive electrode cell to the negative electrode cell to maintain electrical neutrality. During discharge, the opposite reaction occurs to maintain electrical neutrality.

[0764] The solvent used in the electrolyte is not particularly limited, and examples thereof include water, alcohols, nitriles, esters, ketones, ethers, aliphatic hydrocarbons, aromatic hydrocarbons, etc. Among these, water is preferred from the viewpoint of improving the safety of the redox flow battery cell during operation.

[0765] If the above-mentioned solvents are given as specific examples, they include alcohols such as methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, and glycerol; nitriles such as acetonitrile, propionitrile, and benzonitrile; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as diethyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, ethylene glycol diethyl ether, and diethylene glycol dimethyl ether; aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, octane, chloroform, dichloromethane, and tetrachloromethane; aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, phenol, and cresol, etc.

[0766] The solvent used in the electrolyte may be a single type or a combination of two or more types.

[0767] An electrolyte may be further used in the electrolyte. The electrolyte is a substance that dissociates into ions in the electrolyte and improves the conductivity of the electrolyte. The electrolyte is not particularly limited, and examples thereof include sulfuric acid, hydrochloric acid, nitric acid, acetic acid, phosphoric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium acetate, and the like.

[0768] The electrolyte used in the electrolytic solution may be a single type or a combination of two or more types.

[0769] Additives can be added to the electrolyte according to the desired characteristics of the electrolyte. As additives, there are no particular limitations, and ethylene glycol, diethylene glycol, polyethylene glycol, glycerol, mannitol, sorbitol, pentaerythritol, tris (hydroxymethyl) aminomethane, corn starch, corn syrup, gelatin, glycerol, guar gum, pectin, surfactants, etc. can be listed.

[0770] The additives used in the electrolyte may be a single type or a combination of two or more types.

[0771] <Electrode>

[0772] The electrode used in the redox flow battery unit of the present embodiment is not particularly limited, and is preferably a carbon electrode. As a carbon electrode, in order to allow the electrolyte to pass through, it is preferably a continuous void, and more preferably a porous body with continuous voids. As a carbon electrode with continuous voids, for example, carbon felt, carbon paper, carbon foam, carbon cloth, carbon knitted fabric, carbon nanofiber sheet, activated carbon fiber sheet, etc. can be listed, preferably carbon felt, carbon paper, carbon foam. Among these, carbon foam is preferred from the viewpoint of being able to reduce resistance due to high flexibility and large surface area. The carbon foam preferably has a three-dimensional continuous structure of the carbon part. From the aspect of being able to achieve high flexibility and high surface area, thereby obtaining high power efficiency, the carbon foam preferably has a linear portion and a bonding portion that combines the aforementioned linear portions.

[0773] Specific examples of carbon felt and carbon paper include SIGRACET (registered trademark) KFD series, GFA series, GFD series, SGL series and SIGRACET (registered trademark) series manufactured by SGL CARBON, carbon felt (e.g., XF30A, BW-309) manufactured by Toyobo Co., Ltd., CARBORON (registered trademark) GF series (e.g., GF-20, GF-3F) manufactured by Nippon Carbon Co., Ltd., TORAYCA (trademark) TGP series manufactured by Toray Industries, Ltd., PYROFIL (trademark) series, GRAFIL (trademark) series manufactured by Mitsubishi Chemical Corporation, VGCF (registered trademark) sheet manufactured by Showa Denko K.K., carbon felt and graphite felt manufactured by MERSEN, etc. These may be subjected to activation treatment such as oxidation as needed.

[0774] Carbon foam can be produced by a known method (International Patent Application Publication No. 2018 / 096895, International Patent Application Publication No. 2018 / 168741, and International Patent Application Publication No. 2020 / 045645).

[0775] The first electrode and the second electrode may be a single electrode or different electrodes, and the first electrode and / or the second electrode may be a single electrode or a combination of multiple electrodes.

[0776] <Diaphragm>

[0777] In this embodiment, the diaphragm is a membrane arranged between the first electrolyte and the second electrolyte, and has at least a first cation exchange resin layer and an anion exchange resin layer. The equivalent weight of the above-mentioned diaphragm is less than 1150g / eq, and the thickness of the above-mentioned anion exchange resin layer is greater than 0.001μm and less than 5μm. In the unit for redox flow battery, the anion exchange resin layer of the above-mentioned diaphragm is arranged on the electrode side that acts as the negative electrode.

[0778] The equivalent weight of the diaphragm is not particularly limited, but is preferably less than 1150 g / eq, more preferably less than 1100 g / eq, from the perspective of a tendency to reduce the movement resistance of protons and improve power efficiency. From the perspective of a tendency to improve the hydrophilicity of the diaphragm, it is more preferably less than 1050 g / eq, particularly preferably less than 1030 g / eq, and further particularly preferably less than 1000 g / eq. From the perspective of a tendency to improve the solubility of the diaphragm in the electrolyte, it is preferably more than 500 g / eq, more preferably more than 700 g / eq. From the perspective of a tendency to improve the mechanical strength of the diaphragm, such as pulsation of the electrolyte, contact with the electrode, etc., it is further preferably more than 800 g / eq, particularly preferably more than 880 g / eq.

[0779] It should be noted that the equivalent weight refers to the dry mass grams of the ion exchange resin relative to each 1 equivalent of the ion exchange group with ion exchange capacity in the ion exchange resin as a resin with ion exchange capacity, and in the first cation exchange resin layer, refers to the dry mass grams of the first cation exchange resin layer relative to each 1 equivalent of the ion exchange group possessed by the first cation exchange resin layer. Hereinafter, the expression of equivalent weight is appropriately used in this embodiment. In addition, in the determination of equivalent weight, the following method can be used: salt replacement is carried out on the ion exchange resin, and the solution is back-titrated using an alkaline solution. The equivalent weight can be appropriately adjusted by the copolymerization ratio of the monomers as the raw materials of the ion exchange resin, the selection of monomer types, etc.

[0780] In the present embodiment, the anion exchange resin layer contained in the diaphragm is preferably arranged on the electrode side that functions as the negative electrode, preferably arranged in the vicinity of the electrode side. Proximity means that the distance of the anion exchange resin layer relative to the electrode that functions as the negative electrode is smaller than the distance relative to the electrode that functions as the positive electrode. In the present application, the inventors found that by configuring the anion exchange resin layer on the electrode side that functions as the negative electrode, the power efficiency is surprisingly improved. The reason for the improvement in power efficiency is still uncertain, but it is speculated that the amount of redox active substances moving from the positive electrode to the negative electrode is different from the amount of redox active substances moving from the negative electrode to the positive electrode, and the anion exchange resin layer functions more effectively relative to any redox active substance that moves more. It should be noted that it is speculated that due to the influence of configuring the anion exchange resin layer on the electrode side that functions as the negative electrode, the amount of redox active substances moving from the negative electrode to the positive electrode is effectively played.

[0781] The distance D between the anion exchange resin layer of the separator and the electrode functioning as the negative electrode neg The distance D between the anion exchange resin layer of the separator and the electrode functioning as the positive electrodepos The following relationship is preferably shown.

[0782] D neg / D pos <1

[0783] Here, the distance D neg It refers to the distance from the surface of the anion exchange resin layer closest to the negative electrode to the surface closest to the negative electrode. pos It refers to the distance from the surface of the anion exchange resin layer closest to the positive electrode to the surface closest to the positive electrode.

[0784] From the perspective of further improving power efficiency, D neg / D pos It is preferably 0.8 or less, more preferably 0.7 or less, further preferably 0.6 or less, and more preferably 0.5 or less. neg / D pos The lower limit of is not particularly limited, and may be, for example, greater than or equal to 0. That is, the anion exchange resin layer may be in contact with the negative electrode.

[0785] From the viewpoint of further improving power efficiency, the first cation exchange resin layer is preferably disposed closer to the electrode functioning as the positive electrode than the anion exchange resin layer.

[0786] <First Cation Exchange Resin Layer>

[0787] The first cation exchange resin layer is a layer formed of a substance containing a resin (hereinafter also referred to as a “cation exchange resin”) having an ion exchange capacity for cations (hereinafter also referred to as “Cation”).

[0788] The cation exchange resin is not particularly limited, and examples thereof include hydrocarbon resins and fluororesins. From the viewpoint of reducing the manufacturing cost of the redox flow battery cell, hydrocarbon resins are preferred, and from the viewpoint of improving the durability of the redox flow battery cell, fluororesins are preferred.

[0789] The hydrocarbon resin and the fluororesin may be used alone or in combination.

[0790] The functional groups having ion exchange capacity contained in the cation exchange resin are not particularly limited, and examples thereof include sulfonic group (SO3H), carboxyl group (CO2H), phenolic hydroxyl group (OH), phosphate group (PO3H2), thiol group (SH), and functional groups in which the hydrogen of the aforementioned functional groups is replaced by an alkali metal, an alkaline earth metal, or a transition metal.

[0791] The functional group having an ion exchange ability may be used alone or in combination of two or more.

[0792] Among the functional groups having ion exchange ability, a sulfo group, a carboxyl group and / or a phosphoric acid group is preferred, a sulfo group and / or a carboxyl group is more preferred, and a sulfo group is particularly preferred because they tend to have excellent ion exchange ability.

[0793] The hydrocarbon resin is not particularly limited, and examples thereof include resins containing functional groups having the aforementioned ion exchange capacity, such as polystyrene, polyphenylene ether, polybenzimidazole, polyetheretherketone, polyimide, polyetherimide, polyaryletherketone, polysulfone, polyethersulfone, polyphenylene sulfide, and polyphenylsulfone. The aforementioned resins may be cross-linked or may form copolymers according to the required physical properties, and may also have various substituents (e.g., halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms; aliphatic hydrocarbon groups such as nitrile groups, methyl groups, ethyl groups, vinyl groups, allyl groups, 1-methylvinyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, and tert-butyl groups; aromatic hydrocarbon groups such as benzyl groups, phenyl groups, and nitrile-substituted phenyl groups; amino groups; nitro groups; hydroxyl groups; silyl groups, etc.).

[0794] The hydrocarbon-based resin may be used alone or in combination of two or more.

[0795] The fluororesin is not particularly limited, and examples thereof include partially fluorinated resins and perfluorinated resins containing the aforementioned functional group having ion exchange ability. Examples of partially fluorinated resins and perfluorinated resins include resins in which not all hydrogen atoms on carbon contained in the aforementioned hydrocarbon-based cation exchange resin are replaced by fluorine atoms, but at least one hydrogen atom, and resins in which all hydrogen atoms on carbon are replaced by fluorine atoms.

[0796] As the fluororesin, a fluororesin having a structural unit represented by the general formula G1 (hereinafter also referred to as “fluororesin G1”) is preferred because the durability of the redox flow battery cell tends to be improved.

[0797]

[0798] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0799] The equivalent weight of the first cation exchange resin layer is not particularly limited, but is preferably less than 1100 g / eq, more preferably less than 1050 g / eq, from the perspective of a tendency to reduce the migration resistance of protons and improve power efficiency. Furthermore, from the perspective of a tendency to improve the hydrophilicity of the first cation exchange resin layer, it is more preferably less than 1030 g / eq, and particularly preferably less than 1000. From the perspective of a tendency to improve the solubility in the electrolyte, it is preferably more than 500 g / eq, and more preferably more than 700 g / eq. Furthermore, from the perspective of a tendency to improve the mechanical strength of the pulsation of the electrolyte, the contact with the electrode, etc., it is further preferably more than 800 g / eq, and particularly preferably more than 880 g / eq.

[0800] The thickness of the first cation exchange resin layer is not particularly limited, but is preferably 1 μm or more and 150 μm or less. From the perspective of a tendency to reduce proton transfer resistance and improve power efficiency, it is more preferably 100 μm or less, further preferably 80 μm or less, and particularly preferably 60 μm or less. From the perspective of a tendency to improve mechanical strength such as pulsation of the electrolyte and contact with the electrode, it is more preferably 5 μm or more, further preferably 10 μm or more, particularly preferably 20 μm or more, and further particularly preferably 25 μm or more.

[0801] The content of the cation exchange resin in the first ion exchange resin layer is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. The upper limit of the content of the cation exchange resin is not particularly limited, but is preferably 100% by mass or less in the first ion exchange resin layer. From the perspective of being able to suppress the cost of removing substances different from the cation exchange resin in the first ion exchange resin layer and being able to suppress the cost of the redox flow battery unit, it is more preferably 99.5% by mass or less, and further preferably 99% by mass or less.

[0802] The manufacturing method of the first cation exchange resin layer of the diaphragm of the present embodiment is not particularly limited, and can be obtained by processing the cation exchange resin into a film, or by processing a cation exchange resin precursor having a functional group having ion exchange capacity by hydrolysis into a film and performing the aforementioned hydrolysis treatment and acid treatment. For example, the method of processing the cation exchange resin into a film by melt-kneading the cation exchange resin, using an extruder and using a nozzle or a die head to perform extrusion molding. Another method of forming an ion exchange group by melt-kneading the resin composition of the aforementioned cation exchange resin precursor, using an extruder and using a nozzle or a die head to perform extrusion molding, thereby forming a film, and then performing hydrolysis treatment and acid treatment. In addition, the cation exchange resin can be dispersed in a solvent and then cast on a substrate to form a film.

[0803] The method for producing the fluororesin film G1 is as described above.

[0804] <Anion Exchange Resin Layer>

[0805] The anion exchange resin layer is a layer containing an anion exchange compound. The anion exchange compound refers to a compound having a functional group and molecular structure containing a nitrogen atom such as a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a pyridine ring structure and its derivative structure, a pyridinium group, an imidazole ring structure and its derivative structure, an imidazolium group, a pyrrole ring structure and its derivative structure, and is a compound that is positively charged at least under acidic conditions.

[0806] The separator of this embodiment has an anion exchange resin layer, which can provide the separator with electrostatic repulsion to cations in the electrolyte, inhibit redox active substances with high charge density from penetrating the separator and allow protons with low charge density to pass through the separator, thereby improving power efficiency.

[0807] The anion exchange compound is not particularly limited, and examples thereof include polyvinylpyridine polymers and salts thereof, vinylpyridine / divinylbenzene copolymers and salts thereof, vinylpyridine / styrene copolymers and salts thereof, polyethyleneimine and salts thereof, vinylbenzyltrimethylammonium chloride polymers, polyvinylimidazole polymers and salts thereof, vinylimidazole / divinylbenzene copolymers and salts thereof, vinylimidazole / styrene copolymers and salts thereof, polyvinylpyrrolidone polymers and salts thereof, polybenzimidazole and salts thereof, polymers having a benzimidazole structure and salts thereof, polypyrrole and salts thereof, polyaniline, poly(4-aminostyrene) and salts thereof, anion exchange polymers such as poly(vinylcarbazole) and salts thereof, quaternary ammonium compounds having a quaternary ammonium group such as tetrabutylammonium and octyltrimethylammonium, pyridinium compounds having a pyridinium structure such as butylpyridinium and derivatives thereof, trimethylamine and salts thereof, triethylamine and salts thereof, tributylamine and salts thereof, Triethanolamine and its salts, pyrrole and its salts, pyrrole derivatives and their salts, 1,8-diazabicyclo[5.4.0]undecene-7 and its salts, 1,5-diazabicyclo[4.3.0]nonene-5 and its salts, 1,4-diazabicyclo[2.2.2]octane and its salts, 1-azabicyclo[2.2.2.]octane and its salts, N,N,N',N'-tetramethylbutanediamine and its salts, ethylenediamine, N,N-dimethylethylenediamine, N -Methylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyldipropylenetriamine, 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, 4-aminopyridine, 1,2,3-triaminobenzene, hexamethylenetetramine, imidazole, oxazole, thiazole, pyrazole, aminobenzimidazole, 4-aminopiperidine, tetrafluoro-p-phenylenediamine, hexamethylenediamine, 4,4'-diaminodiphenyl ether, 4-benzylpyridine, etc.

[0808] The anion exchange compound may be an anion exchange fluororesin represented by the following general formula B17, a saponified product thereof, or a salt thereof.

[0809] -[CFX 1 CX 2 X 3 ] a -[CF2-CF((-O-CF2-(CF(CF2X 4 ))) b -O c -(CFR 1 ) d -(CFR 2 ) e -(CF2) f -Ae)] g -[B17]

[0810] (Where X 1 , X 2 , X3 and X 4 Optionally the same or different, are a halogen atom and a perfluoroalkyl group having 1 to 10 carbon atoms which may be substituted or unsubstituted, or a cyclic perfluoroalkyl group. As the aforementioned halogen atom, it is a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. X 1 and X 2 , or X 1 and X 3 may be a cyclic structure. R 1 , R 2 Optionally the same or different, are a hydrogen atom, a halogen atom, a perfluoroalkyl group having 1 to 10 carbon atoms which may be substituted or unsubstituted, and a fluorochloroalkyl group. As the aforementioned halogen atom, it is a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Ae is -CONX 6 Ax, -SO2NX 6 a monovalent group represented by the chemical formula of Ax, X 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms which may be substituted or unsubstituted, or an aromatic hydrocarbon group. Ax is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heteroaromatic group having 1 to 20 carbon atoms which may be substituted or unsubstituted and contains at least 1 nitrogen atom. a and g represent molar ratios in all structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1. b is an integer from 0 to 8. c is 0 or 1. d, e, and f are optionally the same or different and are integers from 0 to 6 (wherein when d, e, and f are all 0, Ae is -CF(CF2Az)2, and Az is -CONX 6 Ax, -SO2NX 6 a monovalent group represented by the chemical formula of Ax, Ax and X 6 are the same as those described above.)

[0811] The anion-exchangeable compound may be used alone or in combination of multiple kinds.

[0812] It should be noted that the substituents in the case of "substituted" are the same as the substituents exemplified in General Formula 1.

[0813] As the anion exchange compound, from the aspect of suppressing dissolution in the electrolyte and improving the durability of the redox flow battery unit, it is preferably selected from polyvinyl pyridine polymers and salts thereof, vinyl pyridine / divinylbenzene copolymers and salts thereof, vinyl pyridine / styrene copolymers and salts thereof, polyethylene imine and salts thereof, vinyl benzyl trimethyl ammonium chloride polymers, polyvinyl imidazole polymers and salts thereof, vinyl imidazole / divinylbenzene copolymers and salts thereof, vinyl imidazole / styrene copolymers and salts thereof, polyvinyl pyrrolidone polymers and salts thereof, polybenzimidazole and salts thereof, polymers having a benzimidazole structure and salts thereof, polypyrrole and salts thereof, polyaniline, poly(4- The present invention further comprises at least one anion exchange compound selected from the group consisting of polyvinylpyridine polymers and salts thereof, vinylpyridine / divinylbenzene copolymers and salts thereof, vinylpyridine / styrene copolymers and salts thereof, polyvinylimidazole polymers and salts thereof, vinylimidazole / divinylbenzene copolymers and salts thereof, vinylimidazole / styrene copolymers and salts thereof, polybenzimidazole and salts thereof, polymers having a benzimidazole structure and salts thereof, and anion exchange fluororesins represented by the general formula B17, and more preferably at least one anion exchange compound selected from the group consisting of polyvinylpyridine polymers and salts thereof, vinylpyridine / divinylbenzene copolymers and salts thereof, vinylpyridine / styrene copolymers and salts thereof, polyvinylimidazole polymers and salts thereof, vinylimidazole / divinylbenzene copolymers and salts thereof, vinylimidazole / styrene copolymers and salts thereof, polybenzimidazole and salts thereof, polymers having a benzimidazole structure and salts thereof, and anion exchange fluororesins represented by the general formula B17. From the perspective of increasing the electrostatic repulsion of the anion exchange resin layer to cations and tending to improve the power efficiency of the redox flow battery unit, it is further preferred to use at least one anion exchange compound selected from the group consisting of polyvinyl pyridine polymers and their salts, polyvinyl imidazole polymers and their salts, polybenzimidazole and their salts, polymers having a benzimidazole structure and their salts, and anion exchange fluororesins represented by the general formula B17, and particularly preferred is at least one anion exchange compound selected from the group consisting of polyvinyl pyridine polymers and their salts, polyvinyl imidazole polymers and their salts, and anion exchange fluororesins represented by the general formula B17.

[0814] The saponified product of the anion exchange fluororesin represented by the general formula B17 is a saponified product obtained by reacting the anion exchange fluororesin with an alkaline substance. Examples of the alkaline substance include amine compounds such as dimethylamine, diethylamine, monomethylamine, and monoethylamine; alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and alkaline earth metal hydroxides. Among these, sodium hydroxide or potassium hydroxide is preferred.

[0815] The salt of the anion exchange fluororesin is a salt of the anion exchange fluororesin and an acidic substance. Examples of the acidic substance include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as oxalic acid, acetic acid, formic acid, and trifluoroacetic acid.

[0816] Among the anion exchange resins represented by the above-mentioned general formula B17 that can be used as anion exchange compounds, from the viewpoint of a tendency for the chemical stability of the anion exchange fluororesin, such as resistance to oxidative degradation, to be improved, and from the viewpoint of a tendency for the manufacturing cost of the anion exchange fluororesin to be suppressed and the manufacturing cost of the unit for redox flow battery to be suppressed, it is preferred that the anion exchange fluororesin comprises a structural unit represented by the following general formula B16, and at least one selected from the group consisting of a structural unit represented by the following general formula B18, a structural unit represented by the following general formula B19, and a structural unit represented by the following general formula B20.

[0817] -(CF2-CF2)-[B16]

[0818] -(CF2-CF(-O-(CF2CFXO) N -Ag))-[B18]

[0819] (wherein, X represents F or a perfluoroalkyl group having 1 to 3 carbon atoms. Ag represents (CF2) M -SO2NX 6 Ax(X 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group, or a heteroaromatic group containing at least one nitrogen atom. N represents an integer of 0 to 5. M represents an integer of 0 to 6. Wherein N and M are not 0 at the same time.))

[0820] -(CF2-CF(-O-(CF2) P -CFX(-O-(CF2) K -SO2NX 6 Ax)))-[B19]

[0821] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aromatic hydrocarbon group, and Ax is a substituted or unsubstituted aliphatic hydrocarbon group with 1 to 20 carbon atoms, an aromatic hydrocarbon group, or a heteroaromatic group containing at least one nitrogen atom. P represents an integer of 0 to 12, and K represents an integer of 1 to 5. P and K are not 0 at the same time.)

[0822] -(CF2-CF(-O-(CF2) Q -CFX(-(CF2) L -O-(CF2) o -SO2NX 6 Ax)))-[B20]

[0823] (In the formula, X represents a perfluoroalkyl group having 1 to 3 carbon atoms. X 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms which may be substituted or unsubstituted, or an aromatic hydrocarbon group, Ax is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heteroaromatic group having 1 to 20 carbon atoms which may be substituted or unsubstituted and contains at least 1 nitrogen atom. Q represents an integer of 0 to 12, L represents an integer of 1 to 5, and o represents an integer of 0 to 6. Among them, Q and O are not 0 at the same time).

[0824] The anion-exchangeable fluororesin more preferably contains a structural unit represented by the general formula B16 and at least one selected from the group consisting of a structural unit represented by the general formula B18, a structural unit represented by the general formula B19, and a structural unit represented by the general formula B20. From the same viewpoint, it is further preferred to contain a structural unit represented by the general formula B16 and a structural unit represented by the general formula B18 (wherein X is F or trifluoromethyl, n is an integer of 0 to 2, and m is an integer of 1 to 4). Particularly preferably, it contains a structural unit represented by the general formula B16 and a structural unit represented by the general formula B18 (wherein X is F or trifluoromethyl, n is 0 or 1, and m is an integer of 2 to 4).

[0825] The anion-exchangeable fluororesin more preferably has a structural unit represented by the following general formula B21, and further preferably has a structural unit represented by the following general formula B22.

[0826] -[CF2CF2] a -[CF2-CF((-O-CF2-(CF(CF3))) b -O-(CF2)2-SO2NX 6 Ax)] g -[B21]

[0827] (In the formula, X 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, Ax is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heteroaromatic group having 1 to 20 carbon atoms which may be substituted or unsubstituted and contains at least 1 nitrogen atom. a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1. b is 0 or 1).

[0828] -[CF2CF2] a -[CF2-CF((-O-CF2-(CF(CF3)))-O-(CF2)2-SO2NX 6 Ax)] g -[B22]

[0829] (wherein X 6 is a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms which may be substituted or unsubstituted, or an aromatic hydrocarbon group, and Ax is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heteroaromatic group having 1 to 20 carbon atoms which may be substituted or unsubstituted and contains at least 1 nitrogen atom. a and g represent molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1.)

[0830] In the above general formulas B17 to B22, from the aspect of easy manufacture of the anion-exchangeable fluororesin and a tendency to be able to suppress the manufacturing cost of the unit for the redox flow battery, X 6 is preferably a hydrogen atom or an aliphatic hydrocarbon group having 1 to 10 carbon atoms which may be substituted or unsubstituted. From the viewpoint of further suppressing the manufacturing cost of the anion-exchangeable fluororesin, it is more preferably a hydrogen atom, and from the viewpoint of improving the stability of the anion-exchangeable fluororesin under alkaline conditions, it is more preferably an unsubstituted aliphatic hydrocarbon group having 1 to 2 carbon atoms.)

[0831] In the above general formulas B17 to B22, from the aspect of reducing the cost of raw materials and a tendency to be able to suppress the manufacturing cost of the unit for the redox flow battery, Ax is preferably an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heteroaromatic group having 1 to 20 carbon atoms which may be unsubstituted and contains at least 1 nitrogen atom, and more preferably an aliphatic hydrocarbon group having 1 to 10 carbon atoms which may be unsubstituted and contains at least 1 nitrogen atom, or a heteroaromatic group. As a more specifically preferred structure of the nitrogen atom contained in Ax, it is a primary amino group, a secondary amino group, a tertiary amino group, a pyridine ring structure and its derivative structure, a pyridinium group, an imidazole ring structure and its derivative structure, an imidazolium group, a pyrrole ring structure and its derivative structure, and more preferably a tertiary amino group, a pyridine ring structure and its derivative structure, an imidazole ring structure and its derivative structure.)

[0832] As a method for manufacturing the anion-exchangeable fluororesin, there is no particular limitation, and examples thereof include a method of reacting the aforementioned fluororesin precursor with the aforementioned anion-exchangeable compound (hereinafter also referred to as "modifying compound") that does not include the anion-exchangeable fluororesin.)

[0833] As the modifying compound, examples thereof include a modifying compound having at least 2 nitrogen atom-containing groups, and the aforementioned nitrogen atom-containing groups include at least 1 kind selected from the group consisting of the following structures:

[0834] Primary amino group;

[0835] Secondary amino group;

[0836] Tertiary amino group;

[0837] An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound;

[0838] Heterocyclic structures containing nitrogen atoms;

[0839] A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; and

[0840] Quaternary ammonium group.

[0841] Among these, at least one nitrogen atom-containing group is preferably a primary amino group or a secondary amino group, and more preferably a primary amino group, because the reactivity with the fluororesin precursor tends to be improved. Among them, the quaternary ammonium group is a quaternary ammonium group different from the aforementioned amino salt structure or the aforementioned salt structure.

[0842] More specific examples of the modified compound include ethylenediamine, N-methylethylenediamine, N-ethylethylenediamine, N,N-dimethylethylenediamine, N,N'-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N-benzylethylenediamine, N,N-dibutylethylenediamine, 1,2-diphenylethylenediamine, N,N'-dicyclohexyl-1,2-ethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldiamine, Propylene triamine, N,N-dibutyl dipropylene triamine, N,N-diethyl-1,3-propylene diamine, N,N-dimethyl-1,4-butane diamine, N,N-diethyl-1,4-butane diamine, N,N-dimethyl-1,6-hexane diamine, N,N-dimethyl-1,4-cyclohexane diamine, 3-aminopiperidine, isophorone diamine, 4-(aminomethyl)piperidine, 3-aminopyrrolidine, 4-aminopiperidine, 3-aminopyrrole alkane, N,N-dimethyltrimethylenediamine, N,N-dibutyltrimethylenediamine, 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(ethylaminomethyl)pyridine, 4-(4-piperidinyl)pyridine, 2-methyltryptamine, 5-methoxytryptamine, 6-methoxytryptamine, necrostatin-1, alosetron, sulfonamide methoxypyridazine, 1-(3-chloroanilino) -4-phenylphthalazine, 4-amino-5-aminomethyl-2-methylpyrimidine, 2-(aminomethyl)-5-methylpyrazine, 2-(4-piperidinyl)benzimidazole, 2-(4-aminophenyl)benzimidazole, 5-amino-2-(4-aminophenyl)benzimidazole, 6-(aminomethyl)quinoline, 2-methyl-7-[phenyl(phenylamino)methyl]-8-hydroxyquinoline, 1-(2-amino-1-naphthyl)isoquinoline.

[0843] The modifying compound may be used alone or in combination of two or more.

[0844] As the modifying compound, ethylenediamine, N-methylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldipropylenetriamine, N,N-dibutyldipropylenetriamine, N,N-dimethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, N,N-dimethyltrimethylenediamine, N,N-dibutyltrimethylenediamine, 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(ethylaminomethyl)pyridine, 4-(2-aminoethyl)pyridine, 4-(4-piperidinyl)pyridine, 2-(4-piperidinyl)benzimidazole, 2-(4-aminophenyl)benzimidazole, 5-amino-2-(4-aminophenyl)benzimidazole, from monomers for redox flow batteries In view of the tendency of having a good balance in current efficiency, voltage efficiency and power efficiency when using redox flow batteries, more preferred are N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyldipropylenetriamine, N,N-dibutyldipropylenetriamine, N,N-dimethyl-1,4-butanediamine, N,N-dimethyl-1,6-hexanediamine, N,N-dimethyltrimethylenediamine, Preferably, the present invention further comprises 1-(3-aminopropyl)imidazole, 4-(2-aminoethyl)pyridine, 4-aminomethylpyridine, isonicotinamide, 4-(4-piperidyl)pyridine, and 2-(4-aminophenyl)benzimidazole. From the same viewpoint, more preferably, N,N-dimethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyldipropylenetriamine, N,N-dimethyltrimethylenediamine, 1-(3-aminopropyl)imidazole, 4-aminomethylpyridine, and 4-(2-aminoethyl)pyridine.

[0845] The anion exchange resin layer is preferably a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a polyetheretherketone resin, a polysulfone resin, a polyethersulfone resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a polyphenylene ether resin, a polyphenylene sulfide resin, a syndiotactic polystyrene resin, polyetherimide, a siloxane-modified polyetherimide resin, a polyamideimide resin, a cycloolefin resin, a cycloolefin copolymer, a polyetherketoneetherketoneketone resin, a polyallyletherketone resin, and a fluororesin, and may further contain a styrene resin, a vinyl chloride resin, a chlorinated polyethylene, a polyamide resin, a polyphenylene ether / polystyrene resin, a high-density polyethylene resin, a low-density polyethylene resin, a linear low-density polyethylene resin, a syndiotactic polystyrene resin, a cycloolefin resin, a cycloolefin copolymer, and a fluororesin represented by the above general formula G1.

[0846] The resin optionally contained in the anion exchange resin layer may be used alone or in combination of two or more.

[0847] From the viewpoint that the durability of the redox flow battery cell tends to be improved, fluororesins are preferred.

[0848] The content of the anion exchange compound contained in the anion exchange resin layer is not particularly limited, but is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more from the viewpoint of suppressing the tendency of the redox active substance to pass through the diaphragm. The upper limit of the content of the anion exchange compound contained in the anion exchange resin layer is not particularly limited, but is preferably 100% by mass or less. In the case where it is easy to obtain and the cost of forming the anion exchange resin layer can be reduced, it is more preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and further preferably 99% by mass or less.

[0849] When the anion exchange resin layer contains an anion exchange compound and a fluororesin, the content of the anion exchange compound contained in the anion exchange resin layer is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and particularly preferably 15% by mass or more from the viewpoint of increasing the tendency of suppressing the redox active substance to permeate the diaphragm. From the viewpoint of increasing the durability of the anion exchange resin layer, it is preferably 99% by mass or less, more preferably 90% by mass or less, further preferably 80% by mass or less, and particularly preferably 70% by mass or less.

[0850] The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm. From the perspective of reducing the resistance to proton transfer and improving power efficiency, it is preferably 4 μm or less, more preferably 3 μm or less, and more preferably 1.5 μm or less. From the perspective of inhibiting the redox active material from penetrating the diaphragm and improving power efficiency, it is preferably 0.01 μm or more, more preferably 0.02 μm or more, and particularly preferably 0.04 μm or more. From the perspective of improving the mechanical strength of the pulsation of the electrolyte and the contact with the electrode, it is more preferably 0.1 μm or more, particularly preferably 0.3 μm or more, and more particularly preferably 0.4 μm or more.

[0851] The method for producing a separator including at least a first cation exchange resin layer and an anion exchange resin layer according to the present embodiment can be produced by a process including a step of forming the first cation exchange resin layer and a step of forming the anion exchange resin layer.

[0852] The method for manufacturing the separator of the present embodiment preferably includes:

[0853] a step of reacting a fluororesin precursor layer as a precursor of the first cation exchange resin layer, the fluororesin precursor layer containing at least one selected from the group consisting of a halogenated sulfonyl group, an acyl halide group, and a halogenated phosphoric acid group, with a modifying compound having at least two nitrogen atom-containing groups; and

[0854] After the above step, a step of converting at least one selected from the group consisting of halogenated sulfonyl groups, acyl halide groups and halogenated phosphoric acid groups contained in the fluororesin precursor layer into at least one selected from the group consisting of sulfonic groups, carboxyl groups and phosphoric acid groups,

[0855] The nitrogen atom-containing group comprises at least one selected from the group consisting of the following structures:

[0856] Primary amino group;

[0857] Secondary amino group;

[0858] Tertiary amino group;

[0859] An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound;

[0860] Heterocyclic structures containing nitrogen atoms;

[0861] A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; and

[0862] Quaternary ammonium group.

[0863] Here, the quaternary ammonium group is a quaternary ammonium group different from the aforementioned amino salt structure and the aforementioned salt structure.

[0864] The fluororesin precursor layer is a layer that becomes a precursor of the first cation exchange resin layer, and is a layer containing at least one selected from the group consisting of a halogenated sulfonyl group, an acyl halide group, and a halogenated phosphoric acid group.

[0865] The method for producing the anion exchange resin layer is not particularly limited, and examples thereof include: a method in which the anion exchange compound or a mixture containing the anion exchange compound is molten, and extruded into a film using an extruder, a nozzle or a die, etc.; a method in which the anion exchange compound or a mixture containing the anion exchange compound is molten, and the solution is applied to a substrate using a die, a gravure roll, a doctor blade, or a sprayer, and dried, thereby processing the solution into a film.

[0866] After the anion exchange resin layer is formed, the separator can be manufactured by laminating the anion exchange resin layer and the first cation exchange resin layer. The lamination method is not particularly limited, and examples thereof include a method of laminating by heat pressing and / or heat roll pressing.

[0867] The diaphragm can also be manufactured by the following method: the above-mentioned fluororesin precursor is melt-kneaded, processed into a film by extrusion molding using an extruder and a nozzle or a die, and then brought into contact with a mixture containing a modifying compound to form a layer containing an anion exchange fluororesin, and then the fluororesin is formed by hydrolysis to form a layer containing the fluororesin to become the first cation exchange resin layer and a layer containing the anion exchange resin to become the anion exchange resin layer.

[0868] When manufacturing the separator, a substrate may be used. By using a substrate, the first cation exchange resin layer and / or the anion exchange resin layer may be manufactured more stably.

[0869] The material used for the aforementioned substrate is not particularly limited, and examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, cycloolefin polymers, polycarbonate, polyamide, polyimide, polyamideimide, polyvinyl chloride, polystyrene, polyphenylene ether, polyetheretherketone, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide resin, polyetherketoneetherketoneketone, and polyallyletherketone.

[0870] The above substances may be modified as necessary, and may be used alone or in combination of two or more.

[0871] The solvent used when the mixture containing the anion exchange compound is made into a solution is not particularly limited, and examples thereof include saturated hydrocarbon compounds such as n-pentane, n-hexane, n-octane, n-decane, cyclopentane, cyclohexane and cyclooctane; aromatic hydrocarbon compounds such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbon compounds such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, cyclohexanol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone and cyclohexanone; and ethyl Esters such as ethyl acetate, butyl acetate and methyl benzoate; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, etc.; polyols such as ethylene glycol, propylene glycol, glycerol and polymers of compounds having two hydroxyl groups in the polyols, and polyols; and esterified compounds of the aforementioned polymers, nitriles such as acrylonitrile and benzonitrile; nitromethane; N,N-dimethylformamide; dimethyl sulfoxide; hexamethylphosphoric triamide; carbon disulfide; fluorine-based compounds (for example, Novec (trademark) manufactured by 3M Company, Asahi Clean manufactured by Asahi Glass Co., Ltd., etc.), etc.

[0872] These solvents may be used alone or in combination of two or more.

[0873] <Second Cation Exchange Resin Layer>

[0874] The separator of this embodiment may further include a second cation exchange resin layer. In the above separator, the second cation exchange resin layer may include a first cation exchange resin layer, an anion exchange resin layer, and a second cation exchange resin layer in this order.

[0875] In the diaphragm using the second cation exchange resin layer, the thickness of the first cation exchange resin layer is greater than the thickness of the second cation exchange resin layer. The thickness of the second cation exchange resin layer is not particularly limited as long as it is a value less than the thickness of the first cation exchange layer, and is preferably 0.01 μm or more and less than 150 μm. From the perspective of a tendency to reduce proton transfer resistance and improve power efficiency, it is more preferably 100 μm or less, further preferably 50 μm or less, and particularly preferably 20 μm or less. From the perspective of a tendency to improve mechanical strength such as pulsation of the electrolyte and contact with the electrode, it is more preferably 0.1 μm or more, further preferably 0.5 μm or more, and particularly preferably 1 μm or more.

[0876] The value obtained by dividing the thickness of the second ion exchange resin layer by the thickness of the first cation exchange resin layer is not particularly limited, but is preferably less than 0.7. The anion exchange resin layer can be arranged closer to the electrode side that functions as the negative electrode. From the perspective of suppressing the redox active material from penetrating the diaphragm and having a tendency to improve power efficiency, it is more preferably less than 0.6, and further preferably less than 0.5. The value obtained by dividing the thickness of the second ion exchange resin layer by the thickness of the first cation exchange resin layer can be a value greater than 0. From the perspective of easier manufacture of the second ion exchange resin layer, it is preferably greater than 0.0001. From the perspective of a tendency to improve mechanical strength such as pulsation of the electrolyte and contact with the electrode, it is further preferably greater than 0.001, and particularly preferably greater than 0.01.

[0877] The second cation exchange resin layer is a layer formed of a substance containing a cation exchange resin, similarly to the first cation exchange resin layer. The cation exchange resin used for the second cation exchange resin layer is not particularly limited, and the cation exchange resin used is preferably the same as that of the first cation exchange resin layer. From the viewpoint of the tendency to improve the durability of the redox flow battery cell, the second cation exchange resin layer more preferably contains a fluorine-based cation exchange resin.

[0878] The cation exchange resin contained in the first cation exchange resin layer and the cation exchange resin contained in the second cation exchange resin layer may be the same as or different from each other.

[0879] The method for manufacturing the diaphragm having the first cation exchange resin layer, the anion exchange resin layer and the second cation exchange resin layer is not particularly limited, and examples thereof include: a method of manufacturing by melt-kneading the cation exchange resin to be the second cation exchange resin layer on a two-layer membrane having the first cation exchange resin layer and the anion exchange resin layer, and then extruding it using an extruder and using a nozzle or a die head, thereby processing it into a film shape; a method of manufacturing by melt-kneading the cation exchange resin precursor to be the second cation exchange resin layer, and then extruding it using an extruder and using a nozzle or a die head, thereby processing it into a film shape, and then performing the aforementioned hydrolysis treatment and acid treatment to form an ion exchange group; a method of manufacturing by dispersing the cation exchange resin to be the second cation exchange resin layer in a solvent and then casting it into a film shape, etc. In addition, it is also possible to manufacture by overlapping the two-layer membrane having two kinds of cation exchange resin layers and anion exchange resin layers with the anion exchange resin layer. When the stacking is performed, heat pressing and / or hot roll pressing may be used from the viewpoint of being able to reduce the tendency of the anion exchange resin layers to peel off from each other.

[0880] The diaphragm of the present embodiment may also use a support. As the support, there is no particular limitation, and examples thereof include a support formed by polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, cycloolefin polymer, polyamide, polyimide, polyamideimide, polyvinyl chloride, polystyrene, polyphenylene oxide, polyetheretherketone, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyetherimide, polyimide resin, polyetherketoneetherketoneketone, polyallyletherketone, fluororesin, etc.

[0881] It is preferable not to use a support because gaps may be generated between the cation exchange resin layer, the anion exchange resin layer, and the support, which may deteriorate the characteristics of the redox flow battery cell.

[0882] <Separator Electrode Assembly>

[0883] The diaphragm electrode assembly in the present embodiment is a structure in which at least one of the first electrode and the second electrode is joined to the diaphragm. The joining means that at least one of the first electrode and the second electrode is connected to the diaphragm, and by joining, at least one of the first electrode and the second electrode can be integrated with the diaphragm. For example, in a diaphragm electrode assembly having a first electrode, a second electrode and a diaphragm, when assembling a unit for a redox flow battery, there is no need to assemble the first electrode, the diaphragm and the second electrode in sequence, and it can be set as one process, which has a tendency to suppress manufacturing costs, and is therefore sometimes preferably used.

[0884] The method of bonding at least one of the first electrode and the second electrode to the separator is not particularly limited, and examples thereof include a method using heat pressing and / or heat roll pressing.

[0885] The temperature during the bonding is not particularly limited, but when the bonding between the diaphragm and the electrode is insufficient, the elastic modulus of the diaphragm will decrease, and from the perspective of the tendency to improve the bonding between the diaphragm and the electrode, it is preferably set to room temperature or above. From the perspective of the tendency to suppress the deterioration of the diaphragm, the temperature during the bonding is preferably 250°C or less, more preferably 200°C or less, further preferably 170°C or less, and particularly preferably 150°C or less.

[0886] The pressure during the bonding is not particularly limited, but is a pressure greater than 0 MPa. From the perspective of the tendency of the bonding between the diaphragm and the electrode to be improved, it is preferably 0.01 MPa or more, more preferably 0.05 MPa or more, further preferably 0.08 MPa or more, and particularly preferably 0.1 MPa or more. From the perspective of the tendency to suppress the deterioration of the electrode, it is preferably 100 MPa or less, more preferably 50 MPa or less, further preferably 20 MPa or less, and particularly preferably 10 MPa or less.

[0887] The time of bonding is not particularly limited, and is a time greater than 0 seconds. From the perspective of the tendency of improving the bonding between the diaphragm and the electrode, it is preferably 0.01 seconds or more, more preferably 0.1 seconds or more, further preferably 0.5 seconds or more, and particularly preferably 1 second or more. From the perspective of the tendency of being able to reduce the cost when manufacturing the diaphragm electrode assembly, it is preferably 10 hours or less, more preferably 5 hours or less, further preferably 2 hours or less, and particularly preferably 1 hour or less.

[0888] The atmosphere during bonding is not particularly limited, and examples thereof include air, nitrogen, and argon. Air and nitrogen are preferred, and air is more preferred, from the viewpoint of the tendency to reduce the cost of manufacturing the separator electrode assembly.

[0889] <Redox Flow Battery>

[0890] By stacking the redox flow battery cells of this embodiment, a redox flow battery can be produced. When stacking, electricity can be conducted between the redox flow battery cells via the bipolar plates.

[0891] The material of the bipolar plate is not particularly limited, and examples thereof include carbon, graphite, and metal. In addition, the aforementioned material may be dispersed with carbon particles, carbon fibers, metal particles, metal fibers, graphene, and carbon nanotubes.

[0892] One type may be used alone or two or more types may be used in combination.

[0893] From the perspective of sometimes being able to improve the contact between the electrode and the electrolyte, the bipolar plate may also have various flow paths. The flow paths are not particularly limited, and examples thereof include Serpentine, Interdigitated, Parallel, Multi-parallel, Discontinuous, and a combination of the aforementioned flow paths.

[0894] By using the redox flow battery unit and the redox flow battery of the present embodiment, it is possible to provide a mechanism for smoothing the supply / demand of electricity and stabilizing the variable electricity obtained from renewable energy sources such as solar energy and wind energy. If illustrated more specifically, it is possible to provide the merging of electricity obtained from renewable energy sources, peak load shifting of electricity, stabilization of the transmission and distribution network, base load power, energy arbitrage, support for weak transmission and distribution networks, frequency adjustment, and any combination of the foregoing. In addition, it can also be used as a power source for remote camping, front-line combat bases, transmission and distribution telecommunications, remote sensors, etc. that do not utilize the transmission and distribution network.

[0895] The redox flow battery cell and the redox flow battery of the present embodiment may include a control system and a power adjustment unit.

[0896] By using a control system, the actions of various valves, pumps, circulation loops, sensors, mitigation devices, other electronic / hardware control devices, safety protection devices, etc. can be controlled.

[0897] By using the power conditioning unit, the voltage and current of the input power can be converted into a form that is most suitable for the redox flow battery unit and / or the redox flow battery, and the voltage and current of the output power can be converted into a form that is most suitable for any purpose. For example, when the redox flow battery unit and / or the redox flow battery is connected to the power transmission and distribution network, in the charging cycle, the power conditioning unit can convert the input AC power into DC power of a suitable voltage and current. In addition, in the discharge cycle, the redox flow battery unit and / or the redox flow battery generates DC power, and the power conditioning unit can convert the aforementioned DC power into AC power of a voltage and frequency suitable for transmission to the power transmission and distribution network.

[0898] [Fourth embodiment]

[0899] Next, a fourth embodiment will be described.

[0900] Patent Document 5 uses a solvent containing a large amount of ethanol as a protic solvent (in the example of Patent Document 1, the ethanol content is 50% by mass). When the fluororesin content in the solution is increased, the viscosity of the solution tends to increase, and it is difficult to store the solution in a viscosity range that is most suitable for the film forming process based on coating and drying. In addition, the time-dependent change rate of the solution viscosity tends to increase, and it is difficult to store the solution in a viscosity range that is most suitable for the film forming process based on coating and drying.

[0901] In Patent Document 6, N,N-dimethylformamide is used as a hydrophilic and high-boiling-point solvent. When an ion exchange membrane is manufactured by applying, drying, and heat-treating a polymer electrolyte solution, the N,N-dimethylformamide remaining in the ion exchange membrane is decomposed to produce dimethylamine as an impurity in the ion exchange membrane. Therefore, depending on the application, there is a problem that the characteristics are reduced due to the above impurities.

[0902] In Patent Document 7 and Non-Patent Document 1, it is difficult to sufficiently increase the molecular weight of a perfluorosulfonic acid polymer having a large sulfonic acid group ratio. In addition, when an ion exchange membrane is obtained by coating and drying a solution of a perfluorosulfonic acid polymer having a large sulfonic acid group ratio but not having a sufficiently large molecular weight, a membrane having sufficient mechanical strength cannot be obtained with respect to the solvent composition of the conventionally known technology. Therefore, a membrane of a perfluorosulfonic acid polymer having a large sulfonic acid group ratio and having sufficient mechanical strength is required.

[0903] In patent document 8, by co-extruding a perfluorosulfonic acid polymer precursor with an incompatible polymer, an ion exchange membrane with a film thickness of less than 25 μm, which is difficult to manufacture in the extrusion molding of the known prior art, is obtained. However, the ion exchange membrane made by the invention is compared with the ion exchange membrane of the perfluorosulfonic acid polymer of the known extrusion molding, although the anisotropy is reduced, for example, in the use of the ion exchange membrane in a state of being immersed in an electrolyte or a solvent, such as a redox flow battery or water electrolysis, the polymer electrolyte membrane swells due to the anisotropy in the plane derived from the molding method, so the ion exchange membrane anisotropically changes in size relative to the membrane surface, which may have an adverse effect on the characteristics. That is, it is required to include an ion exchange membrane of a perfluorosulfonic acid polymer that further reduces the anisotropy.

[0904] As described above, in the conventionally known technology, it is difficult to obtain: a polymer electrolyte solution in which the viscosity of a solution containing a fluororesin having a large sulfonic acid ratio changes little over time, and the viscosity of the aforementioned solution can be made to be within the viscosity range most suitable for the membrane formation process based on coating and drying; and an ion exchange membrane obtained by coating and drying the aforementioned solution, wherein the ion exchange membrane has sufficient mechanical strength, few cracks per unit area, an appropriate film thickness that can achieve low resistance, and reduced in-plane anisotropy of the electrolyte membrane.

[0905] An object of the present embodiment is to provide a novel polymer electrolyte solution and the like for forming a polymer film.

[0906] The polymer electrolyte solution of the present embodiment includes: a fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq; and

[0907] A solvent comprising water, an aliphatic alcohol and an aliphatic carboxylic acid,

[0908] The mass ratio of the total amount of the aliphatic carboxylic acid and the reaction product thereof to the total mass of the solvent is 100:1 to 100:50.

[0909]

[0910] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0911] According to the present embodiment, a novel polymer electrolyte solution and the like for forming a polymer film can be provided.

[0912] In addition, according to the above embodiments, a polymer electrolyte solution can be provided, the viscosity of which changes little over time, and the viscosity of the solution can be made into the viscosity range most suitable for the film forming process based on coating and drying, and contains a fluororesin with a large sulfonic acid ratio. In addition, an ion exchange membrane containing a fluororesin with a large sulfonic acid ratio can be provided, which has sufficient mechanical strength, and has few broken spots per unit area, is an appropriate film thickness that can be low in resistance, has a small anisotropy in the plane of the electrolyte membrane, and has excellent film thickness uniformity and a sufficiently large area. Furthermore, a redox flow battery unit and a redox flow battery using the above ion exchange membrane can be provided.

[0913] (Fluororesin G1)

[0914] The fluororesin in the present embodiment (hereinafter also referred to as “fluororesin G1”) has an equivalent weight of 500 g / eq or more and less than 1,000 g / eq and has a structural unit represented by the following general formula G1.

[0915]

[0916] (In the formula, the definitions of the substituents are the same as those in the above general formula G1.)

[0917] In the fourth embodiment, the fluororesin G1 preferably has a structural unit represented by the following general formula C3.

[0918] -[CF2CX 1 X 2 ] a -[CF2-CF((-O-CF2-CF(CF2X 3 )) b -O c -(CFR 1 ) d -(CFR 2 ) e -(CF2) f -X 4 )] g -[C3]

[0919] (Where X 1 , X 2 and X 3 Each R is independently a halogen atom or a perfluoroalkyl group having 1 to 3 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. 1 , R 2 X is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a fluorochloroalkyl group, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 4It is a monovalent group represented by the chemical formula of -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, or a divalent group represented by the chemical formula of -COOMOOC-, -SO3MO3S-, -PO3M2O3P-, or -PO3HMHO3P-. 4 When the fluororesin G1 is a divalent group, the fluororesin G1 can be connected to each other through X 4 Cross-linking is performed. Z is a hydrogen atom, an alkali metal atom or an amine. M is an alkaline earth metal atom. X 4 When it is -PO3Z2, the two Zs may be the same or different from each other.)

[0920] X 1 , X 2 and X 3 Each independently represents a halogen atom or a perfluoroalkyl group having 1 to 3 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. 1 , X 2 and X 3 In view of easy acquisition of raw materials and a tendency to reduce the manufacturing cost of the fluororesin G1, a fluorine atom, a chlorine atom, or a perfluoroalkyl group having 1 to 3 carbon atoms is preferred, a fluorine atom, a chlorine atom, or a perfluoroalkyl group having 1 carbon atoms is more preferred, a fluorine atom and a chlorine atom are further preferred, and a fluorine atom and a chlorine atom are particularly preferred.

[0921] R 1 , R 2 R is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a fluorochloroalkyl group, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 1 , R 2 , from the viewpoint of easy availability of raw materials and the tendency to reduce the production cost of the fluororesin G1, preferably a fluorine atom or an unsubstituted perfluoroalkyl group having 1 to 3 carbon atoms. Furthermore, from the viewpoint of the tendency to improve the chemical stability such as the resistance to oxidative degradation of the fluororesin G1, more preferably a fluorine atom and a trifluoromethyl group, and particularly preferably a fluorine atom.

[0922] X 4 It is a monovalent group represented by the chemical formula of -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, or a divalent group represented by the chemical formula of -COOMOOC-, -SO3MO3S-, -PO3M2O3P-, or -PO3HMHO3P-. 4 When the fluororesin G1 is a divalent group, the fluororesin G1 can be connected to each other through X 4 Cross-linking is performed. Z is a hydrogen atom, an alkali metal atom, or an amine. M is an alkaline earth metal atom. X 4When it is -PO3Z2, the two Zs are optionally the same as or different from each other. The aforementioned alkali metal is not particularly limited, and is preferably a lithium atom, a sodium atom, or a potassium atom, and more preferably a sodium atom or a potassium atom. As the aforementioned amine, there is no particular limitation, and examples thereof include NH4, NH3R 10 , NH2R 10 R 11 , NHR 10 R 11 R 12 , NR 10 R 11 R 12 R 13 structures. R 10 , R 11 , R 12 and R 13 are optionally the same as or different from each other, and as long as they are commonly used structures, there is no particular limitation, and examples thereof include aliphatic hydrocarbon groups and aromatic hydrocarbon groups. As the aforementioned aliphatic hydrocarbon group, it is preferably a monovalent group represented by C n H 2n+1 (n represents an integer of 1 or more, preferably an integer of 1 to 20, and more preferably an integer of 1 to 10). As the aforementioned aromatic hydrocarbon group, it is preferably a phenyl group or a naphthyl group. M is an alkaline earth metal atom, which is not particularly limited, and is preferably a magnesium atom or a calcium atom.

[0923] a and g are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1. b is an integer from 0 to 8. c is 0 or 1. d, e, and f are each independently an integer from 0 to 6 (wherein d, e, and f are not simultaneously 0).

[0924] In the fluororesin G1 having the structural unit represented by the above general formula C3, from the viewpoint of more balanced consideration of dispersibility and film strength, it is preferably represented by the following general formula C1 or the following general formula C4, and more preferably represented by the following general formula C4.

[0925] -[CF2CF2] a -[CF2-CF((-O-CF2-CF(CF3)) b -O-(CF2) c -SO3X)] d -[C1]

[0926] (In the formula, a and d are 0 ≤ a < 1, 0 ≤ d < 1, and a + d = 1. b is an integer from 1 to 8. c is an integer from 0 to 10. X is a hydrogen atom or an alkali metal atom.)

[0927] -[CF2CF2] e -[CF2-CF((-O-(CF2) f -SO3X)] g -[C4]

[0928] (In the formula, e and g are 0≤e<1, 0≤g<1, and e+g=1. f is an integer from 0 to 10. Y is a hydrogen atom or an alkali metal atom.)

[0929] As the fluororesin G1, a product prepared by a known method or a commercially available product can be used.

[0930] (Polymer Electrolyte)

[0931] The polymer electrolyte in this embodiment includes a fluororesin G1 as one type of polymer electrolyte. The ratio of the fluororesin G1 to the polymer electrolyte is preferably 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 98% by mass or more. When the ratio of the fluororesin G1 to the polymer electrolyte is 70% by mass or more, when used in a fuel cell, there is a tendency that the current efficiency of the fuel cell is excellent.

[0932] The fluororesin G1 used in the polymer electrolyte may be used alone or in combination of two or more.

[0933] The polymer electrolyte of this embodiment may contain, as polymer electrolytes different from the fluororesin G1, perfluorocarboxylic acid polymers, partially fluorinated sulfonic acid polymers, partially fluorinated carboxylic acid polymers, etc. as acidic polymers, and azole polymers (including imidazole polymers), amine polymers, etc. as basic polymers.

[0934] The acidic polymer and the basic polymer may be used alone or in combination of two or more.

[0935] When an electrolyte comprising the fluororesin G1 and the above-mentioned basic polymer is used as the polymer electrolyte, a fuel cell using the obtained ion exchange membrane tends to have improved chemical durability during fuel cell operation.

[0936] The polymer electrolyte of the present embodiment may contain a polymer such as polyethylene glycol, polyphenylene ether, polyphenylene sulfide, polyetherimide, polysulfone, polyetherketone, polyetheretherketone, polyetheretherimide, polyamide, polyimide, or polyamideimide.

[0937] The above-mentioned polymers may be used alone or in combination of two or more.

[0938] The mass % of the aforementioned optionally contained polymer contained in the polymer electrolyte is preferably 5 mass % or less, more preferably 3 mass % or less, and further preferably 1 mass % or less, from the perspective of imparting the characteristics possessed by the aforementioned optionally contained polymer to the ion exchange membrane and tending to suppress a decrease in the mechanical strength of the ion exchange membrane.

[0939] From the viewpoint of reducing the electrical resistance of the diaphragm when the ion exchange membrane containing the fluororesin G1 is used as a diaphragm for a redox flow battery and from the viewpoint of improving the mechanical strength of the diaphragm, the equivalent mass of the fluororesin G1 having the structural unit represented by the general formula C1 (hereinafter also referred to as "EW") is preferably 600 g / eq or more and less than 1,000 g / eq, more preferably 650 g / eq or more and less than 980 g / eq, and further preferably 700 g / eq or more and less than 950 g / eq.

[0940] In addition, "equivalent weight (EW) of fluororesin G1" means the dry weight with respect to 1 equivalent of sulfonic acid group.

[0941] From the viewpoint of reducing the electrical resistance of the diaphragm when the ion exchange membrane containing the fluororesin G1 is used as a diaphragm for a redox flow battery and from the viewpoint of improving the mechanical strength of the diaphragm, the equivalent mass (EW) of the fluororesin G1 having the structural unit represented by the general formula C4 is preferably 400 g / eq or more and less than 1,000 g / eq, more preferably 450 g / eq or more and less than 980 g / eq, further preferably 500 g / eq or more and less than 950 g / eq, further preferably 600 g / eq or more and less than 950 g / eq, and further preferably 700 g / eq or more and less than 950 g / eq.

[0942] The degree of polymerization of the fluororesin G1 precursor can be measured using the melt flow rate (hereinafter also referred to as "MFR") as an indicator. The MFR of the fluororesin G1 precursor is not particularly limited, but is preferably 100 g / 10 minutes or less, more preferably 50 g / 10 minutes or less, and further preferably 30 g / 10 minutes or less. By making the MFR less than 100 g / 10 minutes, there is a tendency to obtain an ion exchange membrane with excellent mechanical strength. In addition, the MFR is preferably 0.01 g / 10 minutes or more, more preferably 0.1 g / 10 minutes or more, and further preferably 0.3 g / 10 minutes or more. By making the MFR more than 0.01 g / 10 minutes, when the fluororesin G1 is made into a solution, there is a tendency to be able to further microdisperse / dissolve more efficiently. It should be noted that the MFR can be measured by the method described in the examples.

[0943] (Polymer electrolyte solution)

[0944] The polymer electrolyte solution of the present embodiment contains: a fluororesin G1 having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq; and a solvent containing water, an aliphatic alcohol, an aliphatic carboxylic acid, and an aliphatic ester.

[0945] The dissolving device for obtaining a uniform and colorless and transparent polymer electrolyte solution from an emulsion containing fluororesin G1 and a solvent is not particularly limited, but preferably a device for continuously dissolving fluororesin G1 and a solvent is used. The continuous dissolving device is heated by a heating means described later, and according to the conditions in the dissolving device, the perfluorosulfonic acid polymer in the emulsion passing through the dissolving device is dissolved in the solvent, and a uniform polymer electrolyte solution can be discharged from the dissolving device.

[0946] The continuous dissolving device preferably comprises: a pump for continuously supplying an emulsion containing fluororesin G1 and a solvent into the dissolving device; a dissolving device for continuously dissolving fluororesin G1 in the solvent; a heating means for heating the dissolving device; and a cooling means.

[0947] The aforementioned pump is used to continuously supply the emulsion containing the fluororesin G1 and the solvent into the dissolution device.

[0948] The type of pump is not particularly limited, and examples thereof include turbine pumps, piston pumps, plunger pumps, diaphragm pumps, gear pumps, vane pumps, screw pumps, and the like. Among these, plunger pumps, diaphragm pumps, multi-connected pumps, and accumulators are preferred as pumps with excellent pressure resistance, high quantitative performance, and high discharge pressure from the perspective of productivity from the perspective of safety. In addition, multi-connected pumps and accumulators are more preferred from the perspective of being able to suppress pulsation.

[0949] The pumps may be used alone or in combination of two or more.

[0950] The dissolution device is not particularly limited, and examples thereof include devices in which the flow of the fluid in the dissolution device is a plug flow type.

[0951] As the shape of the dissolving equipment, there is no particular limitation, for example, it is preferably a tube. By being a tube shape, there is a tendency to further improve productivity and dissolution efficiency. The tube shape is not particularly limited, and a straight line, a coil shape, a square shape, etc. can be cited. Among them, from the viewpoint of setting area and stable operation, it is preferably a coil shape. From the viewpoint of productivity and dissolution efficiency, the outer diameter of the tube is preferably 1 / 16 to 2 inches, more preferably 1 / 4 to 1 / 2 inches. It should be noted that a conventional commercially available 6A to 500A tube can also be used. In addition, from the viewpoint of productivity and dissolution efficiency, an online mixer, a metal mesh, a metal filler, etc. can also be provided in the tube.

[0952] There is no particular limitation on the dissolving equipment, and a tubular metal equipment is preferred. The material of the dissolving equipment is not particularly limited, and the best material can be selected from the viewpoint of corrosion resistance, and SUS-based materials, Hastelloy-based materials, titanium-based materials, zirconium oxide-based materials, tantalum-based materials, etc. can be listed. Among these, from the perspective of excellent balance between corrosion resistance and cost, SUS-based materials and materials with the same composition as Hastelloy (Hastelloy, a registered trademark of Haynes Company, USA) are preferred, SUS316 and materials with the same composition as Hastelloy C are more preferred, and materials with the same composition as Hastelloy C276 are particularly preferred. It should be noted that the same composition as Hastelloy, Hastelloy C and Hastelloy C276 is a material containing 56-60% by mass of Ni, 16-22% by mass of Cr, 13-16% by mass of Mo, 2-6% by mass of W, 3-8% by mass of Fe, and 2.5% or less by mass of Co. By using such a metal dissolving device, the dissolving process can be carried out at high temperature and high pressure, and the perfluorosulfonic acid polymer contained in the obtained polymer electrolyte solution has a tendency to improve the stability of the main chain end of the perfluorosulfonic acid polymer. The inner wall of the tube can be lined. As the lining, there is no particular limitation, for example, fluorine lining, glass lining, etc. can be listed. By using this dissolving device with a lining applied, the dissolving process can be carried out at a relatively low temperature and low pressure, and the concentration of F ions and Fe ions in the obtained polymer electrolyte solution is suppressed to a lower tendency.

[0953] The tube wall thickness is not particularly limited, and the optimal wall thickness may be selected from the viewpoint of pressure resistance. The inner diameter of the tube is not particularly limited, and is preferably 1 to 50 mm, more preferably 4 to 50 mm, from the viewpoint of productivity and dissolution efficiency.

[0954] The surface roughness of the inner wall of the tube is not particularly limited, and may be concave-convex or mirror-finished. From the viewpoint of dissolution efficiency, the maximum height of the surface roughness of the inner wall of the tube is preferably 50 μm or less, more preferably 25 μm or less, and further preferably 10 μm or less. The maximum height of the surface roughness of the inner wall of the tube refers to, for example, a value obtained by extracting only a reference length from the roughness curve along its average line using a laser microscope, and measuring the interval between the peak top line and the valley bottom line of the extracted part in the direction of the longitudinal magnification of the roughness curve.

[0955] The tube length depends on the required dissolution time (=retention time). Specifically, the tube length can be calculated based on the relationship with the tube inner diameter so that the product of the dissolution time (min) and the supply rate (L / min) is equal to or less than the internal volume of the heated tube.

[0956] Dissolution time (min) × supply speed (L / min) ≤ tube volume

[0957] The internal volume of the tube = (tube inner diameter / 2)2×π×tube length

[0958] When multiple dissolving devices in the form of tubes are used in series, joints of the same shape or different shapes, T-joints, check valves, safety valves, back pressure valves, pressure gauges, thermometers, etc., which connect the dissolving devices, may be provided between the dissolving devices. It should be noted that by using multiple dissolving devices in parallel to increase the internal volume, productivity can also be improved.

[0959] The heating means of the dissolving device is used to heat the dissolving device. The heating method is not particularly limited, and examples thereof include a method of heating the dissolving device using a heat medium such as hot air, hot water, steam, or silicone oil.

[0960] The heat medium may be used alone or in combination of two or more.

[0961] Among the heat media, hot air can be easily used, and therefore, the dissolution device can be preferably placed in a thermostatic bath in which the atmosphere is set to a specific temperature using hot air.

[0962] The pressure in the dissolving device in the continuous dissolving device is not particularly limited, but preferably further comprises a pressure regulating means for regulating the pressure in a manner exceeding the vapor pressure of the solvent at the heating temperature of the dissolving device. The pressure regulating means may be provided on the downstream side of the supply direction of the dissolving device, may be provided on the upstream side of the supply direction, may be provided on both the upstream and downstream sides, or may be provided inside the dissolving device.

[0963] As pressure regulating means, there is no particular limitation, and for example, a back pressure valve, an automatic pressure regulating valve (PIC) and the above-mentioned pump can be listed. By using a back pressure valve or an automatic pressure regulating valve (PIC), the pressure in the dissolving device is kept constant, that is, the pressure fluctuation is suppressed as much as possible, thereby having a tendency to improve the dispersibility of the polymer electrolyte solution and prevent clogging in the dissolving device. In addition, the dissolving device can also be pressurized by using a pump.

[0964] It should be noted that the pressure regulating means (back pressure valve) from the pump can also be treated as a closed container with constant pressure. In the above-mentioned continuous dissolution equipment, the dispersibility of the polymer electrolyte in the polymer electrolyte solution is further improved, and there is a tendency to obtain an electrolyte solution with this improved dispersibility at a higher concentration and in a shorter time.

[0965] The continuous dissolution device preferably has a cooling means downstream of the dissolution device, wherein the cooling means cools the polymer electrolyte solution while maintaining a pressure exceeding the vapor pressure of the solvent at the heating temperature in the dissolution device. By having such a cooling means, there is a tendency to further suppress clogging in the dissolution device when discharging the polymer electrolyte solution.

[0966] The cooling method is not particularly limited, and examples thereof include a method of cooling the polymer electrolyte solution by passing it through a cooling tube, and a method of air cooling the polymer electrolyte solution by passing it through a tube at room temperature instead of passing it through the cooling tube.

[0967] <Solvent>

[0968] The polymer electrolyte solution of the present embodiment comprises water, an aliphatic alcohol and an aliphatic carboxylic acid. The polymer electrolyte solution of the present embodiment may contain a reactant of an aliphatic carboxylic acid. As the reactant of an aliphatic carboxylic acid, an aliphatic carboxylic acid ester obtained by condensing an aliphatic carboxylic acid with an aliphatic alcohol can be cited.

[0969] The mass ratio of the total amount of the aliphatic carboxylic acid and its reaction product relative to the total mass of the solvent is 100:1 to 100:50. By setting it in this range, the generation of cracks and bad spots in the obtained ion exchange membrane can be suppressed. The mass ratio is preferably 100:3 to 100:40, more preferably 100:4 to 100:35, and even more preferably 100:5 to 100:30.

[0970] (Aliphatic Carboxylic Acid)

[0971] In the present embodiment, the aliphatic carboxylic acid refers to a compound having a carboxyl group (-COOH group), and the carbon number of the aliphatic carboxylic acid is preferably 1 to 5, and examples thereof include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, and the like. From the perspective of having a tendency to have a good balance between miscibility with water and solvation of the hydrophobic sites of the polymer electrolyte when water coexists when the polymer electrolyte solution is used for film formation, the carbon number of the aliphatic carboxylic acid is more preferably 1 to 4, further preferably 1 to 3, and particularly preferably acetic acid. From the perspective of having a tendency to improve the drying property during film formation, the boiling point of the carboxylic acid is preferably 165° C. or less, and more preferably 150° C. or less.

[0972] From the aspect of the tendency of excell...

Claims

1. An ion exchange membrane comprising a resin composition, the resin composition comprising: a side-chain heteroaromatic resin having a structural unit represented by the following general formula 1, and a cation exchange resin, In formula 1, R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the heteroaromatic group having at least 1 nitrogen atom within the heteroaromatic ring structure and comprising a 5-membered ring and / or a 6-membered ring structure.

2. The ion exchange membrane according to claim 1, wherein The weight ratio of the side-chain heteroaromatic resin to the cation exchange resin is 1:100 to 100:

1.

3. The ion exchange membrane according to claim 1, wherein The cation exchange resin is a fluororesin.

4. The ion exchange membrane according to claim 3, wherein The fluororesin has a structural unit represented by the following general formula G1, In formula G1, X 5 , X 6 , X 7 and X 8 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 5 With X 6 , or X 5 With X 7 optionally bonded to each other to form a ring structure, R 5 and R 6 each of which is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, X 9 is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, Z is at least one selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkaline earth metal atom and an amine, and the fluororesins are optionally bonded to each other via X 9 Crosslinking is carried out by ionic crosslinking, h and p represent molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ h < 1, 0 < p ≤ 1, and h + p = 1, i is an integer from 0 to 8, j is 0 or 1, k, l and m are each optionally the same or different and are integers of 0 to 6. When k, l and m are all 0, X 9 CF(CF2X 10 )2,X 10 It is a group represented by -COOZ, -SO3Z, -PO3Z2, or -PO3HZ, and Z is the same as described above.

5. The ion exchange membrane according to claim 1, which alternately has at least one layer each of a layer (L) containing the resin composition and a layer (M) containing a fluororesin, The fluororesin has a structural unit represented by the following general formula G1, In formula G1, the definitions of the respective substituents are the same as the meanings of the aforementioned general formula G1.

6. The ion exchange membrane according to claim 5, which has one layer each of the layer (L) and the layer (M).

7. The ion exchange membrane according to claim 5, which successively has the layer (L), the layer (M), and the layer (L).

8. An ion exchange membrane comprising: a side-chain heteroaromatic resin having a structural unit represented by the following general formula 2, In formula 2, R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the heteroaromatic group having at least 1 nitrogen atom within the heteroaromatic ring structure and comprising a 5-membered ring and / or a 6-membered ring structure, Rf is an aliphatic hydrocarbon group substituted with at least 1 fluorine atom, X - as counter anion.

9. The ion exchange membrane according to claim 8, which alternately has at least one layer each of a layer (L) containing the side-chain heteroaromatic resin and a layer (M) containing a fluororesin, The fluororesin has a structural unit represented by the following general formula G1, In formula G1, the definitions of the respective substituents are the same as the meanings of the aforementioned general formula G1.

10. The ion exchange membrane according to claim 9, which has one layer each of the layer (L) and the layer (M).

11. The ion exchange membrane according to claim 9, which successively has the layer (L), the layer (M), and the layer (L).

12. The ion exchange membrane according to claim 9, wherein The layer (L) further contains a cation exchange resin.

13. The ion exchange membrane according to claim 12, wherein The weight ratio of the side-chain heteroaromatic resin to the cation exchange resin is 1:100 to 100:

1.

14. The ion exchange membrane according to claim 12, wherein The cation exchange resin is a fluororesin.

15. The ion exchange membrane according to claim 14, wherein The fluororesin has a structural unit represented by the following general formula G1, In formula G1, the definitions of the respective substituents are the same as the meanings of the aforementioned general formula G1.

16. The ion exchange membrane according to claim 1, wherein The side-chain heteroaromatic resin further has a structural unit represented by the following general formula 2, In formula 2, R 1 , R 2 and R 3 Each of them may be the same or different and is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, R 4 is a direct bond, a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the heteroaromatic group having at least 1 nitrogen atom within the heteroaromatic ring structure and comprising a 5-membered ring and / or a 6-membered ring structure, Rf is an aliphatic hydrocarbon group substituted with at least 1 fluorine atom, X - as counter anion.

17. The ion exchange membrane according to claim 16, wherein The molar ratio of the structural unit represented by the general formula 1 to the structural unit represented by the general formula 2 is 1:100 to 100:

1.

18. The ion exchange membrane according to claim 16, wherein The weight ratio of the side-chain heteroaromatic resin to the cation-exchange resin is 1:100 to 100:

1.

19. The ion exchange membrane according to claim 16, wherein The cation-exchange resin is a fluororesin.

20. The ion exchange membrane according to claim 16, wherein The fluororesin has a structural unit represented by the following general formula G1, In formula G1, the definitions of the respective substituents are the same as the meanings of the foregoing general formula G1.

21. The ion-exchange membrane according to claim 20, which alternately has at least one layer each of a layer (L) containing the resin composition and a layer (M) containing a fluororesin, The fluororesin has a structural unit represented by the following general formula G1, In formula G1, the definitions of the respective substituents are the same as the meanings of the foregoing general formula G1.

22. The ion-exchange membrane according to claim 21, which has one layer each of the layer (L) and the layer (M).

23. The ion-exchange membrane according to claim 21, which successively has the layer (L), the layer (M), and the layer (L).

24. An ion-exchange membrane, which has a layer (L1) and a layer (M1), The layer (L1) contains: a fluororesin having a heteroaromatic structure having a structural unit represented by the following general formula A1, its saponified product, or its salt; The layer (M1) contains: a fluororesin (G1) having a structural unit represented by the following general formula G1, In formula A1, X 1 , X 2 , X 3 and X 4 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 1 With X 2 , or X 1 With X 3 optionally bonded to each other to form a ring structure, R 1 , R 2 each of which is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, R 3 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, R 4 NR 3 The connecting group to Hc is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, X 10 It is a divalent group represented by the chemical formula of -CO2-, -SO2-, Hc is a substituted or unsubstituted heteroaromatic group having 4 to 30 carbon atoms, the heteroaromatic group contains at least one nitrogen atom, and contains a 5-membered ring and / or a 6-membered ring structure, a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1, b is an integer of 0 to 8, c is 0 or 1, d, e and f are each optionally the same or different and are integers from 0 to 6, wherein: d, e, and f are not simultaneously 0, In formula G1, the definitions of the respective substituents are the same as the meanings of the foregoing general formula G1.

25. The ion-exchange membrane according to claim 24, which alternately has three or more layers of the layer (L1) and the layer (M1).

26. The ion exchange membrane according to claim 24, wherein The thickness of the layer (L1) is 10 μm or less.

27. The ion exchange membrane according to claim 24, wherein The thickness of the ion-exchange membrane is 200 μm or less.

28. An ion-exchange membrane, which contains a layer (L3) and a layer (M3), The layer (L3) contains: a fluororesin having a side-chain nitrogen atom having a structural unit represented by the following general formula A3, its saponified product, or its salt; The layer (M3) contains: a fluororesin (G1) having a structural unit represented by the following general formula G1, In formula A3, X 20 , X 21 , X 22 and X 23 Each of them is optionally the same or different and is a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted cyclic perfluoroalkyl group having 5 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and X 20 With X 21 , or X 20 With X 22 Optionally forming a ring structure, R 20 and R 21 each of which is optionally the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted perfluoroalkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted fluorochloroalkyl group having 1 to 10 carbon atoms, wherein the halogen atom is a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, R 22 and R 24 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, R 26 and R 27 is a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, R 26 and R 27 At least one of is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, R 23 and R 25 Each of the R is the same or different and is a substituted or unsubstituted divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, and when h is 2 or more, the repeated R 23 Each can be the same or different. X 24 is a divalent group represented by -CO2- or -SO2-, a and g represent the molar ratios in all the structural units contained in the resin, and are numbers satisfying 0 ≤ a < 1, 0 < g ≤ 1, and a + g = 1, b is an integer of 0 to 8, c is 0 or 1, d, e, f and h are each optionally the same or different and are integers from 0 to 6, wherein: d, e, and f are not simultaneously 0, In formula G1, the definitions of the respective substituents are the same as the meanings of the foregoing general formula G1.

29. The ion-exchange membrane according to claim 28, which alternately has three or more layers of the layer (L3) and the layer (M3).

30. The ion exchange membrane according to claim 28, wherein The thickness of the layer (L3) is 10 μm or less.

31. The ion exchange membrane according to claim 28, wherein The thickness of the ion-exchange membrane is 200 μm or less.

32. The ion exchange membrane according to any one of claims 1 to 31, which is used in a redox flow battery.

33. A membrane electrode assembly, wherein: The ion exchange membrane according to any one of claims 1 to 31 is joined to at least one electrode. The membrane electrode assembly according to claim 33 , which is used in a redox flow battery.

35. A cell for a redox flow battery, comprising: a first electrolyte solution containing a first redox active material, a second electrolyte solution containing a second redox active material, a first electrode in contact with the first electrolyte, a second electrode in contact with the second electrolyte, and a separator disposed between the first electrolyte and the second electrolyte, The membrane is the ion exchange membrane according to any one of claims 1 to 31. 36 . The redox flow battery cell according to claim 35 , which is a membrane electrode assembly in which a separator and at least one electrode are joined together.

37. The redox flow battery cell according to claim 35, wherein: At least one of the first electrode and the second electrode is a carbon electrode.

38. The redox flow battery cell according to claim 35, wherein: At least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials.

39. A redox flow battery comprising a stack of the redox flow battery cells according to claim 35.

40. A cell for a redox flow battery, comprising: a first electrolyte solution containing a first redox active material, a second electrolyte solution containing a second redox active material, a first electrode in contact with the first electrolyte, a second electrode in contact with the second electrolyte, and a separator disposed between the first electrolyte and the second electrolyte, The separator comprises at least a first cation exchange resin layer and an anion exchange resin layer. The equivalent weight of the diaphragm is less than 1150 g / eq, The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm. The anion exchange resin layer of the separator is disposed on the electrode side functioning as the negative electrode.

41. The redox flow battery cell according to claim 40, wherein: The first cation exchange resin layer is disposed closer to the electrode functioning as a positive electrode than the anion exchange resin layer.

42. The redox flow battery cell according to claim 40, wherein: The distance D between the anion exchange resin layer of the separator and the electrode functioning as the negative electrode neg The distance D between the anion exchange resin layer of the separator and the electrode functioning as the positive electrode is pos The following relationship is shown, D neg / D pos <1.

43. The redox flow battery cell according to claim 40, wherein: The first cation exchange resin layer has a thickness of 1 μm to 150 μm.

44. The redox flow battery cell according to claim 40, wherein: The first cation exchange resin layer contains a fluororesin.

45. The redox flow battery cell according to claim 40, wherein: The first cation exchange resin layer has at least one functional group selected from the group consisting of a sulfonic group, a carboxyl group, and a phosphoric acid group.

46. ​​The redox flow battery cell according to claim 40, wherein: The first cation exchange resin layer comprises: a fluororesin having a structural unit represented by the following general formula G1, In formula G1, the definition of each substituent is the same as that of the aforementioned general formula G1.

47. The redox flow battery cell according to claim 40, wherein: The anion exchange resin layer comprises at least one selected from the group consisting of the following structures: Primary amino group; Secondary amino group; Tertiary amino group; An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound; Heterocyclic structures containing nitrogen atoms; A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; as well as Quaternary ammonium group.

48. The redox flow battery cell according to claim 40, wherein: The diaphragm comprises: the first cation exchange resin layer, The anion exchange resin layer, and The second cation exchange resin layer, The thickness of the first cation exchange resin layer is greater than the thickness of the second cation exchange resin layer.

49. The redox flow battery cell according to claim 48, wherein: The first cation exchange resin layer is disposed closer to the electrode side functioning as a positive electrode than the anion exchange resin layer.

50. The redox flow battery cell according to claim 48, wherein: The distance D between the anion exchange resin layer of the separator and the electrode functioning as the negative electrode neg The distance D between the anion exchange resin layer of the separator and the electrode functioning as the positive electrode is pos The following relationship is shown, D neg / D pos <1.

51. The redox flow battery cell according to claim 48, wherein: The second cation exchange resin layer contains a fluororesin.

52. The redox flow battery cell according to claim 48, wherein: The second cation exchange resin layer has a thickness of 0.01 μm or more and less than 150 μm.

53. The redox flow battery cell according to claim 48, wherein: A value obtained by dividing the thickness of the second ion exchange resin layer by the thickness of the first cation exchange resin layer is less than 0.

7.

54. The redox flow battery cell according to claim 40, wherein: At least one of the first electrode and the second electrode is a carbon electrode.

55. The redox flow battery cell according to claim 40, wherein: At least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials. 56 . The redox flow battery cell according to claim 40 , which is a separator-electrode assembly in which at least one of the first electrode and the second electrode is joined to a separator. 57 . A redox flow battery comprising a stack of the redox flow battery cells according to claim 40 .

58. A method for manufacturing a diaphragm, wherein: The separator comprises at least a first cation exchange resin layer and an anion exchange resin layer. The equivalent weight of the diaphragm is less than 1150 g / eq, The thickness of the anion exchange resin layer is 0.001 μm or more and less than 5 μm. The manufacturing method comprises: a step of forming the first cation exchange resin layer, and A step of forming the anion exchange resin layer.

59. The method for manufacturing a diaphragm according to claim 58, comprising: a step of reacting a fluororesin precursor layer as a precursor of the first cation exchange resin layer with a modifying compound having at least two nitrogen atom-containing groups, the fluororesin precursor layer containing at least one selected from the group consisting of a halogenated sulfonyl group, an acyl halide group, and a halogenated phosphoric acid group; and After the above step, a step of converting at least one selected from the group consisting of halogenated sulfonyl groups, acyl halide groups and halogenated phosphoric acid groups contained in the fluororesin precursor layer into at least one selected from the group consisting of sulfonic groups, carboxyl groups and phosphoric acid groups, The nitrogen atom-containing group comprises at least one selected from the group consisting of the following structures: Primary amino group; Secondary amino group; Tertiary amino group; An amino salt structure which is a reaction product of at least one amino group selected from the group consisting of a primary amino group, a secondary amino group and a tertiary amino group and at least one selected from the group consisting of an acidic substance and a halogen atom-containing aliphatic hydrocarbon compound; Heterocyclic structures containing nitrogen atoms; A nitrogen-containing heterocyclic salt structure, which is a reaction product of a nitrogen-containing heterocyclic structure and at least one selected from the group consisting of an acidic substance and a halogen-containing aliphatic hydrocarbon compound; as well as Quaternary ammonium group.

60. The method for manufacturing a diaphragm according to claim 58, wherein the diaphragm comprises: the first cation exchange resin layer, The anion exchange resin layer, and The second cation exchange resin layer, The thickness of the first cation exchange resin layer is greater than the thickness of the second cation exchange resin layer, and the manufacturing method comprises: forming the first cation exchange resin layer, a step of forming the anion exchange resin layer, and A step of forming the second cation exchange resin layer. 61 . The method for producing a separator according to claim 60 , comprising: a step of overlapping the anion exchange resin layers of the membranes having the first cation exchange resin layer and the anion exchange resin layer.

62. A polymer electrolyte solution comprising: A fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq; and A solvent comprising water, an aliphatic alcohol and an aliphatic carboxylic acid, in, The total mass ratio of the aliphatic carboxylic acid and its reaction product to the total mass of the solvent is 100:1 to 100:50, In formula G1, the definition of each substituent is the same as that of the aforementioned general formula G1.

63. The polymer electrolyte solution according to claim 62, wherein The mass ratio of the aliphatic carboxylic acid to the aliphatic alcohol is 100:1 to 1:

100.

64. An ion exchange membrane comprising a fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq, The number of broken spots per unit area of ​​the ion exchange membrane is less than 10 / m 2 , In formula G1, the definition of each substituent is the same as that of the aforementioned general formula G1.

65. The ion exchange membrane of claim 64, wherein The orientation ratio OR in the film surface direction measured by X-ray scattering measurement is 1.0 or more and less than 1.

1. The ion exchange membrane according to claim 64 , which has an average membrane thickness of 75 μm or less. The ion exchange membrane according to claim 66 , which has an average membrane thickness of 25 μm or more.

68. The ion exchange membrane of claim 64, wherein The minimum film thickness is 90% or more of the average film thickness, and the maximum film thickness is 110% or less of the average film thickness.

69. A wound body formed by winding the ion exchange membrane according to claim 64.

70. The wound body according to claim 69, wherein The ion exchange membrane has a width of 50 mm or more and 5,000 mm or less.

71. The wound body according to claim 69, wherein The length of the ion exchange membrane is greater than 100 mm.

72. A membrane electrode assembly, wherein: The ion exchange membrane according to any one of claims 64 to 68 is joined to at least one electrode.

73. The ion exchange membrane according to any one of claims 64 to 68, which is used in a redox flow battery.

74. The membrane electrode assembly according to claim 72, which is used in a redox flow battery.

75. A cell for a redox flow battery, comprising: a first electrolyte solution containing a first redox active material, a second electrolyte solution containing a second redox active material, a first electrode in contact with the first electrolyte, a second electrode in contact with the second electrolyte, and a separator disposed between the first electrolyte and the second electrolyte, The diaphragm is the ion exchange membrane according to any one of claims 64 to 68.

76. The redox flow battery cell according to claim 75, wherein: The separator is joined to at least one electrode.

77. The redox flow battery cell according to claim 75, wherein: At least one of the first electrode and the second electrode is a carbon electrode.

78. The redox flow battery cell according to claim 75, wherein: At least one of the first redox active material and the second redox active material is at least one selected from the group consisting of metallic redox active materials, non-metallic redox active materials, and organic redox active materials.

79. A redox flow battery comprising a stack of the redox flow battery cells according to claim 75.

80. A method for producing an ion exchange membrane, comprising the steps of applying and drying the polymer electrolyte solution according to claim 62 or 63, The ion exchange membrane comprises a fluororesin having a structural unit represented by the following general formula G1 and having an equivalent weight of 500 g / eq or more and less than 1,000 g / eq, and the number of cracks per unit area of ​​the ion exchange membrane is less than 10 / m 2 , In formula G1, the definition of each substituent is the same as that of the aforementioned general formula G1.

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