Electrolytes, secondary batteries and composites

Abstract

To provide an electrolyte having stretchability and softness, a secondary battery, and a composite material, which can prevent a decrease in electrolyte durability. The problem is solved by an electrolyte containing: a polymer in which a monomer represented by the following formula (1) is polymerized; a glyme represented by the following formula (2); and at least one salt selected from the group consisting of lithium salts, sodium salts, magnesium salts, potassium salts, and calcium salts; in formula (1), R1 and R2 each independently represent H or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, X1 and X2 each independently represent O or NH, when X2 is O, n represents an average integer of 0 to 30, and when X2 is NH, n represents an average integer of 1 to 30; in formula (2), R3 and R4 each independently represent an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 4.

Description

Technical Field

[0001] The disclosure of this application relates to electrolytes, secondary batteries, and composite materials. Background Technology

[0002] Lithium-ion batteries have high energy density. Therefore, they are used as power sources for portable electronic devices such as laptops and mobile phones, as well as automobiles. Furthermore, the use of lithium-ion batteries is expected to expand in the future, and new applications are anticipated.

[0003] Lithium-ion batteries have traditionally used liquid electrolytes. However, lithium-ion batteries using liquid electrolytes are susceptible to electrolyte fire if the battery temperature rises abnormally. Additionally, electrolyte vaporization can cause an increase in internal pressure, potentially leading to battery rupture.

[0004] The need to prevent lithium-ion batteries from catching fire and rupture, and to further improve safety, has led to the research and development of a scheme using solid electrolytes in lithium-ion batteries to enhance safety.

[0005] Examples of solid electrolytes include polymer-based electrolytes and inorganic solid electrolytes. In particular, polymer-based electrolytes can be easily manufactured by coating an electrolyte composition containing monomers and then polymerizing it. Furthermore, compared to inorganic solid electrolytes, polymer-based electrolytes offer superior formability and processability, making them particularly suitable for applications requiring flexibility. Moreover, due to their greater shape freedom and ease of stacking, improvements in output density and energy density can be expected.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2016-197590;

[0009] Patent Document 2: Japanese Patent Application Publication No. 2009-176523. Summary of the Invention

[0010] The problem the invention aims to solve

[0011] Patent documents 1 and 2 describe electrolytes using polymers. While polymer-based electrolytes can be used in various shapes due to their elasticity and flexibility, maintaining this shape during use places significant stress on the electrolyte. Consequently, the electrolyte's durability may decrease due to breakage, thinning, or other reasons. Therefore, electrolytes with greater elasticity and flexibility than conventional electrolytes are desired.

[0012] Therefore, this application discloses a flexible and soft electrolyte, a secondary battery, and a composite material capable of preventing degradation of electrolyte durability. Any other additional effects disclosed in this application are apparent in the embodiments of the invention.

[0013] Problem-solving methods

[0014] (1) An electrolyte containing:

[0015] A polymer that has polymerized a monomer represented by the following formula (1);

[0016] [Chemical Formula 1]

[0017]

[0018] Dimethyl glycol ether represented by the following formula (2); and

[0019] [Chemical Formula 2]

[0020]

[0021] Choose at least one salt from the group consisting of lithium, sodium, magnesium, potassium, and calcium salts.

[0022] In formula (1), R1 and R2 each independently represent H or a straight-chain, branched, or cyclic alkyl group with 1 to 20 carbon atoms, and X1 and X2 each independently represent O or NH. When X2 is O, n averages an integer from 0 to 30; when X2 is NH, n averages an integer from 1 to 30.

[0023] In formula (2), R3 and R4 each independently represent alkyl groups with 1 to 4 carbon atoms, and m represents an integer from 1 to 4.

[0024] (2) According to the electrolyte described in (1) above, wherein the anion of the salt is selected from PF6. - BF4 - ClO4 - B(C2O4)2 - N(FSO2)2 - and N(CF3SO2)2 - At least one of the groups.

[0025] (3) According to the electrolyte described in (2) above, the anion of the salt is N(FSO2)2. - or N(CF3SO2)2 - .

[0026] (4) The electrolyte according to any one of (1) to (3) above, wherein the salt is a lithium salt.

[0027] (5) The electrolyte according to any one of (1) to (4) above, wherein, in formula (1), when X2 is O, n averages 3 to 14, and when X2 is NH, n averages 4 to 15.

[0028] (6) The electrolyte according to any one of (1) to (5) above, wherein in formula (2), m is 4.

[0029] (7) A secondary battery, comprising at least:

[0030] anode;

[0031] cathode; and

[0032] The electrolyte layer between the anode and cathode,

[0033] The electrolyte layer is any one of (1) to (6) above.

[0034] (8) A composite material comprising:

[0035] The electrolyte described in any one of (1) to (6) above; and

[0036] Porous carrier.

[0037] (9) The composite material according to (8) above, wherein the porous carrier includes through holes extending in the thickness direction.

[0038] (10) The composite material according to (8) or (9) above, wherein the porous carrier is a honeycomb membrane.

[0039] (11) A secondary battery, comprising at least:

[0040] anode;

[0041] cathode; and

[0042] The electrolyte layer between the anode and cathode,

[0043] The electrolyte layer is a composite material as described in any one of (8) to (10) above.

[0044] Invention Effects

[0045] It can provide electrolytes that are flexible and soft. Attached Figure Description

[0046] Figure 1 This is a schematic cross-sectional view of the battery.

[0047] Figure 2 This is a graph showing the temperature dependence of the ionic conductivity of electrolytes 1 to 4.

[0048] Figure 3 Figure A is a diagram showing the mechanical properties of electrolyte 1 manufactured in Example 1; Figure 3 B is a photo surrogate, a photo of the electrolyte 4 manufactured in Example 4 when it is deformed.

[0049] Figure 4 This is a graph showing the charge and discharge characteristics of electrolyte 1.

[0050] Figure 5 This is a graph showing the results of linear sweep voltammetry for electrolyte 1.

[0051] Figure 6 Figure A is a graph showing the results of chronoamperometric analysis of electrolyte 1; Figure 6 Figure B is a graph showing the results of the AC impedance measurement of electrolyte 1.

[0052] Figure 7 This is a substitute photograph of a honeycomb membrane viewed from the thickness direction.

[0053] Figure 8 This is a graph showing the temperature dependence of the ionic conductivity of composite material 1.

[0054] Figure 9 This is a graph showing the charge-discharge characteristics of composite material 1; Figure 7 A shows the charge-discharge characteristics measured over a period of 0–100 hours; Figure 7 Figure B shows the charge-discharge characteristics measured over a period of 600–700 hours.

[0055] Figure 10 This is a graph showing the results of linear scanning voltammetry for composite material 1.

[0056] Figure 11 Figure A is a graph showing the results of chronoamperometric analysis of composite material 1; Figure 11 Figure B is a graph showing the results of AC impedance measurement of composite material 1.

[0057] Figure 12 A is a photograph of electrolyte 5 represented by a picture; Figure 12 B is a photograph of electrolyte 9 represented by a picture; Figure 12 C is a photograph of electrolyte 13 represented by a picture.

[0058] Figure 13 Figure A is a graph showing the temperature dependence of the ionic conductivity of electrolytes 5–8; Figure 13 Figure B is a graph showing the temperature dependence of the ionic conductivity of electrolytes 9–12; Figure 13 C is a graph showing the temperature dependence of the ionic conductivity of electrolyte 13. Detailed Implementation

[0059] The following is a more detailed explanation of electrolytes.

[0060] Furthermore, in this specification, the numerical range indicated by "~" refers to the range including the values ​​stated before and after "~" as the lower and upper limits. Additionally, in this specification, the terms "numerical value," "numerical range," and "qualitative expression" (e.g., "same," "identical," etc.) are interpreted as representing numerical values, numerical ranges, and properties that include errors generally permissible in the art.

[0061] (Implementation methods of electrolytes)

[0062] The electrolyte involved in the implementation method contains:

[0063] A polymer that has polymerized a monomer represented by the following formula (1);

[0064] [Chemical Formula 3]

[0065]

[0066] (In formula (1), R1 and R2 each independently represent H or a straight-chain, branched, or cyclic alkyl group with 1 to 20 carbon atoms. X1 and X2 each independently represent O or NH. When X2 is O, n averages an integer from 0 to 30; when X2 is NH, n averages an integer from 1 to 30.)

[0067] Dimethyl glycol ether represented by the following formula (2); and

[0068] [Chemical Formula 4]

[0069]

[0070] (In formula (2), R3 and R4 each independently represent alkyl groups with 1 to 4 carbon atoms, and m represents an integer from 1 to 4.)

[0071] Choose at least one salt from the group consisting of lithium, sodium, magnesium, potassium, and calcium salts.

[0072] Electrolytes are manufactured by polymerizing a composition comprising a monomer represented by formula (1), glycol dimethyl ether, and a salt. The materials required for the manufacture of electrolytes are described below.

[0073] [Monomer represented by equation (1)]

[0074] The electrolyte uses a polymer that polymerizes the monomer represented by formula (1). The monomer represented by formula (1) has polymeric groups at both ends, thus the resulting polymer forms a cross-linked network. In addition, glycol dimethyl ether is a plasticizer. Therefore, the polymer is a plasticized cross-linked network polymer containing ethylene oxide.

[0075] In formula (1), R1 and R2 each independently represent H or an alkyl group having 1 to 20 carbon atoms. Furthermore, R1 and R2 may be the same or different. The alkyl group having 1 to 20 carbon atoms can be any of straight-chain, branched, or cyclic. R1 and R2 are preferably H or an alkyl group having 1 to 5 carbon atoms, more preferably H or a straight-chain alkyl group having 3 or fewer carbon atoms, and even more preferably H or CH3.

[0076] X1 and X2 can each independently represent O or NH. Furthermore, X1 and X2 can be the same or different.

[0077] Regarding n, when X2 is 0, the average value is in the range of 0 to 30, preferably in the range of 1 to 20, and more preferably in the range of 3 to 14. Furthermore, when X2 is NH, the average value of n is in the range of 1 to 30, preferably in the range of 2 to 20, and more preferably in the range of 4 to 15.

[0078] More specifically, when X2 is 0, the minimum value of n can be 0 or above, 1 or above, 2 or above, 3 or above, 4 or above, 5 or above, 6 or above, 7 or above, 8 or above, 9 or above, 10 or above, 11 or above, 12 or above, 13 or above, 14 or above, 15 or above, 16 or above, 17 or above, 18 or above, 19 or above, or 20 or above, and the maximum value of n can be 30 or below, 29 or below, 28 or below, 27 or below, 26 or below, 25 or below, 24 or below, 23 or below, 22 or below, 21 or below, 20 or below, 19 or below, 18 or below, 17 or below, 16 or below, 15 or below, 14 or below, 13 or below, 12 or below, 11 or below. When X2 is NH, the minimum value of n can be an average of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher, 6 or higher, 7 or higher, 8 or higher, 9 or higher, 10 or higher, 11 or higher, 12 or higher, 13 or higher, 14 or higher, 15 or higher, 16 or higher, 17 or higher, 18 or higher, 19 or higher, or 20 or higher. The maximum value of n can be an average of less than 30, less than 29, less than 28, less than 27, less than 26, less than 25, less than 24, less than 23, less than 22, less than 21, less than 20, less than 19, less than 18, less than 17, less than 16, less than 15, less than 14, less than 13, less than 12, less than 11, or less than 10. Furthermore, the range of n can be arbitrarily chosen as long as the minimum and maximum values ​​of n do not overlap.

[0079] Furthermore, the monomer represented by formula (1) is preferably a liquid at room temperature. If it is a liquid, no solvent is needed when manufacturing the electrolyte, and glycol dimethyl ether and salt can be dissolved in the monomer.

[0080] The monomer represented by formula (1) contains ethylene oxide units, thus the polymer polymer exhibits improved stretchability and flexibility. Furthermore, the ethylene oxide units of the polymer polymer form a solvation structure with the cations of the salt. Therefore, the polymer can contain a large number of cations, and the electrolyte possesses high ionic conductivity.

[0081] If the monomer contains few ethylene oxide units, the following problems will occur.

[0082] 1) With fewer ethylene oxide units, the polymer’s elasticity and flexibility decrease.

[0083] 2) The number of cations contained in the polymer can be reduced.

[0084] 3) The solubility of glycol dimethyl ether and salt contained in the electrolyte is reduced.

[0085] Conversely, if there are more ethylene oxide units in the monomer, the polymer will have higher stretchability, flexibility, and solubility in glycol dimethyl ether and salts, but the crosslinking density will be lower, making it difficult to maintain the mechanical properties of the polymer.

[0086] Specific examples of monomers represented by formula (1) include poly(ethylene glycol) di(meth)acrylate and poly(ethylene glycol) di(meth)acrylamide. The average molecular weight of the monomers represented by formula (1) is in the range of 200 to 1500, preferably in the range of 240 to 1100, and more preferably in the range of 320 to 800.

[0087] Furthermore, in this specification, "(meth)acrylate" refers to a concept that includes both "acrylate" and "methacrylate". The same applies to similar terms; for example, "(meth)acrylic acid" includes both "acrylic acid" and "methacrylic acid", "(meth)acryloyl" includes both "acryloyl" and "methacryloyl", and "(meth)acrylamide" includes both "acrylamide" and "methacrylamide".

[0088] In the composition used to manufacture the electrolyte, the content of the monomer represented by formula (1) is not particularly limited, but is 10% by weight or more, more preferably 20% by weight or more, and even more preferably 30% by weight or more, based on the total amount of the composition. In addition, based on the total amount of the composition, the content of the monomer is 90% by weight or less, preferably 80% by weight or less.

[0089] [Glycol dimethyl ether]

[0090] Glycol dimethyl ether, represented by formula (2), is used as a plasticizer to plasticize polymers polymerized with monomers represented by formula (1).

[0091] In equation (2), R3 and R4 each independently represent alkyl groups with 1 to 4 carbon atoms. m represents an integer from 1 to 4.

[0092] Examples of alkyl groups in R3 and R4 include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. Methyl or ethyl groups are particularly preferred.

[0093] In formula (2), m is 1 to 4, preferably 3 or 4, and more preferably 4. Specific examples of glycol dimethyl ether represented by formula (2) include monoethylene glycol dimethyl ether (also known as ethylene glycol dimethyl ether), diethylene glycol dimethyl ether (also known as diethylene glycol dimethyl ether), triethylene glycol dimethyl ether (also known as triethylene glycol dimethyl ether), and tetraethylene glycol dimethyl ether (also known as tetraethylene glycol dimethyl ether). Among these, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether is preferred, and tetraethylene glycol dimethyl ether is more preferred.

[0094] The content of glycol dimethyl ether in the composition used to manufacture the electrolyte is not particularly limited, but is 5% to 50% by weight, preferably 10% to 20% by weight, based on the total amount of the composition.

[0095] [Salt]

[0096] The salts contained in electrolytes are electrolyte salts. These salts can be lithium salts, sodium salts, magnesium salts, potassium salts, or calcium salts.

[0097] Examples of salt anions include halide ions (I2). - Cl - ,Br - etc.), SCN - BF4 - BF3 (CF3) - BF3 (C2F5) - BF3 (C3F7) - BF3(C4F9) - PF6 - ClO4 - SbF6 - N(FSO2)2 - (Sometimes also represented as [FIS]) - N(CF3SO2)2 - (Sometimes also represented as [TFSI]) - ), N(C2F5SO2)2 - BPh4 - B(C2H4O2) - C(SO2F)3 - (Sometimes also represented as [f3C]) - C(SO2CF3)3 - CF3COO- CF3SO2O - C6F5SO2O - B(C2O4)2 - (Sometimes also represented as [BOB]) - ), RCOO - (R represents an alkyl, phenyl, or naphthyl group having 1 to 4 carbon atoms). PF6 is preferred. - BF4 - [FSI] - [TFSI] - [BOB] - ClO4 - More preferably [FSI] - [TFSI] - .

[0098] Examples of lithium salts that can be used as salts include LiPF6, LiBF4, Li[FSI], Li[TFSI], Li[f3C], Li[BOB], LiClO4, LiBF3(CF3), LiBF3(C2F5), LiBF3(C3F7), LiBF3(C4F9), LiC(SO2CF3)3, LiCF3SO2O, LiCF3COO, and LiRCOO (where R represents an alkyl, phenyl, or naphthyl group with 1 to 4 carbon atoms). They can be used alone or in combination of two or more.

[0099] Examples of sodium salts that can be used as salts include NaPF6, NaBF4, Na[FSI], Na[TFSI], Na[f3C], Na[BOB], NaClO4, NaBF3(CF3), NaBF3(C2F5), NaBF3(C3F7), NaBF3(C4F9), NaC(SO2CF3)3, NaCF3SO2O, NaCF3COO, and NaRCOO (where R represents an alkyl, phenyl, or naphthyl group with 1 to 4 carbon atoms). They can be used alone or in combination of two or more.

[0100] Examples of magnesium salts that can be used as salts include Mg(PF6)2, Mg(BF4)2, Mg[FSI]2, Mg[TFSI]2, Mg[f3C]2, Mg[BOB]2, Mg(ClO4)2, Mg[BF3(CF3)]2, Mg[BF3(C2F5)]2, Mg[BF3(C3F7)]2, Mg[BF3(C4F9)]2, Mg[C(SO2CF3)3]2, Mg(CF3SO2O)2, Mg(CF3COO)2, and Mg(RCOO)2 (where R represents an alkyl, phenyl, or naphthyl group with 1 to 4 carbon atoms). They can be used alone or in combination of two or more.

[0101] Examples of potassium salts that can be used as salts include KPF6, KBF4, K[FSI], K[TFSI], K[f3C], K[BOB], KClO4, KBF3(CF3), KBF3(C2F5), KBF3(C3F7), KBF3(C4F9), KC(SO2CF3)3, KCF3SO2O, KCF3COO, and KRCOO (where R represents an alkyl, phenyl, or naphthyl group with 1 to 4 carbon atoms). They can be used alone or in combination of two or more.

[0102] Examples of calcium salts that can be used as salts include Ca(PF6)2, Ca(BF4)2, Ca[FSI]2, Ca[TFSI]2, Ca[f3C]2, Ca[BOB]2, Ca(ClO4)2, Ca[BF3(CF3)]2, Ca[BF3(C2F5)]2, Ca[BF3(C3F7)]2, Ca[BF3(C4F9)]2, Ca[C(SO2CF3)3]2, Ca(CF3SO2O)2, Ca(CF3COO)2, and Ca(RCOO)2 (where R represents an alkyl, phenyl, or naphthyl group having 1 to 4 carbon atoms). They can be used alone or in combination of two or more.

[0103] From the perspective of ion conductivity, lithium salts are preferred, and LiPF6, LiBF4, Li[FSI], Li[TFSI], Li[f3C], Li[BOB], and LiClO4 are more preferred, with Li[FSI] and Li[TFSI] being even more preferred.

[0104] The oxygen in the ethylene oxide of the polymer forms a solvated structure with the cation in the salt. Therefore, the maximum salt content depends on the number of ethylene oxide units in the polymer. Thus, the salt content in the composition is not particularly limited when manufacturing the electrolyte, as long as it is a molar number less than the number of molars of ethylene oxide units in the polymer.

[0105] [Polymerization initiator]

[0106] The electrolyte involved in this embodiment is manufactured by polymerization of monomers represented by formula (1). A polymerization initiator is used in this process. The polymerization initiator is not particularly limited as long as it can polymerize monomers represented by formula (1). Among the polymerization initiators are photopolymerization initiators and thermal polymerization initiators. Compared with thermal polymerization initiators, photopolymerization initiators cure faster. In addition, photopolymerization initiators include photoradical polymerization initiators, photoanionic polymerization initiators, and photocationic polymerization initiators. Since photoradical polymerization initiators rapidly perform addition reactions on double bonds, they do not generate reaction-induced impurities. When manufacturing an electrolyte, if the polymerization reaction is slow, the resulting polymer may easily crystallize due to molecular alignment. Therefore, it is important to carry out the polymerization reaction rapidly when manufacturing an electrolyte. In addition, if no impurities are generated, it is not necessary to remove impurities after the polymerization reaction, which simplifies the electrolyte manufacturing process.

[0107] Therefore, in the polymerization reaction of the monomer represented by formula (1), a photoradical polymerization initiator is preferably used. The cross-linked network polymer formed by the photoradical polymerization initiator polymerizes rapidly before the molecular arrangement within the polymer is completed. That is, the cross-linked network polymer is formed in an amorphous state.

[0108] As photoradical polymerization initiators, they are not particularly restricted as long as the monomers are polymerized. Examples include acetophenone-based photoradical polymerization initiators, benzophenone-based photoradical polymerization initiators, thioxanone-based photoradical polymerization initiators, and acylphosphine-based photoradical polymerization initiators. Specifically, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, benzoylbenzoic acid, 2,2-diethoxyacetophenone, 2,4-diethyl-9H-thioxanthrol-9-one, 4,4'-dimethoxybenzyl, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 2-ethoxy-2-phenylacetone, 2-ethylanthraquinone, 1-hydroxycyclohexylphenyl ketone, 2-(hydroxyimino)phenylacetone, 2-hydroxy-2-phenylacetophenone, 2-methyl-4'-(methylthio)-2-morpholinophenylacetone, and p,p'-tetramethyldiaminobenzophenone are preferred, with 2,2-dimethoxy-2-phenylacetophenone being even more preferred.

[0109] The amount of polymerization initiator used is not particularly limited, for example, it is 0.001 to 0.1 parts by weight, preferably 0.005 to 0.01 parts by weight, relative to 100 parts by weight of monomer.

[0110] Electrolytes can be manufactured by mixing a monomer represented by formula (1), glycol dimethyl ether represented by formula (2), a salt, and a polymerization initiator, and then polymerizing them. Furthermore, the monomer represented by formula (1) is liquid at room temperature as described above, thus dissolving the glycol dimethyl ether, salt, and polymerization initiator. Therefore, electrolytes do not require solvents. Additionally, by simply irradiating the composition containing the above materials with light such as ultraviolet light or an electron beam, heat treatment or other methods for stabilizing the post-polymerization structure are unnecessary. Therefore, electrolytes can be easily manufactured.

[0111] The electrolyte involved in the implementation method has the following effects.

[0112] (1) The electrolyte involved in the embodiment is a plasticized cross-linked network polymer, which has elasticity, softness, and sufficient mechanical strength. Therefore, it is possible to suppress the stress generated when the electrolyte is bent or stretched to change its shape. Therefore, it is possible to prevent the electrolyte from being damaged, thinned, or otherwise degraded in durability.

[0113] (2) The electrolyte involved in the embodiment is a plasticized cross-linked network polymer with sufficient ethylene oxide units. The ethylene oxide units form a solvated structure with the cations of the salt, thus allowing the electrolyte to contain a large number of cations. Therefore, the electrolyte has high ionic conductivity.

[0114] (3) The number of ethylene oxide units in the electrolyte involved in the embodiment increases, thereby increasing the elasticity and flexibility. In addition, the content of cations in the salt also increases. Therefore, by increasing n of the monomer represented by formula (1), the effects of (1) and (2) above can be obtained synergistically.

[0115] (4) It is generally known that in electrolytes utilizing polymers, if the polymer has a crystalline structure, the ionic conductivity decreases. In manufacturing the electrolyte according to the embodiments, when using a fast-reacting photoradical polymerization initiator, polymerization is performed before polymer crystallization. Therefore, the electrolyte becomes amorphous, preventing a decrease in ionic conductivity.

[0116] (5) The electrolytes described in the embodiments can be manufactured without the use of solvents. For example, when organic solvents are used, they tend to evaporate, making them difficult to handle during electrolyte manufacturing. Furthermore, depending on the type of polymer in the electrolyte and the type of organic solvent, the polymer and solvent may separate, resulting in a significant reduction in the ionic conductivity and mechanical strength of the electrolyte. However, the electrolytes described in the embodiments do not use solvents, thus avoiding these problems.

[0117] (Implementation methods for composite materials)

[0118] The electrolyte described in the above embodiments can also be used in composite materials. The composite material contains an electrolyte and a porous carrier.

[0119] Porous supports have pores within which electrolytes are carried. Therefore, when using composite materials in secondary batteries, porous supports isolate the positive and negative electrodes and ensure ion conductivity. Furthermore, by carrying electrolytes on porous supports, ion diffusion can be suppressed. Thus, porous supports function as membranes.

[0120] The structure of a porous carrier is not particularly limited, as long as it has voids that can carry the electrolyte and ensure ion conductivity between the positive and negative electrodes in a secondary battery. The structure of a porous carrier can have either regularly arranged voids or randomly arranged voids. In the case of regularly arranged voids, the porous carrier can be, for example, a honeycomb membrane with a honeycomb structure. The honeycomb structure can be any three-dimensional structure, such as columnar (e.g., polygonal prisms and cylinders), conical (e.g., pyramids and cones), spherical (e.g., ellipsoids), arranged without gaps on any plane. Furthermore, the honeycomb membrane can be composed of a single layer of three-dimensional layers arranged without gaps, or multiple layers can be stacked in a direction perpendicular to any plane. Additionally, examples of porous carriers with randomly arranged voids include nonwoven fabrics, uniaxially stretched porous membranes, biaxially stretched porous membranes, and particle-cast porous membranes.

[0121] The porosity of the porous carrier ranges from 0.1 μm to 60 μm. More specifically, the porosity can be greater than 0.1 μm, greater than 0.2 μm, greater than 0.3 μm, greater than 0.4 μm, greater than 0.5 μm, greater than 0.6 μm, greater than 0.7 μm, greater than 0.8 μm, greater than 0.9 μm, greater than 1 μm, greater than 2 μm, greater than 3 μm, greater than 4 μm, greater than 5 μm, greater than 6 μm, greater than 7 μm, greater than 8 μm, greater than 9 μm, greater than 10 μm, greater than 11 μm, greater than 12 μm, greater than 13 μm, greater than 14 μm, greater than 15 μm, greater than 16 μm, greater than 17 μm, greater than 18 μm, greater than 19 μm, or greater than 20 μm. In addition, the pore size can be below 60μm, 59μm, 58μm, 57μm, 56μm, 55μm, 54μm, 53μm, 52μm, 51μm, 50μm, 49μm, 48μm, 47μm, 46μm, 45μm, 44μm, 43μm, 42μm, 41μm, 40μm, 39μm, 38μm, 37μm, 36μm, 35μm, 33μm, 32μm, 31μm, 30μm, 29μm, 28μm, 27μm, 26μm, 25μm, 24μm, 23μm, 22μm, 21μm, or 20μm. Furthermore, the range of the gap can be arbitrarily selected in a manner that the above values ​​do not overlap. In this specification, when the gap is the aforementioned three-dimensional structure within the honeycomb film, the size of the gap is the diameter of the sphere inscribed within the aforementioned three-dimensional structure.

[0122] However, as mentioned above, the porous support functions as a membrane. The membrane ensures ion conductivity between the positive and negative electrodes, but by making the distribution caused by ion flow between the positive and negative electrodes, i.e., the current distribution, uniform, it can suppress dendrite formation. Therefore, in order to adjust the ion flow between the positive and negative electrodes and make the current distribution uniform, the porous support preferably has through-holes in its thickness direction. Furthermore, the through-holes in the porous support refer to holes that connect the first and second surfaces opposite each other in the thickness direction of the porous support. The through-holes only need to connect the first and second surfaces; for example, multiple voids in the porous support can be connected to connect the first and second surfaces, or a single void can be used to connect the first and second surfaces.

[0123] Porous carriers are not particularly limited as long as they are materials capable of forming pores and insoluble in electrolytes. Examples include polymers such as polybutadiene, polyisoprene, polystyrene, polycarbonate, polylactic acid, polycaprolactone, polyimide, polyamide, and polyolefins; and inorganic oxides such as silica, titanium dioxide, and alumina. Furthermore, porous carriers are not particularly limited as long as they can be manufactured using methods that allow for the formation of pores. For example, in the manufacture of honeycomb membranes, the breath figure method can be used to produce the membrane (SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS, 2018, Vol. 19, No. 1, pp. 802-822).

[0124] The electrolyte involved in the above embodiments is a plasticized cross-linked network polymer. Therefore, in order to manufacture the composite material, any method that supports the polymer on a porous carrier is acceptable, and any known method can be used. For example, a composite material can be manufactured by polymerizing a composition containing the monomer represented by formula (1), glycol dimethyl ether, and salt, which is held in the pores of a porous carrier by impregnation, coating, or the like.

[0125] In addition to the effects of the electrolyte involved in the embodiments, the composite material involved in the embodiments can also synergistically exert the following effects.

[0126] (1) In composite materials, the electrolyte is supported on a porous carrier, thus improving mechanical properties such as mechanical strength and thermal stability.

[0127] (2) When the porous carrier has through-holes in the thickness direction, the flow of ions is adjusted. Therefore, the composite material has high ion conductivity. In addition, it can make the current distribution uniform and suppress dendrite formation.

[0128] (3) When the porous carrier is a honeycomb membrane, the pores are arranged regularly without gaps, so the structure of the composite material becomes uniform and the flow of ions is easy to control.

[0129] (4) In composite materials, even if dendrites are formed, dendrite penetration can be prevented.

[0130] (Implementation method of secondary batteries)

[0131] Reference Figure 1 The secondary battery will be explained. Figure 1 This is a schematic cross-sectional view of a secondary battery. Secondary battery 1 sequentially comprises a positive electrode 2, an electrolyte layer 3, and a negative electrode 4. Positive electrode 2 comprises a positive current collector 5 and a positive active material layer 6. Negative electrode 4 comprises a negative current collector 7 and a negative active material layer 8.

[0132] The positive electrode current collector 5 can be any material as long as it does not undergo changes such as dissolution or oxidation during battery use. Examples include aluminum, stainless steel, titanium, and carbon materials. Furthermore, its shape is not limited; examples include perforated foil, porous metal mesh, and foamed metal sheets.

[0133] The thickness of the positive electrode current collector 5 can be 1 μm to 100 μm, preferably 5 μm to 50 μm, and more preferably 10 μm to 20 μm.

[0134] Examples of positive electrode active materials used in the positive electrode active material layer 6 include LiCoO2 and Li. 0.3 MnO2, Li4Mn5O 12 , V2O5, LiMn2O4, LiNiO2, LiFePO4, LiCo 1 / 3 N 1 / 3 Mn 1 / 3 O2, Li 1.2 (Fe 0.5 Mn 0.5 ), Li 1.2 (Fe 0.4 Mn 0.4 Ti 0.2 ) 0.8 O2, Li 1+x (Ni 0.5 Mn 0.5 ) 1-x O2 (where x = 0~1), LiNi 0.5 Mn 1.5 O4, Li2MnO3, Li 0.76 Mn 0.51 Ti 0.49 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, Fe2O3, LiCoPO4, LiMnPO4, Li2MPO4F (M=Fe, Mn), LiMn 0.875 Fe 0.125 PO4, Li2FESiO4, Li 2-x MSi 1-x P x O4 (M=Fe, Mn) (where x=0 to 1), LiMBO3 (M=Fe, Mn), FeF3, Li3FeF6, Li2FeS2, TiS2, MoS2, FeS.

[0135] The thickness of the positive electrode active material layer 6 can be 10 μm to 100 μm, preferably 20 μm to 80 μm, and more preferably 30 μm to 60 μm.

[0136] The electrolyte layer 3 can use the electrolyte or composite material involved in the embodiments. The thickness of the electrolyte layer 3 can be 1 μm to 200 μm, preferably 3 μm to 100 μm, and more preferably 5 μm to 70 μm. If the thickness is 1 μm or more, short circuits between electrodes can be prevented. In addition, if the thickness is 200 μm or less, the energy density can be improved.

[0137] The material of the negative electrode current collector 7 can be, for example, copper, stainless steel, titanium, nickel, carbon, etc. Furthermore, its shape is not limited; for example, it can be a perforated foil, a porous metal mesh, or a foamed metal plate.

[0138] The thickness of the negative electrode current collector 7 can be 1μm to 100μm, preferably 5μm to 50μm, and more preferably 10μm to 20μm.

[0139] The negative electrode active material used in the negative electrode active material layer 8 can include, for example, metallic lithium, lithium alloys, metal compounds, carbon materials, metal complexes, and organic polymer compounds. Among these, carbon materials are preferred. Examples of carbon materials include graphite, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal cracking black, amorphous carbon, and carbon fibers.

[0140] The secondary battery that uses the electrolyte or composite material involved in the embodiments for the electrolyte layer 3 can achieve a long lifespan by improving the mechanical durability of the electrolyte or composite material and by containing more cations in the electrolyte.

[0141] The following examples illustrate the implementation methods disclosed in this application, but these examples are for illustrative purposes only and do not limit or restrict the scope of the invention disclosed in this application.

[0142] Example

[0143] <Example 1>

[0144] [Manufacturing of Electrolyte 1]

[0145] The electrolyte shall be manufactured in the order described below.

[0146] 〔Material〕

[0147] • Poly(ethylene glycol) diacrylate (PEGDA; average molecular weight 700 (n~13), manufactured by Sigma-Aldrich) 0.2 ml (0.36 mol)

[0148] Tetraethylene glycol dimethyl ether (manufactured by Sigma-Aldrich) 0.17 ml (0.77 mol)

[0149] • Li[TFSI] (manufactured by Kanto Chemical Co., Ltd.) 0.22g (0.77mol)

[0150] [Manufacturing Method]

[0151] The above materials were mixed in a glass bottle and stirred overnight. DMPA (7.32 mg) was added to the solution, and stirring was continued for 2 hours. Next, the solution was transferred to a glass plate and photopolymerized by exposing the plate to a UV lamp (Chibi Light DX BOX-S1100) for 5 exposures every 5 minutes (365 nm, 20 W). The cured material was then peeled off the glass and dried in a vacuum oven at 60°C for 24 hours to produce electrolyte 1.

[0152] In the obtained electrolyte 1, the ratio of the number of moles of ethylene oxide units to the number of moles of lithium ions ([EO] / [Li)) + The value is 6.

[0153] <Example 2>

[0154] [Manufacturing of Electrolyte 2]

[0155] When manufacturing the electrolyte, 0.4 ml (0.71 mol) of PEGDA was used. Otherwise, electrolyte 2 was manufactured following the same procedures as in Example 1. The [EO] / [Li] ratio of the resulting electrolyte was... + The value is 12.

[0156] <Example 3>

[0157] [Manufacturing of Electrolyte 3]

[0158] When manufacturing the electrolyte, 0.7 ml (1.07 mol) of PEGDA was used. Otherwise, electrolyte 3 was manufactured following the same procedures as in Example 1. The [EO] / [Li] ratio of the resulting electrolyte was... + The value is 18.

[0159] <Example 4>

[0160] [Manufacturing of Electrolyte 4]

[0161] When manufacturing the electrolyte, 0.9 ml (1.43 mol) of PEGDA was used. Otherwise, electrolyte 4 was manufactured following the same procedures as in Example 1. The [EO] / [Li] ratio of the resulting electrolyte was... + The value is 24.

[0162] <Example 5>

[0163] [Temperature dependence of ionic conductivity of electrolytes 1-4]

[0164] The ionic conductivity of the electrolytes 1-4 prepared in Examples 1-4 was measured at multiple temperatures. A sample containing an electrolyte (8 mm in diameter) was placed within a battery assembly (manufactured by Hosen Co., Ltd.) using two stainless steel (SUS304, manufactured by Nilaco) electrodes. Ionic conductivity was measured using an AC impedance gauging device (Hioki 3532-80LCR HiTester). Measurements were performed at 5°C intervals within a temperature range of 25°C to 90°C. Sufficient time intervals were maintained between each temperature to ensure thermal equilibrium and data reproducibility.

[0165] The ionic conductivity of the electrolytes prepared in Examples 1-4, measured at various temperatures, is shown below. Figure 2 Electrolytes 1-4 showed linearity within the measured range. Furthermore, it was shown that electrolytes 1-4 possess sufficient ionic conductivity. Additionally, it was shown that the higher the lithium ion content in the electrolyte, the higher the ionic conductivity.

[0166] <Example 6>

[0167] [Mechanical properties of electrolytes]

[0168] Tensile / force-displacement measurements were performed using electrolyte 1 manufactured in Example 1. Electrolyte 1, approximately rectangular in shape (30 mm × 10 mm) and about 0.4 mm thick, was used as a sample. Using a measuring holder (manufactured by IMADA Co., Ltd.), the sample was pulled away from the measuring holder in the vertical direction at an elongation rate of 1.0 mm / min at room temperature, and the measurement was performed.

[0169] The results are shown in Figure 3 A. From Figure 3 As can be seen from A, electrolyte 1 has an elongation of approximately 30%, exhibiting good mechanical properties for extension. Therefore, it can prevent the effects of stress applied to the electrolyte. Furthermore, from... Figure 3 As shown in A, electrolyte 1 extends by about 10% with a small force. This demonstrates that electrolyte 1 is easily deformable even under relatively small forces. When the electrolyte is used in a secondary battery, the temperature changes, charging, and discharging caused by the battery's use result in expansion and contraction of the electrolyte, placing a load on it. However, since electrolyte 1 can deform even under relatively small forces, it is expected to suppress the effects of temperature changes and charging / discharging, and reduce the load on the electrolyte. Furthermore, because it deforms flexibly with relatively small forces, it is also expected to avoid short circuits between electrodes, reducing the risk of fire.

[0170] Figure 3 Figure B shows the results of experiments involving the stretching and bending of the prepared electrolyte 4 using tweezers. Figure 3Similarly, in A, it was confirmed that the electrolyte extended well.

[0171] <Example 7>

[0172] [Charge and discharge characteristics of electrolyte 1]

[0173] The electrolyte 1 manufactured in Example 1 was used for polarization treatment. In the polarization test, a symmetrical cell composed of Li / electrolyte 1 / Li was used at 60°C for 30 minutes and 0.1 mA / cm². 2 The current density is used to repeatedly charge and discharge the device.

[0174] The results of the polarization experiment are shown in Figure 4 .from Figure 4 It can be confirmed that even after 100 hours, the Li / electrolyte 1 / Li battery maintains stable charge and discharge performance. Further analysis from... Figure 4 It can be inferred that even after a period of time, the voltage decay is very gradual, thus maintaining stable charge-discharge characteristics even after 100 hours. Therefore, when electrolyte 1 is used in a secondary battery, it is expected to produce a long-life secondary battery.

[0175] <Example 8>

[0176] [Linear sweep voltammetry for electrolyte 1]

[0177] Linear sweep voltammetry (LSV) was performed using electrolyte 1 manufactured in Example 1.

[0178] Using a battery constructed from stainless steel (SUS304, manufactured by Nilaco) / electrolyte 1 / Li, the scan range was set to 1.0–7.0 V (vs. Li). + The voltage ( / Li) was scanned at a rate of 1 mV / s for measurement. The measurement temperature was set to 60°C. The measuring apparatus used was a 1470E potentiostat / galvanostat (manufactured by Solartron Analytical).

[0179] The results are shown in Figure 5 .from Figure 5 As shown, electrolyte 1 stabilizes at around 4.5V. This indicates that electrolyte 1 has a wide potential window.

[0180] <Example 9>

[0181] [Calculation of lithium-ion mobility for electrolyte 1]

[0182] The lithium-ion mobility (t) of electrolyte 1 was calculated using chronoamperometric analysis and AC impedance spectroscopy.Li+ ).

[0183] Regarding lithium-ion mobility (t) Li+ The current was calculated using a Li / electrolyte 1 / Li battery assembled inside an argon-filled glove box (O2 and H2O < 0.1 ppm) through chronoamperometry and AC impedance spectroscopy. In the chronoamperometry, an initial current (I0) was measured by applying a potential of 10 mV to the battery after it had stabilized at 60°C overnight. Then, a potential of 10 mV was continuously applied to the battery, and the steady-state current (I0) was measured when the current reached a stable value. s In addition, in the AC impedance measurement, the initial interface resistance (R0) of the battery stabilized overnight at 60°C and the stable interface resistance (R) of the battery that reached a stable state after being subjected to a potential of 10mV were measured. s The measurements were performed using a frequency response analyzer (1470E, manufactured by Solartron Analytical). Li+ It is calculated using the Bruce-Vincent-Evans formula as shown below.

[0184] [Mathematical Expression 1]

[0185]

[0186] The results of the chronoamperometric analysis are shown in Figure 6 A. Additionally, the results of the AC impedance measurement are shown in... Figure 6 B. From Figure 6 A and Figure 6 The result shown in B calculates the t of electrolyte 1. Li+ t of electrolyte 1 Li+ It is 0.30.

[0187] <Example 10>

[0188] [Manufacturing of Composite Material 1]

[0189] 〔Material〕

[0190] ·1,2-Polybutadiene (RB820, manufactured by JSR Corporation)

[0191] • The surfactant represented by the following formula (3) (in formula (3), X is approximately 0.8, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0192] • Poly(ethylene glycol) diacrylate (PEGDA; average molecular weight 700 (n-13), manufactured by Sigma-Aldrich) 0.9 ml (1.43 mmol)

[0193] Tetraethylene glycol dimethyl ether (manufactured by Sigma-Aldrich) 0.6819 ml (3.0 mmol)

[0194] • Li [TFSI] (manufactured by Kanto Chemical Co., Ltd.) 0.8886g (3.0mmol)

[0195] [Chemical Formula 5]

[0196]

[0197] [Creating a honeycomb membrane]

[0198] [1] 1,2-polybutadiene and the surfactant represented by formula (3) were mixed at a weight ratio of 10:1 to prepare a solution of 5.0 mg / ml.

[0199] [2] The adjusted solutions were cast onto a 10cm×30cm glass substrate in volumes of 20ml, 25ml and 45ml respectively.

[0200] [3] Cellular membranes with pore sizes of 3 μm, 8 μm and 14 μm were obtained by blowing humidified air (relative humidity >90%, flow rate 130 l / min). Figure 7 This shows a scanning electron microscope image taken along the thickness of a 3 μm pore size honeycomb film. Figure 7 The honeycomb film is shown to have through holes in the thickness direction.

[0201] [Fabrication of Composite Material 1]

[0202] [1] The honeycomb membrane with a pore size of 3 μm prepared above was scooped into ethanol or water and placed onto a PET film frame cut out of 50 mm square, and then dried.

[0203] [2] A mixed solution of PEGDA, tetraethylene glycol dimethyl ether, LiTFSI, and DMPA (7.32 mg) was spread on a culture dish, and a honeycomb membrane was placed on it. The mixed solution was then coated onto the honeycomb membrane. Additionally, the [EO] / [Li] ratio in the mixed solution... + The value is 6.

[0204] [3] The honeycomb membrane coated with the mixed solution was degassed from the mixed solution under reduced pressure to remove air bubbles, and then photocrosslinked with UV light (wavelength 365 nm, 20 W) in the same manner as when using electrolyte alone, to obtain composite material 1. The obtained composite material 1 was annealed at 60 °C for 24 hours to complete the crosslinking. In addition, the presence of electrolyte in the through-holes was confirmed by observation with a scanning electron microscope.

[0205] <Example 11>

[0206] [Temperature dependence of ionic conductivity of composite material 1]

[0207] The ionic conductivity of composite material 1 manufactured in Example 10 was measured at multiple temperatures. The measurements were the same as in Example 5, except that the sample was used as composite material 1.

[0208] The results are shown in Figure 8 Composite material 1 exhibits linearity within the measurement range. Furthermore, composite material 1 also exhibits 10% linearity at room temperature. -4 The composite material exhibits high ionic conductivity exceeding S / cm. This is attributed to the presence of electrolytes loaded on the honeycomb membrane, which inhibits ion diffusion and modulates ion conduction flow, thus enhancing the ionic conductivity of the composite material 1.

[0209] <Example 12>

[0210] [Charge-discharge characteristics of composite material 1]

[0211] The composite material 1 manufactured in Example 10 was subjected to polarization treatment. In the polarization test, a composite battery consisting of Li foil / composite material 1 / LiFePO4 (LFP) electrode was used, and charge-discharge tests were conducted at 60°C using a 580 Battery Test System (manufactured by Scribner Associates).

[0212] The results are shown in Figure 9 .from Figure 9 A was confirmed to be able to perform stable charging and discharging even after 100 hours. Figure 9 B was confirmed to maintain stable charge and discharge even after 700 hours. Furthermore, compared to... Figure 9 A and Figure 9 B, then Figure 9 The voltage decay of B is significant. However, the voltage decay is very gradual. Therefore, when composite material 1 is used in a secondary battery, a long-life secondary battery can be expected.

[0213] <Example 13>

[0214] [LSV determination of composite material 1]

[0215] LSV was performed using composite material 1 manufactured in Example 10. The determination was the same as in Example 8, except that the sample was composite material 1.

[0216] The results are shown in Figure 10 . Figure 10The composite material 1 is shown to stabilize to around 4.7V. This demonstrates that composite material 1 has a wide potential window. Furthermore, it is shown that the composite material has a wider potential window than the electrolyte alone (Example 8).

[0217] <Example 14>

[0218] [Li in composite material 1] + [Calculation of mobility]

[0219] Using the composite material 1 manufactured in Example 10, chronoamperometry and AC impedance spectroscopy were performed to calculate the Li of the composite material. + Mobility. Besides using the sample as composite material 1, Li + The mobility calculation is the same as in Example 9.

[0220] The results of the chronoamperometric analysis are shown in Figure 11 A. Additionally, the results of the AC impedance measurement are shown in... Figure 11 B. By Figure 11 A and Figure 11 The result shown in B calculates the t of composite material 1. Li+ , result t Li+ It is 0.416.

[0221] <Example 15>~<Example 23>

[0222] [Manufacturing of Electrolytes 5 to 13]

[0223] In manufacturing the electrolytes, electrolytes 5 to 13 were manufactured using the same steps as in Example 1, except that the materials were added in the amounts shown in Table 1 below. The resulting electrolytes 5 to 13 had a [EO] / [Li] ratio of... + As shown in Table 1.

[0224] [Table 1]

[0225]

[0226] Electrolytes 5, 9, and 13 produced are shown in... Figure 12 Electrolytes 5, 9, and 13, which used different average molecular weights of PEGDA, were all transparent and retained their shape even when held with tweezers. Since electrolytes 5, 9, and 13 maintained their shape even when held with tweezers, they are considered to possess sufficient mechanical strength.

[0227] <Example 24>

[0228] [Temperature dependence of ionic conductivity of electrolytes 5-13]

[0229] The ionic conductivity of electrolytes 5-13 manufactured in Examples 15-23 was measured at multiple temperatures. The measurements were the same as in Example 5, except that the samples were electrolytes 5-13.

[0230] The ionic conductivity of electrolytes 5-13 manufactured in Examples 15-23, measured at various temperatures, is shown below. Figure 13 . Figure 13 Figure A shows the results of using electrolytes 5-8 with PEGDA of average molecular weight 250 (n-3). Figure 13 Figure B shows the results of using electrolytes 9-12 with PEGDA of average molecular weight 575 (n-10). Figure 13 Figure C shows the results for electrolyte 13 using PEGDA with an average molecular weight of 1000 (n ~ 20). Electrolytes 5 to 13 showed linearity within the measurement range. Furthermore, it was shown that electrolytes 5 to 13 possess sufficient ionic conductivity. Additionally, it was shown that the ionic conductivity of the electrolyte tends to increase as the average molecular weight of the PEGDA used increases.

[0231] The above results demonstrate that the electrolyte disclosed in this application does not break even when bent, exhibiting sufficient flexibility. Furthermore, the composite material using the electrolyte is shown to be more stable and has a higher migration rate compared to the electrolyte alone.

[0232] Industrial application

[0233] The electrolyte disclosed in this application can provide an electrolyte that is elastic and flexible. Furthermore, since the electrolyte can be used in batteries, it is useful in the field of battery technology.

[0234] Symbol Explanation

[0235] 1: Secondary battery;

[0236] 2: Anode;

[0237] 3: Electrolyte layer;

[0238] 4: Negative electrode;

[0239] 5: Positive current collector;

[0240] 6: Positive electrode active material layer;

[0241] 7: Negative electrode current collector;

[0242] 8: Negative electrode active material layer.

Claims

1. An electrolyte comprising: A polymer that has polymerized monomers represented by the following formula (1); [Chemical Formula 1] Dimethyl glycol ether represented by the following formula (2); and [Chemical Formula 2] Choose at least one salt from the group consisting of lithium, sodium, magnesium, potassium, and calcium salts. In formula (1), R1 and R2 each independently represent H or a straight-chain, branched, or cyclic alkyl group with 1 to 20 carbon atoms, and X1 and X2 each independently represent O or NH. When X2 is O, n averages an integer from 0 to 30; when X2 is NH, n averages an integer from 1 to 30. In formula (2), R3 and R4 each independently represent alkyl groups with 1 to 4 carbon atoms, and m represents an integer from 1 to 4. The glycol dimethyl ether is a plasticizer for the polymer. The monomer functions as a solvent, therefore no organic solvents are used in the manufacturing process of the electrolyte.

2. The electrolyte according to claim 1, wherein, The anion of the salt is selected from PF6. - BF4 - ClO4 - B(C2O4)2 - N(FSO2)2 - and N(CF3SO2)2 - At least one of the groups.

3. The electrolyte according to claim 2, wherein, The anion of the salt is N(FSO2)2. - or N(CF3SO2)2 - .

4. The electrolyte according to any one of claims 1 to 3, wherein, The salt is a lithium salt.

5. The electrolyte according to any one of claims 1 to 3, wherein, In equation (1), when X2 is 0, the average value of n is 3 to 14, and when X2 is NH, the average value of n is 4 to 15.

6. The electrolyte according to any one of claims 1 to 3, wherein, In equation (2), m is 4.

7. A secondary battery, comprising at least: anode; cathode; as well as The electrolyte layer between the anode and cathode, The electrolyte layer is the electrolyte according to any one of claims 1 to 6.

8. A composite material, comprising: The electrolyte according to any one of claims 1 to 6; and Porous carrier.

9. The composite material according to claim 8, wherein, Porous carriers include through holes that extend through the thickness direction.

10. The composite material according to claim 8 or 9, wherein, The porous carrier is a honeycomb membrane.

11. A secondary battery, comprising at least: anode; cathode; as well as The electrolyte layer between the anode and cathode, The electrolyte layer is the composite material according to any one of claims 8 to 10.

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