Electrochemical device, composition, electrode mixture, electrode, and secondary battery

Abstract

To provide an electrochemical device which is excellent in an initial capacity and a capacity maintenance rate, and a composition, an electrode mixture, an electrode and a secondary battery which can improve an initial capacity and a capacity maintenance rate of an electrochemical device.SOLUTION: An electrochemical device includes an electrode active substance and a lithium replenishing agent in a positive electrode and / or a negative electrode, and includes a fibrillated resin in the positive electrode and / or the negative electrode.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an electrochemical device, a composition, an electrode binder, an electrode, and a secondary battery.

Background Art

[0002] Secondary batteries such as lithium-ion secondary batteries are used in small and portable electrical and electronic devices such as notebook computers, mobile phones, smartphones, tablet computers, and ultrabooks because of their high voltage, high energy density, low self-discharge, low memory effect, and ultra-lightweight. Furthermore, they are being put into practical use as a wide range of power sources, from in-vehicle power sources for driving such as those for automobiles to large stationary power sources. There is a demand for further increasing the energy density of secondary batteries and further improving battery characteristics.

[0003] Patent Document 1 and Non-Patent Document 1 describe adding lithium compounds such as Li2NiO2 and Li5FeO4 to the positive electrode of a battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present disclosure aims to provide an electrochemical device excellent in initial capacity and capacity retention rate, and a composition, an electrode binder, an electrode, and a secondary battery capable of improving the initial capacity and capacity retention rate of the electrochemical device.

Means for Solving the Problems

[0007] The present disclosure (1) is an electrochemical device including an electrode active material and a lithium replenishing agent in a positive electrode and / or a negative electrode, and including a fibrillatable resin in the positive electrode and / or the negative electrode.

[0008] The present disclosure (2) is the electrochemical device according to the present disclosure (1), wherein the lithium replenishing agent is at least one selected from the group consisting of Li5FeO4, Li5AlO, and Li2NiO2.

[0009] The present disclosure (3) is the electrochemical device according to the present disclosure (1) or (2), wherein the lithium replenishing agent is at least one selected from the group consisting of Li5FeO4 and Li2NiO2.

[0010] The present disclosure (4) is the electrochemical device according to any one of the present disclosures (1) to (3), having a coating layer of the lithium replenishing agent on the surface of the electrode active material.

[0011] The present disclosure (5) is the electrochemical device according to any one of the present disclosures (1) to (4), wherein the negative electrode includes at least one selected from the group consisting of graphite and Si.

[0012] The present disclosure (6) is the electrochemical device according to any one of the present disclosures (1) to (5), wherein the positive electrode and / or the negative electrode including the fibrillatable resin is manufactured by a dry process.

[0013] The present disclosure (7) is the electrochemical device according to any one of the present disclosures (1) to (6), wherein the fibrillatable resin is a tetrafluoroethylene-based polymer.

[0014] The present disclosure (8) is an electrochemical device according to any one of the present disclosures (1) to (7), wherein the fibrillatable resin is polytetrafluoroethylene.

[0015] The present disclosure (9) is an electrochemical device according to any one of the present disclosures (1) to (8), wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene composed only of a polymerization unit based on a tetrafluoroethylene unit and a hexafluoropropylene unit.

[0016] The present disclosure (10) is an electrochemical device according to any one of the present disclosures (1) to (9), wherein the amount of the fibrillatable resin with respect to the electrode binder in the positive electrode and / or the negative electrode is 0.3 to 10% by mass.

[0017] The present disclosure (11) is an electrochemical device according to any one of the present disclosures (1) to (10), wherein the positive electrode contains the lithium replenishing agent and the fibrillatable resin.

[0018] The present disclosure (12) is an electrochemical device according to any one of the present disclosures (1) to (11), which is an electrolytic solution secondary battery or an electrolytic solution capacitor.

[0019] The present disclosure (13) is an electrochemical device according to any one of the present disclosures (1) to (12), which is a lithium ion secondary battery.

[0020] The present disclosure (14) is a composition containing a lithium replenishing agent and a fibrillatable resin.

[0021] The present disclosure (15) is a composition according to the present disclosure (14), wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene composed only of a polymerization unit based on a tetrafluoroethylene unit and a hexafluoropropylene unit.

[0022] The present disclosure (16) is the composition according to the present disclosure (14) or (15), wherein the lithium replenisher is at least one selected from the group consisting of Li5FeO4 and Li2NiO2.

[0023] The present disclosure (17) is the composition according to any one of the present disclosures (14) to (16), wherein the total amount of the lithium replenisher and the fibrillatable resin with respect to the composition is 95% by mass or more.

[0024] The present disclosure (18) is the composition according to any one of the present disclosures (14) to (17), wherein the mass ratio of the fibrillatable resin to the Li replenisher (fibrillatable resin / Li replenisher) is 50 / 50 or more and 70 / 30 or less.

[0025] The present disclosure (19) is the composition according to any one of the present disclosures (14) to (18), wherein the liquid amount is 10% by mass or less.

[0026] The present disclosure (20) is the composition according to any one of the present disclosures (14) to (19), which is a powder.

[0027] The present disclosure (21) is the composition according to any one of the present disclosures (14) to (20), which is a binder for an electrochemical device.

[0028] The present disclosure (22) is the composition according to any one of the present disclosures (14) to (21), which is a binder for a lithium-ion secondary battery.

[0029] The present disclosure (23) is an electrode mixture containing the composition according to any one of the present disclosures (14) to (22) and an electrode active material.

[0030] The present disclosure (24) is the electrode mixture according to the present disclosure (23), which is a sheet.

[0031] The present disclosure (25) is an electrode containing the composition according to any one of the present disclosures (14) to (22), an electrode active material, and a current collector.

[0032] The present disclosure (26) is a secondary battery including an electrode mixture described in the present disclosure (23) and a current collector.

Advantages of the Invention

[0033] According to the present disclosure, it is possible to provide an electrochemical device excellent in initial capacity and capacity retention rate, and a composition, an electrode mixture, an electrode, and a secondary battery capable of improving the initial capacity and capacity retention rate of the electrochemical device.

Modes for Carrying Out the Invention

[0034] In the present disclosure, the “organic group” means a group containing one or more carbon atoms, or a group formed by removing one hydrogen atom from an organic compound. As the above organic group, an alkyl group which may have one or more substituents is preferable.

[0035] Hereinafter, the present disclosure will be specifically described.

[0036] The present disclosure provides an electrochemical device including an electrode active material and a lithium (Li) replenisher in a positive electrode and / or a negative electrode, and including a fibrillatable resin in the positive electrode and / or the negative electrode.

[0037] The electrochemical device of the present disclosure has the above configuration, and thus is excellent in initial capacity and capacity retention rate. When a fibrillatable resin such as a TFE-based polymer is used as a binder, the fibrillatable resin may react with Li in the system, and Li necessary for the electrochemical device reaction may be lost. Further, when a Si-based active material such as Si or SiO is used for the negative electrode, particularly at the first charge, Li in the system may be irreversibly consumed by the reaction with these active materials. The above Li replenisher is a compound capable of irreversibly releasing Li and can supplement the lost Li, so that the initial capacity and capacity retention rate of the electrochemical device can be improved.

[0038] In the electrochemical device of the present disclosure, the above Li replenisher may be contained in only one of the positive electrode and the negative electrode, or may be contained in both. However, in terms of further improving the initial capacity and capacity retention rate, it is preferably contained in the positive electrode. The above fibrillatable resin may be contained in only one of the positive electrode and the negative electrode, or may be contained in both. In addition, the above Li replenisher and the above fibrillatable resin may be contained in the same electrode, or may be contained in separate electrodes. Among these, it is preferable that at least the positive electrode contains the above Li replenisher and the above fibrillatable resin.

[0039] The above Li replenisher may be a Li-containing compound that undergoes an oxidation reaction in the charge-discharge potential range of the positive electrode active material and does not substantially undergo a reduction reaction. "Undergoes an oxidation reaction in the charge-discharge potential range of the positive electrode active material" means that in the charge-discharge potential range of the positive electrode active material, it is possible to undergo an oxidation reaction and release Li ions and electrons (including being decomposed by the oxidation reaction and releasing Li ions). Also, "does not substantially undergo a reduction reaction in the charge-discharge potential range of the positive electrode active material" means that in the charge-discharge potential range of the positive electrode active material, under normal reaction conditions for those skilled in the art, it is impossible or substantially impossible to undergo a reduction reaction and receive Li ions and electrons, or to be generated through a reduction reaction. "Normal reaction conditions for those skilled in the art" means, for example, the conditions when discharging a lithium secondary battery. Also, "it is substantially impossible to undergo a reduction reaction and receive Li ions and electrons, or to be generated through a reduction reaction" means that among the Li replenisher oxidized by charging the battery, in terms of volume ratio, 80% or more of the Li replenisher cannot undergo a reduction reaction and receive Li ions and electrons, or be generated through a reduction reaction. "Charge-discharge potential range of the positive electrode active material" means the potential range in which the oxidation reaction and reduction reaction of the positive electrode active material contained in the positive electrode can occur. Since the Li replenisher can sufficiently supply Li to the negative electrode during the first charge, it can replenish the Li consumed at the negative electrode in subsequent cycles, and can improve the initial capacity and capacity retention rate of the electrochemical device.

[0040] Examples of the above Li replenisher include lithium oxides such as Li2O2; lithium nitrides such as Li3N; Li 1+x (Ti 1-y Fe y ) 1-x O2 (0 < x ≤ 0.25, 0.4 < y ≤ 0.9), Li 2-x Ti 1-z Fe z O 3-y (0 ≤ x < 2, 0 ≤ y ≤ 1, 0.05 ≤ z ≤ 0.95), iron-based lithium oxides such as Li5FeO4; Li5AlO; Li2NiO2, etc. One or more of these can be used. Among them, at least one selected from the group consisting of iron-based lithium oxides, Li5AlO, and Li2NiO2 is preferable, at least one selected from the group consisting of Li5FeO4, Li5AlO, and Li2NiO2 is more preferable, at least one selected from the group consisting of Li5FeO4 and Li2NiO2 is still more preferable, and Li5FeO4 is even more preferable.

[0041] The content of the above Li replenisher is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, even more preferably 2.0% by mass or more, and preferably 10% by mass or less, more preferably 8.0% by mass or less, still more preferably 7.0% by mass or less, even more preferably 5.0% by mass or less, even more preferably 4.0% by mass or less with respect to the electrode binder in the electrode (positive electrode and / or negative electrode) containing the Li replenisher in terms of further improving the initial capacity and capacity retention rate of the electrochemical device.

[0042] In the electrochemical device of the present disclosure, the fibrillatable resin may function as a binder for holding an electrode active material or the like.

[0043] The fibrillatable resin is a resin that easily fibrillates when a shear stress is applied. A higher molecular weight makes it easier to fibrillate. The molecular weight of the fibrillatable resin is, for example, 500,000 or more, preferably 1,000,000 or more, more preferably 5,000,000 or more, still more preferably 10,000,000 or more, even more preferably 20,000,000 or more, and may be 200,000,000 or less. The above molecular weight may be the number average molecular weight (Mn) and can be determined by the following formula. SSG = -0.0579 log Mn + 2.6113 In the formula, SSG is the standard specific gravity of the polymer, and is measured by the water displacement method in accordance with ASTM D 792 using a sample molded in accordance with ASTM D 4895 89.

[0044] The fibrillatable resin is preferably polymerized using a fluorine-containing surfactant, and also preferably polymerized using a hydrocarbon surfactant, and more preferably polymerized using a hydrocarbon surfactant, in that it can further improve the initial capacity and capacity retention rate of the electrochemical device, and in that the powder fluidity is further improved.

[0045] The fibrillatable resin preferably has a thermal instability index (TII) of 10 or more. A fibrillatable resin having a TII of 10 or more can be obtained by using a hydrocarbon surfactant. In terms of further improving the initial capacity and capacity retention rate of the electrochemical device, and in terms of further improving the powder fluidity, the TII is more preferably 15 or more, still more preferably 20 or more, even more preferably 25 or more, and preferably 80 or less, more preferably 50 or less. The above TII is measured in accordance with ASTM D 4895-89.

[0046] The fibrillatable resin may have a 0.1% mass loss temperature of 400 °C or less. The fibrillatable resin with a 0.1% mass loss temperature of 400 °C or lower can be obtained by using a hydrocarbon-based surfactant. The above 0.1% mass loss temperature is the value measured by the following method. Precisely weigh about 10 mg of the fibrillatable resin without a heating history at a temperature of 300 °C or higher, place it in a dedicated aluminum pan, and measure it with a TG·DTA (differential thermal and thermogravimetric simultaneous measurement device). The 0.1% mass loss temperature is the temperature corresponding to the point where the weight loss is ".1 mass% when the temperature of the aluminum pan is raised from 25 °C to 600 °C at a rate of 10 °C / min in an air atmosphere.

[0047] The above fibrillatable resin may have a 1.0% mass loss temperature of 492 °C or lower. The fibrillatable resin with a 1.0% mass loss temperature of 492 °C or lower can be obtained by using a hydrocarbon-based surfactant. The above 1.0% mass loss temperature is the value measured by the following method. Precisely weigh about 10 mg of the fibrillatable resin without a heating history at a temperature of 300 °C or higher, place it in a dedicated aluminum pan, and measure it with a TG·DTA (differential thermal and thermogravimetric simultaneous measurement device). The 1.0% mass loss temperature is the temperature corresponding to the point where the weight loss is 1.0 mass% when the temperature of the aluminum pan is raised from 25 °C to 600 °C at a rate of 10 °C / min in an air atmosphere.

[0048] The above fibrillatable resin preferably has an endothermic peak temperature exceeding 330 °C, more preferably 333 °C or higher, still more preferably 335 °C or higher, even more preferably 337 °C or higher, particularly preferably 340 °C or higher, and also preferably 350 °C or lower, more preferably 346 °C or lower, in that it can form a composite sheet with even better strength. The above endothermic peak temperature is the temperature corresponding to the minimum point in the melting heat curve obtained by performing differential scanning calorimetry [DSC] on the fibrillatable polymer without a heating history at a temperature of 300 °C or higher at a heating rate of 10 °C / min. When there are two or more minimum points in one melting peak, each is taken as the endothermic peak temperature.

[0049] Examples of the fibrillatable resin include tetrafluoroethylene (TFE)-based polymers, polyethylene, polyester, liquid crystal polymer (LCP), acrylic resin, and the like. As the fibrillatable resin, TFE-based polymers, polyethylene, and polyester are preferable, and TFE-based polymers are more preferable.

[0050] The TFE-based polymer may be a homopolymer of TFE or a TFE copolymer containing a polymerization unit based on TFE (TFE unit) and a polymerization unit based on a modified monomer copolymerizable with TFE (modified monomer unit). The TFE-based polymer may be polytetrafluoroethylene (PTFE). The PTFE includes a homopolymer of TFE and a modified PTFE containing 99.0 mass% or more of TFE units and 1.0 mass% or less of modified monomer units. The TFE-based polymer is preferably PTFE and more preferably modified PTFE in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. In the present disclosure, the TFE copolymer refers to one having a content of modified monomer units of 10 mass% or less with respect to all polymerization units, and the homopolymer of TFE refers to one having a content of modified monomer units of less than 0.0001 mass% with respect to all polymerization units.

[0051] The content of the modified monomer unit is preferably in the range of 0.0001 to 10% by mass with respect to all polymerization units in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. As the lower limit of the content of the modified monomer unit, 0.001% by mass is more preferable, 0.010% by mass is still more preferable, 0.015% by mass is still more preferable, and 0.020% by mass is particularly preferable. As the upper limit of the content of the modified monomer unit, 5.0% by mass is preferable, 3.0% by mass is more preferable, 1.0% by mass is still more preferable, 0.80% by mass is still more preferable, 0.60% by mass is still more preferable, 0.50% by mass is still more preferable, 0.40% by mass is still more preferable, 0.30% by mass is still more preferable, and 0.20% by mass is particularly preferable. In this specification, the above-mentioned modified monomer unit means a part of the molecular structure of the TFE-based polymer that is derived from the modified monomer.

[0052] The content of each of the above-mentioned polymerization units can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the type of monomer.

[0053] The above-mentioned modified monomer is not particularly limited as long as it can copolymerize with TFE. For example, perfluoroolefins such as hexafluoropropylene [HFP]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perhaloolefins such as chlorotrifluoroethylene [CTFE]; perfluorovinyl ether; perfluoroallyl ether; (perfluoroalkyl)ethylene, ethylene, monomers having a polar group, etc. can be mentioned. Further, the modified monomer used may be one type or a plurality of types.

[0054] The above-mentioned perfluorovinyl ether is not particularly limited. For example, the following general formula (A): CF2=CF-ORf 1 (A) (In the formula, Rf 1represents a perfluoro organic group. Examples include perfluoro unsaturated compounds represented by (). In this specification, the above "perfluoro organic group" means an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The above perfluoro organic group may have an ether oxygen.

[0055] Examples of the above perfluorovinyl ether include perfluoro(alkyl vinyl ether) [PAVE]. Preferably, in the above general formula (A), Rf 1 is PAVE in which the perfluoroalkyl group has 1 to 10 carbon atoms. The number of carbon atoms of the above perfluoroalkyl group is preferably 1 to 5.

[0056] Examples of the perfluoroalkyl group in the above PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, and the like.

[0057] Examples of the above perfluorovinyl ether further include those in which, in the above general formula (A), Rf 1 is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms, and Rf 1 is a group represented by the following formula:

[0058]

Chemical formula

[0059] (wherein m represents an integer of 0 or 1 to 4), and those in which Rf 1 is a group represented by the following formula:

[0060]

Chemical formula

[0061] (wherein n represents an integer of 1 to 4), and the like.

[0062] (Perfluoroalkyl)ethylene [PFAE] is not particularly limited. For example, (perfluorobutyl)ethylene [PFBE], (perfluorohexyl)ethylene, etc. can be mentioned.

[0063] As the perfluoroallyl ether, for example, the general formula (B): CF2=CF-CF2-ORf 2 (B) (In the formula, Rf 2 represents a perfluoro organic group.) The fluoromonomer represented by is mentioned.

[0064] The above Rf 2 is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. As the above perfluoroallyl ether, at least one selected from the group consisting of CF2=CF-CF2-O-CF3, CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9 is preferable, at least one selected from the group consisting of CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9 is more preferable, and CF2=CF-CF2-O-CF2CF2CF3 is still more preferable.

[0065] The above modified monomer is represented by the following general formula (i): CX 1 X 2 =CX 3 X 4 (i) (In the formula, X 1 ~X 3 are each independently H or F. X 4 is F, Cl, Rf or O-Rf. Rf is a perfluoro organic group.) It is preferably a compound represented by.

[0066] As Rf in the general formula (i), a perfluoroalkyl group having 1 to 10 carbon atoms is preferable, a perfluoroalkyl group having 1 to 5 carbon atoms is more preferable, and a perfluoroalkyl group having 1 to 4 carbon atoms is still more preferable.

[0067] The monomer having the polar group may be a non-fluorinated monomer or a fluorinated monomer.

[0068] Examples of the non-fluorinated monomer include non-fluorinated monomers having a hydroxyl group such as hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether; non-fluorinated monomers having a carboxy group such as acrylic acid, methacrylic acid, itaconic acid, succinic acid, fumaric acid, crotonic acid, maleic acid, citraconic acid, undecylenic acid, and acetylenedicarboxylic acid; non-fluorinated monomers having an acid anhydride residue such as itaconic anhydride (hereinafter also referred to as "IAH"), citraconic anhydride (hereinafter also referred to as "CAH"), 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), succinic anhydride, fumaric anhydride, and maleic anhydride; non-fluorinated monomers having a sulfo group such as vinylsulfonic acid; non-fluorinated monomers having an epoxy group (glycidyl group) such as glycidyl vinyl ether and glycidyl allyl ether; non-fluorinated monomers having an amino group such as aminoalkyl vinyl ether and aminoalkyl allyl ether; non-fluorinated monomers having an amide group such as (meth)acrylamide and methylolacrylamide; non-fluorinated monomers having a nitrile group such as acrylonitrile and methacrylonitrile, and the like. Among these, non-fluorinated monomers having a carboxy group and non-fluorinated monomers having an acid anhydride residue are preferable, non-fluorinated monomers having an acid anhydride residue are more preferable, and cyclic non-fluorinated monomers having an acid anhydride residue are still more preferable.

[0069] The monomer having the above polar group preferably includes a modified monomer having a functional group capable of reacting by radical polymerization and a hydrophilic group (hereinafter referred to as "modified monomer (A)").

[0070] Examples of the hydrophilic group in the above modified monomer (A) include -NH2, -PO3M, -OPO3M, -SO3M, -OSO3M, -COOM (in each formula, M is H, a metal atom, NR 7 4, imidazolium which may have a substituent, pyridinium which may have a substituent or phosphonium which may have a substituent, R 7 is H or an organic group, and they may be the same or different. Any two of them may be bonded to each other to form a ring.). Among the above hydrophilic groups, -SO3M or -COOM is preferable. R 7 is preferably H or an organic group of C 1-10 is more preferably H or an organic group of C 1-4 is still more preferably H or an alkyl group of C 1-4 . Examples of the above metal atom include monovalent and divalent metal atoms, such as alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K or Li is preferable.

[0071] Examples of the "functional group capable of reacting by radical polymerization" in the above modified monomer (A) include groups having an ethylenically unsaturated bond such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond has the following formula: CX e X g =CX f R- (In the formula, X e , X f and X g are each independently F, Cl, H, CF3, CF2H, CFH2, or CH3; and R is a linking group.). Examples of the linking group of R include the linking group as R a described later. Preferably -CH=CH2, -CF=CH 2、 -CH=CF 2、Groups having an unsaturated bond such as -CF=CF2, -CH2-CH=CH2, -CF2-CF=CH2, -CF2-CF=CF2, -(C=O)-CH=CH2, -(C=O)-CF=CH2, -(C=O)-CH=CF2, -(C=O)-CF=CF2, -(C=O)-C(CH3)=CH2, -(C=O)-C(CF3)=CH2, -(C=O)-C(CH3)=CF2, -(C=O)-C(CF3)=CF2, -O-CH2-CH=CH2, -O-CF2-CF=CH2, -O-CH2-CH=CF2, -O-CF2-CF=CF2, etc. are exemplified.

[0072] Since the above-mentioned modified monomer (A) has a functional group capable of reacting by radical polymerization, when used in polymerization, it reacts with the fluorine-containing monomer in the initial stage of the polymerization reaction, and it is presumed that particles having a hydrophilic group derived from the above-mentioned modified monomer (A) and having high stability are formed. Therefore, when polymerization is carried out in the presence of the above-mentioned modified monomer (A), it is considered that the number of particles increases.

[0073] The above-mentioned modified monomer (A) may be used alone or in combination of two or more.

[0074] As the above-mentioned modified monomer (A), a compound having an unsaturated bond can be used.

[0075] The modified monomer (A) is preferably at least one selected from the group consisting of compounds represented by the following formulas (4a) to (4e). CF2=CF-(CF2) n1 -Y 3 (4a) (In the formula, n1 represents an integer of 1 to 10, and Y 3 represents -SO3M 1 or -COOM 1 and M 1 represents H, NH4 or an alkali metal.) CF2=CF-(CF2C(CF3)F) n2 -Y 3 (4b) (In the formula, n2 represents an integer of 1 to 5, and Y 3 is the same as the above definition.) CF2=CF-O-(CFX 1 ) n3 -Y 3 (4c) (In the formula, X 1 represents F or CF3, n3 represents an integer from 1 to 10, and Y 3 is the same as defined above.) CF2=CF-O-(CF2CFX 1 O) n4 -CF2CF2-Y 3 (4d) (In the formula, n4 represents an integer from 1 to 10, and Y 3 and X 1 are the same as defined above.) CX 2 2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-Y 3 (4e) (In the formula, each X 2 is the same, and represents F or H. n5 represents 0 or an integer from 1 to 10, and Y 3 is the same as defined above.) Examples of the alkali metal include Na, K, etc.

[0076] In the above formula (4a), n1 is preferably an integer of 5 or less, more preferably an integer of 2 or less. The above Y 3 is preferably -COOM 1 in terms of obtaining appropriate water solubility and surface activity, and M 1 is preferably H or NH4 in terms of being difficult to remain as an impurity and improving the heat resistance of the obtained molded body.

[0077] Examples of the perfluorovinyl alkyl compound represented by the above formula (4a) include, for example, CF2=CFCF2COOM 1 (In the formula, M 1 is the same as defined above.)

[0078] In the above formula (4b), n2 is preferably an integer of 3 or less in terms of emulsifying ability, and Y 3is -COOM in terms of obtaining appropriate water solubility and surface activity. 1 is preferably, 1 and M

[0079] In the above formula (4c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is -COOM in terms of obtaining appropriate water solubility and surface activity. 1 is preferably, 1 and M

[0080] In the above formula (4d), X 1 is preferably -CF3 in terms of surface activity performance, n4 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is -COOM in terms of obtaining appropriate water solubility and surface activity. 1 is preferably, 1 and M

[0081] Examples of the perfluorovinyl ether compound represented by the above formula (4d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM 1 (wherein M 1 represents H, NH4 or an alkali metal).

[0082] In the above formula (4e), n5 is preferably 0 or an integer of 1 to 5 in terms of emulsifying ability, more preferably 0, 1 or 2, and even more preferably 0 or 1. Y 3 is -COOM in terms of obtaining appropriate water solubility and surface activity. 1 is preferably, 1 and M

[0083] Examples of the perfluorovinyl alkyl compound represented by the above formula (4e) include CH2=CFCF2OCF(CF3)COOM 1 , CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM1 (where M 1 is the same as defined above).

[0084] As the above-mentioned modified monomer, at least one selected from the group consisting of HFP, PAVE, PFAE, and a monomer having a polar group is preferable in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. More preferably, at least one selected from the group consisting of HFP, perfluoro(methyl vinyl ether) [PMVE], perfluoro(propyl vinyl ether) [PPVE], PFBE, a non-fluorine monomer having an acid anhydride residue, and the modified monomer (A) is more preferable. Even more preferably, at least one selected from the group consisting of HFP, PMVE, PPVE, a cyclic non-fluorine monomer having an acid anhydride residue, and a compound represented by the general formula (4e) is even more preferable. Even more preferably, at least one selected from the group consisting of HFP, PMVE, and PPVE is even more preferable, and HFP is even more preferable.

[0085] The above-mentioned TFE-based polymer is preferably at least one selected from the group consisting of a homopolymer of TFE and a modified PTFE containing a polymerization unit based on a TFE unit and HFP, and more preferably at least one selected from the group consisting of a homopolymer of TFE and a modified PTFE consisting only of a polymerization unit based on a TFE unit and HFP.

[0086] The above TFE-based polymer may have a core-shell structure. Examples of the TFE-based polymer having a core-shell structure include, for example, a TFE copolymer containing a core of a high molecular weight TFE-based polymer and a shell of a lower molecular weight TFE-based polymer or a TFE copolymer in the particles. Also, modified PTFE containing a core of high molecular weight PTFE and a shell of lower molecular weight PTFE or modified PTFE in the particles is also included. Examples of such modified PTFE include, for example, the PTFE described in Japanese Patent Application Laid-Open No. 2005-527652.

[0087] The above TFE-based polymer is preferably non-melt processable. In this specification, being non-melt processable means that the melt flow rate (MFR) is less than 0.25 g / 10 min, preferably less than 0.10 g / 10 min, more preferably less than 0.05 g / 10 min, and still more preferably less than 0.01 g / 10 min. The above MFR is a value obtained as the mass (g / 10 min) of the polymer flowing out per 10 minutes from a nozzle having an inner diameter of 2.095 mm and a length of 8 mm at 372°C and a load of 5 kg using a melt indexer in accordance with ASTM D1238.

[0088] The above TFE-based polymer preferably has a TII of 10 or more, more preferably 15 or more, still more preferably 20 or more, and even more preferably 25 or more, and also preferably 80 or less, more preferably 50 or less, in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. A TFE-based polymer having a TII of 10 or more can be obtained by using a hydrocarbon-based surfactant.

[0089] The above TFE-based polymer preferably has a standard specific gravity (SSG) of 2.280 or less, more preferably 2.250 or less, still more preferably 2.220 or less, even more preferably 2.200 or less, even more preferably 2.190 or less, particularly preferably 2.180 or less, and most preferably 2.170 or less, in that it can form a composite sheet with even better strength. The above SSG is preferably 2.130 or more, more preferably 2.140 or more, and still more preferably 2.150 or more. The above SSG is measured by the water displacement method in accordance with ASTM D 792 using a sample molded in accordance with ASTM D 4895 89.

[0090] The content of the fibrillatable resin is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more, based on the electrode binder in the electrode (positive electrode and / or negative electrode) containing the fibrillatable resin, in that it can further improve the initial capacity and capacity retention rate of the electrochemical device. Also, it is preferably 10% by mass or less, more preferably 8.0% by mass or less, still more preferably 7.0% by mass or less, even more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0091] The electrodes (positive electrode and / or negative electrode) included in the electrochemical device of the present disclosure contain an electrode active material.

[0092] Examples of the above electrode active material include a positive electrode active material and a negative electrode active material.

[0093] The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release alkali metal ions. For example, a material containing an alkali metal and at least one transition metal is preferable. Specific examples include alkali metal-containing transition metal composite oxides, alkali metal-containing transition metal phosphate compounds, and the like. Among them, as the positive electrode active material, an alkali metal-containing transition metal composite oxide that produces a high voltage is particularly preferable. Examples of the alkali metal ions include lithium ions, sodium ions, potassium ions, and the like. In a preferred embodiment, the alkali metal ions can be lithium ions. That is, in this embodiment, the alkali metal ion secondary battery is a lithium ion secondary battery.

[0094] Examples of the alkali metal-containing transition metal composite oxide include Formula: M a Mn 2-b M 1 b O4 (In the formula, M is at least one metal selected from the group consisting of Li, Na, and K; 0.9 ≦ a; 0 ≦ b ≦ 1.5; M 1 is at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge) an alkali metal-manganese spinel composite oxide (such as lithium-manganese spinel composite oxide), Formula: MNi 1-c M 2 c O2 (In the formula, M is at least one metal selected from the group consisting of Li, Na, and K; 0 ≦ c ≦ 0.5; M 2 is at least one metal selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge) an alkali metal-nickel composite oxide (such as lithium-nickel composite oxide), or Formula: MCo 1-d M 3 d O2 (wherein M is at least one metal selected from the group consisting of Li, Na, and K; 0 ≦ d ≦ 0.5; M 3 is at least one metal selected from the group consisting of Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge). Examples of the alkali metal-cobalt composite oxide (such as lithium-cobalt composite oxide) represented by the above formula include those described above. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and still more preferably Li.

[0095] Among them, from the viewpoint of providing a secondary battery with high energy density and high output, MCoO2, MMnO2, MNiO2, MMn2O4, MNi 0.8 Co 0.15 Al 0.05 O2, or MNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc. are preferable, and it is preferable that the compound is represented by the following general formula (3). MNi h Co i Mn j M 5 k O2(3) (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M 5 represents at least one selected from the group consisting of Fe, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge, and (h + i + j + k) = 1.0, 0 ≦ h ≦ 1.0, 0 ≦ i ≦ 1.0, 0 ≦ j ≦ 1.5, 0 ≦ k ≦ 0.2).

[0096] Examples of the alkali metal-containing transition metal phosphate compound include, for example, the following general formula (4): M e M 4 f (PO4) g (4) (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M 4represents at least one selected from the group consisting of V, Ti, Cr, Mn, Fe, Co, Ni, and Cu, where 0.5 ≦ e ≦ 3, 1 ≦ f ≦ 2, and 1 ≦ g ≦ 3. Compounds represented by the above formula are exemplified. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li. That is, as the above alkali metal-containing transition metal phosphate compound, a lithium-containing transition metal phosphate compound is preferred.

[0097] As the transition metal of the above lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferred. Specific examples include, for example, iron phosphates such as LiFePO4, Li3Fe2(PO4)3, LiFeP2O7, cobalt phosphates such as LiCoPO4, and those in which a part of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are substituted with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc. As the above lithium-containing transition metal phosphate compound, those having an olivine-type structure are preferred.

[0098] Other positive electrode active materials include lithium-nickel-based composite oxides. As the above lithium-nickel-based composite oxide, the following general formula (5): Li y Ni 1-x M x O2(5) (wherein x is 0.01 ≦ x ≦ 0.7, y is 0.9 ≦ y ≦ 2.0, and M represents a metal atom (excluding Li and Ni)) is preferred as the positive electrode active material.

[0099] Other positive electrode active materials include MFePO4, MNi 0.8 Co 0.2 O2, M 1.2 Fe 0.4 Mn 0.4 O2, MNi 0.5 Mn 1.5 O2, MV3O6, M2MnO3, etc. are also included. In particular, M2MnO3, MNi 0.5 Mn1.5 Positive electrode active materials such as O2 (where M is at least one metal selected from the group consisting of Li, Na, and K) are preferable in that the crystal structure does not collapse even when the secondary battery is operated at a voltage exceeding 4.4 V or a voltage of 4.6 V or higher. Therefore, an electrochemical device such as a secondary battery using a positive electrode material containing the positive electrode active material exemplified above is preferable because the remaining capacity hardly decreases even when stored at a high temperature, the resistance increase rate hardly changes, and the battery performance does not deteriorate even when operated at a high voltage.

[0100] As other positive electrode active materials, solid solution materials such as M2MnO3 and M 6 O2 (where M is at least one metal selected from the group consisting of Li, Na, and K, and M 6 is a transition metal such as Co, Ni, Mn, Fe, etc.) can also be mentioned.

[0101] Examples of the solid solution material include, for example, an alkali metal manganese oxide represented by the general formula Mx[Mn (1-y) M 7 y O z . Here, M in the formula is at least one metal selected from the group consisting of Li, Na, and K, and M 7 consists of at least one metal element other than M and Mn, and includes, for example, one or more elements selected from the group consisting of Co, Ni, Fe, Ti, Mo, W, Cr, Zr, and Sn. Also, the values of x, y, and z in the formula are in the range of 1 < x < 2, 0 ≤ y < 1, and 1.5 < z < 3. Among them, a manganese-containing solid solution material in which LiNiO2 or LiCoO2 is solid-solved based on Li2MnO3 such as Li 1.2 Mn 0.5 Co 0.14 Ni 0.14 O2 is preferable in that it can provide an alkali metal ion secondary battery having a high energy density.

[0102] In addition, it is preferable to include lithium phosphate in the positive electrode active material because the continuous charging characteristics are improved. There is no restriction on the use of lithium phosphate, but it is preferably used by mixing it with the above-mentioned positive electrode active material. The amount of lithium phosphate used is preferably at least 0.1% by mass, more preferably at least 0.3% by mass, still more preferably at least 0.5% by mass, and preferably at most 10% by mass, more preferably at most 8% by mass, still more preferably at most 5% by mass, based on the total of the above positive electrode active material and lithium phosphate.

[0103] Alternatively, a material having a composition different from that of the above positive electrode active material may be used by adhering to the surface of the positive electrode active material. Examples of the surface-adhering substance include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide; sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and aluminum sulfate; carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate; and carbon.

[0104] These surface-adhering substances can be adhered to the surface of the positive electrode active material by, for example, a method of dissolving or suspending them in a solvent, impregnating and adding them to the positive electrode active material, and then drying; a method of dissolving or suspending a surface-adhering substance precursor in a solvent, impregnating and adding it to the positive electrode active material, and then reacting it by heating or the like; or a method of adding it to a positive electrode active material precursor and firing them simultaneously. In the case of adhering carbon, a method of mechanically adhering carbonaceous matter in the form of, for example, activated carbon can also be used.

[0105] The amount of the surface-attached substance is, by mass relative to the positive electrode active material, preferably 0.1 ppm or more as the lower limit, more preferably 1 ppm or more, and even more preferably 10 ppm or more, and preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less as the upper limit. The surface-attached substance can suppress the oxidation reaction of the electrolyte on the surface of the positive electrode active material and improve the battery life, but if the amount of attachment is too small, the effect will not be fully exerted, and if it is too large, the movement of lithium ions is hindered, which may increase the resistance.

[0106] The shape of the particles of the positive electrode active material may be any of the conventional shapes such as block, polyhedron, sphere, oval sphere, plate, needle, column, etc. Furthermore, primary particles may aggregate to form secondary particles.

[0107] The tap density of the positive electrode active material is preferably 0.5 g / cm 3 More preferably, 0.8 g / cm 3 More preferably, 1.0 g / cm 3 That is all. If the tap density of the positive electrode active material is below the above lower limit, the amount of dispersion medium required when forming the positive electrode active material layer increases, and the amounts of conductive material and binder required also increase, which may restrict the filling rate of the positive electrode active material in the positive electrode active material layer and restrict the battery capacity. By using a composite oxide powder with a high tap density, a high-density positive electrode active material layer can be formed. Generally, the higher the tap density, the better, and there is no particular upper limit. However, if the tap density is too high, the diffusion of lithium ions in the positive electrode active material layer using the electrolyte as a medium becomes rate-limiting, and the load characteristics may be easily reduced. Therefore, the upper limit is preferably 4.0 g / cm. 3 or less, more preferably 3.7 g / cm 3 More preferably 3.5 g / cm or less 3 The following is the result. The tap density is the powder packing density (tap density) in g / cm when 5 to 10 g of positive electrode active material powder is placed in a 10 ml glass measuring cylinder and tapped 200 times with a stroke of approximately 20 mm. 3 is required.

[0108] The median diameter d50 of the particles of the positive electrode active material (when primary particles aggregate to form secondary particles, it is the secondary particle diameter) is preferably 0.3 μm or more, more preferably 0.5 μm or more, still more preferably 0.8 μm or more, and most preferably 1.0 μm or more. Also, it is preferably 30 μm or less, more preferably 27 μm or less, still more preferably 25 μm or less, and most preferably 22 μm or less. If it is less than the above lower limit, it may be impossible to obtain a product with a high tap density. If it exceeds the upper limit, it takes time for lithium diffusion within the particles, which may cause problems such as a decrease in battery performance. Here, by mixing two or more types of the above positive electrode active materials having different median diameters d50, the filling property during the production of the positive electrode can be further improved.

[0109] The above median diameter d50 is measured by a known laser diffraction / scattering type particle size distribution measuring device. When using LA-920 manufactured by HORIBA as the particle size distribution meter, as the dispersion medium used for measurement, an aqueous solution of 0.1 mass% sodium hexametaphosphate is used, and after ultrasonic dispersion for 5 minutes, the measurement refractive index is set to 1.24 for measurement.

[0110] When primary particles aggregate to form secondary particles, the average primary particle diameter of the above positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.2 μm or more. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If it exceeds the above upper limit, it is difficult to form spherical secondary particles, which may adversely affect the powder filling property or significantly reduce the specific surface area, resulting in a high possibility of a decrease in battery performance such as output characteristics. Conversely, if it is less than the above lower limit, problems such as poor reversibility of charge and discharge may occur because the crystal is usually underdeveloped. The above average primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10,000 times, the longest value of the section by the left and right boundary lines of the primary particles with respect to a horizontal straight line is obtained for any 50 primary particles, and the average value is calculated.

[0111] The BET specific surface area of the positive electrode active material is preferably 0.1 m 2 / g or more, more preferably 0.2 m 2 / g or more, still more preferably 0.3 m 2 / g or more, and the upper limit is preferably 50 m 2 / g or less, more preferably 40 m 2 / g or less, still more preferably 30 m 2 / g or less. If the BET specific surface area is smaller than this range, the battery performance is likely to deteriorate. If it is larger, it is difficult to increase the tap density, and problems may easily occur in the processability during the formation of the positive electrode active material layer. The above BET specific surface area is defined as a value measured by the nitrogen adsorption BET one-point method by the gas flow method using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken Co., Ltd.). After pre-drying the sample at 150 °C for 30 minutes under a nitrogen flow, a nitrogen-helium mixed gas is accurately adjusted so that the relative pressure value of nitrogen with respect to atmospheric pressure becomes 0.3.

[0112] When the electrochemical device of the present disclosure is used as a large lithium-ion secondary battery for hybrid vehicles or distributed power sources, high output is required. Therefore, the particles of the positive electrode active material are preferably mainly secondary particles. The particles of the positive electrode active material preferably contain 0.5 to 7.0% by volume of fine particles having an average particle diameter of the secondary particles of 40 μm or less and an average primary particle diameter of 1 μm or less. By containing fine particles having an average primary particle diameter of 1 μm or less, the contact area with the electrolyte increases, and the diffusion of lithium ions between the electrode binder and the electrolyte can be made faster. As a result, the output performance of the battery can be improved.

[0113] For the production of the positive electrode, the above positive electrode active material may be used alone, or two or more kinds having different compositions may be used in combination in any combination or ratio. Preferred combinations in this case include LiCoO2 and LiNi 0.33 Co 0.33 Mn 0.33Examples include combinations with ternary systems such as O2, combinations of LiCoO2 and LiMn2O4 or those in which part of this Mn is replaced with other transition metals, etc., or combinations of LiFePO4 and LiCoO2 or those in which part of this Co is replaced with other transition metals, etc.

[0114] In terms of high battery capacity, the content of the above positive electrode active material is preferably 50 to 99.5% by mass, more preferably 80 to 99% by mass, of the positive electrode mixture. Also, the content in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, particularly preferably 84% by mass or more. Also, the upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

[0115] The negative electrode active material is not particularly limited. For example, lithium metal, artificial graphite, graphite carbon fiber, resin-fired carbon, thermally decomposed vapor-phase grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-fired carbon, polyacene, pitch-based carbon fiber, vapor-phase grown carbon fiber, natural graphite, and those containing carbonaceous materials such as non-graphitizable carbon, silicon and silicon-containing compounds such as silicon alloys, Li4Ti5O 12 Any selected from these, or mixtures of two or more, etc. can be mentioned. Among them, those containing at least a part of a carbonaceous material and silicon-containing compounds can be particularly preferably used.

[0116] In the present disclosure, it is preferable that the negative electrode active material used contains silicon as a constituent element. By using a material containing silicon as a constituent element, a high-capacity battery can be manufactured.

[0117] As the silicon-containing material, silicon particles, particles having a structure in which fine silicon particles are dispersed in a silicon-based compound, silicon oxide particles represented by the general formula SiOx (0.5 ≤ x ≤ 1.6), or a mixture thereof are preferable. By using these, a negative electrode mixture for a lithium-ion secondary battery with higher first charge-discharge efficiency, higher capacity, and excellent cycle characteristics can be obtained.

[0118] The silicon oxide in the present disclosure is a general term for amorphous silicon oxides, and the silicon oxide before disproportionation is represented by the general formula SiOx (0.5 ≤ x ≤ 1.6). It is preferable that 0.8 ≤ x < 1.6, and more preferably 0.8 ≤ x < 1.3. This silicon oxide can be obtained, for example, by cooling and depositing silicon monoxide gas generated by heating a mixture of silicon dioxide and metallic silicon.

[0119] Particles having a structure in which fine silicon particles are dispersed in a silicon-based compound can be obtained, for example, by firing a mixture of fine silicon particles and a silicon-based compound, or by subjecting silicon oxide particles before disproportionation represented by the general formula SiOx to heat treatment at a temperature of 400°C or higher, preferably 800 to 1,100°C, in an inert non-oxidizing atmosphere such as argon to perform a disproportionation reaction. In particular, the material obtained by the latter method is suitable because the fine crystals of silicon are uniformly dispersed. By the disproportionation reaction as described above, the size of the silicon nanoparticles can be made 1 to 100 nm. Regarding the silicon oxide in the particles having a structure in which the silicon nanoparticles are dispersed in the silicon oxide, it is desirable that it be silicon dioxide. It can be confirmed by a transmission electron microscope that silicon nanoparticles (crystals) are dispersed in amorphous silicon oxide.

[0120] The physical properties of the silicon-containing particles can be appropriately selected according to the target composite particles. For example, the average particle size is preferably 0.1 to 50 μm, more preferably 0.2 μm or more, and still more preferably 0.5 μm or more for the lower limit. The upper limit is more preferably 30 μm or less, and still more preferably 20 μm or less. The above average particle size is represented by the weight average particle size in the particle size distribution measurement by the laser diffraction method.

[0121] The BET specific surface area is preferably from 0.5 to 100 m 2 / g, more preferably from 1 to 20 m 2 / g. If the BET specific surface area is 0.5 m 2 / g or more, there is no risk that the adhesiveness during electrode processing will decrease and the battery characteristics will deteriorate. Also, if it is 100 m 2 / g or less, the proportion of silicon dioxide on the particle surface increases, and there is no risk that the battery capacity will decrease when used as a negative electrode material for a lithium ion secondary battery.

[0122] By carbon coating the silicon-containing particles, conductivity can be imparted and an improvement in battery characteristics can be observed. As methods for imparting conductivity, there are a method of mixing the silicon-containing particles with conductive particles such as graphite, a method of coating the surface of the silicon-containing particles with a carbon film, and a method of combining both. However, the method of coating with a carbon film is preferred, and the method of chemical vapor deposition (CVD) is more preferred.

[0123] The negative electrode active material preferably contains at least one selected from the group consisting of graphite and Si, and may contain Si. When a Si-based active material such as Si is used for the negative electrode, especially during the first charge, Li in the system is irreversibly consumed by the reaction with these active materials, and the initial capacity and capacity retention rate of the electrochemical device may decrease. Since the electrochemical device of the present disclosure has a positive electrode and / or a negative electrode containing a Li replenisher, even when Si is contained as the negative electrode active material, the consumed Li can be replenished, and the initial capacity and capacity retention rate of the electrochemical device can be improved.

[0124] The content of the negative electrode active material is preferably 40% by mass or more, more preferably 50% by mass or more, and particularly preferably 60% by mass or more in the electrode mixture in order to increase the capacity of the obtained electrode mixture. The upper limit is preferably 99% by mass or less, more preferably 98% by mass or less.

[0125] In the electrode containing the above Li replenishing agent, it is preferable that the electrode active material has a coating layer of the above Li replenishing agent on its surface. Thereby, the initial capacity and the capacity retention rate of the electrochemical device can be further improved. The coating layer of the above Li replenishing agent can be formed by mixing the electrode active material and the Li replenishing agent. It is preferable to mix the electrode active material and the Li replenishing agent before mixing other components. The coating area is preferably 10% or more, more preferably 20% or more, and still more preferably 50% or more of the surface area of the active material particles.

[0126] The above electrode preferably further contains a conductive assistant. As the above conductive assistant, known conductive materials can be arbitrarily used. Specific examples include metal materials such as copper and nickel, graphite (graphite) such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black, carbon materials such as needle coke, carbon nanotubes, fullerenes, and amorphous carbons such as VGCF. These may be used alone or in combination of two or more in any combination and ratio.

[0127] The content of the conductive assistant is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more in the electrode mixture, and is usually used to contain 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

[0128] The above electrode may further contain a thermoplastic polymer. Examples of the thermoplastic polymer include polyvinylidene fluoride, vinylidene fluoride copolymer, polypropylene, polyethylene, polystyrene, polyethylene terephthalate, polyethylene oxide, etc. The thermoplastic polymer may be a resin or an elastomer. Also, one kind may be used alone, or two or more kinds may be used in combination at any combination and ratio.

[0129] The proportion of the thermoplastic polymer with respect to the electrode active material is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and usually 3.0% by mass or less, preferably 2.5% by mass or less, more preferably 2.0% by mass or less. By adding the thermoplastic resin, the mechanical strength of the electrode can be improved. Also, if it exceeds this range, problems such as a decrease in the proportion of the electrode active material in the electrode mixture and a decrease in the capacity of the battery, or an increase in the resistance between the active materials may occur.

[0130] The above positive electrode is preferably composed of a current collector and an electrode mixture sheet containing the above positive electrode active material. Examples of the material of the current collector for the positive electrode include metals such as aluminum, titanium, tantalum, stainless steel, nickel, or metal materials such as their alloys; carbon materials such as carbon cloth and carbon paper. Among them, metal materials, particularly aluminum or its alloy, are preferable.

[0131] The density of the positive electrode mixture sheet is preferably 2.80 g / cm 3 or more, more preferably 3.00 g / cm 3 or more, still more preferably 3.20 g / cm 3 or more, and preferably 3.80 g / cm 3 or less, more preferably 3.75 g / cm 3 or less, still more preferably 3.70 g / cm 3 or less. If it exceeds this range, cracks may easily occur in the sheet. Also, if it is less than this range, the conductivity between the active materials decreases, increasing the battery resistance and making it impossible to obtain high output in some cases.

[0132] The thickness of the positive electrode is not particularly limited. However, from the viewpoints of high capacity and high output, the thickness of the mixture layer obtained by subtracting the thickness of the metal foil of the current collector from the thickness of the positive electrode is preferably 10 μm or more, more preferably 20 μm or more, as the lower limit with respect to one side of the current collector, and is preferably 500 μm or less, more preferably 450 μm or less.

[0133] The negative electrode is preferably composed of a current collector and an electrode mixture sheet containing the negative electrode active material. Examples of the material of the current collector for the negative electrode include metals such as copper, nickel, titanium, tantalum, and stainless steel, or metal materials such as alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among them, metal materials, particularly copper, nickel, or alloys thereof, are preferred.

[0134] The density of the negative electrode mixture sheet is preferably 1.3 g / cm 3 or more, more preferably 1.4 g / cm 3 or more, still more preferably 1.5 g / cm 3 or more, and is preferably 2.0 g / cm 3 or less, more preferably 1.9 g / cm 3 or less, still more preferably 1.8 g / cm 3 or less. If it exceeds this range, cracks may easily occur in the sheet. If it is below this range, the conductivity between the active materials may decrease, increasing the battery resistance and making it impossible to obtain high output in some cases.

[0135] The thickness of the negative electrode is not particularly limited. However, from the viewpoints of high capacity and high output, the thickness of the mixture layer obtained by subtracting the thickness of the metal foil of the current collector from the thickness of the negative electrode is preferably 10 μm or more, more preferably 20 μm or more, as the lower limit with respect to one side of the current collector, and is preferably 500 μm or less, more preferably 450 μm or less.

[0136] Examples of the current collectors for the positive and negative electrodes include metal foils, expanded metals, punched metals, foamed metals, etc. Among these, metal foils are preferred. The metal foil may be formed into a mesh shape as appropriate. The thickness of the metal foil is arbitrary, but it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, the handleability may be impaired.

[0137] Also, it is preferable that the surface of the current collector is roughened from the viewpoint of improving the adhesiveness between the current collector and the active material layer and reducing the electrical contact resistance. The surface roughness of the current collector represented by Sa (arithmetic mean height) is preferably about 260 nm or more, more preferably about 280 nm or more, and still more preferably about 300 nm or more.

[0138] Also, it is preferable that a conductive auxiliary agent is applied to the surface of the current collector from the viewpoint of reducing the electrical contact resistance between the current collector and the active material layer. Examples of the conductive auxiliary agent include carbon and noble metals such as gold, platinum, and silver. Carbon is particularly preferable in terms of its low weight.

[0139] The manufacturing methods of the above positive and negative electrodes are not limited and may be conventional methods. However, the positive and / or negative electrodes containing the fibrillatable resin are preferably manufactured by a dry process, that is, manufactured without preparing a slurry. Examples of such a method include a method of laminating an electrode mixture sheet prepared by the method described later and a current collector via an adhesive and pressing them.

[0140] An example of a specific manufacturing method of an electrode mixture sheet containing a fibrillatable resin as a binder is shown below. The above electrode mixture sheet Step (0) of preparing a mixture containing an electrode active material and, if necessary, a conductive auxiliary agent, Step (1) of mixing a binder with the mixture obtained in the above step (0) to prepare a composition for electrode production, A step (2) of applying a shearing force while mixing the electrode preparation composition, A step (3) of forming the electrode mixture obtained in the above step (2) into a bulk shape, and A step (4) of rolling the bulk electrode mixture obtained in the above step (3) into a sheet shape can be obtained by a manufacturing method having the above steps.

[0141] In the above step (1), a fibrillatable resin or a Li replenishing agent may be additionally added and mixed.

[0142] In the above step (2), at the stage where a shearing force is applied while mixing the electrode preparation composition, the obtained electrode preparation composition exists in a state where the electrode active material, binder, etc. are simply mixed and have no definite shape. Specific mixing methods include mixing using a drum type mixer, a conical screw type mixer, a single-screw kneader, a twin-screw kneader, a mix muller, a stirring mixer, a planetary mixer, a Henschel mixer, a high-speed mixer, etc.

[0143] In the above step (2), the mixing conditions may be appropriately set for the rotation speed and the mixing time. For example, the rotation speed is preferably 5000 rpm or less. Preferably it is 10 rpm or more, more preferably 15 rpm or more, still more preferably 20 rpm or more. Also, preferably it is 4000 rpm or less, more preferably 3500 rpm or less, still more preferably in the range of 3000 rpm. If it is below the above range, it will take time for mixing and affect productivity. Also, if it exceeds the range, fibrillation may progress excessively, resulting in an electrode mixture sheet with inferior strength and flexibility.

[0144] In the above step (3), forming into a bulk shape means making the electrode preparation composition into one mass. Specific methods of forming into a bulk shape include extrusion molding, press molding, etc. Further, the "bulk form" is not particularly defined in terms of shape, and it only needs to be in a single lump state, including forms such as rod-shaped, sheet-shaped, spherical, and cube-shaped. The size of the above lump preferably has a diameter or the smallest side of its cross-section of 10,000 μm or more. More preferably, it is 20,000 μm or more.

[0145] As a specific rolling method in the above step (4), there is a method of rolling using a roll press, a flat plate press, a calendar roll machine, etc.

[0146] Also, after step (4), it is also preferable to have a step (5) of applying a larger load to the obtained rolled sheet and further rolling it into a thinner sheet form. It is also preferable to repeat step (5). In this way, rather than thinning the rolled sheet at once, by rolling it in stages little by little, the flexibility becomes better. The number of times of step (5) is preferably 2 or more and 10 or less, and more preferably 3 or more and 9 or less. As a specific rolling method, for example, there is a method of rotating two or a plurality of rolls and passing the rolled sheet between them to process it into a thinner sheet form. It is desirable to heat during rolling. The lower limit of the temperature range is preferably 40 degrees or more, more preferably 50 degrees or more, and even more preferably 60 degrees or more. Also, the upper limit is preferably 300 degrees or less, more preferably 250 degrees or less, and even more preferably 200 degrees or less. By heating, the sheet softens and can be easily rolled.

[0147] Also, from the perspective of adjusting the fibril diameter, it is also preferable to have a step (6) of crushing the rolled sheet and then remolding it into a bulk form and rolling it into a sheet form after step (4) or step (5). It is also preferable to repeat step (6). The number of times of step (6) is preferably 1 or more and 12 or less, and more preferably 2 or more and 11 or less.

[0148] In step (6), specific methods for crushing the rolled sheet to form a bulk shape include folding the rolled sheet, or forming it into a rod or thin film sheet shape, or chipping it. In the present disclosure, "crushing" means changing the form of the rolled sheet obtained in step (4) or step (5) to another form in order to roll it into a sheet in the next step, and includes cases where the rolled sheet is simply folded.

[0149] Also, after step (6), step (5) may be performed, or may be repeated. Also, uniaxial stretching or biaxial stretching may be performed in steps (3) to (4), (5), and (6). Also, the fibril diameter can be adjusted according to the degree of crushing in step (6).

[0150] In the above steps (4), (5), or (6), the rolling rate is preferably 10% or more, more preferably 20% or more, and also preferably 80% or less, more preferably 65% or less, and even more preferably 50% or less. If it is below the above range, it will take time as the number of rolling passes increases, affecting productivity. Also, if it exceeds the range, fibrillation may progress excessively, resulting in an electrode binder sheet with inferior strength and flexibility. Here, the rolling rate refers to the reduction rate of the thickness after processing with respect to the thickness of the sample before rolling. The sample before rolling may be a bulk electrode composition or a sheet-like electrode composition. The thickness of the sample refers to the thickness in the direction where the load is applied during rolling.

[0151] The above electrode binder sheet includes step (a): mixing a powder component (such as an electrode active material) and a binder to form an electrode binder, and step (b): calendaring or extrusion molding the electrode binder to produce a sheet and the mixing in step (a) (a1) a step of homogenizing the powder component and the binder to form a powder, (a2) Step of preparing an electrode mixture by mixing the powdery electrode composition obtained by step (a1). It can also be preferably manufactured by a manufacturing method characterized by including this.

[0152] For example, PTFE has two transition temperatures at about 19 °C and about 30 °C. Below 19 °C, PTFE can be easily mixed while maintaining its shape. However, above 19 °C, the structure of PTFE particles becomes loose and more sensitive to mechanical shear. At temperatures above 30 °C, more advanced fibrillation occurs.

[0153] Therefore, the homogenization of (a1) is preferably carried out at a temperature of 19 °C or lower, preferably 0 °C to 19 °C. That is, in such (a1), it is preferable to mix and homogenize while suppressing fibrillation. Next, the mixing in (a2), which is the subsequent step, is preferably carried out at a temperature of 30 °C or higher to promote fibrillation.

[0154] The above step (a2) is preferably carried out at a temperature of 30 °C to 150 °C, more preferably 35 °C to 120 °C, and even more preferably 40 °C to 100 °C. In one embodiment, the calendaring or extrusion in the above step (b) is carried out at a temperature between 30 °C and 150 °C, preferably between 35 °C and 120 °C, and more preferably between 40 °C and 100 °C.

[0155] The mixing in the above step (a) is preferably carried out while applying a shearing force. Specific mixing methods include methods of mixing using a drum-type mixer, a conical screw-type mixer, a single-screw kneader, a twin-screw kneader, a mix muller, a stirring mixer, a planetary mixer, a Henschel mixer, a high-speed mixer, etc.

[0156] The mixing conditions may be appropriately set for the rotation speed and the mixing time. For example, it is preferable that the rotation speed be 15000 rpm or less. Preferably, it is 10 rpm or more, more preferably 50 rpm or more, still more preferably 100 rpm or more, and also preferably 12000 rpm or less, more preferably 10000 rpm or less, still more preferably 8000 rpm or less. If it is below the above range, it will take time for mixing, which will affect productivity. If it exceeds the range, fibrillation may progress excessively, and there is a risk of obtaining an electrode binder sheet with poor strength. In step (a1), it is preferable to perform the process with a shearing force weaker than that in step (a2). Also, in step (a1), it is desirable to perform the process in a shorter time than in step (a2).

[0157] In the above step (a2), it is preferable that the electrode manufacturing composition does not contain a liquid solvent, but a small amount of lubricant may be used. That is, a lubricant may be added to the powdery electrode manufacturing composition obtained in the above step (a1) to prepare a paste.

[0158] The above lubricant is not particularly limited, and examples include water, ether compounds, alcohols, ionic liquids, carbonates, aliphatic hydrocarbons (low-polarity solvents such as heptane and xylene), isoparaffin-based hydrocarbon compounds, and petroleum fractions (gasoline (C4 - C10), naphtha (C4 - C11), kerosene / paraffin (C10 - C16), and mixtures thereof).

[0159] It is preferable that the above lubricant has a water content of 1000 ppm or less. In terms of reducing the deterioration of the electrochemical device, it is preferable that the water content is 1000 ppm or less. More preferably, the above water content is 500 ppm or less.

[0160] When using the above lubricant, it is particularly preferable that it is a low-polarity solvent such as butyl butyrate or an ether compound.

[0161] When using the above lubricant, the amount thereof may be 5.0 to 35.0 parts by weight, preferably 10.0 to 30.0 parts by weight, more preferably 15.0 to 25.0 parts by weight, based on the total weight of the composition to be subjected to step (a1).

[0162] The above composition for electrode production preferably does not substantially contain a liquid medium. In the conventional method for forming an electrode binder, it was common to prepare a slurry in which powder, which is an electrode binder component, was dispersed using a solvent in which a binder was dissolved, and to prepare an electrode binder sheet by applying and drying the slurry. In this case, a solvent for dispersing or dissolving the binder is used. However, solvents that can dissolve the conventionally commonly used binder resin are limited to specific solvents such as N-methylpyrrolidone. They have high polarity, and processes and costs due to the use of solvents are incurred because they undergo a drying process. In addition, since these react with electrolytes such as electrolytic solutions and solid electrolytes to deteriorate the electrolytes, residual components during slurry preparation or after drying may cause a decrease in battery performance. Also, in low-polarity solvents such as heptane, the binder resin that can be dissolved is very limited, and the flash point is low, which may make handling complicated.

[0163] By using a powdery binder with little moisture without using a solvent when forming the electrode binder sheet, a battery with less electrolyte deterioration can be manufactured. Furthermore, in the manufacturing method as described above, an electrode binder sheet containing a binder having a fine fiber structure can be manufactured, and also, by not preparing a slurry, the burden on the manufacturing process can be reduced.

[0164] Step (b) is calendaring or extrusion. Calendaring and extrusion can be performed by well-known methods. Thereby, it can be formed into the shape of an electrode binder sheet. Step (b) preferably includes (b1) a step of forming the electrode binder obtained by the above step (a) into a bulk shape, and (b2) a step of calendaring or extrusion-molding the bulk electrode binder.

[0165] To form in a bulk shape means to make the electrode binder into one mass. Specific methods for forming in a bulk shape include extrusion molding, press molding, and the like. Also, "bulk shape" does not particularly specify a shape, and it only needs to be in a state of being one mass, including forms such as rod shape, sheet shape, spherical shape, cube shape, etc. It is preferable that the size of the above-mentioned mass has a diameter or the smallest side of its cross-section of 10,000 μm or more. More preferably, it is 20,000 μm or more.

[0166] As a specific method of calendaring or extrusion molding in the above step (b2), a method of rolling the electrode binder using a roll press machine, a calendar roll machine, or the like can be mentioned.

[0167] The above step (b) is preferably carried out at 30 to 150 °C. As described above, since PTFE has a glass transition temperature near 30 °C, it easily fibrillates at 30 °C or higher. Therefore, step (b) is preferably carried out at such a temperature.

[0168] And since calendaring or extrusion involves shear force, PTFE fibrillates thereby and forming is carried out.

[0169] It is also preferable to have a step (c) of applying a larger load to the obtained rolled sheet after step (b) and rolling it into an even thinner sheet shape. It is also preferable to repeat step (c). In this way, by rolling the rolled sheet in stages little by little instead of thinning it all at once, the flexibility becomes better. The number of times of step (c) is preferably 2 or more and 10 or less, and more preferably 3 or more and 9 or less. As a specific rolling method, for example, a method of rotating two or a plurality of rolls and passing the rolled sheet between them to process it into an even thinner sheet shape can be mentioned.

[0170] From the perspective of adjusting the sheet strength, it is also preferable to have a step (d) in which after step (b) or step (c), the rolled sheet is crushed and then formed into a bulk shape again and rolled into a sheet shape. It is also preferable to repeat step (d). The number of times of step (d) is preferably 1 or more and 12 or less, more preferably 2 or more and 11 or less.

[0171] In step (d), specific methods for crushing the rolled sheet and forming it into a bulk shape include folding the rolled sheet, or forming it into a rod or thin film sheet shape, chipping, etc. In the present disclosure, "crushing" means changing the form of the rolled sheet obtained in step (b) or step (c) to another form in order to roll it into a sheet shape in the next step, and includes cases where the rolled sheet is simply folded.

[0172] Also, after step (d), step (c) may be performed, or may be repeated. Also, uniaxial stretching or biaxial stretching may be performed in steps (a) to (b), (c), and (d). Also, the sheet strength can be adjusted depending on the degree of crushing in step (d).

[0173] In the above steps (b), (c) or (d), the rolling rate is preferably 10% or more, more preferably 20% or more, and is also preferably 80% or less, more preferably 65% or less, still more preferably 50% or less. If it is below the above range, it will take time as the number of rolling times increases, affecting productivity. Also, if it exceeds the range, fibrillation may progress excessively, resulting in an electrode binder sheet with poor strength and flexibility. Here, the rolling rate refers to the reduction rate of the thickness after processing with respect to the thickness of the sample before rolling. The sample before rolling may be a bulk electrode manufacturing composition or a sheet-shaped electrode manufacturing composition. The thickness of the sample refers to the thickness in the direction of applying a load during rolling. The above steps (c) to (d) are preferably carried out at 30°C or higher, more preferably 60°C or higher. Also, it is preferably carried out at 150°C or lower.

[0174] Examples of the electrochemical device of the present disclosure include a battery, a capacitor, and the like. Examples of the battery include secondary batteries such as lithium ion batteries. The capacitor is not particularly limited, but is preferably an electrochemical capacitor. Examples of the electrochemical capacitor include an electric double layer capacitor, a hybrid capacitor, a redox capacitor, and the like. Examples of the hybrid capacitor include a sodium ion capacitor, a lithium ion capacitor, and a magnesium ion capacitor. Among these, an electric double layer capacitor is particularly preferable. The electrochemical device of the present disclosure is preferably a battery, more preferably a secondary battery, and even more preferably a lithium ion secondary battery.

[0175] The above secondary battery may be a secondary battery using an electrolytic solution (electrolytic solution secondary battery) or a solid secondary battery. In the present specification, the solid secondary battery may be a secondary battery including a solid electrolyte, and may be a semi-solid secondary battery including a solid electrolyte and a liquid component as an electrolyte, or a all-solid secondary battery including only a solid electrolyte as an electrolyte.

[0176] The electrochemical device of the present disclosure is preferably an electrolytic solution secondary battery or an electrolytic solution capacitor. Since the positive electrode and / or the negative electrode of the electrochemical device of the present disclosure contains a Li replenisher, the initial capacity and the capacity retention rate can be improved without adding an excessive amount of Li salt that causes an increase in viscosity to the electrolytic solution. For the above electrolytic solution secondary battery or electrolytic solution capacitor, an electrolytic solution, a separator, etc. used in a known secondary battery or capacitor can be used. Hereinafter, the electrolytic solution secondary battery will be described in detail.

[0177] As the above electrolyte, a non-aqueous electrolyte is preferably used. As the non-aqueous electrolyte, a known electrolyte salt dissolved in a known organic solvent for dissolving the electrolyte salt can be used.

[0178] The organic solvent for dissolving the electrolyte salt is not particularly limited, but known hydrocarbon solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; one or more fluorine-based solvents such as fluoroethylene carbonate, fluoroether, and fluorinated carbonate can be used.

[0179] Examples of the electrolyte salt include LiClO4, LiAsF6, LiBF4, LiPF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, etc. Particularly, LiPF6, LiBF4, LiN(SO2CF3)2, LiN(SO2C2F5)2, or a combination thereof is preferable in terms of good cycle characteristics.

[0180] The concentration of the electrolyte salt is preferably 0.8 mol / liter or more, more preferably 1.0 mol / liter or more. The upper limit depends on the organic solvent for dissolving the electrolyte salt, but is usually 4.0 mol / liter or less.

[0181] The above electrolyte secondary battery preferably further includes a separator. The material and shape of the above separator are not particularly limited as long as they are stable in the electrolyte and have excellent liquid retention properties, and known ones can be used. Among them, resins, glass fibers, inorganic substances, etc. formed of materials stable to the above electrolyte are used, and it is preferable to use a porous sheet or a non-woven fabric-like form having excellent liquid retention properties.

[0182] The above solid secondary battery is preferably an all-solid secondary battery. The above solid secondary battery is preferably a lithium-ion battery and is also preferably a sulfide-based solid secondary battery. The above-mentioned solid secondary battery preferably includes a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode.

[0183] The solid electrolyte used in the binder for the solid secondary battery may be a sulfide-based solid electrolyte or an oxide-based solid electrolyte. In particular, when using a sulfide-based solid electrolyte, there is an advantage of flexibility.

[0184] The above-mentioned sulfide-based solid electrolyte is not particularly limited, and any one selected from Li2S-P2S5, Li2S-P2S3, Li2S-P2S3-P2S5, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, LiI-Li2S-SiS2-P2S5, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li3PS4-Li4GeS4, Li 3.4 P 0.6 Si 0.4 S4, Li 3.25 P 0.25 Ge 0.76 S4, Li 4-x Ge 1-x P x S4(x = 0.6 to 0.8), Li 4+y Ge 1-y Ga y S4(y = 0.2 to 0.3), LiPSCl, LiCl, Li 7-x-2y PS 6-x-y Cl x (0.8 ≤ x ≤ 1.7, 0 < y ≤ -0.25x + 0.5), Li 10 SnP2S 12 Any one selected from the above, or a mixture of two or more thereof can be used.

[0185] The above-mentioned sulfide-based solid electrolyte preferably contains lithium. The sulfide-based solid electrolyte containing lithium is used in a solid battery using lithium ions as carriers, and is particularly preferable in terms of an electrochemical device having a high energy density.

[0186] The above oxide-based solid electrolyte preferably contains oxygen atoms (O), has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and has electron insulation properties.

[0187] Specific examples of the compound include, for example, Li xa La ya TiO3 [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT), Li xb La yb Zr zb M bb mb O nb (M bb is at least one element of Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, Sn, xb satisfies 5 ≤ xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, and nb satisfies 5 ≤ nb ≤ 20.) Li xc B yc M cc zc O nc (M cc is at least one element of C, S, Al, Si, Ga, Ge, In, Sn, xc satisfies 0 ≤ xc ≤ 5, yc satisfies 0 ≤ yc ≤ 1, zc satisfies 0 ≤ zc ≤ 1, and nc satisfies 0 ≤ nc ≤ 6.) Li xd (Al, Ga) yd (Ti, Ge) zd Si ad P md O nd (However, 1 ≤ xd ≤ 3, 0 ≤ yd ≤ 2, 0 ≤ zd ≤ 2, 0 ≤ ad ≤ 2, 1 ≤ md ≤ 7, 3 ≤ nd ≤ 15), Li (3-2xe) M ee xe D ee O (xe represents a number from 0 or more to 0.1 or less, M ee represents a divalent metal atom. D ee represents a halogen atom or a combination of two or more halogen atoms.) Li xf Si yf O zf (1 ≤ xf ≤ 5, 0 < yf ≤ 3, 1 ≤ zf ≤ 10), Li xg S yg Ozg (1 ≤ xg ≤ 3, 0 < yg ≤ 2, 1 ≤ zg ≤ 10), Li3BO3 - Li2SO4, Li2O - B2O3 - P2O5, Li2O - SiO2, Li6BaLa2Ta2O 12 , Li3PO (4-3 / 2w) N w (where w < 1), Li having a LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4, La having a perovskite type crystal structure 0.51 Li 0.34 TiO 2.94 , La 0.55 Li 0.35 TiO3, LiTi2P3O having a NASICON (Natrium super ionic conductor) type crystal structure 12 , Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 (however, 0 ≤ xh ≤ 1, 0 ≤ yh ≤ 1), Li7La3Zr2O having a garnet type crystal structure 12 (LLZ), etc. can be mentioned. Also, ceramic materials obtained by performing element substitution on LLZ are also known. For example, for LLZ, Li 6.24 La3Zr2Al 0.24 O 11.98 , Li 6.25 Al 0.25 La3Zr2O 12 , or Li substituted with Ta 6.6 La3Zr 1.6 Ta 0.4 O 12 , Li substituted with Nb 6.75 La3Zr 1.75 Nb 0.25 O 12Examples include the above. In addition, there are also LLZ-based ceramic materials in which at least one element substitution of Mg (magnesium) and A (A is at least one element selected from the group consisting of Ca (calcium), Sr (strontium), and Ba (barium)) is performed on LLZ. Also, phosphorus compounds containing Li, P, and O are desirable. For example, lithium phosphate (Li3PO4), LiPON in which part of the oxygen in lithium phosphate is substituted with nitrogen, LiPOD 1 (D 1 is at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc.) and the like. Also, LiA 1 ON (A 1 is at least one selected from Si, B, Ge, Al, C, Ga, etc.) and the like can also be preferably used. As specific examples, for example, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li2O-Al2O3-SiO2-P2O5-TiO2, etc. can be mentioned.

[0188] The above oxide-based solid electrolyte preferably contains lithium. The oxide-based solid electrolyte containing lithium is used in a solid battery that uses lithium ions as carriers, and is particularly preferable in terms of an electrochemical device having a high energy density.

[0189] The above oxide-based solid electrolyte is preferably an oxide having a crystal structure. An oxide having a crystal structure is particularly preferable in terms of good Li ion conductivity. Examples of the oxide having a crystal structure include perovskite type (La 0.51 Li 0.34 TiO 2.94 etc.), NASICON type (Li 1.3 Al 0.3 Ti 1.7 (PO4)3 etc.), garnet type (Li7La3Zr2O 12 (LLZ) etc.) and the like. Among them, the garnet type is preferable.

[0190] The volume average particle diameter of the oxide-based solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.03 μm or more. The upper limit is preferably 100 μm or less, and more preferably 50 μm or less. The measurement of the average particle diameter of the oxide-based solid electrolyte particles is performed according to the following procedure. The oxide-based solid electrolyte particles are diluted and adjusted to a 1 mass% dispersion in a 20 ml sample bottle using water (heptane in the case of substances unstable in water). The diluted dispersion sample is irradiated with ultrasonic waves at 1 kHz for 10 minutes and used for the test immediately thereafter. Using this dispersion sample, data is captured 50 times at a temperature of 25 °C using a quartz cell for measurement with a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by HORIBA, Ltd.) to obtain the volume average particle diameter. For other detailed conditions, refer to the description in JIS Z8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method" as necessary. Five samples are prepared for each level and the average value is adopted.

[0191] The above-mentioned solid secondary battery may include a separator between the positive electrode and the negative electrode. Examples of the separator include porous membranes such as polyethylene and polypropylene; and non-woven fabrics made of resins such as polypropylene, and non-woven fabrics such as glass fiber non-woven fabrics.

[0192] The above-mentioned solid secondary battery may further include a battery case. The shape of the battery case is not particularly limited as long as it can accommodate the above-mentioned positive electrode, negative electrode, solid electrolyte layer, etc. Specifically, examples include cylindrical, rectangular, coin-shaped, laminated, etc.

[0193] The above-mentioned solid secondary battery can be manufactured, for example, by laminating a positive electrode, a solid electrolyte layer sheet, and a negative electrode in this order and pressing them.

[0194] The present disclosure also provides a composition containing a Li replenisher and a fibrillatable resin.

[0195] By having the above configuration, the composition of the present disclosure can improve the initial capacity and capacity retention rate of the electrochemical device. Also, when in the form of a powder, the fluidity can be improved. Since the composition of the present disclosure can be used dry, it is not necessary to use a large amount of dispersion media such as water and organic solvents, and a wide range of electrode active materials and solid electrolytes to be combined can be selected, which is advantageous in the production process. Also, the processes and costs due to the use of the dispersion medium can be reduced. Furthermore, since the composition of the present disclosure has excellent adhesion to the active material and the electrolyte, the amount used can be reduced.

[0196] As the Li replenisher and fibrillatable resin in the composition of the present disclosure, those similar to those described for the electrochemical device of the present disclosure above can be used, and the preferred embodiments are also the same.

[0197] The content of the fibrillatable resin with respect to the composition of the present disclosure is preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, still more preferably 35% by mass or more, still more preferably 40% by mass or more, and also preferably 99% by mass or less, more preferably 97% by mass or less, still more preferably 90% by mass or less, still more preferably 85% by mass or less, still more preferably 80% by mass or less, still more preferably 75% by mass or less, and particularly preferably 70% by mass or less, in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity.

[0198] The mass ratio of the fibrillatable resin to the Li replenisher (fibrillatable resin / Li replenisher) is preferably 99 / 1 or less, more preferably 97 / 3 or less, still more preferably 90 / 10 or less, even more preferably 85 / 15 or less, even more preferably 80 / 20 or less, even more preferably 75 / 25 or less, particularly preferably 70 / 30 or less, in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. Also, it is preferably 20 / 80 or more, more preferably 30 / 70 or more, still more preferably 40 / 60 or more, even more preferably 45 / 55 or more, and particularly preferably 50 / 50 or more.

[0199] The total amount of the fibrillatable resin and the Li replenisher in the composition of the present disclosure is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, in terms of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving the powder fluidity. Also, it may be less than 100% by mass, may be 99% by mass or less, or may be 97% by mass or less.

[0200] The composition of the present disclosure may contain other components as necessary. Examples of other components include polymers other than the fibrillatable resin, conductive materials, dispersants, thickeners, and the like. For example, as the thickener, celluloses such as carboxymethyl cellulose (CMC) and methyl cellulose (MC) can be preferably used.

[0201] The composition of the present disclosure may not contain an electrode active material and a solid electrolyte.

[0202] The composition of the present disclosure may contain at least one compound selected from the group consisting of a compound represented by the following general formula (1) (hereinafter also referred to as compound (1)) and a compound represented by the following general formula (2) (hereinafter also referred to as compound (2)). General formula (1): (H-(CF2) m-1 -COO) p M 1 (In the formula, m is 4 to 20. M 1 is H, a metal atom, NR 5 4 (R 5 may be the same or different and is H or an organic group having 1 to 10 carbon atoms), imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent. p is 1 or 2.) General formula (2): (H-(CF2) n -SO3) q M 2 (In the formula, n is 4 to 20. M 2 is H, a metal atom, NR 5 4 (R 5 is the same as above), imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent. q is 1 or 2.)

[0203] The above M 1 and M 2 Examples of the above metal atoms include monovalent and divalent metal atoms, such as alkali metals (Group 1) or alkaline earth metals (Group 2), and specifically, Na, K, Li, etc. are exemplified. The four Rs 5 may be the same or different. R 5 is preferably H or an organic group having 1 to 10 carbon atoms, and more preferably H or an organic group having 1 to 4 carbon atoms. The organic group as R 5 is preferably an organic group not containing fluorine.

[0204] In general formula (1), m is preferably 6 or more, more preferably 8 or more, still more preferably 11 or more, even more preferably 13 or more, particularly preferably 15 or more, and preferably 18 or less, more preferably 16 or less. In general formula (2), n is preferably 6 or more, more preferably 8 or more, still more preferably 11 or more, even more preferably 13 or more, particularly preferably 15 or more, and preferably 18 or less, more preferably 16 or less.

[0205] The composition of the present disclosure may contain one or more of compound (1), or may contain two or more, or may contain three or more.

[0206] When the composition of the present disclosure contains compound (1), the content of compound (1) (when two or more are present, the content for each component) may be 10 mass ppm or less with respect to the above composition, preferably 5000 mass ppb or less, more preferably 1000 mass ppb or less, still more preferably 500 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, and particularly preferably 10 mass ppb or less. The lower limit is not particularly limited, and may be 0.1 mass ppb or may be 1 mass ppb.

[0207] The composition of the present disclosure may contain one or more of compound (2), or may contain two or more, or may contain three or more.

[0208] When the composition of the present disclosure contains compound (2), the content of compound (2) (when there are two or more kinds, the content for each component) may be 10 mass ppm or less, preferably 5000 mass ppb or less, more preferably 1000 mass ppb or less, still more preferably 500 mass ppb or less, still more preferably 100 mass ppb or less, still more preferably 50 mass ppb or less, still more preferably 25 mass ppb or less, still more preferably 10 mass ppb or less, still more preferably 1 mass ppb or less, still more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantification. The lower limit is not particularly limited and may be an amount less than the lower limit of quantification.

[0209] The composition containing compound (1) and / or (2) can be obtained by using a hydrocarbon surfactant. The composition of the present disclosure may contain a hydrocarbon surfactant together with the fibrillatable resin, the Li / Na compound, and compound (1) and / or (2). The content of the hydrocarbon surfactant in the composition is not particularly limited, but is usually 100 mass ppm to 10 mass%. It is preferable that in the hydrocarbon surfactant, the ratio of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0210] The composition of the present disclosure preferably does not substantially contain a compound represented by the following general formula (3) (hereinafter also referred to as compound (3)). General formula (3): (H-(CF2)8-SO3) q M 2 (In the formula, M 2 is H, a metal atom, NR 5 4 (R 5may be the same or different, and is H, an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. q is 1 or 2.)

[0211] Substantially free of compound (3) means that the content of compound (3) is 25 mass ppb or less with respect to the above composition. The content of compound (3) is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, and still more preferably 10 mass ppb or less with respect to the above composition. The lower limit is not particularly limited, and may be 0 mass ppb, may be 0.1 mass ppb, or may be 1 mass ppb.

[0212] The composition of the present disclosure contains at least one compound selected from the group consisting of a compound represented by the following general formula (4) (hereinafter also referred to as compound (4)) and a compound represented by the following general formula (4') (hereinafter also referred to as compound (4')), and the content of each of them is preferably 1000 mass ppb or less with respect to the above composition. General formula (4): (H-(CF2) 15 -COO) p M 1 (In the formula, M 1 is H, a metal atom, NR 5 4 (R 5 may be the same or different, and is H, an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.) General formula (4'): (H-(CF2) 16 -COO) p M 1 (In the formula, M 1 is H, a metal atom, NR 5 4 (R 5is the same as described above), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.)

[0213] When the composition of the present disclosure contains compound (4), the content of compound (4) is more preferably 500 mass ppb or less, still more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less with respect to the above composition. The lower limit is not particularly limited and may be 0.1 mass ppb or may be 1 mass ppb.

[0214] When the composition of the present disclosure contains compound (4'), the content of compound (4') is more preferably 500 mass ppb or less, still more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less with respect to the above composition. The lower limit is not particularly limited and may be 0.1 mass ppb or may be 1 mass ppb.

[0215] The composition of the present disclosure contains at least one compound selected from the group consisting of a compound represented by the following general formula (5) (hereinafter also referred to as compound (5)) and a compound represented by the following general formula (5') (hereinafter also referred to as compound (5')), and the content of each of them is preferably 1000 mass ppb or less with respect to the above composition. General formula (5): (H-(CF2) 13 -COO) p M 1 (In the formula, M 1 is H, a metal atom, NR 5 4 (R 5may be the same or different, and is H, an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.) General formula (5’): (H-(CF2) 14 -COO) p M 1 (In the formula, M 1 is H, a metal atom, NR 5 4 (R 5 is the same as above), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.)

[0216] When the composition of the present disclosure contains compound (5), the content of compound (5) is more preferably 500 mass ppb or less, still more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less with respect to the above composition. The lower limit is not particularly limited and may be 0.1 mass ppb or 1 mass ppb.

[0217] When the composition of the present disclosure contains compound (5’), the content of compound (5’) is more preferably 500 mass ppb or less, still more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less with respect to the above composition. The lower limit is not particularly limited and may be 0.1 mass ppb or 1 mass ppb.

[0218] The contents of compounds (1), (2), (3), (4), (4’), (5) and (5’) are the values measured by liquid chromatography mass spectrometry.

[0219] The composition of the present disclosure can be suitably used in a dry process. The liquid content of the above composition is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, still more preferably 1% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less. Examples of the above liquid include substances that are liquid at 25°C and 1 atm, such as water and organic solvents. The above liquid content is measured by the following method. Measure the mass of the composition before and after vacuum heating at 100°C for 5 hours, and calculate according to the following formula. Take the sample three times, calculate each time, then find the average, and adopt the average value. Liquid content (% by mass) = [(mass of the composition before heating (g)) - (mass of the composition after heating (g))] / (mass of the composition before heating (g)) × 100

[0220] The composition of the present disclosure preferably contains substantially no organic solvent. Thereby, the processes and costs due to the use of organic solvents can be reduced. Containing substantially no organic solvent means that the organic solvent content in the above composition is 5% by mass or less. The above organic solvent content is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less.

[0221] The composition of the present disclosure preferably contains substantially no water. This can suppress gas generation and deterioration of the characteristics of the electrochemical device. Also, since the electrode active materials and solid electrolytes to be combined can be widely selected, it is advantageous in terms of the production process. Substantially no water means that the water content in the above composition is 0.050% by mass or less. The above water content is preferably 0.030% by mass or less, more preferably 0.010% by mass or less, still more preferably 0.005% by mass or less, still more preferably 0.003% by mass or less, still more preferably 0.002% by mass or less, and particularly preferably 0.001% by mass or less. The above water content is measured by the following method. Measure the mass of the composition before and after heating at 150 °C for 2 hours, and calculate according to the following formula. Take the sample three times, calculate each time, then find the average, and adopt the average value. Water content (% by mass) = [(mass of the composition before heating (g)) - (mass of the composition after heating (g))] / (mass of the composition before heating (g)) × 100

[0222] The composition of the present disclosure preferably contains substantially no fluorine-containing compound having a molecular weight of 1000 or less. Substantially no fluorine-containing compound means that the amount of the fluorine-containing compound is 25 mass ppb or less with respect to the above composition. The amount of the above fluorine-containing compound is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, still more preferably 10 mass ppb or less, still more preferably less than 10 mass ppb, still more preferably 1 mass ppb or less, still more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantification. The lower limit is not particularly limited and may be an amount less than the lower limit of quantification.

[0223] The amount of the above fluorine-containing compound having a molecular weight of 1000 or less is measured by the following method. Weigh 1 g of the sample, add 10 g (12.6 ml) of methanol, perform ultrasonic treatment for 60 minutes to obtain an extract. Appropriately concentrate the obtained extract by nitrogen purging, and measure the fluorine-containing compound in the concentrated extract by LC / MS / MS. Extract the molecular weight information from the obtained LC / MS spectrum and confirm the match with the structural formula of the candidate fluorine-containing compound. Prepare aqueous solutions with a content of 5 levels or more of the standard substance, perform LC / MS analysis on the aqueous solutions of each content, plot the relationship between the content and the area of the area corresponding to the content, and draw a calibration curve. Using the above calibration curve, convert the area of the LC / MS chromatogram of the fluorine-containing compound in the extract into the content of the fluorine-containing compound. Note that the lower limit of quantification in this measurement method is 10 mass ppb.

[0224] Examples of the fluorine-containing compound having a molecular weight of 1000 or less include fluorine-containing compounds having a hydrophilic group with a molecular weight of 1000 g / mol or less. The molecular weight of the above fluorine-containing compound is preferably 800 or less, and more preferably 500 or less. Polymer particles obtained by polymerization carried out in the presence of a fluorine-containing surfactant usually contain, in addition to the target polymer, a fluorine-containing surfactant. In this specification, the fluorine-containing surfactant is the one used during polymerization. The fluorine-containing compound having a molecular weight of 1000 or less may be a compound that is not added during polymerization, for example, a compound that is by-produced during the polymerization process. Note that when the fluorine-containing compound having a molecular weight of 1000 or less contains an anionic part and a cationic part, it means a fluorine-containing compound in which the molecular weight of the anionic part is 1000 or less. The fibrillatable resin is not included in the fluorine-containing compound having a molecular weight of 1000 or less.

[0225] Examples of the above hydrophilic group may be -COOM, -SO2M, or -SO3M, and -COOM, -SO3M (in each formula, M is H, a metal atom, NR 14. It may be an imidazolium optionally having a substituent, a pyridinium optionally having a substituent, or a phosphonium optionally having a substituent, and R 1 is H or an organic group. Anionic groups such as ()) etc. can be mentioned.

[0226] As the above fluorine-containing surfactant, a surfactant containing fluorine with a molecular weight of the anionic part of 1000 or less (anionic fluorine-containing surfactant) can also be used. The above "anionic part" means the part excluding the cation of the above fluorine-containing surfactant. For example, in the case of F(CF2) n1 COOM, it is the part of "F(CF2) n1 COO". As the above anionic fluorine-containing surfactant, the following general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl or and F. Rf n0 is an alkylene group having 3 to 20 carbon atoms, linear, branched or cyclic, and part or all of the H is substituted by F, and the alkylene group may contain one or more ether bonds, and part of the H may be substituted by Cl. Y 0 is an anionic group.) Compounds represented by are mentioned. Y 0 The anionic group of may be -COOM, -SO2M, or -SO3M, and may be -COOM or -SO3M. M is H, a metal atom, NR 1 4. It may be an imidazolium optionally having a substituent, a pyridinium optionally having a substituent, or a phosphonium optionally having a substituent, and R 1 is H or an organic group. Examples of the above metal atoms include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and for example, Na, K or Li. R 1 may be H or an organic group of C 1-10 and may be H or C1-4 may be an organic group of H or C 1-4 and may be an alkyl group. M is H, a metal atom or NR 1 4, may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 1 4, may be H, Na, K, Li or NH4. Said Rf n0 may be one in which 50% or more of H is substituted with fluorine.

[0227] The above fluorine-containing surfactant may be one kind of fluorine-containing surfactant or a mixture containing two or more kinds of fluorine-containing surfactants.

[0228] Examples of the above fluorine-containing surfactant include compounds represented by the following formulas. The fluorine-containing surfactant may be a mixture of these compounds. F(CF2)7COOM, F(CF2)5COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, and [Chemical formula] (In each formula, M is H, a metal atom, NR 14. It is an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. R 1 is H or an organic group.). The composition of the present disclosure preferably does not substantially contain any of the fluorine-containing compounds represented by the above formulae.

[0229] In each of the above formulae, M may be H, a metal atom or NR 1 4, may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 1 4, and may be H, Na, K, Li or NH4. R 1 is H or an organic group of C 1-10 and may be H or an organic group of C 1-4 and may be H or an organic group of C 1-4 and may be an alkyl group of C

[0230] When the composition of the present disclosure does not substantially contain any of the fluorine-containing compounds represented by the above formulae, generation of gas and deterioration of the characteristics of the electrochemical device can be further suppressed. Not substantially containing any of the fluorine-containing compounds represented by the above formulae means that the amount of the fluorine-containing compound is 25 mass ppb or less with respect to the above composition. The amount of the fluorine-containing compound is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, still more preferably 10 mass ppb or less, even more preferably less than 10 mass ppb, even more preferably 1 mass ppb or less, even more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantification. The lower limit is not particularly limited and may be an amount less than the lower limit of quantification.

[0231] The composition of the present disclosure has the following general formula: [C n-1 F 2n-1 COO - M + (In the formula, n is an integer from 9 to 14, preferably an integer from 9 to 12, M+ represents a cation. It is also preferable that the composition substantially does not contain a fluorine-containing compound represented by (). Thereby, generation of gas and deterioration of the characteristics of the electrochemical device can be further suppressed. The cation M in the above formula + The M that constitutes is the same as the above-described M. Substantially not containing the fluorine-containing compound represented by the above formula means that the amount of the fluorine-containing compound is 25 mass ppb or less with respect to the above composition. The amount of the fluorine-containing compound is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, still more preferably 10 mass ppb or less, still more preferably less than 10 mass ppb, still more preferably 1 mass ppb or less, still more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantification. The lower limit is not particularly limited and may be an amount less than the lower limit of quantification.

[0232] In terms of being able to form a sizing sheet with further excellent strength, the endothermic peak temperature of the composition of the present disclosure is preferably 333 ° C or higher, more preferably 335 ° C or higher, still more preferably 337 ° C or higher, still more preferably 340 ° C or higher, and preferably 350 ° C or lower, more preferably 346 ° C or lower. The endothermic peak temperature is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry [DSC] at a heating rate of 10 ° C / min for a composition having no history of heating to a temperature of 300 ° C or higher. When there are two or more minimum points in one melting peak, each is taken as the endothermic peak temperature.

[0233] In terms of being able to form a sizing sheet with further excellent strength, the melting point of the composition of the present disclosure is preferably 315 ° C or higher, more preferably 320 ° C or higher, still more preferably 323 ° C or higher, still more preferably 325 ° C or higher, and preferably 335 ° C or lower, more preferably 330 ° C or lower. The melting point is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry [DSC] at a heating rate of 10 °C / min for a composition having a history of being heated to a temperature of 300 °C or higher.

[0234] The composition of the present disclosure may have an average secondary particle diameter of 350 μm or more, preferably 400 μm or more, more preferably 450 μm or more, still more preferably 500 μm or more, still more preferably 550 μm or more, particularly preferably 600 μm or more, and preferably 1000 μm or less, more preferably 900 μm or less, still more preferably 800 μm or less, still more preferably 700 μm or less. The average secondary particle diameter is measured in accordance with JIS K 6891.

[0235] In terms of excellent handleability, the composition of the present disclosure may have an average aspect ratio of 2.0 or less, preferably 1.8 or less, more preferably 1.7 or less, still more preferably 1.6 or less, still more preferably 1.5 or less, still more preferably 1.4 or less, particularly preferably 1.3 or less, most preferably 1.2 or less, and most preferably 1.1 or less. The average aspect ratio may also be 1.0 or more. The average aspect ratio is determined from the average of the ratios of the major axis to the minor axis by observing the composition with a scanning electron microscope (SEM) and performing image processing on 200 or more randomly extracted particles.

[0236] In terms of excellent handleability, the composition of the present disclosure preferably has an apparent density of 0.40 g / ml or more, more preferably 0.43 g / ml or more, still more preferably 0.45 g / ml or more, still more preferably 0.48 g / ml or more, particularly preferably 0.50 g / ml or more. The upper limit is not particularly limited, and it may be 0.70 g / ml. The apparent density is measured in accordance with JIS K 6892.

[0237] Although the form of the composition of the present disclosure is not limited, it is preferably in powder form in that it can be mixed with the electrode active material and the solid electrolyte without using a large amount of dispersion medium. In addition, the above composition may be in a form other than powder, for example, a dispersion or a molded body.

[0238] The composition of the present disclosure can be produced by mixing a fibrillatable resin and a Li replenishing agent. By mixing the fibrillatable resin and the Li replenishing agent before mixing with the electrode active material and the solid electrolyte, the powder fluidity of the composition is improved and the handleability is improved. In addition, by improving the dispersibility of the fibrillatable resin, when mixing with the electrode active material and the solid electrolyte to prepare a mixture, the fibrillatable resin and the Li replenishing agent are uniformly dispersed, so that the initial capacity, capacity retention rate and other electrochemical device characteristics can be improved.

[0239] The method for mixing the fibrillatable resin and the Li replenishing agent is not limited, but it is preferably mixed dry. Further, the fibrillatable resin and the Li replenishing agent are preferably mixed in powder form. Mixing can be performed using, for example, pneumatic mixing, a V-type mixer, a conical screw mixer, or the like.

[0240] The raw material fibrillatable resin can be preferably produced by a production method including, for example, step (A) of obtaining an aqueous dispersion of the fibrillatable resin, step (B) of coagulating the aqueous dispersion to obtain a wet powder, and step (C) of drying (heat-treating) the wet powder.

[0241] The aqueous dispersion in step (A) can be produced by emulsion polymerization. The above emulsion polymerization can be carried out by a known method. For example, in the presence of an anionic surfactant and a polymerization initiator, the emulsion polymerization of the monomers necessary to form the fibrillatable resin is carried out in an aqueous medium to obtain an aqueous dispersion containing particles (primary particles) of the fibrillatable resin. In the above emulsion polymerization, a chain transfer agent, a buffer, a pH adjuster, a stabilization aid, a dispersion stabilizer, a radical scavenger, etc. may be used as necessary.

[0242] The above emulsion polymerization is preferably carried out in the presence of a hydrocarbon-based surfactant. Hereinafter, the method for producing a TFE-based polymer by emulsion polymerization using a hydrocarbon-based surfactant will be described in detail.

[0243] In the hydrocarbon-based surfactant, the ratio of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0244] The above hydrocarbon-based surfactant is preferably a carboxylic acid type hydrocarbon-based surfactant. The carboxylic acid type hydrocarbon-based surfactant is not limited as long as it has a carboxy group (-COOH) or a group in which a hydrogen atom of the carboxy group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.). For example, from among specific hydrocarbon-based surfactants described later and other compounds having surfactant properties, a hydrocarbon-based surfactant having a carboxy group or a group in which a hydrogen atom of the carboxy group is substituted with an inorganic cation can be used.

[0245] The hydrocarbon surfactant is preferably a sulfonic acid type hydrocarbon surfactant. The sulfonic acid type hydrocarbon surfactant is not limited as long as it has a -SO3H group, -OSO3H group, or a group in which a hydrogen atom of these groups is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.). For example, from the specific hydrocarbon surfactants described later and other compounds having surfactant properties, a hydrocarbon surfactant having a -SO3H group, -OSO3H group, or a group in which a hydrogen atom of these groups is substituted with an inorganic cation can be used.

[0246] The hydrocarbon surfactant preferably exhibits water solubility in terms of good emulsifying performance. That the hydrocarbon surfactant exhibits water solubility means that the maximum concentration of the hydrocarbon surfactant dissolved in water at 85 °C is 100 mass ppm or more. The maximum concentration in water is preferably 500 mass ppm or more, more preferably 1000 mass ppm or more, still more preferably 2000 mass ppm or more, still more preferably 3000 mass ppm or more, still more preferably 5000 mass ppm or more, still more preferably 1 mass% or more, still more preferably 3 mass% or more, still more preferably 5 mass% or more, particularly preferably 10 mass% or more, and may be 50 mass% or less.

[0247] The emulsion polymerization preferably includes a step of performing emulsion polymerization of only tetrafluoroethylene or emulsion polymerization of tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene in an aqueous medium in the presence of a specific hydrocarbon surfactant, and a step of continuously adding the specific hydrocarbon surfactant in the above step.

[0248] The continuous addition of a specific hydrocarbon surfactant means, for example, adding the specific hydrocarbon surfactant not all at once, but over time, without interruption or in portions. The specific hydrocarbon surfactant is, for example, a hydrocarbon surfactant having one or more carbonyl groups (excluding the carbonyl group in the carboxy group), or a hydrocarbon surfactant obtained by subjecting a hydrocarbon surfactant having one or more carbonyl groups (excluding the carbonyl group in the carboxy group) to radical treatment or oxidation treatment. The above radical treatment may be any treatment that generates radicals in a hydrocarbon surfactant having one or more carbonyl groups (excluding the carbonyl group in the carboxy group). For example, deionized water and a hydrocarbon surfactant are added to a reactor, the reactor is sealed, the system is purged with nitrogen, the reactor is heated and pressurized, a polymerization initiator is charged, stirred for a certain period of time, and then the reactor is depressurized until it reaches atmospheric pressure and cooled. The above oxidation treatment is a treatment in which an oxidizing agent is added to a hydrocarbon surfactant having one or more carbonyl groups (excluding the carbonyl group in the carboxy group). Examples of the oxidizing agent include oxygen, ozone, hydrogen peroxide solution, manganese(IV) oxide, potassium permanganate, potassium dichromate, nitric acid, sulfur dioxide, and the like. By the above production method, it is possible to produce a TFE-based polymer having a molecular weight equivalent to that of a production method using a conventional fluorine-containing surfactant without using a conventional fluorine-containing surfactant.

[0249] In the above manufacturing method, in the step of continuously adding the specific hydrocarbon surfactant, it is preferable that the addition of the hydrocarbon surfactant to the aqueous medium is started when the solid content of the TFE-based polymer formed in the aqueous medium is less than 0.60% by mass. When it is 0.5% by mass or less, it is preferable that the addition of the specific hydrocarbon surfactant to the aqueous medium is started. It is more preferable that the addition of the specific hydrocarbon surfactant is started when the solid content is 0.3% by mass or less, still more preferable when it is 0.2% by mass or less, still more preferably when it is 0.1% by mass or less, and particularly preferably, the addition is started together with the start of polymerization. The solid content is the concentration with respect to the total of the aqueous medium and the TFE-based polymer.

[0250] In the step of continuously adding the specific hydrocarbon surfactant, the addition amount of the specific hydrocarbon surfactant is preferably 0.01 to 10% by mass with respect to 100% by mass of the aqueous medium. A more preferable lower limit is 0.05% by mass, a still more preferable lower limit is 0.1% by mass, a more preferable upper limit is 5% by mass, and a still more preferable upper limit is 1% by mass.

[0251] In the step of performing emulsion polymerization of only tetrafluoroethylene or emulsion polymerization of tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene in an aqueous medium in the presence of the specific hydrocarbon surfactant, it is preferable that the amount of the specific hydrocarbon surfactant is large, and it is preferably 0.0001 to 10% by mass with respect to 100% by mass of the aqueous medium. A more preferable lower limit is 0.001% by mass, and a more preferable upper limit is 1% by mass. If it is less than 0.0001% by mass, the dispersing power may be insufficient, and if it exceeds 10% by mass, an effect commensurate with the amount cannot be obtained, and instead, there is a risk of a decrease in the polymerization rate or a reaction stop. The amount of the specific hydrocarbon surfactant is appropriately determined according to the type of monomer used, the molecular weight of the target TFE-based polymer, and the like.

[0252] As the specific hydrocarbon surfactant, the formula: R-X (wherein R is a fluorine-free organic group having 1 to 2000 carbon atoms and having one or more carbonyl groups (excluding the carbonyl group in the carboxy group), and X is -OSO3X 1 , -COOX 1 or -SO3X 1 (X 1 is H, a metal atom, NR 1 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium, and R 1 is H or an organic group (preferably an organic group not containing fluorine), and they may be the same or different.)) The surfactant represented by, and at least one selected from the group consisting of the surfactant (e) described later is preferable. R preferably has 500 or less carbon atoms, more preferably 100 or less carbon atoms, still more preferably 50 or less carbon atoms, and still more preferably 30 or less carbon atoms. As the specific hydrocarbon surfactant, the following formula (a):

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0253] The surfactant (a) can be produced, for example, by the production method described in International Publication No. 2020 / 022355.

[0254] The surfactant (b) can be produced, for example, by the production method described in International Publication No. 2020 / 022355.

[0255] The surfactant (c) can be produced, for example, by the production method described in International Publication No. 2020 / 022355.

[0256] The surfactant (d) can be produced, for example, by the production method described in International Publication No. 2020 / 022355.

[0257] The surfactant (e) can be produced by a known production method.

[0258] It is also preferable that the specific hydrocarbon-based surfactant is a carboxylic acid-type hydrocarbon-based surfactant. The carboxylic acid-type hydrocarbon-based surfactant is not limited as long as it has a carboxy group (-COOH) or a group in which a hydrogen atom of the carboxy group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.). For example, from among the specific hydrocarbon-based surfactants described above, a hydrocarbon-based surfactant having a carboxy group or a group in which a hydrogen atom of the carboxy group is substituted with an inorganic cation can be used. It is preferable that the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms in the carboxylic acid-type hydrocarbon-based surfactant is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0259] Preferably, as the carboxylic acid-type hydrocarbon-based surfactant, among at least one selected from the group consisting of the surfactant (c) represented by the above formula (c) and the surfactant (d) represented by the above formula (d), those having a carboxy group (-COOH) or a group in which a hydrogen atom of the carboxy group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.) are preferable.

[0260] The above-mentioned specific hydrocarbon surfactant is also preferably a sulfonic acid type hydrocarbon surfactant. The sulfonic acid type hydrocarbon surfactant is not limited as long as it has a -SO3H group, -OSO3H group, or a group in which a hydrogen atom of these groups is substituted with an inorganic cation (e.g., a metal atom, ammonium, etc.). For example, among the above-mentioned specific hydrocarbon surfactants, a hydrocarbon surfactant having a -SO3H group, -OSO3H group, or a group in which a hydrogen atom of these groups is substituted with an inorganic cation can be used. It is preferable that the proportion of hydrogen atoms bonded to carbon atoms in the sulfonic acid type hydrocarbon surfactant replaced by fluorine atoms is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0261] The TFE-based polymer composition of the present disclosure can be efficiently produced by using at least one of the above-mentioned specific hydrocarbon surfactants. Further, the TFE-based polymer composition of the present disclosure may be produced by simultaneously using two or more of the above-mentioned specific hydrocarbon surfactants, or may be produced by simultaneously using a compound having other surfactant properties other than the above-mentioned specific hydrocarbon surfactant as long as it has volatility or can remain in a molded article made of a TFE-based polymer or the like.

[0262] As the compound having other surfactant properties, for example, those described in JP-T-2013-542308, JP-T-2013-542309, JP-T-2013-542310, etc. can be used.

[0263] The compound having other surfactant properties may be a surfactant having a hydrophilic part and a hydrophobic part on the same molecule, for example, a hydrocarbon surfactant (excluding the above-mentioned specific hydrocarbon surfactant). These may be cationic, nonionic or anionic. Preferably, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms in the above compound is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0264] The cationic surfactant usually has a positively charged hydrophilic moiety such as alkylated ammonium bromide or other alkylated ammonium halides, and a hydrophobic moiety such as a long-chain fatty acid. Preferably, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms in the above cationic surfactant is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0265] The anionic surfactant usually has a hydrophilic moiety such as carboxylate, sulfonate or sulfate, and a hydrophobic moiety which is a long-chain hydrocarbon moiety such as alkyl. Preferably, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms in the above anionic surfactant is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0266] The nonionic surfactant usually does not contain a charged group and has a hydrophobic moiety which is a long-chain hydrocarbon. The hydrophilic moiety of the nonionic surfactant contains a water-soluble functional group such as a chain of ethylene ether derived from the polymerization with ethylene oxide. Preferably, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms in the above nonionic surfactant is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted with fluorine atoms at all).

[0267] Examples of compounds having other surface activity include those represented by R-L-M (wherein R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when the number of carbon atoms is 3 or more, it may contain a monovalent or divalent heterocyclic ring or may form a ring; L is -ArSO3 - , -SO3 - , -SO4-, -PO3 - or -COO - , and M is H, a metal atom, NR 5 4 (R 5 may be the same or different and is H or an organic group (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. -ArSO3 - is an aryl sulfonate.). Also included are anionic surfactants represented by the formula. R 5 is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms. Specifically, those represented by CH3-(CH2) n -L-M (wherein n is an integer of 6 to 17; L and M are the same as above) typified by lauric acid can be mentioned. Mixtures in which R is an alkyl group having 12 to 16 carbon atoms and L-M is a sulfate or sodium dodecyl sulfate (SDS) can also be used. Examples of compounds having other surface activity also include R 6 (-L-M)2 (wherein R 6 is a linear or branched alkylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkylene group having 3 or more carbon atoms which may have a substituent, and when the number of carbon atoms is 3 or more, it may contain a monovalent or divalent heterocyclic ring or may form a ring; L is -ArSO3 - , -SO3 - , -SO4-, -PO3 - or -COO - , and M is H, a metal atom, NR 54. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group (preferably an organic group not containing fluorine), -ArSO3 - is an aryl sulfonate. An anionic surfactant represented by) is also included. As other compounds having surfactant properties, R 7 (-L-M)3 (wherein R 7 is a linear or branched alkylidine group having 1 or more carbon atoms which may have a substituent, or a cyclic alkylidine group having 3 or more carbon atoms which may have a substituent. When the number of carbon atoms is 3 or more, it may contain a monovalent or divalent heterocyclic ring or may form a ring. L is -ArSO3 - , -SO3 - , -SO4-, -PO3 - or -COO - and M is H, a metal atom, NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group (preferably an organic group not containing fluorine). -ArSO3 - is an aryl sulfonate. An anionic surfactant represented by) is also included.

[0268] Examples of siloxane hydrocarbon-based surfactants include those described in Silicone Surfactants, R.M. Hill, Marcel Dekker, Inc., ISBN: 0-8247-00104. The structure of the silicone surfactant includes a distinct hydrophobic part and a hydrophilic part. The hydrophobic part contains one or more dihydrocarbyl siloxane units, where the substituents on the silicon atom are completely hydrocarbons. When the carbon atoms of the hydrocarbyl group can be substituted by a halogen such as fluorine, these siloxane surfactants can also be regarded as hydrocarbon surfactants in the sense that they are completely substituted by hydrogen atoms, that is, the monovalent substituents on the carbon atoms of the hydrocarbyl group are hydrogen. Preferably, in the above siloxane surfactant, the proportion of hydrogen atoms bonded to carbon atoms substituted by fluorine atoms is 50% or less, more preferably 25% or less, still more preferably 10% or less, and most preferably 0% (not substituted by fluorine atoms at all).

[0269] The siloxane hydrocarbon surfactant is also disclosed in U.S. Patent No. 6,841,616.

[0270] As other compounds having surfactant properties, an anionic hydrocarbon surfactant is preferred. As the anionic hydrocarbon surfactant, those described above can be adopted. For example, the following hydrocarbon surfactants can be preferably adopted.

[0271] As the above anionic hydrocarbon surfactant, for example, the following formula (α): R 100 -COOM (α) (In the formula, R 100 is a monovalent organic group containing one or more carbon atoms (preferably an organic group not containing fluorine). M is H, a metal atom, NR 101 4, an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, and R 101 is H or an organic group (preferably an organic group not containing fluorine), and they may be the same or different.) The compound (α) represented by the formula is exemplified. As the organic group of R 101 , an alkyl group is preferred. As R 101 , H or an organic group having 1 to 10 carbon atoms is preferred, H or an organic group having 1 to 4 carbon atoms is more preferred, and H or an alkyl group having 1 to 4 carbon atoms is still more preferred. From the viewpoint of surfactant properties, R 100It preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms. From the viewpoint of water solubility, R 100 preferably has 29 or fewer carbon atoms, more preferably 23 or fewer carbon atoms. Examples of the metal atom of M include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K, or Li is preferable. As M, H, a metal atom, or NR 101 4 is preferable, H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 101 4 is more preferable, H, Na, K, Li, or NH4 is even more preferable, Na, K, or NH4 is even more preferable, Na or NH4 is particularly preferable, and NH4 is most preferable.

[0272] Examples of the compound (α) also include an anionic surfactant represented by R 102 -COOM (wherein R 102 is a linear or branched alkyl group, alkenyl group, alkylene group, or alkenylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group, or alkenylene group having 3 or more carbon atoms which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocyclic ring or may form a ring. M is the same as above). Specifically, those represented by CH3-(CH2) n -COOM (wherein n is an integer of 2 to 28. M is the same as above) are included.

[0273] Examples of the anionic hydrocarbon surfactant also include, for example, the following formula (β): R 100 -SO3M (β) (wherein R 100 is a monovalent organic group containing 1 or more carbon atoms (preferably an organic group not containing fluorine). M is H, a metal atom, NR 101 4, an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, and R 101is H or an organic group (preferably an organic group not containing fluorine), and they may be the same or different. The compound (β) represented by ) is also included. R 101 As the organic group, an alkyl group is preferred. R 101 is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and still more preferably H or an alkyl group having 1 to 4 carbon atoms. From the viewpoint of surfactant properties, R 100 preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms. Also, from the viewpoint of water solubility, R 100 preferably has 29 or fewer carbon atoms, more preferably 23 or fewer carbon atoms. Examples of the metal atom of M include alkali metals (Group 1), alkaline earth metals (Group 2), etc., and Na, K, or Li is preferred. M is preferably H, a metal atom, or NR 101 4, more preferably H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 101 4, still more preferably H, Na, K, Li, or NH4, even more preferably Na, K, or NH4, particularly preferably Na or NH4, and most preferably NH4.

[0274] Examples of the compound (β) include R 102 -SO3M (wherein R 102 is a linear or branched alkyl group, alkenyl group, alkylene group, or alkenylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group, or alkenylene group having 3 or more carbon atoms which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocyclic ring or may form a ring. M is the same as above.). An anionic surfactant represented by this is also included. Specifically, those represented by CH3-(CH2) n -SO3M (wherein n is an integer of 2 to 28. M is the same as above) are included.

[0275] Examples of the above anionic hydrocarbon surfactant include the following formula I: R-(XZ) n (I) (In the formula, R is a hydrophobic hydrocarbon moiety containing one or more saturated or unsaturated, acyclic or cyclic aliphatic groups. The percentage of the total number of CH3 groups relative to the total of CH3, CH2 and CH groups in one or more aliphatic groups is at least about 70%, and the hydrophobic moiety does not contain siloxane units. Each X may be the same or different and represents an ionic hydrophilic moiety. Each Z may be the same or different and represents one or more counterions of the ionic hydrophilic moiety. n is 1 to 3.) Compound I represented by the formula is also included.

[0276] Compound I exhibits low reactivity with polymerization initiators and / or growing fluoropolymer radicals in the emulsion polymerization of fluoromonomers.

[0277] Compound I has the following formula:

Chemical formula

[0278] Compound I has the following formula II:

Chemical formula

[0279] As the compound II, for example, the following compounds are preferred. [Chemical formula] Y in the above formula + may be hydrogen, ammonium, or alkali metal.

[0280] Compound I is represented by the following formula III: [Chemical formula] (In the formula, R 3 , R 4’ , and R 4’’ are the same or different and are hydrogen or a saturated or unsaturated, acyclic or cyclic aliphatic group having 4 to 16 carbon atoms, and the percentage of the total of CH3 with respect to the total of CH3, CH2, and CH groups in the R 3 , R 4’ , and R 4’’ groups is at least about 70%. However, at least one of R 3 , R 4’ , and R 4’’ is not hydrogen, and when R 4’ and R 4’’ are hydrogen, R 3 is not hydrogen, and when R 3 is hydrogen, R 4’ and R 4’’ are not hydrogen. Y + is hydrogen, ammonium, quaternary ammonium, nitrogen heterocycle, alkali metal, or alkaline earth metal. It is also preferably the compound III represented by the formula ().

[0281] As the compound III, for example, the following compounds are preferred. [Chemical formula] Y in the above formula + may be hydrogen, ammonium, or an alkali metal.

[0282] Even when the above-mentioned specific hydrocarbon surfactant is not used, the TFE-based polymer composition of the present disclosure can be obtained by a production method including a polymerization step of polymerizing tetrafluoroethylene alone or tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene in an aqueous medium having a pH of 4.0 or higher in the presence of a hydrocarbon surfactant and a polymerization initiator to obtain a TFE-based polymer. Conventionally, since a polymerization initiator showing acidity was used in the polymerization step for producing a TFE-based polymer, the pH of the aqueous medium used in the polymerization was less than 4.0. As a result of intensive studies by the present inventors, it was unexpectedly found that by setting the pH of the aqueous medium used in the polymerization to 4.0 or higher, the polymerization stability is improved and a TFE-based polymer having a high molecular weight can be produced. In the above production method, tetrafluoroethylene alone or tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene are polymerized in an aqueous medium having a pH of 4.0 or higher. The above pH may be 4.0 or higher, preferably more than 4.0, more preferably 4.5 or higher, still more preferably 5.0 or higher, still more preferably 5.5 or higher, particularly preferably 6.0 or higher, particularly preferably 6.5 or higher, particularly preferably 7.0 or higher, particularly preferably 7.5 or higher, and particularly preferably 8.0 or higher. The upper limit value of the above pH is not particularly limited, but may be, for example, 13.0 or lower. From the viewpoint of corrosion of the polymerization tank, it is preferably 12.0 or lower, more preferably 11.5 or lower, and still more preferably 11.0 or lower. The above pH can be measured by a pH meter.

[0283] The TFE-based polymer composition of the present disclosure can obtain a TFE-based polymer by polymerizing only tetrafluoroethylene or tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene in an aqueous medium in the presence of an anionic hydrocarbon surfactant and a polymerization initiator even without using the specific hydrocarbon surfactant described above. The hydrocarbon surfactant can also be obtained by a process including a salt of the hydrocarbon surfactant. In other words, at least a part of the anionic hydrocarbon surfactant in the polymerization step is in the form of a salt. As a result of intensive studies by the present inventors, unexpectedly, it has been found that the stability of polymerization is improved by including a salt of an anionic hydrocarbon surfactant, and a TFE-based polymer having a large molecular weight can be produced. This is presumably because the water solubility of the anionic surfactant is improved by including the salt, and the emulsifying performance is likely to be exhibited. The anionic hydrocarbon surfactant will be described later. That the anionic hydrocarbon surfactant includes a salt of the hydrocarbon surfactant can be confirmed by measuring the conductivity. In the above production method, it is preferable that the concentration of the salt of the anionic hydrocarbon surfactant is 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more, and particularly preferably 95% by mass or more with respect to the total mass of the anionic hydrocarbon surfactant. The ratio of the salt can be measured by the solution concentration and the conductivity. In the above production method, it is more preferable that the hydrocarbon surfactant is a carboxylic acid type hydrocarbon surfactant. The hydrocarbon surfactant does not contain fluorine. In the salt of the anionic hydrocarbon surfactant, the cation (excluding a hydrogen atom) that replaces the hydrogen atom of the acid is, for example, a metal atom, NR y 4(R yis each independently the same or different and is H or an organic group (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. The above R y is preferably H or an alkyl group, more preferably H or an alkyl group having 1 to 10 carbon atoms, and still more preferably H or an alkyl group having 1 to 4 carbon atoms. As the above cation in the salt of an anionic hydrocarbon surfactant, a metal atom or NR y 4 is preferred, and NR y 4 is more preferred, and NH4 is still more preferred. Since the conductivity changes greatly with the influence of temperature, a constant temperature bath is used to keep the sample solution temperature at 25 °C, and the temperature of the cell of the pH meter is also made the same, and then the conductivity is measured.

[0284] The TFE-based polymer composition of the present disclosure can be preferably produced by a production method including an addition step of adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator. The above addition step is performed during the step of performing the above emulsion polymerization in an aqueous medium. By adding a radical scavenger or a decomposer of a polymerization initiator, the radical concentration during polymerization can be adjusted. From the viewpoint of reducing the radical concentration, a radical scavenger is preferred.

[0285] As the above radical scavenger, a compound having no restart ability after addition or chain transfer to free radicals in the polymerization system is used. Specifically, a stable radical that easily undergoes a chain transfer reaction with a primary radical or a growing radical and then does not react with a monomer, or a compound having a function of easily undergoing an addition reaction with a primary radical or a growing radical to generate a stable radical is used. What is generally called a chain transfer agent is characterized by its activity in terms of a chain transfer constant and a restart efficiency, but among chain transfer agents, those with a restart efficiency of almost 0% are called radical scavengers. The above radical scavenger can also be, for example, a compound having a chain transfer constant with TFE at the polymerization temperature greater than the polymerization rate constant and a restart efficiency of substantially 0%. "The restart efficiency is substantially 0%" means that the generated radicals are converted into stable radicals by the radical scavenger. Preferably, it is a compound having a chain transfer constant (Cs) (= chain transfer rate constant (kc) / polymerization rate constant (kp)) with TFE at the polymerization temperature greater than 0.1. For the above compound, it is more preferable that the chain transfer constant (Cs) is 0.5 or more, still more preferable that it is 1.0 or more, even more preferable that it is 5.0 or more, and particularly preferable that it is 10 or more.

[0286] As the above radical scavenger in the present disclosure, for example, at least one selected from the group consisting of aromatic hydroxy compounds, aromatic amines, N,N - diethylhydroxylamine, quinone compounds, terpenes, thiocyanates, and cupric chloride (CuCl2) is preferable. Examples of the aromatic hydroxy compound include unsubstituted phenol, polyhydric phenol, salicylic acid, m - or p - salicylic acid, gallic acid, naphthol, and the like. Examples of the above unsubstituted phenol include o -, m - or p - nitrophenol, o -, m - or p - aminophenol, p - nitrosophenol, and the like. Examples of the polyhydric phenol include catechol, resorcinol, hydroquinone, pyrogallol, phloroglucin, naphthoresorcinol, and the like. Examples of the aromatic amines include o -, m - or p - phenylenediamine, benzidine, and the like. Examples of the above quinone compound include o -, m - or p - benzoquinone, 1,4 - naphthoquinone, alizarin, and the like. Examples of the thiocyanate include ammonium thiocyanate (NH4SCN), potassium thiocyanate (KSCN), sodium thiocyanate (NaSCN), and the like. Among the above radical scavengers, aromatic hydroxy compounds are preferable, unsubstituted phenol or polyhydric phenol is more preferable, and hydroquinone is still more preferable.

[0287] From the viewpoint of reducing the standard specific gravity, the addition amount of the above radical scavenger is preferably an amount corresponding to 3 to 500% (molar basis) of the polymerization initiator concentration. A more preferable lower limit is 5% (molar basis), still more preferably 8% (molar basis), still more preferably 10% (molar basis), even more preferably 15% (molar basis), particularly preferably 20% (molar basis), especially preferably 25% (molar basis), particularly preferably 30% (molar basis), and particularly preferably 35% (molar basis). A more preferable upper limit is 400% (molar basis), still more preferably 300% (molar basis), even more preferably 200% (molar basis), and particularly preferably 100% (molar basis).

[0288] As the decomposer of the polymerization initiator, any compound capable of decomposing the polymerization initiator used may be used. For example, at least one selected from the group consisting of sulfites, bisulfites, bromates, diimines, diimine salts, oxalic acid, oxalates, copper salts, and iron salts is preferable. Examples of the sulfite include sodium sulfite and ammonium sulfite. Examples of the copper salt include copper(II) sulfate, and examples of the iron salt include iron(II) sulfate. The addition amount of the above decomposer of the polymerization initiator is added in the range of 25 to 300% by mass based on the amount of the oxidizing agent combined as the polymerization initiator (redox initiator described later). Preferably, it is 25 to 150% by mass, and more preferably 50 to 100% by mass. From the viewpoint of reducing the standard specific gravity, the addition amount of the above decomposer of the polymerization initiator is preferably an amount corresponding to 3 to 500% (molar basis) of the polymerization initiator concentration. A more preferable lower limit is 5% (molar basis), still more preferably 8% (molar basis), still more preferably 10% (molar basis), even more preferably 13% (molar basis), and even more preferably 15% (molar basis). A more preferable upper limit is 400% (molar basis), still more preferably 300% (molar basis), even more preferably 200% (molar basis), and particularly preferably 100% (molar basis).

[0289] At least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator is preferably added when the concentration of the TFE-based polymer formed in the aqueous medium is 5% by mass or more. More preferably, it is when the concentration is 10% by mass or more. Also, it is preferably added when the concentration of the TFE-based polymer formed in the aqueous medium is 40% by mass or less. More preferably, it is when the concentration is 35% by mass or less, and still more preferably, it is when the concentration is 30% by mass or less.

[0290] The above addition step may be a step of continuously adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator. Continuously adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator means, for example, adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator not all at once, but over time, continuously or in portions.

[0291] The above polymerization step may be one in which tetrafluoroethylene is polymerized in the presence of a nucleating agent.

[0292] As the above nucleating agent, for example, it is preferably at least one selected from the group consisting of fluoropolyethers, nonionic surfactants, and chain transfer agents. In this case, the above polymerization step is preferably a step of obtaining a TFE-based polymer by polymerizing tetrafluoroethylene in an aqueous medium in the presence of a hydrocarbon-based surfactant and the above nucleating agent.

[0293] As the above fluoropolyether, perfluoropolyether is preferred.

[0294] The above fluoropolyether preferably has repeating units represented by formulas (1a) to (ld). (-CFCF3-CF2-O-) n (1a) (-CF2-CF2-CF2-O-)n (1b) (-CF2-CF2-O-) n -(-CF2-O-) m (1c) (-CF2-CFCF3-O-) n -(-CF2-O-) m (1d) (In formulas (1a) to (1d), m and n are integers of 1 or more.)

[0295] As the above fluoropolyether, a fluoropolyether acid or its salt is preferable. The above fluoropolyether acid is preferably a carboxylic acid, a sulfonic acid, a sulfonamide, or a phosphonic acid, and more preferably a carboxylic acid. Among the fluoropolyether acid or its salt, a salt of the fluoropolyether acid is preferable, an ammonium salt of the fluoropolyether acid is more preferable, and an ammonium salt of the fluoropolyether carboxylic acid is still more preferable.

[0296] The above fluoropolyether acid or its salt can have any chain structure in which oxygen atoms in the main chain of the molecule are separated by saturated fluorocarbon groups having 1 to 3 carbon atoms. Two or more types of fluorocarbon groups can be present in the molecule.

[0297] As the above fluoropolyether acid or its salt, the following formula: CF3-CF2-CF2-O(-CFCF3-CF2-O-) n CFCF3-COOH, CF3-CF2-CF2-O(-CF2-CF2-CF2-O-) n -CF2-CF2COOH, or, HOOC-CF2-O(-CF2-CF2-O-) n -(-CF2-O-) m CF2COOH (In the formula, m and n are the same as above.) It is preferably a compound represented by these or their salts.

[0298] These structures have been studied by Kasai in J. Appl. Polymer Sci., 57, 797 (1995). As disclosed herein, such fluoropolyethers can have carboxylic acid groups or their salts at one or both ends. Similarly, such fluoropolyethers can have sulfonic or phosphonic acid groups or their salts at one or both ends. In addition, fluoropolyethers having acid functional groups at both ends can have different groups at each end. For monofunctional fluoropolyethers, the other end of the molecule is usually perfluorinated, but may contain hydrogen or chlorine atoms.

[0299] Fluoropolyethers having acid groups at one or both ends have at least two ether oxygens, preferably at least four ether oxygens, and even more preferably at least six ether oxygens. Preferably, at least one of the fluorocarbon groups separating the ether oxygens, more preferably at least two of such fluorocarbon groups, has two or three carbon atoms. Even more preferably, at least 50% of the fluorocarbon groups separating the ether oxygens have two or three carbon atoms. Also preferably, the fluoropolyether has in total at least 15 carbon atoms, for example, the preferred minimum value of n or n + m in the above repeating unit structure is at least 5. Two or more fluoropolyethers having acid groups at one or both ends can be used in the method according to the present disclosure. Typically, unless special care is taken in the production of a single specific fluoropolyether compound, the fluoropolyether can contain multiple compounds in various proportions within the molecular weight range relative to the average molecular weight.

[0300] The above fluoropolyether preferably has a number average molecular weight of 800 g / mol or more. Since the fluoropolyether acid or its salt may be difficult to disperse in an aqueous medium, it preferably has a number average molecular weight of less than 6000 g / mol. The fluoropolyether acid or its salt more preferably has a number average molecular weight of 800 to 3500 g / mol, and even more preferably 1000 to 2500 g / mol.

[0301] The amount of the above fluoropolyether is preferably 5 to 3000 ppm with respect to the aqueous medium, more preferably 5 to 2000 ppm. The even more preferable lower limit is 10 ppm, and the even more preferable upper limit is 100 ppm.

[0302] Examples of the nonionic surfactant as the above nucleating agent include the nonionic surfactants described above, and a nonionic surfactant not containing fluorine is preferred. For example, as the nonionic surfactant, the following general formula (i) R 3 -O-A 1 -H (i) (In the formula, R 3 is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, and A 1 is a polyoxyalkylene chain.) The compound represented by the formula is exemplified. R 3 Preferably has 10 to 16 carbon atoms, more preferably 12 to 16 carbon atoms. When the carbon number of R 3 is 18 or less, good dispersion stability of the aqueous dispersion is easily obtained. When the carbon number of R 3 exceeds 18, the flow temperature is high and it is difficult to handle. When the carbon number of R 3 is less than 8, the surface tension of the aqueous dispersion becomes high, and the permeability and wettability are likely to decrease.

[0303] The polyoxyalkylene chain may consist of oxyethylene and oxypropylene. It is a polyoxyalkylene chain composed of an average repeat number of 5 to 20 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups, and is a hydrophilic group. The number of oxyethylene units may include either a broad or narrow unimodal distribution that is usually provided, or a broader or bimodal distribution obtained by blending. When the average repeat number of oxypropylene groups exceeds 0, the oxyethylene groups and oxypropylene groups in the polyoxyalkylene chain may be arranged in a block or random manner. From the viewpoints of the viscosity and stability of the aqueous dispersion, a polyoxyalkylene chain composed of an average repeat number of 7 to 12 of oxyethylene groups and an average repeat number of 0 to 2 of oxypropylene groups is preferable. Especially when A 1 has an average of 0.5 to 1.5 oxypropylene groups, it has good low-foaming properties and is preferable.

[0304] More preferably, R 3 is (R’)(R’’)HC-, where R’ and R’’ are the same or different linear, branched, or cyclic alkyl groups, and the total amount of carbon atoms is at least 5, preferably 7 to 17. Preferably, at least one of R’ or R’’ is a branched or cyclic hydrocarbon group.

[0305] Specific examples of the above polyoxyethylene alkyl ether include C 13 H 27 -O-(C2H4O) 10 -H, C 12 H 25 -O-(C2H4O) 10 -H, C 10 H 21 CH(CH3)CH2-O-(C2H4O)9-H, C 13 H 27 -O-(C2H4O)9-(CH(CH3)CH2O)-H, C 16 H 33 -O-(C2H4O) 10 -H, HC(C5H 11 )(C7H 15)-O-(C2H4O)9-H and the like can be mentioned. Examples of commercially available polyoxyethylene alkyl ethers include, for example, Genapol X080 (product name, manufactured by Clariant), Neugen TDS series (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) such as Neugen TDS-80 (trade name), Leoicol TD series (manufactured by Lion Corporation) such as Leoicol TD-90 (trade name), Lionol (registered trademark) TD series (manufactured by Lion Corporation), T-Det A series (manufactured by Harcros Chemicals Inc.) such as T-Det A138 (trade name), Triton (registered trademark) 15S series (manufactured by Dow) and the like.

[0306] The above nonionic surfactant is preferably an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 4 to about 18 ethylene oxide units, an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 6 to about 12 ethylene oxide units, or a mixture thereof. This type of nonionic surfactant is also commercially available, for example, as TERGITOL TMN-6, TERGITOL TMN-10, and TERGITOL TMN-100X (all product names, manufactured by Dow Chemical Company).

[0307] Also, the hydrophobic group of the nonionic surfactant may be any of an alkylphenol group, a linear alkyl group, and a branched alkyl group. For example, as the polyoxyethylene alkylphenyl ether-based nonionic compound, for example, the following general formula (ii) R 4 -C6H4-O-A 2 -H (ii) (In the formula, R 4 is a linear or branched primary or secondary alkyl group having 4 to 12 carbon atoms, and A 2 is a polyoxyalkylene chain.) Compounds represented by are mentioned. Specific examples of the polyoxyethylene alkylphenyl ether-based nonionic compound include Triton (registered trademark) X-100 (product name, manufactured by Dow Chemical Company) and the like.

[0308] As other nonionic surfactants, a bifunctional block copolymer supplied as the Pluronic® R series from BASF, a tridecyl alcohol alkoxylate supplied as the Iconol® TDA series from BASF Corporation, a hydrocarbon-containing siloxane surfactant, preferably a hydrocarbon surfactant, wherein when the above hydrocarbyl group can be substituted by a halogen such as fluorine, it is completely substituted by a hydrogen atom, whereby these siloxane surfactants can also be regarded as hydrocarbon surfactants, i.e., the monovalent substituent on the hydrocarbyl group is hydrogen.

[0309] In addition, in the above production method, in addition to the above specific hydrocarbon-based surfactant and other compounds having surfactant properties used as desired, additives can be used to stabilize each compound. Examples of the above additives include buffers, pH adjusters, stabilization aids, dispersion stabilizers, and the like.

[0310] As the stabilization aid, paraffin wax, fluorine-based oil, fluorine-based solvent, silicone oil, etc. are preferred. The stabilization aid may be used alone or in combination of two or more. As the stabilization aid, paraffin wax is more preferred. The paraffin wax may be liquid, semi-solid or solid at room temperature, but a saturated hydrocarbon having 12 or more carbon atoms is preferred. The melting point of the paraffin wax is usually preferably 40 to 65 °C, more preferably 50 to 65 °C.

[0311] The amount of the stabilization aid used is preferably 0.1 to 12% by mass, more preferably 0.1 to 8% by mass based on the mass of the aqueous medium used. It is desirable that the stabilization aid is sufficiently hydrophobic and is completely separated from the TFE-based polymer aqueous emulsion after the emulsion polymerization of TFE and does not become a contaminating component.

[0312] In the above manufacturing method, the emulsion polymerization can be carried out by charging an aqueous medium, the above hydrocarbon surfactant, monomers and, if necessary, other additives into a polymerization reactor, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, then adding a predetermined amount of a polymerization initiator to initiate the polymerization reaction. After the start of the polymerization reaction, monomers, polymerization initiators, chain transfer agents, the above surfactant, etc. may be additionally added according to the purpose. The above hydrocarbon surfactant may be added after the polymerization reaction has started.

[0313] In the above emulsion polymerization, the polymerization temperature and polymerization pressure are appropriately determined according to the type of monomers used, the molecular weight of the target TFE-based polymer, and the reaction rate. Usually, the polymerization temperature is 5 to 150 °C, preferably 10 °C or higher, more preferably 30 °C or higher, still more preferably 50 °C or higher. Also, it is more preferably 120 °C or lower, still more preferably 100 °C or lower. The polymerization pressure is 0.05 to 10 MPaG. The polymerization pressure is more preferably 0.3 MPaG or higher, still more preferably 0.5 MPaG or higher. Also, it is more preferably 5.0 MPaG or lower, still more preferably 3.0 MPaG or lower. In particular, from the viewpoint of improving the yield, it is preferably 1.0 MPaG or higher, more preferably 1.2 MPaG or higher, still more preferably 1.5 MPaG or higher, even more preferably 1.8 MPaG or higher, and particularly preferably 2.0 MPaG or higher.

[0314] In the above emulsion polymerization, the hydrocarbon surfactant is preferably added when the concentration of the TFE-based polymer formed in the aqueous medium is less than 0.60% by mass. More preferably, the above concentration is 0.50% by mass or less, still more preferably 0.36% by mass or less, even more preferably 0.30% by mass or less, particularly preferably 0.20% by mass or less, and most preferably added together with the start of polymerization. The above concentration is the concentration with respect to the total of the aqueous medium and the TFE-based polymer. In addition, in the above emulsion polymerization, the amount of the hydrocarbon-based surfactant at the start of polymerization is preferably 1 ppm or more with respect to the aqueous medium. The amount of the hydrocarbon-based surfactant at the start of polymerization is preferably 10 ppm or more, more preferably 50 ppm or more, still more preferably 100 ppm or more, and even more preferably 200 ppm or more. The upper limit is not particularly limited, but for example, it is preferably 100,000 ppm, and more preferably 50,000 ppm. By the amount of the hydrocarbon-based surfactant at the start of polymerization being within the above range, an aqueous dispersion with a smaller average primary particle diameter and better stability can be obtained.

[0315] The above polymerization initiator is not particularly limited as long as it can generate radicals in the above polymerization temperature range, and known oil-soluble and / or water-soluble polymerization initiators can be used. Further, polymerization can also be initiated as a redox in combination with a reducing agent or the like. The concentration of the above polymerization initiator is appropriately determined according to the type of monomer, the molecular weight of the target TFE-based polymer, and the reaction rate.

[0316] As the above polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0317] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, for example, dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate and di-sec-butyl peroxydicarbonate, peroxy esters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, and dialkyl peroxides such as di-t-butyl peroxide can be mentioned as typical ones.

[0318] The water-soluble radical polymerization initiator may be a known water-soluble peroxide. For example, ammonium salts, potassium salts, sodium salts of persulfuric acid, perboric acid, perchloric acid, phosphoric acid, percarbonic acid, etc., t-butyl permaleate, t-butyl hydroperoxide, etc. may be mentioned. Reducing agents such as sulfites and sulfites may also be included, and the amount used may be 0.1 to 20 times that of the peroxide.

[0319] For example, when polymerization is carried out at a low temperature of 30 °C or lower, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. Examples of the oxidizing agent include persulfates, organic peroxides, potassium permanganate, manganese triacetate, ammonium cerium nitrate, bromates, etc. Examples of the reducing agent include sulfites, bisulfites, bromates, diimines, oxalic acid, etc. Examples of the persulfate include ammonium persulfate and potassium persulfate. Examples of the sulfite include sodium sulfite and ammonium sulfite. In order to increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the combination of the redox initiator. Examples of the copper salt include copper(II) sulfate, and examples of the iron salt include iron(II) sulfate.

[0320] As the above redox initiator, it is preferable that the oxidizing agent is permanganic acid or its salt, persulfate, manganese triacetate, cerium(IV) salt, or bromic acid or its salt, and the reducing agent is dicarboxylic acid or its salt, or diimine. More preferably, the oxidizing agent is permanganic acid or its salt, persulfate, or bromic acid or its salt, and the reducing agent is dicarboxylic acid or its salt.

[0321] Examples of the above redox initiator include combinations such as potassium permanganate / oxalic acid, potassium permanganate / ammonium oxalate, manganese triacetate / oxalic acid, manganese triacetate / ammonium oxalate, ammonium cerium nitrate / oxalic acid, ammonium cerium nitrate / ammonium oxalate, etc. When using a redox initiator, either an oxidizing agent or a reducing agent may be charged into the polymerization tank in advance, and then the other may be added continuously or intermittently to initiate polymerization. For example, when using potassium permanganate / ammonium oxalate, it is preferable to charge ammonium oxalate into the polymerization tank and continuously add potassium permanganate thereto. In the redox initiator described in this specification, when "potassium permanganate / ammonium oxalate" is described, it means a combination of potassium permanganate and ammonium oxalate. The same applies to other compounds. As the above redox initiator, it is preferable to use an oxidizing agent or a reducing agent that can make the pH of the aqueous solution of the redox initiator 4.0 or higher. The above aqueous solution of the redox initiator means an aqueous solution with a concentration of 0.50% by mass of the oxidizing agent or an aqueous solution with a concentration of 0.50% by mass of the reducing agent. That is, it is sufficient that the pH of at least one of the aqueous solution with a concentration of 0.50% by mass of the oxidizing agent and the aqueous solution with a concentration of 0.50% by mass of the reducing agent is 4.0 or higher, and it is preferable that the pH of both the aqueous solution with a concentration of 0.50% by mass of the oxidizing agent and the aqueous solution with a concentration of 0.50% by mass of the reducing agent is 4.0 or higher. The pH of the above aqueous solution of the redox initiator (aqueous solution with a concentration of 0.50% by mass of the oxidizing agent or aqueous solution with a concentration of 0.50% by mass of the reducing agent) is more preferably 5.0 or higher, further preferably 5.5 or higher, and particularly preferably 6.0 or higher, respectively.

[0322] The above redox initiator is particularly preferably a combination of an oxidizing agent that is a salt and a reducing agent that is a salt. For example, the oxidizing agent that is the above salt is more preferably at least one selected from the group consisting of persulfates, permanganates, cerium(IV) salts, and bromates, further preferably a permanganate, and particularly preferably potassium permanganate. Also, the reducing agent that is the above salt is more preferably at least one selected from the group consisting of oxalates, malonates, succinates, glutarates, and bromates, further preferably an oxalate, and particularly preferably ammonium oxalate.

[0323] Specific examples of the redox initiator preferably include at least one selected from the group consisting of potassium permanganate / ammonium oxalate, potassium bromate / ammonium sulfite, manganese triacetate / ammonium oxalate, and ammonium cerium nitrate / ammonium oxalate. More preferably, it is at least one selected from the group consisting of potassium permanganate / ammonium oxalate, potassium bromate / ammonium sulfite, and ammonium cerium nitrate / ammonium oxalate.

[0324] By using a redox initiator in the polymerization step, the molecular weight of the obtained TFE-based polymer can be increased. Therefore, the SSG can be decreased, and the polymer can be made stretchable. In addition, by using a redox initiator in the polymerization step, the number of particles of the TFE-based polymer formed in the aqueous dispersion can be increased. Also, the yield of the TFE-based polymer can be increased. When using a redox initiator, the oxidizing agent and the reducing agent may be added all at once at the beginning of polymerization, or the reducing agent may be added all at once at the beginning of polymerization and the oxidizing agent may be added continuously, or the oxidizing agent may be added all at once at the beginning of polymerization and the reducing agent may be added continuously, or both the oxidizing agent and the reducing agent may be added continuously. When using a redox initiator as the polymerization initiator, the addition amount of the oxidizing agent is preferably 5 to 10000 ppm, more preferably 10 to 1000 ppm, and the addition amount of the reducing agent is preferably 5 to 10000 ppm, more preferably 10 to 1000 ppm, with respect to the aqueous medium. In addition, when using a redox initiator in the polymerization step, the polymerization temperature is preferably 100 °C or lower, more preferably 95 °C or lower, and even more preferably 90 °C or lower. Also, it is preferably 10 °C or higher, more preferably 20 °C or higher, and even more preferably 30 °C or higher.

[0325] The addition amount of the polymerization initiator is not particularly limited, but it may be added all at once, sequentially, or continuously at the initial stage of polymerization in an amount such that the polymerization rate does not significantly decrease (for example, several ppm with respect to the water concentration). The upper limit is in the range where the reaction temperature may be increased while removing the heat of polymerization reaction from the equipment surface. A more preferable upper limit is in the range where the heat of polymerization reaction can be removed from the equipment surface. More specifically, for example, 1 ppm or more is preferable with respect to the aqueous medium, 10 ppm or more is more preferable, and 50 ppm or more is still more preferable. Also, 100000 ppm or less is preferable, 10000 ppm or less is more preferable, and 5000 ppm or less is still more preferable.

[0326] The above-mentioned aqueous medium is a reaction medium for carrying out polymerization and means a liquid containing water. The above-mentioned aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as alcohol, ether, ketone, etc., and / or a fluorine-containing organic solvent having a boiling point of 40 °C or lower.

[0327] In the above emulsion polymerization, furthermore, according to the purpose, a known chain transfer agent can be added to adjust the polymerization rate and molecular weight.

[0328] Examples of the above chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, dimethyl succinate, and in addition, isopentane, methane, ethane, propane, isobutane, methanol, ethanol, isopropanol, acetone, various mercaptans, various halogenated hydrocarbons such as carbon tetrachloride, cyclohexane, etc.

[0329] A bromine compound or an iodine compound may be used as the chain transfer agent. Examples of the polymerization method using a bromine compound or an iodine compound include, for example, a method of polymerizing a fluoromonomer in an aqueous medium in the substantial absence of oxygen in the presence of a bromine compound or an iodine compound (iodine transfer polymerization method). Representative examples of the bromine compound or iodine compound to be used include, for example, the general formula: R a Ix Br y (wherein x and y are each an integer of 0 to 2 and satisfy 1 ≦ x + y ≦ 2, and R a is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). Compounds represented by the formula are exemplified. By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a crosslinking point.

[0330] Examples of the iodine compound include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF2Br2, BrCF2CF2Br, CF3CFBrCF2Br, CFClBr2, BrCF2CFClBr, CFBrClCFClBr, BrCF2CF2CF2Br, BrCF2CFBrOCF3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substituents of benzene, diiodomonobromo substituents, and (2-iodoethyl) and (2-bromoethyl) substituents, etc. These compounds may be used alone or in combination with each other.

[0331] Among these, from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, etc., it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane.

[0332] The amount of the chain transfer agent used is usually 1 to 50,000 ppm, preferably 1 to 20,000 ppm, based on the total amount of the fluoromonomer supplied.

[0333] The above chain transfer agent may be added to the reaction vessel all at once before the start of polymerization, or may be added all at once after the start of polymerization, or may be added in multiple portions during polymerization, or may be added continuously during polymerization.

[0334] An aqueous dispersion of the TFE-based polymer can be obtained by the above emulsion polymerization. The above aqueous dispersion usually contains a TFE-based polymer, the compound (1) and / or (2), and an aqueous medium. The solid content concentration of the above aqueous dispersion is not limited, but may be, for example, 1.0 to 70% by mass. The solid content concentration is preferably 8.0% by mass or more, more preferably 10.0% by mass or more, and preferably 60.0% by mass or less, more preferably 50.0% by mass or less. In the above production method, the adhesion amount is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, more preferably 1.0% by mass or less, still more preferably 0.8% by mass or less, still more preferably 0.7% by mass or less, and particularly preferably 0.6% by mass or less, based on the finally obtained TFE-based polymer.

[0335] The coagulation in step (B) can be carried out by a known method. When coagulation is carried out on the aqueous dispersion of the TFE-based polymer, usually, the aqueous dispersion obtained by polymerization such as polymer latex is diluted with water to a polymer concentration of 10 to 25% by mass (preferably a polymer concentration of 10 to 20% by mass), and in some cases, after adjusting the pH to neutral or alkaline, it is carried out by stirring more vigorously than the stirring during the reaction in a container equipped with a stirrer. The above coagulation may be carried out while adding a water-soluble organic compound such as methanol or acetone, an inorganic salt such as potassium nitrate or ammonium carbonate, or an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid as a coagulant. The above coagulation may also be carried out continuously using an in-line mixer or the like.

[0336] The drying (heat treatment) in step (C) is usually carried out using means such as vacuum, high frequency, hot air, etc. while keeping the above-mentioned wet powder in a state where it does not flow much, preferably in a static state. Friction between powders, especially at high temperatures, generally has an unfavorable effect on fine powder type fibrillatable resins. This is because particles composed of this type of fibrillatable resin have the property of easily fibrillating even by a small shear force and losing the original stable particle structure state.

[0337] The drying temperature in step (C) is preferably 130 °C or higher, more preferably 140 °C or higher, still more preferably 150 °C or higher, even more preferably 160 °C or higher, even more preferably 180 °C or higher, even more preferably 200 °C or higher, particularly preferably 220 °C or higher, and preferably 300 °C or lower, more preferably 280 °C or lower, still more preferably 250 °C or lower, in terms of more efficiently removing moisture and fluorine-containing compounds. When using vacuum, drying at a low temperature such as 60 °C or higher, 70 °C or higher, 80 °C or higher, 90 °C or higher is also preferable.

[0338] The drying time in step (C) is preferably 2 hours or more, more preferably 5 hours or more, still more preferably 10 hours or more, even more preferably 15 hours or more, in terms of more efficiently removing moisture and fluorine-containing compounds. The upper limit is not particularly limited, but for example, it is preferably 100 hours, more preferably 50 hours, still more preferably 30 hours.

[0339] The wind speed in step (C) is preferably 0.01 m / s or more, more preferably 0.03 m / s or more, still more preferably 0.05 m / s or more, and even more preferably 0.1 m / s or more, in terms of more efficiently removing moisture and fluorine-containing compounds. Further, from the viewpoint of suppressing the scattering of powder, it is preferably 50 m / s or less, more preferably 30 m / s or less, and still more preferably 10 m / s or less.

[0340] The drying in step (C) can be carried out using an electric furnace or a steam furnace. For example, an electric furnace such as a parallel flow box-type electric furnace, a vented box-type electric furnace, a vented conveyor-type electric furnace, a band electric furnace, a radiation conveyor-type electric furnace, a fluidized bed electric furnace, a vacuum electric furnace, a stirred electric furnace, a pneumatic electric furnace, a hot air circulation electric furnace, etc., or a steam furnace corresponding to the above (a device obtained by replacing the electric furnace in the device name of each of the above electric furnaces with a steam furnace) can be used. In terms of more efficiently removing moisture and fluorine-containing compounds, a parallel flow box-type electric furnace, a vented box-type electric furnace, a vented conveyor-type electric furnace, a band electric furnace, a fluidized bed electric furnace, a hot air circulation electric furnace, and a steam furnace corresponding to the above (a device obtained by replacing the electric furnace in the device name of each of the above electric furnaces with a steam furnace) are preferable.

[0341] The drying in step (C) is preferably carried out by arranging the wet powder in a breathable container on the bottom surface and / or side surface, in terms of more efficiently removing moisture and fluorine-containing compounds. The breathable container on the bottom surface and / or side surface may be any one that can withstand the above drying temperature, but is preferably made of a metal such as stainless steel. As the breathable container on the bottom surface and / or side surface, a tray (bat) having breathability on the bottom surface and / or side surface is preferable, and a tray (mesh tray) made of a mesh on the bottom surface and / or side surface is more preferable. The mesh is preferably either a woven mesh or a punching metal. The mesh opening is preferably 2000 μm or less (10 mesh or more according to ASTM standard), more preferably 595 μm or less (30 mesh or more), still more preferably 297 μm or less (50 mesh or more), even more preferably 177 μm or less (80 mesh or more), particularly preferably 149 μm or less (100 mesh or more), and especially preferably 74 μm or less (200 mesh or more). Also, 25 μm or more (500 mesh or less) is preferable. Examples of the weaving method when the mesh is a woven wire mesh include plain weave, twill weave, plain double weave, and twill double weave. When the mesh is punching metal, the aperture ratio is preferably 10% or more, more preferably 20% or more, and still more preferably 30% or more. Also, 95% or less is preferable.

[0342] In step (C), the amount of the wet powder disposed is preferably 10 g / cm 2 or less in terms of more efficiently removing moisture and the fluorine-containing compound, more preferably 8 g / cm 2 or less, still more preferably 5 g / cm 2 or less, particularly preferably 3 g / cm 2 or less, and preferably 0.01 g / cm 2 or more, more preferably 0.05 g / cm 2 or more, and still more preferably 0.1 g / cm 2 or more.

[0343] In step (C), the water content of the wet powder to be dried is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more with respect to the wet powder in terms of more efficiently removing moisture and the fluorine-containing compound. Also, 150% by mass or less is preferable, and 100% by mass or less is more preferable.

[0344] The composition of the present disclosure can be suitably used as a binder for electrochemical devices. Among them, it can be suitably used as a binder for batteries, and particularly preferably used as a binder for secondary batteries such as lithium ion batteries. It is particularly preferably used as a binder for lithium ion secondary batteries. The composition of the present disclosure may be used for producing an electrochemical device member, preferably a battery member. The composition of the present disclosure can be particularly preferably used as an electrode binder. In terms of further improving the initial capacity and capacity retention rate of an electrochemical device, it is preferably used as a positive electrode binder. The composition of the present disclosure can also be suitably used as a binder in the solid electrolyte layer of a solid secondary battery.

[0345] The present disclosure also provides an electrode mixture containing the above-described composition of the present disclosure and an electrode active material. When the electrode mixture of the present disclosure is used, the initial capacity and capacity retention rate of an electrochemical device can be improved. Further, even when the amount of the binder is small, the electrode active material can be retained, so that more materials for improving the characteristics of an electrochemical device such as an active material and a conductive auxiliary agent can be added.

[0346] As the electrode active material in the electrode mixture of the present disclosure, those described for the electrochemical device of the present disclosure can be used.

[0347] The electrode mixture of the present disclosure may be either a negative electrode mixture or a positive electrode mixture, but is preferably a positive electrode mixture in terms of further improving the initial capacity and capacity retention rate of an electrochemical device.

[0348] The electrode mixture of the present disclosure can be suitably used as an electrode mixture for secondary batteries. In particular, the electrode mixture of the present disclosure is suitable for lithium ion secondary batteries. When the electrode mixture of the present disclosure is used in a secondary battery, it is usually used in a sheet form. The electrode mixture of the present disclosure is preferably a sheet.

[0349] The above sheet (electrode binder sheet) preferably has a thickness of 300 μm or less, more preferably 250 μm or less, still more preferably 200 μm or less, even more preferably 180 μm or less, particularly preferably 150 μm or less, and preferably 10 μm or more, more preferably 15 μm or more, still more preferably 20 μm or more.

[0350] The present disclosure also provides an electrode including the composition of the present disclosure described above, an electrode active material, and a current collector. According to the electrode of the present disclosure, the initial capacity and capacity retention rate of an electrochemical device can be improved. Further, even when the amount of the binder is small, the electrode active material can be retained, so that more materials for improving the characteristics of the electrochemical device such as the active material and the conductive assistant can be added.

[0351] The electrode of the present disclosure may include the above-described electrode binder (preferably an electrode binder sheet) of the present disclosure and a current collector.

[0352] The electrode of the present disclosure is preferably manufactured by a dry process.

[0353] The electrode of the present disclosure may be either a positive electrode or a negative electrode, but is preferably a positive electrode in that the initial capacity and capacity retention rate of the electrochemical device can be further improved.

[0354] The present disclosure also provides a secondary battery including the above-described electrode binder of the present disclosure and a current collector. The secondary battery of the present disclosure is excellent in initial capacity and capacity retention rate. As the specific form of the secondary battery, those described for the electrochemical device of the present disclosure can be adopted.

[0355] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

Examples

[0356] Next, examples will be given to explain the present disclosure in more detail, but the present disclosure is not limited only to these examples.

[0357] Various physical properties were measured by the following methods.

[0358] <Average primary particle diameter> Measured by dynamic light scattering method. An aqueous dispersion of fluoropolymer adjusted to a fluoropolymer solid content concentration of about 1.0 mass% was prepared, and measured at 25 °C and integrated 70 times using ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.). The refractive index of the solvent (water) was 1.3328, and the viscosity of the solvent (water) was 0.8878 mPa·s.

[0359] <Polymer solid content concentration> 1 g of the polymer aqueous dispersion was dried in a forced-air dryer at 150 °C for 60 minutes, and the value obtained by expressing the ratio of the mass of the heat residue to the mass of the aqueous dispersion (1 g) as a percentage was adopted.

[0360] <Endothermic peak temperature> For a composition having no heating history at a temperature of 300 °C or higher, the temperature corresponding to the minimum point in the melting heat curve obtained by performing differential scanning calorimetry [DSC] at a heating rate of 10 °C / min was defined as the endothermic peak temperature. When there are two or more minimum points in one melting peak, each was defined as the endothermic peak temperature.

[0361] <Standard specific gravity (SSG)> Using a sample molded in accordance with ASTM D4895 89, it was measured by the water displacement method in accordance with ASTM D 792.

[0362] <Liquid content> The mass of the composition before and after vacuum heating at 100 °C for 5 hours was measured and calculated according to the following formula. Three samples were taken, each calculated, and then the average was obtained and the average value was adopted. Liquid content (mass%) = [(mass of the composition before heating (g)) - (mass of the composition after heating (g))] / (mass of the composition before heating (g)) × 100

[0363] <Water content> The mass of about 20 g of the composition was measured before and after heating at 150°C for 2 hours, and calculated according to the following formula. Three samples were taken, each calculated, and then the average was obtained and the average value was adopted. Water content (mass%) = [(mass of the composition before heating (g)) - (mass of the composition after heating (g))] / (mass of the composition before heating (g)) × 100

[0364] Synthesis Example 1 White solid A was obtained by the method described in Synthesis Example 1 of International Publication No. 2021 / 045228.

[0365] Production Example 1 A 6-liter SUS reactor equipped with a SUS stirring blade and a temperature control jacket was charged with 3480 g of deionized water, 100 g of paraffin wax, and 5.3 g of the white solid A obtained in Synthesis Example 1. While heating to 70°C, the inside of the reactor was purged with nitrogen gas to remove oxygen. TFE was press-fitted to make the system pressure 0.78 MPaG, and the system temperature was maintained at 70°C while stirring. Next, an aqueous solution prepared by dissolving 15.0 mg of ammonium persulfate in 20 g of water was press-fitted with TFE to initiate the polymerization reaction. As the polymerization reaction proceeded, the system pressure decreased, but TFE was added to maintain the system temperature at 70°C and the system pressure at 0.78 MPaG. When 400 g of TFE was consumed from the start of polymerization, an aqueous solution prepared by dissolving 18.0 mg of hydroquinone in 20 g of water as a radical scavenger was press-fitted with TFE. The polymerization continued thereafter. When the polymerization amount of TFE reached about 1200 g from the start of polymerization, stirring and the supply of TFE were stopped, and immediately the gas in the system was released to normal pressure to terminate the polymerization reaction. The aqueous dispersion was taken out, cooled, and the paraffin wax was separated to obtain a PTFE aqueous dispersion. The average primary particle diameter of the obtained PTFE aqueous dispersion was 310 nm, and the solid content concentration was 25.3 mass%. The obtained PTFE aqueous dispersion was diluted with deionized water to a solid content concentration of 13 mass% and vigorously stirred and coagulated in a container equipped with a stirrer, and then separated from water by filtration to obtain a wet powder. The obtained wet powder was placed on a stainless-steel mesh tray and dried at 210 °C for 18 hours to obtain PTFE powder X. The obtained PTFE powder X had a moisture content of 0.000 mass%, a standard specific gravity of 2.156, a thermal instability index of 0, an endothermic peak temperature of 343 °C, and a liquid content of less than 1 mass%.

[0366] Preparation Example 1 0.273 g of lauric acid was added to 16 g of deionized water, and while stirring, 2.77 g of a 2.8% aqueous ammonia solution was gradually added to obtain aqueous solution C. 10 g of lauric acid was added to 100 g of deionized water, and while stirring, 25 g of a 10% aqueous ammonia solution was gradually added to obtain aqueous solution D. The pH at this time was 9.6.

[0367] Production Example 2 1748 g of deionized water, 90 g of paraffin wax, aqueous solution C obtained in Preparation Example 1, and 0.5 g of ammonium oxalate were added to a 3 L SUS reactor equipped with a stirrer. The pH of the aqueous dispersion at this time was 9.0. The reactor was sealed, the system was purged with nitrogen to remove oxygen. The reactor was heated to 70 °C, 2.0 g of HFP was added, and the pressure was increased with TFE to 2.70 MPa. When a 0.5 mass% potassium permanganate aqueous solution was continuously charged into the reactor as a polymerization initiator, the pressure decreased and the reaction started. TFE was charged so that the reaction pressure was kept constant at 2.70 MPa. When 80 g of TFE was charged, stirring was stopped and the pressure was released until the reaction pressure reached atmospheric pressure. Immediately, the reactor was filled with TFE, the reaction pressure was set to 2.70 MPa, stirring was restarted, and the reaction was continued. At the same time, the aqueous solution D obtained in Preparation Example 1 was continuously charged into the reactor. When 680 g of TFE was charged, stirring was stopped, and the reactor was depressurized until the atmospheric pressure was reached. By the end of the reaction, 56.0 g of potassium permanganate aqueous solution and 26.2 g of aqueous solution D were charged. The aqueous dispersion was taken out from the reactor, cooled, and paraffin wax was separated to obtain an aqueous dispersion of a TFE-based polymer. The pH of the obtained aqueous dispersion of the TFE-based polymer was 8.8, the solid content concentration was 27.1% by mass, and the primary particle diameter was 220 nm.

[0368] The obtained aqueous dispersion of the TFE-based polymer was diluted with deionized water to a solid content concentration of 13% by mass, vigorously stirred in a container equipped with a stirrer to cause coagulation, and then separated from water by filtration to obtain a wet powder. The obtained wet powder was placed on a stainless steel mesh tray and dried at 210 °C for 18 hours to obtain TFE-based polymer powder 1. The water content of the obtained TFE-based polymer powder 1 was 0.002% by mass, the standard specific gravity was 2.170, the thermal instability index was 44, the HFP content was 0.002% by mass, the 0.1% mass loss temperature was 391 °C, the 1.0% mass loss temperature was 491 °C, and the endothermic peak temperature was 342 °C.

[0369] Production Example 1 The PTFE powder X obtained in Production Example 1 and the Li replenisher (Li5FeO4) were mixed at a mass ratio of 2:3, placed in a V-type mixer (VK-1, manufactured by Irie Shokai Co., Ltd.), and mixed at 30 rpm for 10 minutes. The mixture obtained after mixing was designated as Composition A. The liquid amount in Composition A was less than 1% by mass.

[0370] Production Example 2 The TFE-based polymer powder 1 obtained in Production Example 2 and the Li replenisher (Li5FeO4) were mixed at a mass ratio of 2:3, placed in a V-type mixer (VK-1, manufactured by Irie Shokai Co., Ltd.), and mixed at 30 rpm for 10 minutes. The mixture obtained after mixing was designated as Composition B. The liquid amount in Composition B was less than 1% by mass.

[0371] Evaluation of Electrolyte-Containing Batteries The batteries of Examples A1 to A6 and Comparative Example A1 were fabricated and evaluated according to the following procedure.

[0372] <Fabrication of Positive Electrode Composite Sheet> (Examples A1 to A4) The active material and the conductive assistant were weighed, and the materials were put into a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture composed of the active material and the conductive assistant. Then, the weighed binder (PTFE powder X) and the Li replenisher were added to the mixture, and it was sufficiently cooled in a thermostat at 5°C. The mixture composed of the active material, the conductive assistant, the Li replenisher, and the binder was put into a 1-L scale Henschel mixer and homogenized by treating it at 1000 rpm for 3 minutes. After that, after sufficiently heating the mixture in a thermostat at 50°C, fibrillation was promoted by treating it in a Henschel mixer at 3000 rpm for 50 minutes to obtain an electrode composite. The positive electrode composite was put onto metal rolls arranged parallel to the left and right and rolled to obtain a positive electrode composite sheet (left and right roll temperatures: 100°C, left roll rotation speed: 1 m / min, right roll rotation speed: 0.4 m / min). The total amount charged into the Henschel mixer was 1000 g. Table 1 shows the types and compositions of the materials.

[0373] (Example A5) The active material and the conductive assistant were weighed, and the materials were put into a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture composed of the active material and the conductive assistant. Then, the weighed binder (Composition A) was added to the mixture, and it was sufficiently cooled in a thermostat at 5°C. Thereafter, an electrode composite sheet was obtained in the same procedure as in Examples A1 to A4. Table 1 shows the types and compositions of the materials.

[0374] (Example A6) An electrode composite sheet was obtained in the same manner as in Example A5, except that Composition B was used instead of Composition A as the binder. Table 1 shows the types and compositions of the materials.

[0375] (Comparative Example A1) The active material and the conductive aid were weighed, the materials were charged into a V-type mixer, and mixed at 37 rpm for 10 minutes to obtain a mixture composed of the active material and the conductive aid. Thereafter, the weighed binder (PTFE powder X) was added to the mixture, and without adding the Li replenisher, it was sufficiently cooled in a thermostat at 5°C. Thereafter, a positive electrode active material sheet was obtained in the same procedure as in Examples A1 to A4. Table 1 shows the material types and compositions.

[0376]

Table 1

[0377] <Fabrication of the positive electrode> A commercially available carbon-coated aluminum foil with a thickness of 21 μm was prepared as the current collector. The positive electrode active material sheet was placed on the carbon-coated copper foil, and the negative electrode active material sheet and the current collector were bonded together using a roll press heated to 100°C, cut into a desired size, and tabbed to obtain the negative electrode.

[0378] <Fabrication of the negative electrode active material sheet> The active material (SiO) and the conductive aid (SuperP Li) were weighed, the materials were charged into a V-type mixer, and mixed at 37 rpm for 10 minutes to obtain a mixture composed of SiO and the conductive aid. The mixture, the graphite of the active material, and the binder (PTFE powder X) were each weighed and measured into a container. After sufficiently heating the active material and the binder in a thermostat at 80°C, fibrillation was promoted by treating them in a Henschel mixer at 3000 rpm for 30 minutes to obtain a mixture. The mixture was further kneaded (50 rpm, 10 minutes) using a bench-type kneader (PN-1, manufactured by Irie Shokai Co., Ltd.) to promote fibrillation. Subsequently, the mixture was pulverized at 3000 rpm for 10 minutes using a Henschel mixer to enhance the fibrillation promotion and dispersibility of the mixture, thereby obtaining an electrode binder. The electrode binder was introduced onto metal rolls arranged parallel to the left and right (left and right roll temperatures: 100 °C, left roll rotation speed: 1 m / min, right roll rotation speed: 0.4 m / min) and rolled to obtain a negative electrode binder sheet with a thickness of approximately 180 μm. The composition ratio (mass ratio) was set as graphite: SiO: conductive aid: binder = 94:1:1:4.

[0379] <Fabrication of the negative electrode> A commercially available carbon-coated copper foil with a thickness of 10 μm was prepared as the current collector. The negative electrode binder sheet was placed on the carbon-coated copper foil, and the negative electrode binder sheet and the current collector were bonded together using a roll press heated to 50 °C, cut into a desired size, and tabbed to obtain a negative electrode.

[0380] <Fabrication of the electrolyte> As the organic solvent, a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC:EMC = 30:70 (volume ratio)) was measured into a sample bottle, and fluoroethylene carbonate (FEC) and vinylene carbonate (VC) were each dissolved at 3 mass% therein to prepare a mixed solution. To this mixed solution, LiPF6 salt was mixed at 23 °C so that the concentration in the electrolyte became 1.1 mol / L, thereby obtaining a non-aqueous electrolyte.

[0381] <Fabrication of the aluminum laminate cell> The above positive electrode was opposed to the negative electrode via a microporous polyethylene film (separator) with a thickness of 20 μm, the non-aqueous electrolyte obtained above was injected, and after the non-aqueous electrolyte sufficiently penetrated the separator and the like, it was sealed to fabricate a lithium-ion secondary battery.

[0382] <Evaluation of battery characteristics (initial capacity, capacity retention rate)> The lithium-ion secondary battery manufactured above was tested at 60 °C while being sandwiched between plates and pressurized. After constant current-constant voltage charging (0.1C cut-off) to 4.2V at a current corresponding to 0.33C, it was discharged to 3V at a constant current of 0.33C, and this was regarded as one cycle. The initial discharge capacity was determined from the discharge capacity at the third cycle. Here, 1C represents the current value for discharging the reference capacity of the battery in 1 hour. For example, 0.33C represents a current value that is 1 / 3 of that. Cycles were carried out, and the ratio of the discharge capacity after 100 cycles to the initial discharge capacity was determined, and this was defined as the cycle capacity retention rate (%). Cycles were carried out, and the ratio of the discharge capacity after 100 cycles to the initial discharge capacity was determined, and this was defined as the cycle capacity retention rate (%). (Discharge capacity after 103 cycles) ÷ (Discharge capacity at the third cycle) × 100 = Capacity retention rate (%) The capacity retention rate was evaluated according to the following criteria. ◎: 92% or more ○: 88% or more and less than 92% △: 85% or more and less than 88% ×: Less than 85% The results are shown in Table 2. The test results are the average values obtained with N = 4.

[0383]

Table 2

[0384] Powder fluidity evaluation The powder fluidity evaluations of Examples B1, B2 and Comparative Example B1 were carried out according to the following procedure.

[0385] <Powder fluidity evaluation> 80 g of the composition A prepared above was weighed, put into a 250 ml plastic bottle, and the lid was tightened. Then, the container was placed on a mix rotor and rotated at 50 rpm for 4 hours. After rotation, the container was turned over to discharge the composition and the weight was measured to evaluate the amount of the composition adhering to the container. (Example B1) The test was carried out in a dry room environment with a dew point of -40 °C. Composition B was used as Example B2, and PTFE powder X was used as a comparative example for the same evaluation. The powder fluidity of each composition was evaluated according to the following criteria. ◎: Adhesion amount less than 0.2 g ○: Adhesion amount from 0.2 g to less than 0.5 g △: Adhesion amount from 0.5 g to less than 0.8 g ×: Adhesion amount 0.8 g or more The results are shown in Table 3.

[0386]

Table 3

[0387] <Observation of surface coating> The active materials of the cathode binder immediately before forming with the metal rolls of Examples A1 to A6 were observed. The observation was performed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) measurement of Ni, Mn, Co, and Fe. As a result of observation at 3000 times magnification, in the system mixed with Li5FeO4, the presence of the coating layer was confirmed by observing the Fe element of the particles on the surface of the active material. In addition, in the system mixed with Li2NiO2, the presence of the coating layer was confirmed by observing Ni element particles on the surface of the active material where Mn and Co were not observed.

Claims

1. An electrochemical device comprising an electrode active material and a lithium replenisher in a positive electrode and / or a negative electrode, and a fibrillatable resin in the positive electrode and / or the negative electrode.

2. The lithium replenisher is Li ５ FeO ４ , Li ５ AlO and Li ２ NiO ２ The electrochemical device according to claim 1, which is at least one selected from the group consisting of

3. The lithium replenisher is Li ５ FeO ４ and Li ２ NiO ２ The electrochemical device according to claim 1 or 2, which is at least one selected from the group consisting of

4. The electrochemical device according to claim 1 or 2, having a coating layer of the lithium replenisher on the surface of the electrode active material.

5. The electrochemical device according to claim 1 or 2, wherein the negative electrode contains at least one selected from the group consisting of graphite and Si.

6. The electrochemical device according to claim 1 or 2, wherein the positive electrode and / or the negative electrode containing the fibrillatable resin is produced by a dry process.

7. The electrochemical device according to claim 1 or 2, wherein the fibrillatable resin is a tetrafluoroethylene-based polymer.

8. The electrochemical device according to claim 1 or 2, wherein the fibrillatable resin is polytetrafluoroethylene.

9. The electrochemical device according to claim 1 or 2, wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene consisting only of polymerization units based on tetrafluoroethylene units and hexafluoropropylene units.

10. The electrochemical device according to claim 1 or 2, wherein the amount of the fibrillatable resin with respect to the electrode binder in the positive electrode and / or the negative electrode is 0.3 to 10% by mass.

11. The electrochemical device according to claim 1 or 2, wherein the positive electrode contains the lithium replenisher and the fibrillatable resin.

12. The electrochemical device according to claim 1 or 2, which is an electrolytic solution secondary battery or an electrolytic solution capacitor.

13. The electrochemical device according to claim 1 or 2, which is a lithium ion secondary battery.

14. A composition containing a lithium replenisher and a fibrillatable resin.

15. The composition according to claim 14, wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene consisting only of polymerization units based on tetrafluoroethylene units and hexafluoropropylene units.

16. The lithium replenisher is Li ５ FeO ４ and Li ２ NiO ２ The composition according to claim 14 or 15, which is at least one selected from the group consisting of

17. The composition according to claim 14 or 15, wherein the total amount of the lithium replenisher and the fibrillatable resin with respect to the composition is 95% by mass or more.

18. The composition according to claim 14 or 15, wherein the mass ratio of the fibrillatable resin to the Li replenisher (fibrillatable resin / Li replenisher) is 50 / 50 or more and 70 / 30 or less.

19. The composition according to claim 14 or 15, wherein the liquid content is 10% by mass or less.

20. The composition according to claim 14 or 15, which is a powder.

21. The composition according to claim 14 or 15, which is a binder for an electrochemical device.

22. The composition according to claim 14 or 15, which is a binder for a lithium-ion secondary battery.

23. An electrode binder comprising the composition according to claim 14 or 15 and an electrode active material.

24. The electrode binder according to claim 23, which is a sheet.

25. An electrode comprising the composition according to claim 14 or 15, an electrode active material, and a current collector.

26. A secondary battery comprising the electrode binder according to claim 23 and a current collector.

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