Thin film-forming composition for energy storage device electrodes

Abstract

Provided is a composition which is for forming a thin film for an energy storage device electrode, and which provides a primer layer capable of transferring an electrode mixture layer and exhibiting both practical adhesion and excellent adhesion retention after transfer. The composition for forming a thin film for an energy storage device electrode includes: a conductive carbon material; a polymer having an oxazoline group in a side chain; a hydroxyl group-containing polymer having a weight average molecular weight of 50,000-5,000,000; and a solvent.

Description

[Technical Field]

[0001] The present invention relates to a thin film-forming composition for an electrode of an energy storage device. [Background technology]

[0002] In response to demands for smaller, lighter, and more sophisticated portable electronic devices such as smartphones, digital cameras, and portable game consoles, the development of high-performance batteries has been actively pursued in recent years, resulting in a significant increase in demand for secondary batteries that can be repeatedly used by charging. Among these, lithium-ion secondary batteries are currently the most actively developed due to their high energy density, high voltage, and lack of memory effect during charging and discharging. Furthermore, in response to recent environmental concerns, the development of electric vehicles has been actively pursued, and higher performance secondary batteries are being required as their power source.

[0003] A lithium ion secondary battery has a structure in which a positive electrode and a negative electrode capable of absorbing and releasing lithium, and a separator interposed between them, are housed in a container, and the container is filled with an electrolyte (in the case of a lithium ion polymer secondary battery, a gel electrolyte is used instead of a liquid electrolyte).

[0004] Positive and negative electrodes are generally manufactured by applying a composition containing an active material capable of absorbing and releasing lithium, a conductive material mainly made of a carbon material, and a polymer binder to a current collecting substrate such as copper foil or aluminum foil. This binder is used to bond the active material and the conductive material, and also to the metal foil, and commercially available binders include fluorine-based resins such as polyvinylidene fluoride (PVdF) that are soluble in N-methylpyrrolidone (NMP), and aqueous dispersions of olefin polymers.

[0005] However, the adhesive strength of the binder to the current collecting substrate is not sufficient, and during manufacturing processes such as cutting and winding the electrodes, parts of the active material and conductive material peel off and fall off from the current collecting substrate, causing micro-short circuits and variations in battery capacity. Furthermore, over long-term use, swelling of the binder due to the electrolyte and changes in the volume of the electrode mixture due to volume changes caused by lithium absorption and desorption in the active material increase the contact resistance between the electrode mixture and the current collecting substrate, and parts of the active material and conductive material peel off and fall off from the current collecting substrate, resulting in deterioration of battery capacity and safety issues.

[0006] In an attempt to solve the above problems, a method of interposing a conductive undercoat layer between the current collecting substrate and the electrode mixture layer has been developed as a technology for improving adhesion between the current collecting substrate and the electrode mixture layer and reducing contact resistance to reduce the resistance of the battery. For example, Patent Document 1 discloses a technology in which a conductive layer containing carbon as a conductive filler is disposed between the current collecting substrate and the electrode mixture layer as an undercoat layer. It has been shown that the use of a composite current collector with an undercoat layer can reduce the contact resistance between the current collecting substrate and the electrode mixture layer, suppress capacity loss during high-rate discharge, and further suppress battery degradation. Similar technologies are also disclosed in Patent Documents 2 and 3. Patent Documents 4 and 5 disclose undercoat layers using carbon nanotubes as a conductive filler.

[0007] However, while the undercoat layers disclosed in these patent documents are suitable for wet processes in which a slurry-like electrode composite layer-forming composition is applied to the undercoat layer and dried to form an electrode composite layer, they suffer from problems such as insufficient adhesion or difficulty in transfer in dry processes such as a process in which the electrode composite layer-forming composition is first formed into a sheet and then laminated on the undercoat layer by thermocompression or the like, or a process in which an undercoat layer is formed on an electrode composite layer formed on a substrate, a current collecting substrate is laminated thereon, and then the substrate is peeled off to transfer the electrode composite layer. Furthermore, due to production schedules and other factors, there may be a time lag between the formation of the undercoat (primer) layer and its adhesion to the electrode composite layer, and therefore it is required that the adhesion be maintained even after a certain period of storage. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 9-097625 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-011991 [Patent Document 3] Japanese Patent Application Publication No. 11-149916 [Patent Document 4] International Publication No. 2014 / 042080 [Patent Document 5] International Publication No. 2015 / 029949 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a thin film-forming composition for energy storage device electrodes that allows the transfer of an electrode mixture layer and provides a primer layer that has both practical adhesion and excellent adhesion retention after transfer. [Means for solving the problem]

[0010] As a result of extensive research to solve the above problems, the present inventors have found that a composition containing a conductive carbon material, a polymer having an oxazoline group in a side chain, a hydroxyl group-containing polymer having a weight-average molecular weight within a specific range, and a solvent is capable of transferring an electrode mixture layer and provides a thin film (primer layer) that has both practical adhesion and excellent adhesion retention after transfer, thereby completing the present invention.

[0011] That is, the present invention provides an energy storage device electrode. 1. A thin film-forming composition for an energy storage device electrode, comprising a conductive carbon material, a polymer having an oxazoline group in its side chain, a hydroxyl group-containing polymer having a weight-average molecular weight of 50,000 to 5,000,000, and a solvent. 2. The mass ratio of hydroxyl groups in the molecules of the hydroxyl group-containing polymer is 1 x 10 -5 ~100×10 -5 1. A thin film-forming composition for an energy storage device electrode. 3. The mass ratio of hydroxyl groups in the molecules of the hydroxyl group-containing polymer is 1 x 10 -5 ~50×10 -5 2. A thin film-forming composition for an energy storage device electrode. 4. A thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, wherein the content of the hydroxyl group-containing polymer is 25 to 200 parts by mass per 100 parts by mass of the conductive carbon material. 5. The thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, wherein the hydroxyl group-containing polymer is a polyalkylene glycol. 6. The thin film-forming composition for an energy storage device electrode according to 5, wherein the polyalkylene glycol is polyethylene glycol. 7. A thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, wherein the polymer having an oxazoline group in the side chain is a polymer obtained by radical polymerization of an oxazoline monomer represented by formula (1) having a polymerizable carbon-carbon double bond-containing group at the 2-position, and a (meth)acrylic monomer having a hydrophilic functional group. [ka] (wherein X represents a chain hydrocarbon group containing a polymerizable carbon-carbon double bond, R 1 ~R 4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms which may have a branched structure, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 8. A thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, wherein the content of the polymer having an oxazoline group in a side chain is 20 to 60 parts by mass per 100 parts by mass of the conductive carbon material. 9. The thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, wherein the conductive carbon material is one or more selected from the group consisting of acetylene black, carbon black, ketjen black, furnace black, channel black and lamp black. 10. A thin film-forming composition for an energy storage device electrode according to any one of 1 to 3, further comprising a heterocyclic compound represented by the following formula (n1): [ka] (In the formula, R a and R b each independently represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aryl group having 6 to 12 carbon atoms; R a and R b may be bonded to each other to form a ring having 4 to 6 carbon atoms, and X a is N or CH. 11. The thin film-forming composition for an energy storage device electrode of 10, wherein the substituent is at least one selected from the group consisting of a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, and an epoxy group. 12. A thin film-forming composition for an energy storage device electrode according to 10, wherein the heterocyclic compound is represented by the following formula (n2): [ka] (In the formula, Y a represents a hydrogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, or an epoxy group. a is the same as above.) 13. A thin film-forming composition for an energy storage device electrode according to 12, wherein the heterocyclic compound is represented by the following formula (n3): [ka] 14. A primer layer comprising a thin film obtained from the composition for forming a thin film for an energy storage device electrode according to any one of 1 to 3. 15. A composite current collector for an electrode of an energy storage device, comprising a current collecting substrate and a primer layer 14 formed on the current collecting substrate. 16. A composite current collector for an electrode of an energy storage device according to claim 15, wherein the current collecting substrate is copper foil or aluminum foil. 17. An electrode for an energy storage device comprising a composite current collector for an electrode of an energy storage device according to claim 16. 18. Electrode for energy storage device 17, which is for anode electrode. 19. An energy storage device comprising electrodes for an energy storage device according to claim 17. 20. 19 Energy storage devices that are lithium-ion batteries. 21. 20 energy storage devices, which are all-solid-state lithium-ion batteries. 22. A method for producing an energy storage device electrode, comprising applying any one of the compositions for forming a thin film for an energy storage device electrode according to 1 to 3 onto a current collecting substrate, drying the composition to form a primer layer, and then laminating an electrode composite sheet on the primer layer and thermocompression bonding the resulting layer. 23. A step of applying an electrode mixture layer forming composition onto a substrate and drying it to form an electrode mixture layer; a step of applying any one of the compositions for forming a thin film for an energy storage device electrode according to 1 to 3 onto the electrode mixture layer and drying the composition to form a primer layer; The method for producing an energy storage device electrode includes a step of laminating a current collecting substrate on the primer layer, thermocompressing the substrate, and then peeling off the substrate. [Effects of the Invention]

[0012] The composition for forming a thin film for an energy storage device electrode of the present invention allows for the transfer of an electrode mixture layer and provides a primer layer that combines practical adhesion and excellent adhesion retention. Therefore, by using the thin film-forming composition for energy storage device electrodes of the present invention, a dry process for transferring a substrate-attached electrode composite layer composition or an electrode composite layer sheet can be applied, making it possible to produce an electrode having an electrode composite layer that is thick and has excellent thickness precision. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in more detail below. The thin film-forming composition for an energy storage device electrode of the present invention (hereinafter, sometimes simply referred to as "composition") is characterized by comprising a conductive carbon material, a polymer having an oxazoline group in a side chain, a hydroxyl group-containing polymer, and a solvent.

[0014] [1] Conductive carbon materials Specific examples of the conductive carbon material used in the composition of the present invention can be appropriately selected from known conductive carbon materials such as acetylene black, carbon black, ketjen black, furnace black, channel black, lamp black, carbon nanotubes, carbon whiskers, carbon fibers, natural graphite, and artificial graphite, but from the viewpoints of conductivity, dispersibility, adhesion, transferability, etc., acetylene black, carbon black, ketjen black, furnace black, channel black, and lamp black are particularly preferred, acetylene black, carbon black, and ketjen black are more preferred, and acetylene black is even more preferred. The above conductive carbon materials may be used alone or in combination of two or more. Commercially available conductive carbon materials can be used, and specific examples thereof include Denka Black (Li-100, Li-250, Li-400, Li-435, etc.), which is acetylene black manufactured by Denka Corporation, and NH Carbon manufactured by Nippon Chemi-Con Corporation.

[0015] [2] Polymers with oxazoline groups in the side chains In the composition of the present invention, the polymer having an oxazoline group in the side chain (hereinafter referred to as an oxazoline polymer) acts as a dispersant and binder polymer for the conductive carbon material. The polymer is not particularly limited as long as it is a polymer in which an oxazoline group is bonded to a repeating unit constituting the main chain either directly or via a spacer group such as an alkylene group. Specifically, however, it is preferably a polymer having a repeating unit bonded to the polymer main chain or a spacer group at the 2-position of the oxazoline ring, which is obtained by radical polymerization of an oxazoline monomer having a polymerizable carbon-carbon double bond-containing group at the 2-position, as shown in formula (1).

[0016] [ka]

[0017] In the formula, X represents a polymerizable carbon-carbon double bond-containing group, and R 1 ~R 4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms which may have a branched structure, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. The polymerizable carbon-carbon double bond-containing group of the oxazoline monomer is not particularly limited as long as it contains a polymerizable carbon-carbon double bond, but is preferably a chain hydrocarbon group containing a polymerizable carbon-carbon double bond, and for example, an alkenyl group having 2 to 8 carbon atoms, such as a vinyl group, an allyl group, or an isopropenyl group, is preferred. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Specific examples of the alkyl group having 1 to 5 carbon atoms which may have a branched structure include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an n-pentyl group. Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a xylyl group, a tolyl group, a biphenyl group, and a naphthyl group. Specific examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group, a phenylethyl group, and a phenylcyclohexyl group.

[0018] Specific examples of the oxazoline monomer having a polymerizable carbon-carbon double bond-containing group at the 2-position represented by formula (1) include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-4-ethyl-2-oxazoline, 2-vinyl-4-propyl-2-oxazoline, 2-vinyl-4-butyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-vinyl-5-ethyl-2-oxazoline, 2-vinyl-5-propyl-2-oxazoline, 2-vinyl-5-butyl-2-oxazoline, and 2-isopropenyl-2-oxazoline. Examples of oxazoline include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-4-ethyl-2-oxazoline, 2-isopropenyl-4-propyl-2-oxazoline, 2-isopropenyl-4-butyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-5-propyl-2-oxazoline, and 2-isopropenyl-5-butyl-2-oxazoline. From the viewpoint of availability, 2-isopropenyl-2-oxazoline is preferred.

[0019] In addition, in consideration of preparing the conductive carbon material dispersion using an aqueous solvent, the oxazoline polymer is preferably water-soluble. Such a water-soluble oxazoline polymer may be a homopolymer of the oxazoline monomer represented by the above formula (1). However, in order to further enhance the solubility in water, it is preferable that the polymer is obtained by radical polymerization of at least two types of monomers, namely, the oxazoline monomer and a (meth)acrylic acid ester monomer having a hydrophilic functional group.

[0020] Specific examples of (meth)acrylic monomers having a hydrophilic functional group include (meth)acrylic acid, 2-hydroxyethyl acrylate, methoxypolyethylene glycol acrylate, monoesters of acrylic acid and polyethylene glycol, 2-aminoethyl acrylate and its salts, 2-hydroxyethyl methacrylate, methoxypolyethylene glycol methacrylate, monoesters of methacrylic acid and polyethylene glycol, 2-aminoethyl methacrylate and its salts, sodium (meth)acrylate, ammonium (meth)acrylate, (meth)acrylonitrile, (meth)acrylamide, N-methylol (meth)acrylamide, N-(2-hydroxyethyl) (meth)acrylamide, sodium styrenesulfonate, etc. These may be used alone or in combination of two or more. Among these, methoxypolyethylene glycol (meth)acrylate and monoesters of (meth)acrylic acid and polyethylene glycol are preferred.

[0021] In the present invention, other monomers than the above-mentioned oxazoline monomer and (meth)acrylic monomer having a hydrophilic functional group can be used in combination, as long as they do not adversely affect the conductive carbon material dispersibility of the resulting oxazoline polymer. Specific examples of other monomers include (meth)acrylic acid ester monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, perfluoroethyl (meth)acrylate, and phenyl (meth)acrylate; α-olefin-based monomers such as ethylene, propylene, butene, and pentene; haloolefin-based monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; styrene-based monomers such as styrene and α-methylstyrene; vinyl carboxylic acid ester-based monomers such as vinyl acetate and vinyl propionate; and vinyl ether-based monomers such as methyl vinyl ether and ethyl vinyl ether. These may be used alone or in combination of two or more.

[0022] The content of the polymer having an oxazoline group in a side chain in the composition of the present invention is not particularly limited as long as it can disperse the conductive carbon material. However, in consideration of sufficiently dispersing the conductive carbon material and allowing the polymer to function as a binder, the content is preferably 20 to 60 parts by mass, more preferably 30 to 60 parts by mass, and even more preferably 40 to 60 parts by mass, relative to 100 parts by mass of the conductive carbon material.

[0023] [3] Hydroxyl group-containing polymer In the composition of the present invention, the hydroxyl group-containing polymer has a mass ratio of hydroxyl groups in the molecule of the hydroxyl group-containing polymer of 1×10 to improve adhesive strength. -5 ~100×10 -5 Preferably, it is 1×10 -5 ~50×10 -5 It is more preferable that:

[0024] The weight-average molecular weight of the hydroxyl group-containing polymer is 50,000 to 5,000,000, preferably 50,000 to 2,500,000, and more preferably 100,000 to 1,000,000. Polyalkylene glycol and / or polyvinyl alcohol is used. The polyalkylene glycol in the present invention also includes polyalkylene oxide. The weight-average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography.

[0025] In addition, in consideration of the adhesive strength of the primer layer, the lower limit of the melting point of the hydroxyl group-containing polymer is 25°C or higher, and the upper limit is preferably 100°C or lower, more preferably 70°C or lower.

[0026] Specific examples of polyalkylene glycols (polyalkylene oxides) include polyethylene glycol (polyethylene oxide), polypropylene glycol (polypropylene oxide), and polytetramethylene ether glycol. Furthermore, the hydroxyl group-containing polymer may be a copolymer containing multiple types of repeating units, such as a copolymer of alkylene oxide and allyl glycidyl ether. Specific examples of the copolymer include a copolymer of ethylene oxide and allyl glycidyl ether, a copolymer of propylene oxide and allyl glycidyl ether, and a copolymer of ethylene oxide, propylene oxide, and allyl glycidyl ether. The copolymer may be a random copolymer, a block copolymer, or a graft copolymer, with random copolymers being preferred.

[0027] The hydroxyl group-containing polymer may be a commercially available product, for example, Alkox E-240, E-160, E-100, E-75, E-60, E-45, E-30, R-1000, R-400, R-150 (PEG), Alkox CP-A1H, CP-A2H (random copolymer of ethylene oxide, propylene oxide, and allyl glycidyl ether) manufactured by Meisei Chemical Industry Co., Ltd.; Examples of suitable polyvinyl alcohols include polyethylene glycol 2,000, 3,000, 4,000, 6,000, 8,000, 10,000, 12,000, 20,000, and 500,000; polyvinyl alcohol VC-10, 13, 20, and VF-1720 manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.; PEG-2,000, 4,000, 6,000, 10,000, and 20,000 (PEG), and Newball PP-2000 and 4000 (PPG) manufactured by Sanyo Chemical Industries, Ltd.; PEG-2,000, 4,000, 6,000, 10,000, and 20,000 (PEG) manufactured by Alfa Aesar; and PEG-6,000 (PEG) manufactured by Komune Chemical Co., Ltd., but are not limited to these.

[0028] The content of the hydroxyl group-containing polymer in the composition of the present invention is preferably 10 to 200 parts by mass relative to 100 parts by mass of the conductive carbon material, and in consideration of further increasing the adhesion of the primer layer, it is more preferably 30 to 150 parts by mass, and even more preferably 40 to 120 parts by mass.

[0029] In the present invention, in order to improve the adhesion between the current collecting substrate and the primer layer as well as the scratch resistance of the primer layer, it is preferable to further include a nitrogen-containing heterocyclic compound containing two or more nitrogen atoms. The nitrogen-containing heterocyclic compound is not particularly limited as long as it contains two or more nitrogen atoms constituting the ring, and can be appropriately selected from conventionally known compounds. In the present invention, imidazole derivatives, pyrazole derivatives, and triazole derivatives are preferred, imidazole derivatives and triazole derivatives are more preferred, and triazole derivatives are even more preferred. Specific examples of these that can be used are listed below.

[0030] Specific examples of the imidazole derivative include imidazole, benzimidazole, 5-carboxybenzimidazole, and 4-carboxybenzimidazole.

[0031] Specific examples of pyrazole derivatives include pyrazole, 1,2-benzopyrazole, 4-pyrazolecarboxylic acid, 3-pyrazolecarboxylic acid, adenine, and the like.

[0032] The triazole derivative is preferably a benzotriazole-based compound, and specific examples thereof include benzotriazole, carboxybenzotriazole, 5-carboxybenzotriazole, 4-carboxybenzotriazole, 5-hydroxybenzotriazole, 5-aminobenzotriazole, benzotriazole-4-sulfonic acid, 4-methylbenzotriazole, 5-methyl-1H-benzotriazole, 1-carboxybenzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 4-methylbenzotriazole, 5-methyl-1H-benzotriazole, benzotriazole-1-methylamine, 4-methylbenzotriazole-1-methylamine, 5-methylbenzotriazole-1-methylamine, N-methylbenzotriazole-1-methylamine, N-ethylbenzotriazole-1-methylamine, N,N-dimethylbenzotriazole-1-methylamine, N,N-diethylbenzotriazole-1-methylamine, N,N-dipropylbenzotriazole-1-methylamine, and N,N-dibutylbenzotriazole-1-methylamine. N,N-Dihexylbenzotriazole-1-methylamine, N,N-Dioctylbenzotriazole-1-methylamine, N,N-Bis(2-ethylhexyl)benzotriazole-1-methylamine, N,N-Dimethyl-4-benzotriazole-1-methylamine, N,N-Dimethyl-5-benzotriazole-1-methylamine, N,N-Diethyl-4-benzotriazole-1-methylamine, N,N-Diethyl-5-benzotriazole-1-methylamine, N,N-Dipropyl-4-benzotriazole-1-methylamine N,N-dipropyl-5-benzotriazole-1-methylamine, N,N-dibutyl-4-benzotriazole-1-methylamine, N,N-dibutyl-5-benzotriazole-1-methylamine, N,N-dihexyl-4-benzotriazole-1-methylamine, N,N-dihexyl-5-benzotriazole-1-methylamine, N,N-bis(2-ethylhexyl)-4-methylbenzotriazole-1-methylamine, N,N-bis(2-ethylhexyl)-5-methylbenzotriazole-1-methylamine, N,Examples include N-dioleyl-4-methylbenzotriazole-1-methylamine, N,N-dioleyl-5-methylbenzotriazole-1-methylamine, N,N-distearyl-4-methylbenzotriazole-1-methylamine, N,N-distearyl-5-methylbenzotriazole-1-methylamine, 1-hydroxymethylbenzotriazole, 1-(2-ethylhexylamino)methyl)benzotriazole, and 1-(2,3-dihydroxypropyl)benzotriazole.

[0033] In particular, in the present invention, it is preferable to use a compound represented by the following formula (n1).

[0034] [ka]

[0035] Above R a and R b each independently represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkenyl group having 2 to 6 carbon atoms, or an optionally substituted aryl group having 6 to 12 carbon atoms; R a and R b may be bonded to each other to form a ring having 4 to 6 carbon atoms, and X a is N or CH.

[0036] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0037] The alkyl group having 1 to 6 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include linear or branched alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, and n-hexyl groups; and cyclic alkyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups.

[0038] Examples of alkenyl groups having 2 to 6 carbon atoms include ethenyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, and n-1-pentenyl.

[0039] Examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, 1-naphthyl, and 2-naphthyl groups.

[0040] Examples of the substituent include a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, and an epoxy group.

[0041] R a and R b Examples of the ring having 4 to 6 carbon atoms formed by bonding together include a cyclopentane ring, a cyclohexane ring, and a benzene ring.

[0042] Above X a As the group, N is preferred.

[0043] In particular, R a and R b More preferred is a compound represented by the following formula (n2) in which are bonded to each other to form a benzene ring.

[0044] [ka]

[0045] Above Y a represents a hydrogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, or an epoxy group. From the viewpoints of ensuring the migration suppression effect and improving the adhesion between the current collector and the undercoat layer, a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, or an epoxy group is preferred, and a carboxy group is more preferred. Above X ais the same as (n1) above, but N is preferred.

[0046] Therefore, a more preferred embodiment of the heterocyclic compound represented by the above formula (n2) is one represented by the following formula (n3).

[0047] [ka]

[0048] Specific examples of the heterocyclic compound represented by the above formula (n3) include carboxybenzotriazole, 5-carboxybenzotriazole, and 4-carboxybenzotriazole, with carboxybenzotriazole and 5-carboxybenzotriazole being preferred.

[0049] When a nitrogen-containing heterocyclic compound is contained, the content thereof is preferably 0.05 to 200 parts by mass, more preferably 0.1 to 150 parts by mass, even more preferably 5 to 130 parts by mass, still more preferably 10 to 110 parts by mass, and most preferably 10 to 100 parts by mass, relative to 100 parts by mass of the conductive carbon material. The above nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

[0050] [4] Solvent The solvent used in preparing the composition of the present invention is not particularly limited, but water and / or a hydrophilic solvent is preferred. The hydrophilic solvent is an organic solvent that can be mixed with water arbitrarily, and examples thereof include organic solvents such as ethers such as tetrahydrofuran (THF); amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP); ketones such as acetone; alcohols such as methanol, ethanol, n-propanol, and 2-propanol; glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether; and glycols such as ethylene glycol and propylene glycol. These solvents may be used alone or in combination of two or more.

[0051] Among these, water, NMP, DMF, THF, methanol, ethanol, n-propanol, 2-propanol, n-butanol, and t-butanol are preferred in terms of enhancing the dispersibility of the conductive carbon material, and methanol, ethanol, n-propanol, 2-propanol, n-butanol, t-butanol, and ethylene glycol monobutyl ether are preferred in terms of enhancing the coatability of the composition. In particular, from the viewpoint of reducing costs, it is preferable that the solvent contains water, and it is more preferable that the solvent contains 70 mass % or more of water (30 mass % or less of organic solvent).

[0052] [5] Preparation method of the composition The method for preparing the composition of the present invention is not particularly limited, and the composition can be prepared by mixing a conductive carbon material, a polymer having oxazoline groups in the side chains, a hydroxyl group-containing polymer, and a solvent in any order. However, a preferred method is to mix a first liquid prepared by mixing a conductive carbon material, a polymer having oxazoline groups in the side chains, and a solvent, with a second liquid prepared by mixing a hydroxyl group-containing polymer and a solvent.

[0053] In this case, it is preferable to subject the composition to a dispersion treatment, which can further improve the dispersion ratio of the conductive carbon material. Examples of the dispersion treatment include mechanical treatments such as wet treatments using a ball mill, bead mill, jet mill, etc., and ultrasonic treatments using a bath-type or probe-type sonicator, with wet treatments using a jet mill and ultrasonic treatments being particularly preferred. The time for the dispersion treatment is optional, but is preferably about 1 minute to 10 hours, and more preferably about 5 minutes to 5 hours. Heating treatment or cooling treatment may be carried out as necessary.

[0054] In the present invention, the solids concentration of the composition is not particularly limited, but in consideration of forming a primer layer with a desired basis weight and film thickness, it is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less. The lower limit is arbitrary, but from a practical viewpoint, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The solid content means the components other than the solvent that constitute the composition.

[0055] [6] Primer layer and energy storage device electrode The composition described above is applied to at least one surface of a current collector or the surface of an electrode mixture layer, and then dried naturally or by heating to obtain a thin film, which can be suitably used as a primer layer for an energy storage device electrode. Examples of the energy storage device include various energy storage devices such as electric double layer capacitors, lithium secondary batteries, lithium ion secondary batteries, proton polymer batteries, nickel-metal hydride batteries, aluminum solid capacitors, electrolytic capacitors, and lead-acid batteries. The composition of the present invention can be particularly suitably used in electric double layer capacitors and lithium ion secondary batteries.

[0056] The current collector may be any of those conventionally used as current collectors for electrodes of energy storage devices, such as copper, aluminum, titanium, stainless steel, nickel, gold, silver, and alloys thereof, carbon materials, metal oxides, and conductive polymers, but metal foils made of copper, aluminum, nickel, or alloys thereof are preferred. The thickness of the current collector is not particularly limited, but in the present invention, it is preferably 1 to 100 μm.

[0057] The electrode mixture layer can be formed by applying an electrode slurry (composition for forming an electrode mixture layer) prepared by mixing an active material, a binder polymer, and, if necessary, a solvent, onto a substrate and drying naturally or by heating.

[0058] The active material may be any of various active materials conventionally used in electrodes for energy storage devices. For example, in the case of lithium secondary batteries or lithium ion secondary batteries, the positive electrode active material may be a chalcogen compound capable of absorbing and releasing lithium ions, a lithium ion-containing chalcogen compound, a polyanionic compound, elemental sulfur, or compounds thereof.

[0059] Examples of chalcogen compounds capable of absorbing and desorbing lithium ions include FeS2, TiS2, MoS2, V2O6, and V6O 13 , MnO2, etc. Examples of lithium ion-containing chalcogen compounds include LiCoO2, LiMnO2, LiMn2O4, LiMo2O4, LiV3O8, LiNiO2, and Li x Ni y M 1-y O2 (wherein M represents at least one metal element selected from Co, Mn, Ti, Cr, V, Al, Sn, Pb, and Zn, and 0.05≦x≦1.10, 0.5≦y≦1.0). An example of the polyanionic compound is LiFePO4. Examples of sulfur compounds include Li2S and rubeanic acid.

[0060] On the other hand, as the negative electrode active material constituting the negative electrode, at least one element, oxide, sulfide or nitride selected from alkali metals, alkali alloys, and elements in Groups 4 to 15 of the periodic table that absorb and desorb lithium ions, or a carbon material that can reversibly absorb and desorb lithium ions can be used.

[0061] Examples of alkali metals include Li, Na, and K, and examples of alkali metal alloys include Li-Al, Li-Mg, Li-Al-Ni, Na-Hg, and Na-Zn. Examples of the simple substance of at least one element selected from the elements of Groups 4 to 15 of the periodic table that absorbs and releases lithium ions include silicon, tin, aluminum, zinc, and arsenic. Similarly, oxides include silicon monoxide (SiO), silicon dioxide (SiO2), tin silicon oxide (SnSiO3), lithium bismuth oxide (Li3BiO4), lithium zinc oxide (Li2ZnO2), and lithium titanium oxide (Li4Ti5O 12 ), titanium oxide, etc. Similarly, lithium iron sulfide (Li x FeS2 (0≦x≦3)), lithium copper sulfide (Li x CuS (0≦x≦3) and the like. Similarly, examples of nitrides include lithium-containing transition metal nitrides, specifically Li x M y Examples include N (M=Co, Ni, Cu, 0≦x≦3, 0≦y≦0.5), lithium iron nitride (Li3FeN4), etc. Examples of carbon materials capable of reversibly absorbing and desorbing lithium ions include graphite, carbon black, coke, glassy carbon, carbon fiber, carbon nanotubes, and sintered bodies of these.

[0062] In the case of an electric double layer capacitor, a carbonaceous material can be used as the active material. Examples of the carbonaceous material include activated carbon, such as activated carbon obtained by carbonizing a phenolic resin and then activating it.

[0063] The binder polymer can be appropriately selected from known materials, such as polyvinylidene fluoride (PVdF), polyvinylpyrrolidone, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer [P(VDF-HFP)], vinylidene fluoride-chlorotrifluoroethylene copolymer [P(VDF-CTFE)], polyvinyl alcohol, polyimide, ethylene-propylene-diene terpolymer, styrene-butadiene rubber, carboxymethyl cellulose (CMC), polyacrylic acid (PAA), ammonium polyacrylate, polyaniline, polyimide, and polyamide. The amount of binder polymer added is preferably 0.1 to 40 parts by weight, and more preferably 1 to 30 parts by weight, per 100 parts by weight of the active material.

[0064] Examples of the solvent include those exemplified as the solvent for the composition above, and an appropriate solvent may be selected from these depending on the type of binder. In the case of a water-insoluble binder such as PVdF, NMP is suitable, and in the case of a water-soluble binder such as PAA, water is suitable.

[0065] The electrode slurry may contain a conductive material, such as carbon black, ketjen black, acetylene black, carbon whisker, carbon fiber, natural graphite, artificial graphite, titanium oxide, ruthenium oxide, aluminum, or nickel.

[0066] Examples of methods for applying the electrode slurry include spin coating, dip coating, flow coating, inkjet coating, casting, spray coating, bar coating, gravure coating, slit coating, roll coating, flexographic printing, transfer printing, brush coating, blade coating, air knife coating, and die coating. From the standpoint of work efficiency and the like, the inkjet coating, casting, dip coating, bar coating, blade coating, roll coating, gravure coating, flexographic printing, spray coating, and die coating are preferred. The temperature for heating and drying may also be any temperature, but is preferably about 50 to 400°C, and more preferably about 80 to 150°C.

[0067] The composition of the present invention can be applied to the surface of the current collecting substrate or electrode mixture layer by the same method as the above-mentioned method for applying the electrode slurry. The temperature for heat drying may also be any temperature, but is preferably about 50 to 200°C, more preferably about 80 to 150°C.

[0068] Considering the reduction in the internal resistance of the resulting device, the thickness of the primer layer is preferably 1 nm to 10 μm, more preferably 1 nm to 5 μm, and even more preferably 1 nm to 3 μm. The thickness can be determined, for example, by cutting a test piece of an appropriate size from a laminate on which a primer layer has been formed, exposing the cross section by a technique such as tearing it by hand, and observing the exposed part of the primer layer in the cross section with a microscope such as a scanning electron microscope (SEM).

[0069] The amount of the primer layer per surface of the current collector or electrode mixture layer is not particularly limited as long as the above film thickness is satisfied, but it is preferably 3,000 mg / m 2 Less than 2,500 mg / m is preferred 2 Less than 2,000 mg / m is more preferable. 2 On the other hand, in order to ensure the function of the primer layer and to reproducibly obtain batteries with excellent characteristics, the coating weight of the primer layer per surface is 500 mg / m2 More than 750 mg / m 2 More preferably, 1,000 mg / m or more 2 The above is more preferable.

[0070] The weight of the primer layer is determined by the area of ​​the primer layer (m 2 ) and when the primer layer is formed in a pattern, the area is the area of ​​the primer layer only, and does not include the area of ​​the underlying layer such as the current collector exposed between the patterned primer layers. The above-mentioned basis weight may also be an estimated basis weight, which means the estimated basis weight when a composition having a predetermined solid content concentration is applied to the undercoat layer using a predetermined wire bar coater, and can be expressed as the estimated basis weight when a composition having a solid content concentration of 5% by mass is applied to the undercoat layer using a wire bar coater OSP-30, for example.

[0071] The mass of the primer layer can be calculated, for example, by cutting a test piece of an appropriate size from a laminate on which a primer layer is formed, measuring its mass W0, then peeling the primer layer from the laminate, measuring the mass W1 after peeling the primer layer, and calculating the mass from the difference (W0-W1), or by measuring the mass W2 of the current collector in advance, then measuring the mass W3 of the laminate on which the primer layer is formed, and calculating the mass from the difference (W3-W2). Examples of methods for peeling the primer layer include immersing the primer layer in a solvent that dissolves or swells the primer layer, and wiping the primer layer off with a cloth or the like.

[0072] The basis weight and film thickness can be adjusted by known methods. For example, when forming a primer layer by coating, they can be adjusted by changing the solids concentration of the coating liquid (primer layer-forming composition) for forming the primer layer, the number of applications, the clearance of the coating liquid inlet of the coating machine, etc. When a higher basis weight or film thickness is desired, the solids concentration can be increased, the number of applications can be increased, or the clearance can be increased. When a lower basis weight or film thickness is desired, the solids concentration can be decreased, the number of applications can be reduced, or the clearance can be narrowed.

[0073] After forming the primer layer on the current collecting substrate, the electrode slurry is applied to the surface of the primer layer and dried naturally or by heating to form an electrode composite layer, thereby producing an energy storage device electrode. However, as described above, the primer layer of the present invention can also be applied to a dry method, and therefore an energy storage device electrode can also be produced by laminating an electrode composite sheet on the primer layer and heat-pressing it. In this case, the electrode mixture sheet can be prepared by applying the above-mentioned electrode slurry onto the base layer and drying it naturally or by heating to form it into a sheet.

[0074] Alternatively, an energy storage device electrode can be produced by applying the above-described electrode slurry to a substrate and drying it to form an electrode mixture layer, applying the composition of the present invention to the electrode mixture layer and drying it to form a primer layer, laminating a current collecting substrate thereon and thermocompressing the primer layer, and then peeling off the substrate to transfer the electrode mixture layer. Even when the electrode is produced by transfer in this way, the primer layer of the present invention can exhibit high adhesion. In this case, the substrate may be any material, but a substrate made of the same material as the current collector may be used, and copper foil is preferred.

[0075] The temperature during thermocompression bonding is not particularly limited, but in consideration of further increasing the adhesion of the primer layer, it is preferably a temperature equal to or higher than the melting point of the hydroxyl group-containing polymer. The temperature varies depending on the type of hydroxyl group-containing polymer, but is generally preferably less than 115°C, more preferably 110°C or less, and even more preferably 105°C or less. The lower limit is preferably 50°C or more, more preferably 55°C or more, and even more preferably 60°C or more. The pressure during thermocompression is not particularly limited, but the linear pressure is preferably 1 kN / cm or more, more preferably 5 kN / cm or more, and even more preferably 10 kN / cm or more. The pressure bonding can be performed by any commonly used method, but the die pressing method or roll pressing method is particularly preferred.

[0076] [7] Energy storage devices The energy storage device according to the present invention is equipped with the above-described energy storage device electrode, and more specifically, is configured with at least a pair of positive and negative electrodes, a separator interposed between the electrodes, and an electrolyte, and at least one of the positive and negative electrodes is configured from the above-described energy storage device electrode.

[0077] This energy storage device is characterized by using the above-mentioned energy storage device electrodes as electrodes, and other device components such as a separator and electrolyte can be appropriately selected from known materials. Examples of separators include cellulose-based separators and polyolefin-based separators.

[0078] The electrolyte may be either a liquid electrolyte obtained by dissolving an electrolyte salt in a solvent or a solid electrolyte, and may be either aqueous or non-aqueous. However, the electrode for an energy storage device of the present invention is preferably applied to a battery using a solid electrolyte, particularly an all-solid-state battery (e.g., an all-solid-state lithium-ion battery).

[0079] Examples of electrolyte salts include lithium salts such as LiPF, LiBF, LiN(SOF), LiN(CFSO), LiAsF, LiSbF, LiAlF, LiGaF, LiInF, LiClO, LiN(CFSO), LiCFSO, LiSiF, LiN(CFSO), and (CFSO), metal iodides such as LiI, NaI, KI, CsI, and CaI, iodide salts of quaternary imidazolium compounds, iodide salts and perchlorates of tetraalkylammonium compounds, and metal bromides such as LiBr, NaBr, KBr, CsBr, and CaBr. These electrolyte salts may be used alone or in combination of two or more.

[0080] The electrolyte solvent is not particularly limited as long as it does not corrode or decompose the materials constituting the battery, thereby deteriorating performance, and dissolves the electrolyte salt. For example, non-aqueous solvents include cyclic esters such as ethylene carbonate, propylene carbonate, butylene carbonate, and γ-butyrolactone; ethers such as tetrahydrofuran and dimethoxyethane; linear esters such as methyl acetate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; and nitriles such as acetonitrile. These solvents may be used alone or in combination of two or more.

[0081] In addition, as the solid electrolyte, inorganic solid electrolytes such as sulfide-based solid electrolytes and oxide-based solid electrolytes, and organic solid electrolytes such as polymer-based electrolytes can be suitably used. By using these solid electrolytes, an all-solid-state battery can be obtained that does not require an electrolytic solution.

[0082] Examples of sulfide-based solid electrolytes include Li2S-SiS2-lithium compounds (wherein the lithium compound is at least one selected from the group consisting of Li3PO4, LiI, and Li4SiO4), and thiolithium-based materials such as Li2S-P2S5, Li2S-P2O5, Li2S-B2S5, and Li2S-P2S5-GeS2.

[0083] As an oxide-based solid electrolyte, Li5La3M2O, an oxide with a garnet structure, is used. 12 (M=Nb, Ta) and Li7La3Zr2O 12 , γ-Li3PO4 structure-based oxygen acid salt compounds collectively known as LISICON, perovskite type, Li 3.3 PO 3.8 N 0.22 , sodium / alumina, etc.

[0084] Examples of polymer solid electrolytes include polyethylene oxide materials and polymer compounds obtained by polymerizing or copolymerizing monomers such as hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, vinylidene chloride, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, and vinylidene fluoride.

[0085] The polymer solid electrolyte may contain a supporting salt and a plasticizer. Specific examples of the supporting salt include lithium (fluorosulfonylimide), and examples of the plasticizer include succinonitrile. [Example]

[0086] The present invention will be explained in more detail below with reference to Production Examples, Examples, Comparative Examples and Reference Examples, but the present invention is not limited to the following Examples. The devices used in the examples are as follows: (1) Probe-type ultrasonic irradiation device (dispersion of conductive carbon) Hielscher Ultrasonics, UIP1000 (2) Wire bar coater (primer layer formation) PM-9050MC, manufactured by SMT Corporation (3) Roll press machine (electrode compression) SA-602, manufactured by Takumi Giken Co., Ltd. (4) Adhesion and peeling analysis device (adhesion force measurement) VPA-3 manufactured by Kyowa Interface Science Co., Ltd. (5) Differential scanning calorimetry (DSC) (measuring melting point) Equipment: Hitachi High-Tech Science Corporation, Differential Scanning Calorimeter DSC7020 Sample amount: 5-10mg Measuring pan: Aluminum (sealed) Measurement conditions: The temperature was increased from 30°C to 200°C at 10°C / min and held for 1 minute. The temperature was decreased from 200°C to 30°C at 10°C / min and held for 1 minute. Then, the temperature was increased from 30°C to 200°C at 10°C / min, and the temperature at the endothermic peak was taken as the melting point. (6) Tripogear TYPE30S (Scratch test) Shinto Scientific Co., Ltd., Tripogear TYPE30S Load: 500g

[0087] The raw materials used are as follows: AB: Acetylene black, manufactured by Denka Co., Ltd., Denka Black Li435 WS-700: Nippon Shokubai Co., Ltd., aqueous solution containing oxazoline polymer, Epocross (registered trademark) WS-700, weight average molecular weight: 4.0 × 10 4 , solid content concentration: 25.0% by mass WS-300: Nippon Shokubai Co., Ltd., aqueous solution containing oxazoline polymer, Epocross (registered trademark) WS-300, weight average molecular weight: 1.2 × 10 5 , solid content concentration: 10.0% by mass Polyvinylpyrrolidone: Pitzcol (registered trademark) K90, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., weight average molecular weight 1,200,000 E-45: Meisei Chemical Industry Co., Ltd., polyethylene oxide, Alcox (registered trademark) E-45, weight average molecular weight: 600,000, mass ratio of hydroxyl groups in the molecule: 5.7 × 10 -5 , Melting point: 61℃ R-150: Meisei Chemical Industry Co., Ltd., polyethylene oxide, Alcox (registered trademark) R-150, weight average molecular weight: 100,000, mass ratio of hydroxyl groups in the molecule: 3.4 × 10-4 , Melting point: 61℃ CP-A2H: Meisei Chemical Industry Co., Ltd., random copolymer of ethylene oxide, propylene oxide, and allyl glycidyl ether, ALKOX (registered trademark) CP-A2H, weight average molecular weight: 80,000, mass ratio of hydroxyl groups in the molecule: 4.3 × 10 -4 , Melting point: 45℃ E-300: Meisei Chemical Industry Co., Ltd., polyethylene oxide, Alcox (registered trademark) E-300, weight average molecular weight: 7,000,000, mass ratio of hydroxyl groups in the molecule: 4.9 × 10 -6 , Melting point: 70℃ PEG20k: Sanyo Chemical Industries, Ltd., polyethylene glycol, PEG20,000, weight-average molecular weight: 20,000, mass ratio of hydroxyl groups in the molecule: 1.7 × 10 -3 , Melting point: 63℃ PEG10k: Sanyo Chemical Industries, Ltd., polyethylene glycol, PEG10,000, weight-average molecular weight: 10,000, mass ratio of hydroxyl groups in the molecule: 3.4 × 10 -3 Melting point: 62℃ PEG6k: Sanyo Chemical Industries, Ltd., polyethylene glycol, PEG6,000, weight-average molecular weight: 6,000, mass ratio of hydroxyl groups in the molecule: 5.67 × 10 -3 , Melting point: 61℃ 2-Propanol: Junsei Chemical Co., Ltd. CBT-1: Carboxybenzotriazole (CAS RN: 60932-58-3), manufactured by Johoku Chemical Industry Co., Ltd. A-30: Manufactured by Toagosei Co., Ltd., ammonium polyacrylate, Aron (registered trademark) A-30, weight average molecular weight 100,000, solid content 31.6% by mass

[0088] <Calculation of the mass proportion of hydroxyl groups in the molecules of a hydroxyl group-containing polymer> The mass proportion of hydroxyl groups in the molecules of the hydroxyl group-containing polymer was calculated according to the following formula. Percentage of hydroxyl groups = (17 x number of hydroxyl groups) / weight average molecular weight of polymer

[0089] [1] Preparation of dispersion [Production Example 1] Preparation of Dispersion A 1.5 g (100 parts by mass) of acetylene black (hereinafter abbreviated as AB), a conductive carbon material, 3.0 g (50 parts by mass as solids) of WS-700, an aqueous solution containing an oxazoline polymer, 38.36 g of pure water, and 2.14 g of 2-propanol were mixed. The resulting mixture was subjected to ultrasonic treatment for 15 minutes using a probe-type ultrasonic irradiation device, to prepare dispersion A, in which the conductive carbon material was uniformly dispersed.

[0090] [Production Example 2] Preparation of Dispersion B 1.5 g (100 parts by mass) of conductive carbon material AB, 7.5 g (50 parts by mass as solids) of WS-300, an aqueous solution containing an oxazoline polymer, 33.86 g of pure water, and 2.14 g of 2-propanol were mixed. The resulting mixture was subjected to ultrasonic treatment for 15 minutes using a probe-type ultrasonic irradiation device to prepare dispersion B, in which the conductive carbon material was uniformly dispersed.

[0091] [Production Example 3] Preparation of Dispersion C 1.4 g (100 parts by mass) of conductive carbon material AB, 0.7 g (50 parts by mass) of polyvinylpyrrolidone K90, 37.90 g of pure water, and 2.00 g of 2-propanol were mixed together. The resulting mixture was subjected to ultrasonic treatment for 15 minutes using a probe-type ultrasonic irradiation device to prepare dispersion C in which the conductive carbon material was uniformly dispersed.

[0092] [2] Preparation of thin film-forming composition for energy storage device electrodes [Example 1-1] Preparation of thin film forming composition A A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.0 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition A with a solids concentration of 5% by mass. Thin film-forming composition A was a black ink in which AB was uniformly dispersed.

[0093] [Example 1-2] Preparation of thin film forming composition B A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 1.2 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition B with a solids concentration of 5% by mass. Thin film-forming composition B was a black ink in which AB was uniformly dispersed.

[0094] [Example 1-3] Preparation of thin film forming composition C A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 1.6 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition C with a solids concentration of 5% by mass. Thin film-forming composition C was a black ink in which AB was uniformly dispersed.

[0095] [Example 1-4] Preparation of thin film forming composition D A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.4 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition D with a solids concentration of 5% by mass. Thin film-forming composition D was a black ink in which AB was uniformly dispersed.

[0096] [Example 1-5] Preparation of thin film forming composition E A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.8 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition E with a solids concentration of 5% by mass. Thin film-forming composition E was a black ink in which AB was uniformly dispersed.

[0097] [Example 1-6] Preparation of thin film forming composition F A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 4.0 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition F with a solids concentration of 5% by mass. Thin film-forming composition F was a black ink in which AB was uniformly dispersed.

[0098] [Example 1-7] Preparation of thin film forming composition G A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 3.0 g of Dispersion A prepared in Production Example 1 was mixed with 4.0 g of a 5% by mass aqueous solution of E-45 to prepare Thin Film Forming Composition G with a solids concentration of 5% by mass. Thin Film Forming Composition G was a black ink in which AB was uniformly dispersed.

[0099] [Example 1-8] Preparation of thin film forming composition H A 5% by mass aqueous solution of R-150 was prepared by dissolving 0.5 g of the hydroxyl group-containing polymer R-150 in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 4.0 g of the 5% by mass aqueous solution of R-150 to prepare thin film forming composition H with a solids concentration of 5% by mass. Thin film forming composition H was a black ink in which AB was uniformly dispersed.

[0100] [Examples 1-9] Preparation of Thin Film-Forming Composition I A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of Dispersion B prepared in Production Example 2 was mixed with 2.0 g of the 5% by mass aqueous solution of E-45 to prepare Thin Film Forming Composition I with a solids concentration of 5% by mass. Thin Film Forming Composition I was a black ink in which AB was uniformly dispersed.

[0101] [Example 1-10] Preparation of thin film forming composition J A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion B prepared in Production Example 2 was mixed with 4.0 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition J with a solids concentration of 5% by mass. Thin film-forming composition J was a black ink in which AB was uniformly dispersed.

[0102] [Example 1-11] Preparation of thin film forming composition K A 5% by mass aqueous solution of CP-A2H was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of Dispersion A prepared in Production Example 1 was mixed with 2.0 g of a 5% by mass aqueous solution of CP-A2H to prepare Thin Film Forming Composition K with a solids concentration of 5% by mass. Thin Film Forming Composition K was a black ink in which AB was uniformly dispersed.

[0103] [Example 1-12] Preparation of thin film forming composition L A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 0.8 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition L with a solids concentration of 5% by mass. Thin film-forming composition L was a black ink in which AB was uniformly dispersed.

[0104] A summary of the above examples is shown in Table 1.

[0105] [Table 1]

[0106] [Example 1-13] Preparation of thin film forming composition M 0.5 g of E-45, a hydroxyl group-containing polymer, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of E-45. 0.5 g of CBT-1, a heterocyclic compound, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of CBT-1. Furthermore, 1.6 g of A-30 was dissolved in 8.4 g of water to prepare a 5% by mass solution of A-30. 7.5 g of dispersion A prepared in Production Example 1, 2.5 g of a 5% by mass aqueous solution of E-45, 1.0 g of a 5% by mass aqueous solution of CBT-1, and 1.0 g of a 5% by mass aqueous solution of A-30 were mixed to prepare thin film-forming composition M with a solids concentration of 5% by mass. Thin film-forming composition M was a black ink in which AB was uniformly dispersed.

[0107] [Example 1-14] Preparation of thin film forming composition N 0.5 g of E-45, a hydroxyl group-containing polymer, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of E-45. 0.5 g of CBT-1, a heterocyclic compound, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of CBT-1. Furthermore, 1.6 g of A-30 was dissolved in 8.4 g of water to prepare a 5% by mass solution of A-30. 7.5 g of dispersion A prepared in Production Example 1, 2.5 g of a 5% by mass aqueous solution of E-45, 0.5 g of a 5% by mass aqueous solution of CBT-1, and 1.25 g of a 5% by mass aqueous solution of A-30 were mixed to prepare thin film-forming composition N with a solids concentration of 5% by mass. Thin film-forming composition N was a black ink in which AB was uniformly dispersed.

[0108] [Example 1-15] Preparation of thin film forming composition O 0.5 g of E-45, a hydroxyl group-containing polymer, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of E-45. 0.5 g of CBT-1, a heterocyclic compound, was dissolved in 9.5 g of water to prepare a 5% by mass aqueous solution of CBT-1. Furthermore, 1.6 g of A-30 was dissolved in 8.4 g of water to prepare a 5% by mass solution of A-30. 7.5 g of dispersion A prepared in Production Example 1, 2.5 g of a 5% by mass aqueous solution of E-45, 1.0 g of a 5% by mass aqueous solution of CBT-1, and 1.25 g of a 5% by mass aqueous solution of A-30 were mixed to prepare thin film-forming composition M with a solids concentration of 5% by mass. Thin film-forming composition O was a black ink in which AB was uniformly dispersed.

[0109] [Example 1-16] Preparation of thin film forming composition P 0.5 g of E-45, a hydroxyl group-containing polymer, was dissolved in 9.5 g of water to prepare a 5 mass% aqueous solution of E-45. 1.6 g of A-30 was dissolved in 8.4 g of water to prepare a 5 mass% solution of A-30. 7.5 g of dispersion A prepared in Production Example 1, 2.5 g of a 5 mass% aqueous solution of E-45, and 1.25 g of a 5 mass% aqueous solution of A-30 were mixed to prepare thin film-forming composition P with a solids concentration of 5 mass%. Thin film-forming composition P was a black ink in which AB was uniformly dispersed.

[0110] A summary of the above examples is shown in Table 2.

[0111] [Table 2]

[0112] [Comparative Example 1-1] Preparation of thin film forming composition a A 5% by mass aqueous solution of E-45 was prepared by dissolving 0.5 g of E-45, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of Dispersion C prepared in Production Example 3 was mixed with 2.0 g of a 5% by mass aqueous solution of E-45 to prepare thin film-forming composition a with a solids concentration of 5% by mass. Thin film-forming composition a was a black ink in which AB was uniformly dispersed.

[0113] [Comparative Example 1-2] Thin film forming composition b Dispersion A prepared in Production Example 1 was used as it was as thin film-forming composition b.

[0114] [Comparative Example 1-3] Preparation of thin film forming composition c 1.4 g (100 parts by mass) of AB, 0.7 g (50 parts by mass) of the hydroxyl group-containing polymer E-45, 37.90 g of pure water, and 2.00 g of 2-propanol were mixed. The resulting mixture was subjected to ultrasonic treatment for 15 minutes using a probe-type ultrasonic irradiation device. Thin film-forming composition c thickened to a paste-like consistency, and was a heterogeneous dispersion containing aggregates.

[0115] [Comparative Example 1-4] Preparation of thin film forming composition d A 5% by mass aqueous solution of E-300 was prepared by dissolving 0.5 g of E-300, a hydroxyl group-containing polymer, in 9.5 g of water. 6.0 g of Dispersion A prepared in Production Example 1 was mixed with 2.0 g of the 5% by mass aqueous solution of E-300 to prepare Thin Film Forming Composition d, which had a solids concentration of 5% by mass. Thin Film Forming Composition d was a black, viscous ink in which AB was uniformly dispersed.

[0116] [Comparative Example 1-5] Preparation of thin film forming composition e A 5% by mass aqueous solution of PEG20k was prepared by dissolving 0.5 g of hydroxyl group-containing polymer PEG20k in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.0 g of a 5% by mass aqueous solution of PEG20k to prepare thin film-forming composition e with a solids concentration of 5% by mass. Thin film-forming composition e was a black ink in which AB was uniformly dispersed.

[0117] [Comparative Example 1-6] Preparation of thin film forming composition f A 5% by mass aqueous solution of PEG10k was prepared by dissolving 0.5 g of hydroxyl group-containing polymer PEG10k in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.0 g of a 5% by mass aqueous solution of PEG10k to prepare thin film-forming composition f with a solids concentration of 5% by mass. Thin film-forming composition f was a black ink in which AB was uniformly dispersed.

[0118] [Comparative Example 1-7] Preparation of thin film forming composition g A 5% by mass aqueous solution of PEG6k was prepared by dissolving 0.5 g of hydroxyl group-containing polymer PEG6k in 9.5 g of water. 6.0 g of dispersion A prepared in Production Example 1 was mixed with 2.0 g of a 5% by mass aqueous solution of PEG6k to prepare thin film-forming composition g with a solids concentration of 5% by mass. Thin film-forming composition g was a black ink in which AB was uniformly dispersed.

[0119] The comparative examples are summarized in Table 3.

[0120] [Table 3]

[0121] [3] Preparation of thin film (primer layer) [Example 2-1] Composition A prepared in Example 1-1 was uniformly spread on a copper foil (thickness: 10 μm) current collector using a wire bar coater OSP-30, and then dried at 120°C for 20 minutes to form a thin film (primer layer), producing a laminate of copper foil and primer layer. In the obtained laminate, the surface of the copper foil was uniformly covered with the conductive carbon material (estimated basis weight: 1,200 mg / m 2 ). As described above, the estimated basis weight means the estimated basis weight when a thin film-forming composition having a predetermined solid content is applied to a current collector using a predetermined wire bar coater. In the present invention, the estimated basis weight when a thin film-forming composition having a solid content of 5% by mass is used is as follows: OSP-30: 1,200 mg / m 2

[0122] [Examples 2-2 to 2-16, Comparative Examples 2-1 to 2-7] A thin film (primer layer) was formed and a laminate was produced in the same manner as in Example 2-1, except that composition A was changed to compositions B to P and a to g prepared in Examples 1-2 to 1-16 and Comparative Examples 1-1 to 1-7.

[0123] [Film formability] The thin films produced in Examples 2-1 to 2-16 and Comparative Examples 2-1 to 2-7 were visually observed, and their film-forming properties were evaluated according to the following criteria. The results are shown in Tables 4 and 5. A: A laminate in which the surface of copper foil is uniformly covered with conductive carbon material. B: A laminate in which streaky coating defects occurred and the copper foil surface was unevenly covered with the conductive carbon material. -: Film formation is not possible due to poor dispersibility.

[0124] [Table 4]

[0125] [Table 5]

[0126] As shown in Tables 4 and 5, when compositions A to P of Examples 2-1 to 2-16 were used, a uniform thin film (primer layer) could be formed. In contrast, when compositions a to g of Comparative Examples 2-1 to 2-7 were used, a uniform thin film (primer layer) could be formed, similar to compositions A to P, except for compositions c and d. Composition c was a non-uniform dispersion containing aggregates, and therefore a uniform thin film (primer layer) could not be formed. Furthermore, composition d had AB dispersed uniformly, but was a viscous ink with high viscosity, which resulted in streaky coating defects during film formation, resulting in a thin film (primer layer) in which the surface of the copper foil was unevenly covered with the conductive carbon material.

[0127] [Scratch test] To confirm the scratch resistance due to the addition of the heterocyclic compound, the copper foil and primer layer laminates prepared in Examples 2-13 to 2-15 were cut into 40 mm × 90 mm pieces and processed. The laminates were attached and fixed to a TRIBOGIEAR TYPE 30S with the primer layer facing outward. A Prowipe Microsoft Wiper S220 (manufactured by Daio Paper Corporation) was attached to the portion of the TRIBOGIEAR TYPE 30S rubbing jig that came into contact with the primer layer (area 20 mm × 20 mm). A 500 g load was applied, and the primer layer was slid back and forth for a distance of 50 mm. The condition of the primer layer was then visually observed, and the presence or absence of peeling was evaluated according to the following criteria. The results are shown in Table 6. A: The primer layer had high scratch resistance, and no scratches or peeling was observed. B: The primer layer had low scratch resistance, and scratches and peeling were observed.

[0128] [Table 6]

[0129] [4] Preparation of transfer electrodes [Example 3-1] The copper foil and primer layer laminate produced in Example 2-1 was transferred to a dry base (temperature 22°C, dew point -50°C) within 1 hour after film formation. The laminate was then cut into a 30 mm x 100 mm piece and processed. An electrode composite layer composite A in which an electrode composite layer was formed on a copper foil was also cut into a 25 mm x 70 mm piece and processed. The primer layer and the electrode composite layer coated surface were overlapped facing each other and pressed together with a linear pressure of 10 kN / cm using a roll press heated to 60°C, integrating the primer layer-formed laminate and the electrode composite layer composite A. Then, only the copper foil of the electrode composite layer composite A was peeled off from this integrated product to obtain a transfer electrode (immediately after film formation) in which the electrode composite layer was transferred onto the laminate. The electrode mixture layer composite A was prepared by coating a composition of graphite / CMC / SBR (styrene-butadiene rubber) = 97.0 / 1.0 / 2.0 (mass ratio) on copper foil (thickness 10 μm) (coating amount 16.1 mg / cm 2 ) and dried.

[0130] In addition, a transfer electrode (after storage in an air-conditioned room) was prepared in the same manner as above, except that a laminate of copper foil and a primer layer was used that had been left to stand for 72 hours in an air-conditioned room (temperature 22°C, dew point 10-15°C).

[0131] [Examples 3-2 to 3-16, Comparative Examples 3-1 to 3-6] Transfer electrodes (immediately after film formation) and transfer electrodes (after storage in an air-conditioned room) were prepared in the same manner as in Example 3-1, except that the laminates were changed to those prepared in Examples 2-2 to 2-16 and Comparative Examples 2-1, 2-2, and 2-4 to 2-7.

[0132] [Possibility of producing transfer electrodes] The transfer electrodes prepared in Examples 3-1 to 3-16 and Comparative Examples 3-1 to 3-6 were visually observed, and the feasibility of preparing the transfer electrodes was evaluated according to the following criteria. The results are shown in Tables 7 and 8. A: The electrode mixture layer is fixed on the composite current collector. B: The electrode mixture layer is not fixed on the composite current collector. [Adhesion test] The transfer electrodes prepared in Examples 3-1 to 3-16 and Comparative Examples 3-1 to 3-6 were each cut into 25 mm widths, and 20 mm wide double-sided tape was attached to the electrode composite layer surface to fix them to a glass substrate. This was then attached to an adhesive / film peeling analyzer, and a peel test was performed at a peel angle of 90° and a peel rate of 100 mm / min. The adhesion and adhesion retention were calculated using the following formulas. The results are shown in Tables 7 and 8. Adhesion strength (N / m) = measured value * (N) / (sample measurement width (mm) x 10 -3 ) * The measured values ​​were the average values ​​for peel distances from 10 mm to 35 mm. Adhesion retention rate (%) = Adhesion after storage in an air-conditioned room (N / m) / Adhesion immediately after deposition (N / m) x 100 * The adhesion strength was calculated in the same manner both immediately after film formation and after storage in an air-conditioned room.

[0133] [Table 7]

[0134] [Table 8]

[0135] As shown in Tables 7 and 8, when compositions A to P of Examples 3-1 to 3-16 were used, the initial adhesion was high, and a thin film (primer layer) with practical adhesion was obtained. The change in adhesion before and after storage in an air-conditioned room was small, and a high adhesion retention rate was demonstrated. It was confirmed that the use of the composition of the present invention provides practical adhesion and adhesion retention rate. On the other hand, when composition a of Comparative Example 3-1 was used, the initial adhesion was high and a thin film (primer layer) with practical adhesion was obtained, but after storage in an air-conditioned room, the adhesion decreased to 12.8 N / m and the adhesion retention rate was also low at 21.2%. Furthermore, compositions b to g of Comparative Examples 3-2 to 3-6 had low initial adhesion and did not form thin films (primer layers) with practical adhesion, so measurements of adhesion after storage in an air-conditioned room were omitted.

Claims

1. A thin film-forming composition for an energy storage device electrode comprises a conductive carbon material, a polymer having an oxazoline group in a side chain, a hydroxyl group-containing polymer having a weight average molecular weight of 50,000 to 5,000,000, and a solvent.

2. The mass ratio of hydroxyl groups in the molecules of the hydroxyl group-containing polymer is 1×10 -5 ~100 x 10 -5 2. The thin film forming composition for an energy storage device electrode according to claim 1, wherein

3. The mass ratio of hydroxyl groups in the molecules of the hydroxyl group-containing polymer is 1×10 -5 ~50 x 10 -5 3. The thin film forming composition for an energy storage device electrode according to claim 2, wherein

4. 4. The thin film-forming composition for an energy storage device electrode according to claim 1, wherein the content of the hydroxyl group-containing polymer is 25 to 200 parts by mass per 100 parts by mass of the conductive carbon material.

5. 4. The thin film forming composition for an energy storage device electrode according to claim 1, wherein the hydroxyl group-containing polymer is a polyalkylene glycol.

6. 6. The thin film forming composition for an energy storage device electrode according to claim 5, wherein the polyalkylene glycol is polyethylene glycol.

7. 4. The thin film-forming composition for an energy storage device electrode according to claim 1, wherein the polymer having an oxazoline group in a side chain is a polymer obtained by radical polymerization of an oxazoline monomer represented by formula (1) having a polymerizable carbon-carbon double bond-containing group at the 2-position and a (meth)acrylic monomer having a hydrophilic functional group. 【Chemical 1】 (wherein X represents a chain hydrocarbon group containing a polymerizable carbon-carbon double bond, R 1 ~R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms which may have a branched structure, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms.

8. 4. The thin film-forming composition for an energy storage device electrode according to claim 1, wherein the content of the polymer having an oxazoline group in a side chain is 20 to 60 parts by mass per 100 parts by mass of the conductive carbon material.

9. The thin film-forming composition for an energy storage device electrode according to any one of claims 1 to 3, wherein the conductive carbon material is one or more selected from the group consisting of acetylene black, carbon black, ketjen black, furnace black, channel black, and lamp black.

10. The thin film-forming composition for an energy storage device electrode according to any one of claims 1 to 3, further comprising a heterocyclic compound represented by the following formula (n1): 【Chemistry 2】 (In the formula, R a and R b each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkenyl group having 2 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; R a and R b may be bonded to each other to form a ring having 4 to 6 carbon atoms, and X a is N or CH.

11. 11. The thin film-forming composition for an energy storage device electrode according to claim 10, wherein the substituent is at least one selected from the group consisting of a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, and an epoxy group.

12. The thin film-forming composition for an energy storage device electrode according to claim 10, wherein the heterocyclic compound is represented by the following formula (n2): 【Chemistry 3】 (In the formula, Y a represents a hydrogen atom, a carboxy group, a hydroxy group, a thiol group, an amino group, a sulfonic acid group, or an epoxy group. a is the same as above.)

13. The thin film-forming composition for an energy storage device electrode according to claim 12, wherein the heterocyclic compound is represented by the following formula (n3): 【Chemistry 4】

14. A primer layer comprising a thin film obtained from the composition for forming a thin film for an energy storage device electrode according to any one of claims 1 to 3.

15. A composite current collector for an electrode of an energy storage device, comprising: a current collecting substrate; and the primer layer according to claim 14 formed on the current collecting substrate.

16. 16. The composite current collector for an electrode of an energy storage device according to claim 15, wherein the current collecting substrate is a copper foil or an aluminum foil.

17. An electrode for an energy storage device, comprising the composite current collector for an electrode of an energy storage device according to claim 16.

18. The electrode for an energy storage device according to claim 17, which is for an anode electrode.

19. An energy storage device comprising the electrode for an energy storage device according to claim 17.

20. 20. The energy storage device of claim 19, wherein the energy storage device is a lithium ion battery.

21. 21. The energy storage device of claim 20, wherein the energy storage device is an all-solid-state lithium ion battery.

22. A method for producing an energy storage device electrode, comprising: applying the composition for forming a thin film for an energy storage device electrode according to any one of claims 1 to 3 onto a current collecting substrate; drying the composition to form a primer layer; and then laminating an electrode mixture sheet on the primer layer and thermocompression bonding the resulting mixture.

23. a step of applying an electrode mixture layer-forming composition onto a substrate and drying the composition to form an electrode mixture layer; a step of applying the composition for forming a thin film for an energy storage device electrode according to any one of claims 1 to 3 onto the electrode mixture layer and drying it to form a primer layer; The method for producing an energy storage device electrode includes a step of laminating a current collecting substrate on the primer layer, thermocompressing the substrate, and then peeling off the substrate.

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