Polymer material for power storage device using inorganic solid electrolyte, and power storage device containing polymer material for power storage device using inorganic solid electrolyte

Abstract

In a composite solid electrolyte containing an inorganic solid electrolyte and a polymer solid electrolyte containing a polyether polymer, there is room for improvement in dispersibility of the inorganic solid electrolyte and the polyether polymer. The present invention provides a polymer material for an inorganic solid electrolyte, the polymer material containing: a polyether polymer in which the main chain has a polyoxyethylene skeleton; and a phenol-based antioxidant. It has been found that this polymer material improves dispersibility with an inorganic solid electrolyte.

Description

Polymer material for an electric storage device using an inorganic solid electrolyte, and an electric storage device containing the polymer material for an electric storage device using an inorganic solid electrolyte

[0001] The present invention relates to a polymer material for an electricity storage device using an inorganic solid electrolyte, and to an electricity storage device containing the polymer material for an electricity storage device using an inorganic solid electrolyte.

[0002] Conventionally, non-aqueous electrolyte secondary batteries, such as lithium-ion batteries, use electrolytes in solution or paste form due to their ionic conductivity. However, various safety measures are required to prevent leakage of the electrolyte, which can damage the device, and this has been an obstacle to the development of large-scale batteries.

[0003] In response to this, solid electrolytes have been proposed, such as polymer solid electrolytes and inorganic solid electrolytes. Polymer solid electrolytes generally have advantages such as excellent flexibility, bendability, and moldability, which allow for greater freedom in the design of applied devices. However, they have the disadvantage of being limited to battery applications operating at high temperatures due to poor load and low-temperature characteristics. On the other hand, inorganic solid electrolytes have higher ionic conductivity than polymer solid electrolytes, but are composed of crystalline or amorphous electrolytes, making it difficult to alleviate volume changes due to positive and negative electrode active materials during charge and discharge. Furthermore, the high interfacial resistance between the electrodes and the electrolyte results in insufficient charge and discharge characteristics.

[0004] A known method for reducing the interfacial resistance between an electrode and an electrolyte is to mix a polymer into an inorganic solid electrolyte to improve the binding strength within the electrolyte and at the electrode interface. For example, in Patent Document 1, a hydrogenated polymer such as hydrogenated styrene butadiene rubber, which is a branched polymer, is used as a binder in a sulfide-based solid electrolyte. However, such a polymer does not sufficiently suppress the decrease in ionic conductivity. Furthermore, Patent Documents 2 and 3 use polyethylene oxide (polyethylene glycol), which has relatively high ionic conductivity. However, polyethylene oxide is highly crystalline and has a melting point of approximately 60°C, and its ionic conductivity is low below the melting point. Furthermore, when heated above its melting point, it softens, making it unable to maintain its strength and prone to short-circuiting due to fracture.

[0005] The present applicant has also disclosed a composite solid electrolyte containing an inorganic solid electrolyte and a polymer solid electrolyte containing a branched polyether polymer (Patent Document 4).

[0006] International Publication No. 2013-1623 Japanese Patent Application Laid-Open No. 3-129603 Japanese Patent Application Laid-Open No. 2010-33918 International Publication No. 2020-110994

[0007] As a result of investigations by the present inventors, it has become clear that a composite solid electrolyte containing an inorganic solid electrolyte and a polymer solid electrolyte containing a polyether polymer has a problem with the dispersibility of the inorganic solid electrolyte and the polyether polymer, and this is the subject of the present application.

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that a polymer material for an inorganic solid electrolyte containing a polyether polymer having a main chain with a polyoxyethylene skeleton and a phenolic antioxidant can improve dispersibility with the inorganic solid electrolyte. Based on this finding, the present invention has been completed through further research.

[0009] That is, the present invention provides the following aspects of the invention. Item 1: A polymer material for an electricity storage device using an inorganic solid electrolyte containing a polyether polymer whose main chain has a polyoxyethylene skeleton and a phenol-based antioxidant. Item 2: A polymer material for an electricity storage device using an inorganic solid electrolyte according to Item 1, wherein the polyether polymer whose main chain has a polyoxyethylene skeleton is a branched polyether polymer. Item 3: A polymer material for an electricity storage device using an inorganic solid electrolyte according to Item 2, wherein the branched polyether polymer contains a structural unit formed from an epoxy compound having an ethylene oxide unit in a side chain. Item 4: A polymer material for an electricity storage device using an inorganic solid electrolyte according to any one of Items 1 to 3, wherein the polyether polymer whose main chain has a polyoxyethylene skeleton contains a structural unit formed from at least one selected from the group consisting of allyl glycidyl ether, glycidyl ether of acrylic acid, and glycidyl ether of methacrylic acid. Item 5: A polymer material for an electricity storage device using an inorganic solid electrolyte according to any one of Items 1 to 4, wherein the inorganic solid electrolyte is an oxide-based solid electrolyte or a sulfide-based solid electrolyte. Item 6. A composite solid electrolyte containing an inorganic solid electrolyte and a polymer material for an electricity storage device using the inorganic solid electrolyte according to any one of Items 1 to 5. Item 7. An electricity storage device comprising the polymer material for an electricity storage device using the inorganic solid electrolyte according to any one of Items 1 to 5. Item 8. An electricity storage device comprising the composite solid electrolyte according to Item 6.

[0010] According to the present invention, the polyether polymer having a polyoxyethylene skeleton as a main chain is well dispersed in the inorganic solid electrolyte, and therefore, a composite solid electrolyte containing both has excellent workability in mixing, and is expected to exhibit excellent battery characteristics when used in an electricity storage device.

[0011] In this specification, a numerical value connected with "~" means a numerical range that includes the numerical values ​​before and after "~" as the lower limit and upper limit. When multiple lower limit values ​​and multiple upper limit values ​​are listed separately, any lower limit value and upper limit value can be selected and connected with "~".

[0012] The polymer material for an electricity storage device using an inorganic solid electrolyte of the present invention (hereinafter also simply referred to as the polymer material of the present invention) contains at least a polyether polymer whose main chain has a polyoxyethylene skeleton and a phenolic antioxidant. That is, the polymer material of the present invention contains at least a polyether polymer whose main chain has a polyoxyethylene skeleton and a phenolic antioxidant, and is a polymer material that can be suitably used in an electricity storage device using an inorganic solid electrolyte. Because the polymer material of the present invention contains a phenolic antioxidant in addition to a polyether polymer whose main chain has a polyoxyethylene skeleton, the polyether polymer whose main chain has a polyoxyethylene skeleton is well dispersed in the inorganic solid electrolyte.

[0013] The above-mentioned polymer material provides the aforementioned effects, which are presumably due to the following action and effect: The hydroxyl groups of the phenolic antioxidant interact with the oxygen atoms of the polyether polymer whose main chain has a polyoxyethylene skeleton, resulting in good dispersion of the polyether polymer whose main chain has a polyoxyethylene skeleton in the inorganic solid electrolyte.

[0014] The polyether polymer whose main chain has a polyoxyethylene skeleton may be used alone or in combination of two or more types. The polyether polymer whose main chain has a polyoxyethylene skeleton preferably has a structural unit derived from a monomer represented by formula (1). The structural unit derived from the monomer represented by formula (1) forms a polyoxyethylene skeleton, which becomes the main chain. The monomer represented by formula (1) is ethylene oxide. The monomer represented by formula (1) is a basic chemical product and is readily available as a commercially available product.

[0015] The polyether polymer having a polyoxyethylene skeleton in its main chain is preferably a branched polyether polymer, and preferably contains a structural unit derived from an epoxy compound having an ethylene oxide unit in its side chain. When the polyether polymer having a polyoxyethylene skeleton in its main chain is a branched polyether polymer, it is presumed that the hydroxyl groups of the phenolic antioxidant interact more favorably, resulting in better dispersion of the polyether polymer having a polyoxyethylene skeleton in its main chain in the inorganic solid electrolyte. In this specification, the term "branched polyether polymer" refers to a polyether polymer other than a linear polyether polymer, specifically, a linear polyether polymer having a side chain. The size of the side chain is not particularly limited, and the side chain may be a small group such as a methyl group. The branched polyether polymer can be obtained, for example, by using an epoxy compound having an ethylene oxide unit in its side chain as a monomer.

[0016] An example of a structural unit derived from an epoxy compound having an ethylene oxide unit in the side chain is a structural unit derived from a monomer represented by the following formula (2). This results in a polyether polymer having R as a side chain. The structural unit derived from the monomer represented by the following formula (2) may be used alone or in combination of two or more. Note that the monomer represented by the following formula (2) is preferred as the epoxy compound having an ethylene oxide unit in the side chain. [In formula (2), R represents an alkyl group having 1 to 4 carbon atoms, or —CH2O(CH2CH2O) n R １ and R １ is an alkyl group having 1 to 6 carbon atoms, and n is an integer of 0 to 12.

[0017] The alkyl group of 1 to 4 carbon atoms represented by R preferably has 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms.

[0018] The alkyl group having 1 to 4 carbon atoms represented by R may be branched or linear, and examples thereof 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, etc. Of these, a methyl group, an ethyl group, an n-propyl group, and an n-butyl group are preferred, a methyl group and an ethyl group are more preferred, and a methyl group is even more preferred.

[0019] R １ The alkyl group having 1 to 6 carbon atoms preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, further preferably 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms.

[0020] R １ The alkyl group having 1 to 6 carbon atoms may be branched or linear, and examples thereof 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, etc. Of these, a methyl group, an ethyl group, an n-propyl group, and an n-butyl group are preferred, a methyl group and an ethyl group are more preferred, and a methyl group is even more preferred.

[0021] R is -CH2O(CH2CH2O) n R １ It is preferable that:

[0022] n is an integer of 0 to 12, preferably an integer of 0 to 10, more preferably an integer of 0 to 8, even more preferably an integer of 0 to 6, particularly preferably an integer of 0 to 4, and most preferably an integer of 1 to 3.

[0023] Examples of the monomer represented by formula (2) that can be used include propylene oxide, butylene oxide, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, t-butyl glycidyl ether, benzyl glycidyl ether, 1,2-epoxydodecane, 1,2-epoxyoctane, 1,2-epoxyheptane, 2-ethylhexyl glycidyl ether, 1,2-epoxydecane, 1,2-epoxyhexane, glycidyl phenyl ether, 1,2-epoxypentane, glycidyl isopropyl ether, diethylene glycol methyl glycidyl ether, ethylene glycol methyl glycidyl ether, diethylene glycol ethyl glycidyl ether, and ethylene glycol ethyl glycidyl ether. Of these, diethylene glycol methyl glycidyl ether and diethylene glycol ethyl glycidyl ether are preferred, and diethylene glycol methyl glycidyl ether is more preferred.

[0024] The polyether polymer having a polyoxyethylene skeleton in its main chain may have a structural unit derived from a monomer represented by the following formula (3): The monomer represented by the following formula (3) also corresponds to an epoxy compound having an ethylene oxide unit in its side chain, but the structural unit derived from the monomer represented by the following formula (3) has an ethylenically unsaturated group (ethylenically unsaturated bond), and therefore can be crosslinked. Therefore, R in formula (3) ５ is not particularly limited as long as it has an ethylenically unsaturated group (ethylenically unsaturated bond). The structural unit derived from the monomer represented by the following formula (3) may be used alone or in combination of two or more types. [In formula (3), R ５ represents a group containing an ethylenically unsaturated group.

[0025] R ５ Examples of the alkyl group are not particularly limited as long as they have an ethylenically unsaturated group (ethylenically unsaturated bond), but may be hydrocarbon groups having a double bond, particularly cyclic hydrocarbon groups having a double bond, or CH ２ = CH-A １ - (A １may be a direct bond or a hydrocarbon group having 1 to 30 carbon atoms (preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 5) which may have a heteroatom, such as an alkylene group. The heteroatom is preferably an oxygen atom.

[0026] Examples of the monomer of formula (3) include allyl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, α-terpinyl glycidyl ether, cyclohexenylmethyl glycidyl ether, p-vinylbenzyl glycidyl ether, allylphenyl glycidyl ether, vinyl glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-1-pentene, 4,5-epoxy-2-pentene, 1,2-epoxy-5,9-cyclododecanediene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5-cyclooctene, glycidyl acrylate, glycidyl methacrylate, glycidyl sorbate, glycidyl cinnamate, glycidyl crotonate, and glycidyl-4-hexenoate. Of these, allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate are preferred.

[0027] In a polyether polymer having a polyoxyethylene backbone as its main chain, the molar ratios of the structural unit (A) derived from a monomer of formula (1), the structural unit (B) derived from a monomer of formula (2), and the structural unit (C) derived from a monomer of formula (3) can be exemplified as (A) 100 to 0 mol%, (B) 0 to 100 mol%, and (C) 0 to 20 mol%, preferably (A) 95 to 5 mol%, (B) 5 to 95 mol%, and (C) 0 to 20 mol%, more preferably (A) 95 to 60 mol%, (B) 5 to 40 mol%, and (C) 0 to 20 mol%, and particularly preferably (A) 94 to 59 mol%, (B) 5 to 40 mol%, and (C) 1 to 20 mol%. The monomers represented by formulas (1) to (3) may be used singly or in combination of two or more.

[0028] Specific examples of polyether polymers having a polyoxyethylene skeleton in the main chain include ethylene oxide / diethylene glycol methyl glycidyl ether / allyl glycidyl ether terpolymer, ethylene oxide / diethylene glycol methyl glycidyl ether / glycidyl methacrylate terpolymer, ethylene oxide / diethylene glycol methyl glycidyl ether / glycidyl acrylate terpolymer, etc. These may be used alone or in combination of two or more.

[0029] The total content of the structural units (A), (B), and (C) in the polyether polymer is preferably 85 mol% or more, more preferably 90 mol% or more, and particularly preferably 95 mol% or more, and may be 97 mol% or more, or even 100 mol%.

[0030] The molar ratio of the polymerization composition of the polyether polymer is １ The integral value of each unit is determined by H-NMR, and the composition can be determined from the calculation results.

[0031] The polyether polymer may be either a block copolymer or a random copolymer, with the random copolymer being preferred since it has a greater effect of reducing the crystallinity of polyethylene oxide.

[0032] The synthesis of a polyether polymer having a polyoxyethylene skeleton in the main chain can be carried out, for example, as follows: A ring-opening polymerization catalyst is used, which is a coordinated anion initiator such as an organoaluminum-based catalyst system, an organozinc-based catalyst system, or an organotin-phosphate ester condensate catalyst system, or a catalyst containing K as a counter ion. + Polyethers can be obtained by reacting the monomers with an anionic initiator such as potassium alkoxide containing the above-mentioned compound, diphenylmethyl potassium, or potassium hydroxide, in the presence or absence of a solvent, at a reaction temperature of 10 to 120°C, with stirring. From the viewpoints of the degree of polymerization and the properties of the resulting copolymer, a coordinated anionic initiator is preferred. The phenolic antioxidant described below is used in synthesizing a polyether polymer having a polyoxyethylene skeleton, and may be contained therein.

[0033] The weight-average molecular weight of the polyether polymer whose main chain has a polyoxyethylene skeleton is not particularly limited, but may be from 10,000 to 5,000,000, more preferably from 50,000 to 3,500,000, and particularly preferably from 100,000 to 2,500,000. The weight-average molecular weight is calculated by gel permeation chromatography (GPC) using dimethylformamide (DMF) as a solvent in terms of standard polystyrene.

[0034] The ash content of the polyether polymer (relative to 100% by mass) whose main chain has a polyoxyethylene skeleton is preferably 0.1 to 8% by mass, more preferably 0.3 to 6% by mass, and particularly preferably 0.5 to 5% by mass. The ash content can be measured using a TG-DTA by heating the sample in air from room temperature to 500°C, weighing the mass before and after heating with a precision balance, and determining the difference between the masses.

[0035] The polyether polymer whose main chain has a polyoxyethylene skeleton may be crosslinked.

[0036] The polymer material of the present invention may contain a polyether polymer other than a polyether polymer having a polyoxyethylene skeleton in its main chain. However, the content of the polyether polymer having a polyoxyethylene skeleton in its main chain, relative to 100% by mass of the polyether polymer contained in the polymer material of the present invention, is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and may be 100% by mass.

[0037] The content of the polyether polymer in 100% by mass of the polymer material of the present invention is preferably 80 to 99.9% by mass, more preferably 85 to 99.7% by mass, and even more preferably 90 to 99.5% by mass, which tends to more suitably achieve the effects of the present invention.

[0038] The phenolic antioxidant in the polymer material of the present invention is not particularly limited as long as it is a compound having a ring structure (aromatic ring) of an aromatic compound and a hydroxyl group (preferably a compound having a phenolic hydroxyl group). Herein, the phenolic hydroxyl group means a hydroxyl group directly bonded to a ring of an aromatic compound such as a benzene ring. The phenolic antioxidant may be used alone or in combination of two or more types.

[0039] The number of hydroxyl groups (preferably phenolic hydroxyl groups) possessed by the phenol-based antioxidant may be at least 1. There is no particular upper limit, but it is preferably 6 or less, more preferably 4 or less.

[0040] The phenolic antioxidant is preferably a phenolic antioxidant having a branched alkyl group such as a tert-butyl group, more preferably a phenolic antioxidant having 2 to 10 branched alkyl groups such as tert-butyl groups, and more preferably a phenolic antioxidant having 2 to 8 branched alkyl groups such as tert-butyl groups. When the phenolic antioxidant has multiple branched alkyl groups, the branched alkyl groups may be the same or different. The branched alkyl groups preferably have 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms. Furthermore, the phenolic antioxidant preferably has 1 to 8 aromatic rings, and more preferably has 1 to 4 aromatic rings.

[0041] Specific examples of phenolic antioxidants include 2,5-di-(t-amyl)-hydroquinone, 2,5-di-t-butylhydroquinone, and hydroquinone monomethyl ether. Specific examples of monophenolic antioxidants include 1-oxy-3-methyl-4-isopropylbenzene, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-sec-butylphenol, butyl hydroxyanisole, and 2-(1-methylcyclohexyl) -4,6-dimethylphenol, 2,6-di-t-butyl-α-dimethylamino-p-cresol, alkylated phenols, aralkyl-substituted phenols, phenol derivatives, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2-methylenebis(6-α-methyl-benzene 4,4'-butylidenebis(3-methyl-6-tert-butylcresol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 1,1'-bis(4-hydroxyphenyl)-cyclohexane, 2,2'-dihydroxy-3,3'-di-(α-methylcyclohexyl)-5,5-dimethyl diphenylmethane, alkylated bisphenols, butylated reaction products of p-cresol and dicyclopentadiene, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)-ethyl]-4,6-di-tert-pentylphenyl acrylate, 3,9-bis[2-{3(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, butylic acid 3,3-bis(3-tert-butyl-4-hydroxyphenyl)ethylene ester, 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid triester of 1,3,5-tri(2-hydroxyethyl)-s-triazine-2,4,6-(1H,3H,5H)trione, modified polyalkyl phosphite polyhydric phenol, 4,4'-thiazolinone Obis(3-methyl-6-tert-butylphenol), 4,4'-thiobis-(6-tert-butyl-o-cresol), 4,4'-di- and tri-thiobis-(6-tert-butyl-o-cresol), bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,2-thiobis(4-methyl-6-tert-butylphenol), n-octadecyl tetrakis-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4- hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 2,2-thio-diethylenebis[3-(3,5-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-tert-butyl-4-hydroxy-hydrocinnamamide), 2,4-bis[(octylthio)methyl]-o-cresol, 3,5-Di-tert-butyl-4-hydroxybenzyl-phosphonate-diethyl ester, tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid ester, hindered phenol, hindered bisphenol, 2-hydroxynaphthalene-3-carboyl-2'-methoxyanilide, 2-hydroxynaphthalene-3-carboyl-2'-methylanilide, 2-hydroxynaphthalene-3-carboyl-4'-methoxyanilide, 4,4'-bis(N,N'-dimethylamino)-triphenylphosphine Examples of such an alkyl ester include phenylmethane, 2-hydroxynaphthalene-3-carboylanilide, 1,1'-bis(4,4'-N,N'-dimethylaminophenyl)-cyclohexane, 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,2-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 4,4'-thiobis(6-tert-butyl-m-cresol), and 2,5-di-tert-butylhydroquinone. Among these, 4,4'-butylidenebis(6-tert-butyl-m-cresol), 2,6-di-tert-butylphenol, 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 4,4'-thiobis(6-tert-butyl-m-cresol), and 2,5-di-tert-butylhydroquinone are preferred, and 4,4'-butylidenebis(6-tert-butyl-m-cresol) is more preferred. In addition, 2,6-di-tert-butylphenol, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,Preferred are 2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 4,4'-thiobis(6-tert-butyl-m-cresol), and 2,5-di-tert-butylhydroquinone.

[0042] In the polymer material of the present invention, the amount of the phenolic antioxidant is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and particularly preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polyether polymer. In order to obtain better ionic conductivity, the lower limit of the amount of the phenolic antioxidant is preferably 0.6 parts by mass or more, more preferably 0.8 parts by mass or more.

[0043] In the polymer material of the present invention, the total content of the polyether polymer having a polyoxyethylene skeleton as a main chain and the phenol-based antiaging agent is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, based on 100% by mass of the polymer material of the present invention.

[0044] The polymer material of the present invention preferably contains a lithium salt compound. The lithium salt compound is preferably a lithium salt compound having a wide potential window, such as those commonly used in lithium-ion batteries. Examples of lithium salt compounds include, but are not limited to, LiBF, LiPF, LiClO, LiCFSO, LiN(CFSO)(LiTFSI), LiN(SFO)(LiFSI), LiN(CFSO), and LiN[CFSC(CFSO)]. These compounds may be used alone or in combination.

[0045] When the polymer material of the present invention contains a lithium salt compound, the content thereof is preferably such that the value of the number of moles of the lithium salt compound / the total number of moles of ether oxygen atoms in the polyether polymer is in the range of 0.0001 to 5, more preferably 0.001 to 0.5.

[0046] The polymer material of the present invention may also contain a room-temperature molten salt. The room-temperature molten salt is a salt that is at least partially liquid at room temperature, and room temperature refers to the temperature range in which a power supply is expected to operate normally. The temperature range in which a power supply is expected to operate normally has an upper limit of about 120°C, or in some cases about 60°C, and a lower limit of about -40°C, or in some cases about -20°C.

[0047] Room-temperature molten salts are also called ionic liquids, and known quaternary ammonium organic cations include pyridine-based, aliphatic amine-based, and alicyclic amine-based quaternary ammonium organic cations. Examples of quaternary ammonium organic cations include imidazolium ions such as dialkylimidazolium and trialkylimidazolium ions, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, and piperidinium ions. Imidazolium cations are particularly preferred.

[0048] Examples of tetraalkylammonium ions include, but are not limited to, trimethylethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, tetrapentylammonium ion, and triethylmethylammonium ion.

[0049] Examples of alkylpyridinium ions include, but are not limited to, N-methylpyridinium ion, N-ethylpyridinium ion, N-propylpyridinium ion, N-butylpyridinium ion, 1-ethyl-2-methylpyridinium ion, 1-butyl-4-methylpyridinium ion, and 1-butyl-2,4-dimethylpyridinium ion.

[0050] Examples of imidazolium cations include, but are not limited to, a 1,3-dimethylimidazolium ion, a 1-ethyl-3-methylimidazolium ion, a 1-methyl-3-ethylimidazolium ion, a 1-methyl-3-butylimidazolium ion, a 1-butyl-3-methylimidazolium ion, a 1,2,3-trimethylimidazolium ion, a 1,2-dimethyl-3-ethylimidazolium ion, a 1,2-dimethyl-3-propylimidazolium ion, and a 1-butyl-2,3-dimethylimidazolium ion.

[0051] These room-temperature molten salts having cations may be used alone or in combination of two or more.

[0052] When the polymer material of the present invention contains a room-temperature molten salt, the content thereof is preferably 10 to 1,000 parts by mass, more preferably 20 to 500 parts by mass, per 100 parts by mass of the polyether polymer.

[0053] The polymer material of the present invention may contain a plasticizer in addition to the polyether polymer whose main chain has a polyoxyethylene skeleton. The plasticizer is not particularly limited, but dicyano compounds and branched ether compounds are preferred. When a plasticizer is added, it is preferable to crosslink the branched polyether polymer. This crosslinking is chemical crosslinking, which can prevent the plasticizer from leaking out of the electrode.

[0054] Examples of the dicyano compound include succinonitrile, glutaronitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 1,8-dicyanooctane, etc. Examples of the branched ether compound include the following multi-branched ether compounds.

[0055]

[0056]

[0057] When the polymer material of the present invention contains a plasticizer, the content of the plasticizer is preferably 10 to 1000 parts by mass, more preferably 20 to 500 parts by mass, per 100 parts by mass of the polyether polymer.

[0058] The polymer material of the present invention can be produced by appropriately mixing a polyether polymer having a polyoxyethylene skeleton in the main chain, a phenolic antioxidant, and, if necessary, the above-mentioned components.

[0059] As described above, the polymer material of the present invention contains a phenolic antioxidant in addition to a polyether polymer whose main chain has a polyoxyethylene skeleton, and therefore the polyether polymer whose main chain has a polyoxyethylene skeleton is well dispersed in the inorganic solid electrolyte. Here, the inorganic solid electrolyte is not particularly limited, and examples thereof include oxide-based solid electrolytes and sulfide-based solid electrolytes. Among these, oxide-based solid electrolytes are preferred.

[0060] The oxide-based solid electrolyte is not particularly limited as long as it contains oxygen, has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation properties.

[0061] Specific compounds constituting the oxide-based solid electrolyte include Li x La y TiO3 [x=0.3~0.7, y=0.3~0.7] (LLT), Li x La y Zr z M m O n (M is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, x satisfies 5≦x≦10, y satisfies 1≦y≦4, z satisfies 1≦z≦4, m satisfies 0≦m≦2, and n satisfies 5≦n≦20.) Li x B y M z O n (wherein M is at least one element selected from C, S, Al, Si, Ga, Ge, In, and Sn, x satisfies 0≦x≦5, y satisfies 0≦y≦1, z satisfies 0≦z≦1, and n satisfies 0≦n≦6), Li x(Al, Ga) y (Ti, Ge) z Si a P m O n (wherein 1≦x≦3, 0≦y≦1, 0≦z≦2, 0≦a≦1, 1≦m≦7, 3≦n≦13), Li (3-2x) M x DO (x represents a number of 0 or more and 0.1 or less, M represents a divalent metal atom, and D represents a halogen atom or a combination of two or more halogen atoms), Li x Si y O z (1≦x≦5, 0<y≦3, 1≦z≦10), Li x S y O z (1≦x≦3, 0<y≦2, 1≦z≦10), Li3BO3-Li2SO4, Li2O-B2O3-P2O5, Li2O-SiO2, Li6BaLa2Ta2O 12 , LiPO (4-3 / 2w) N w (w is w<1), Li having a LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4, La with perovskite crystal structure 0.55 Li 0.35 TiO3, LiTi2P3O having a NASICON (sodium super ionic conductor) type crystal structure 12 , Li (1+x+y) (Al, Ga) x (Ti, Ge) (2-x) Si y P (3-y) O 12(where 0≦x≦1, 0≦y≦1), LiLaZrO12 having a garnet-type crystal structure, etc. are also desirable. Phosphorus compounds containing Li, P, and O are also desirable. Examples include lithium phosphate (LiPO), LiPON, LiPOD (wherein D is at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc.), etc., in which some of the oxygen in lithium phosphate has been substituted with nitrogen, etc., and LiAON (wherein A is at least one selected from Si, B, Ge, Al, C, Ga, etc.) are also preferably used.

[0062] Among them, Li x La y TiO3 [x=0.3~0.7, y=0.3~0.7] (LLT), Li x La y Zr z M m O n (M is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, x satisfies 5≦x≦10, y satisfies 1≦y≦4, z satisfies 1≦z≦4, m satisfies 0≦m≦2, and n satisfies 5≦n≦20.) Li7La3Zr2O 12 (LLZ), Li3BO3, Li3BO3-Li2SO4, Li3BO3-Li2CO3, Li x (Al, Ga) y (Ti, Ge) z Si a P m O n (wherein 1≦x≦3, 0≦y≦1, 0≦z≦2, 0≦a≦1, 1≦m≦7, 3≦n≦13) are preferred. These may be used alone or in combination of two or more.

[0063] The sulfide-based solid electrolyte is not particularly limited as long as it contains sulfur, has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation. For example, a lithium ion-conductive inorganic solid electrolyte having a composition represented by the following formula can be used.

[0064] Li a M b Pc S d A e

[0065] In the formula, M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. Among them, B, Sn, Si, Al, and Ge are preferred, and Sn, Al, and Ge are more preferred. A represents I, Br, Cl, and F, with I and Br being preferred, and I being particularly preferred. a to e represent the composition ratio of each element, and a:b:c:d:e satisfies the ratio of 1-12:0-1:1:2-12:0-5. a is more preferably 1-9, and more preferably 1.5-4. b is preferably 0-0.5. d is more preferably 3-7, and more preferably 3.25-4.5. e is more preferably 0-3, and more preferably 0-2.

[0066] In the formula, the composition ratio of Li, M, P, S, and A is preferably such that b and e are 0, more preferably b=0, e=0, and the ratio of a, c, and d (a:c:d) is a:c:d=1-9:1:3-7, and even more preferably b=0, e=0, and a:c:d=1.5-4:1:3.25-4.5.

[0067] When the inorganic solid electrolyte is in the form of particles, the particle size is, for example, 0.01 to 100 μm, and preferably 0.1 to 20 μm.

[0068] In the composite solid electrolyte of the present invention, the mass ratio of the inorganic solid electrolyte to the polymer material of the present invention is not particularly limited, but from the viewpoint of more suitably exhibiting excellent charge / discharge characteristics in a solid electrolyte secondary battery, the mass ratio is preferably 0.1 to 1000 parts by mass, more preferably 0.5 to 500 parts by mass, even more preferably 1 to 400 parts by mass, still more preferably 3 to 300 parts by mass, and particularly preferably 20 to 250 parts by mass, relative to 100 parts by mass of the inorganic solid electrolyte.

[0069] The composite solid electrolyte of the present invention contains the polymer material of the present invention in addition to the inorganic solid electrolyte, and therefore, unlike when only an inorganic solid electrolyte is used, it can be suitably formed into a sheet. When the composite solid electrolyte of the present invention is used in a solid electrolyte secondary battery, the thickness is not particularly limited, but may be, for example, about 0.01 to 1 mm, preferably about 0.05 to 0.3 mm.

[0070] The polymer material of the present invention can be used in general electricity storage devices using inorganic solid electrolytes, but can also be used to form a composite solid electrolyte containing an inorganic solid electrolyte and the polymer material of the present invention.

[0071] The composite solid electrolyte of the present invention can be prepared by a conventionally known method, for example, by dispersing an inorganic solid electrolyte in a solvent containing the polymer material of the present invention to prepare a composite solid electrolyte slurry, and then spraying and drying the slurry in hot air to obtain a composite solid electrolyte, by evaporating the solvent of the dispersion slurry by heating under atmospheric pressure or reduced pressure to dryness, or by applying the dispersion slurry to a current collecting sheet or the like and drying it.

[0072] As the dispersion solvent, water, organic solvents, and mixtures of these in any ratio can be used. It is desirable to remove as much remaining solvent and water as possible from the composite solid electrolyte obtained by removing the dispersion solvent. For example, this can be achieved by heating at 30°C to 200°C and evacuating under vacuum for 1 to 48 hours. The dried composite solid electrolyte of the present invention has ionic conductivity and binding properties, so the electrolyte powder itself can be pressure-molded and used as a solid electrolyte material. Furthermore, pressure heat treatment can reduce porosity and increase particle interface adhesion. Polar solvents are preferred as the organic solvent. Specifically, acetonitrile, ethyl alcohol, methyl alcohol, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone, methyl isobutyl ketone, etc. can be used alone or in combination. When an inorganic solid electrolyte is pressure-molded alone, it has almost no binding properties, resulting in a thick electrolyte film. However, in the case of a composite solid electrolyte, the binding properties of the polyether polymer having a polyoxyethylene skeleton as its main chain in the polymer material for an electric storage device using an organic solid electrolyte enable the production of a thinner solid electrolyte.

[0073] Composite solid electrolyte secondary battery The composite solid electrolyte secondary battery of the present invention comprises at least a positive electrode, a negative electrode, and the composite solid electrolyte of the present invention. The composite solid electrolyte of the present invention is as described above. The composite solid electrolyte of the present invention is disposed between the positive electrode and the negative electrode. In particular, as described above, the composite solid electrolyte used in the composite solid electrolyte secondary battery of the present invention contains, in addition to the inorganic solid electrolyte, a polymer solid electrolyte including a polyether polymer whose main chain has a polyoxyethylene skeleton. Therefore, compared to a solid electrolyte formed solely from an inorganic solid electrolyte, the contact area at the interface between the electrode material layer and the composite solid electrolyte layer is thought to be larger. As a result, the interfacial resistance between the electrode and the electrolyte is thought to be reduced, resulting in excellent charge / discharge characteristics. Furthermore, within the composite solid electrolyte, the polymer solid electrolyte is thought to reduce the resistance within the composite solid electrolyte by forming close contact between particles of the inorganic solid electrolyte.

[0074] Known materials can be used for both the positive electrode and the negative electrode, and an example of the electrode is an electrode having an electrode material layer, that is, a positive electrode material layer or a negative electrode material layer, on a current collector.

[0075] Known current collectors can be used for the positive electrode and the negative electrode. Specifically, metals such as aluminum, nickel, stainless steel, gold, platinum, and titanium are used as the current collector for the positive electrode. Metals such as copper, nickel, stainless steel, gold, platinum, and titanium are used as the current collector for the negative electrode.

[0076] The positive electrode material layer and the negative electrode material layer contain at least a positive electrode active material and a negative electrode active material, respectively, and may further contain a conductive additive, a binder, a thickener, and, if necessary, the inorganic solid electrolyte described above.

[0077] The positive electrode active material used in the present invention is a lithium metal-containing composite oxide powder having any one of the following compositions: LiMO2, LiMO4, LiMO3, and LiMEO4. In this formula, M is primarily composed of a transition metal and contains at least one of Co, Mn, Ni, Cr, Fe, and Ti. While M is composed of a transition metal, other elements such as Al, Ga, Ge, Sn, Pb, Sb, Bi, Si, P, and B may also be added. E contains at least one of P and Si. The particle diameter of the positive electrode active material is preferably 50 μm or less, and more preferably 20 μm or less. These active materials have an electromotive force of 3 V (vs. Li / Li+) or more.

[0078] Specific examples of the positive electrode active material include lithium cobalt oxide, lithium nickel oxide, nickel / cobalt / lithium manganese oxide (ternary system), spinel-type lithium manganese oxide, and lithium iron phosphate.

[0079] The negative electrode active material used in the present invention is a carbon material (natural graphite, artificial graphite, amorphous carbon, etc.) having a structure (intercalation compound) capable of absorbing and releasing alkali metal ions such as lithium ions, or a metal such as lithium, an aluminum-based compound, a tin-based compound, a silicon-based compound, or a titanium-based compound capable of absorbing and releasing alkali metal ions such as lithium ions. In the case of a powder, the particle size is preferably 10 nm or more and 100 μm or less, more preferably 20 nm or more and 20 μm or less. A mixed active material of a metal and a carbon material may also be used.

[0080] When a conductive aid is used, a known conductive aid can be used, and examples thereof include conductive carbon black such as graphite, furnace black, acetylene black, and ketjen black, carbon fibers such as carbon nanotubes, and metal powders. These conductive aids may be used alone or in combination of two or more.

[0081] The binder may be one or more compounds selected from fluororesins such as PVDF, fluororubbers, acrylic rubbers, modified acrylic rubbers, styrene-butadiene rubbers, acrylic polymers, vinyl polymers, and the branched polyether polymers described above. These binders are added in an amount of preferably 5 parts by mass or less, more preferably 3 parts by mass or less, for example, 0.01 to 2 parts by mass, per 100 parts by mass of the active material.

[0082] Specific examples of thickeners include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, and their salts (alkali metal salts such as sodium salts, and ammonium salts), polyvinyl alcohol, polyacrylates, polyethylene oxide, etc. These thickeners may be used alone or in combination. These thickeners are added in an amount of preferably 5 parts by mass or less, more preferably 3 parts by mass or less, for example, 0.01 to 2 parts by mass, per 100 parts by mass of the active material. Furthermore, when the viscosity of the coating liquid is low, a thickener can be used in combination.

[0083] The method for producing the positive electrode and negative electrode comprising the current collector and the positive electrode material layer and the negative electrode material layer is not particularly limited, and a common method can be used, for example, by uniformly applying a paste (coating liquid) of the positive electrode material or negative electrode material comprising the positive electrode active material or negative electrode active material, a conductive additive, a binder, a solvent such as water or N-methyl-2-pyrrolidone (NMP), and optionally a thickener, onto the surface of the current collector to an appropriate thickness by a doctor blade method, silk screen method, or the like.

[0084] For example, in the doctor blade method, negative electrode active material powder, positive electrode active material powder, conductive additive, binder, etc. are dispersed in water to form a slurry, which is then applied to a metal electrode substrate and uniformly spread to an appropriate thickness using a blade with a specified slit width. After applying the active material, the electrode is dried, for example, with hot air at 100°C or under reduced pressure at 80°C to remove excess organic solvent. After drying, the electrode is press-molded using a press device to produce an electrode.

[0085] When a positive electrode material layer and a negative electrode material layer are formed on a current collector, voids are generated between the electrode materials of the positive electrode material layer and the negative electrode material, for example, between the active materials, between the active materials and other electrode materials, etc. In the composite solid electrolyte secondary battery of the present invention, such voids may contain the branched polyether polymer, which is an ion-conductive polymer.

[0086] Manufacturing Method of Composite Solid Electrolyte Secondary Battery The manufacturing method of the composite solid electrolyte secondary battery of the present invention is not particularly limited, and the battery is manufactured by a known method, comprising at least a positive electrode, a negative electrode, and the composite solid electrolyte of the present invention. For example, in the case of a coin-shaped lithium ion battery, the positive electrode, the composite solid electrolyte, and the negative electrode are inserted into an outer can. Then, the battery is joined to a sealing body by tab welding or the like, and the sealing body is sealed and crimped to obtain a storage battery. The shape of the battery is not limited, and examples include coin type, cylindrical type, and sheet type, and a structure in which two or more batteries are stacked may also be used.

[0087] The present invention will be described in more detail in the following examples, but the present invention is not limited to these examples.

[0088] Polymer Analysis The monomer-equivalent composition of the polyether polymer was measured using an NMR spectrometer Z (JEOL Ltd.). １ The weight average molecular weight (Mw) and number average molecular weight (Mn) were determined by H NMR spectroscopy. The polymer was dissolved in dimethylformamide (DMF) as a solvent and measured in polystyrene equivalent terms using gel permeation chromatography (GPC). That is, a GPC device manufactured by Shimadzu Corporation was used, a Shodex RI-501 (differential refractometer (RI detector)) was used as a detector, and Shodex columns KD-807, KD-806M, and KD-803 were connected in series in this order as columns. The measurements were performed at a flow rate of 1.0 mL / min, a concentration of 10 mg polymer / 8 mL of DMF, an injection volume of 50 μL, and a column temperature of 60°C.

[0089] Measurement of Ash Content For measurement, a TG-DTA was used, and the temperature was raised in air from room temperature to 500° C. The mass before and after heating was measured using a precision balance, and the ash content was calculated from the difference.

[0090] Production of Polyether Polymerization Catalyst As a polymerization catalyst, the polymerization catalyst used in the Examples section of Japanese Patent No. 4923946 (JP-A-2008-106104) was produced.

[0091] Polymerization Example 1: The interior of a 10 L SUS reactor (equipped with a thermometer and a stirrer) was purged with nitrogen, and 7.0 g of the condensation product catalyst, 4,000 g of normal hexane containing 10 ppm or less of water, 360 g of diethylene glycol methyl glycidyl ether, and 30 g of allyl glycidyl ether were charged. 360 g of ethylene oxide was gradually added while monitoring the polymerization rate by gas chromatography. The polymerization temperature was 20°C, and the reaction was carried out for 21 hours. The polymerization reaction was terminated with methanol. The polymer was removed by decantation and then dried at room temperature under normal pressure for 24 hours and at 30°C under reduced pressure for 10 hours to obtain 730 g of polymer A. Polymer A was analyzed, and its ash content was measured. The results are shown in Table 1.

[0092] 0.5 parts by mass of a phenolic antioxidant (4,4'-butylidenebis(6-tert-butyl-m-cresol), manufactured by Tokyo Chemical Industry Co., Ltd.) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-1.

[0093] 0.5 parts by mass of a phenolic antioxidant (2,6-di-tert-butylphenol) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-2.

[0094] 0.5 parts by mass of a phenolic antioxidant (2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-3.

[0095] 0.5 parts by mass of a phenolic antioxidant (1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-4.

[0096] 0.5 parts by mass of a phenolic antioxidant (2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol]) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-5.

[0097] 0.5 parts by mass of a phenolic antioxidant (4,4'-thiobis(6-tert-butyl-m-cresol)) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-6.

[0098] 0.5 parts by mass of a phenolic antioxidant (2,5-di-tert-butylhydroquinone) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-7.

[0099] Polymer material A-8 was prepared by blending 100 parts by mass of polymer A with 1.0 part by mass of a phenolic antioxidant (2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene).

[0100] 2.0 parts by mass of a phenolic antioxidant (2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene) was blended with 100 parts by mass of Polymer A to prepare Polymer Material A-9.

[0101] Evaluation of Dispersibility A Mazerustar centrifugal mixer manufactured by Kurabo Industries, Ltd. was used, and the mixture was stirred for 3 minutes at a revolution speed of 1480 rpm and a rotation speed of 651 rpm, which was repeated 5 times. After stirring, the sample tube was left to stand, and samples in which inorganic solid oxide precipitated at the bottom of the sample tube were marked with an "X" and samples in which no precipitate was present were marked with an "O".

[0102] Ionic conductivity (AC impedance test) A SUS blocking cell of the composite material was prepared, and an AC impedance test was performed using a potentio / galvanostat device (device name: VMP-300 manufactured by BioLogic). The resistance (Ω) of the composite material was calculated from the diameter of the semicircular arc in the real axis direction obtained from the Cole-Cole plot. The ionic conductivity of the cell was calculated from the thickness and surface area of ​​the cell using the following formula: σ = 1 / R × (d / A) σ: ionic conductivity of the composite material (S / cm) R: resistance of the composite material (Ω) d: thickness of the composite material (cm) A: surface area of ​​the composite material (cm 2 The test temperature was set to 25° C. Measurements were performed with a voltage amplitude of 10 mV and a measurement frequency range of 7 MHz to 100 MHz.

[0103] Example 1 100 parts by mass of polymer material A-1 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-1. １．３ Al ０．３ Ti １．７ P ３ O １２180 parts by mass of a sintered body (average particle size: 1 μm) was added, and dispersibility was evaluated using a planetary mixer. Ion conductivity was also evaluated. When evaluating ion conductivity, 40 parts by mass of LiTFSI was added as a lithium salt compound in addition to the above components. A stirring bar was then placed in the solution, and the mixture was stirred using a stirrer. The mixture was then cast into an SUS coin cell, and the solvent was completely evaporated to prepare a composite material for measuring ion conductivity. The same applies to other examples described below. The results are shown in Table 2.

[0104] Example 2 100 parts by mass of polymer material A-1 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-1. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The results are shown in Table 2.

[0105] Example 3 100 parts by mass of polymer material A-2 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-2. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0106] Example 4 100 parts by mass of polymer material A-3 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-3. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0107] Example 5 100 parts by mass of polymer material A-4 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-4. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0108] Example 6 100 parts by mass of polymer material A-5 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-5. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0109] Example 7 100 parts by mass of polymer material A-6 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-6. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0110] Example 8 100 parts by mass of polymer material A-7 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-7. １．３ Al ０．３ Ti １．７ P ３ O １２The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0111] Example 9 100 parts by mass of polymer material A-8 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-8. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0112] Example 10 100 parts by mass of polymer material A-9 and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer material A-9. １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0113] Comparative Example 1 100 parts by mass of polymer A and 2000 parts by mass of acetonitrile as a solvent were added, and the mixture was stirred at room temperature for 10 hours to completely dissolve the polymer A. An oxide-based solid electrolyte LATP (composition: Li １．３ Al ０．３ Ti １．７ P ３ O １２ The dispersion was evaluated using a planetary mixer. The ionic conductivity was also evaluated. The results are shown in Table 2.

[0114]

[0115] The polymer material for an electricity storage device of the present invention disperses well in an inorganic solid electrolyte, and thus a composite solid electrolyte containing both has excellent workability in mixing. Furthermore, when used in an electricity storage device, it is expected to exhibit excellent battery properties, and it can be suitably used in large-scale battery applications such as in-vehicle applications such as electric vehicles and hybrid electric vehicles, and in storage batteries for home power storage.

Claims

1. A polymer material for energy storage devices that uses a polyether polymer whose main chain has a polyoxyethylene skeleton and an inorganic solid electrolyte containing a phenolic antioxidant.

2. A polymer material for an electricity storage device using an inorganic solid electrolyte according to claim 1, wherein the polyether polymer having a polyoxyethylene skeleton in the main chain is a branched polyether polymer.

3. A polymer material for an electricity storage device using an inorganic solid electrolyte according to claim 2, wherein the branched polyether polymer contains a structural unit formed from an epoxy compound having an ethylene oxide unit in a side chain.

4. A polymer material for an electricity storage device using an inorganic solid electrolyte according to claim 1, wherein the polyether polymer having a polyoxyethylene skeleton in its main chain contains a structural unit formed from at least one selected from the group consisting of allyl glycidyl ether, glycidyl ether of acrylic acid, and glycidyl ether of methacrylic acid.

5. A polymer material for an electricity storage device using an inorganic solid electrolyte according to claim 1, wherein the inorganic solid electrolyte is an oxide-based solid electrolyte or a sulfide-based solid electrolyte.

6. A composite solid electrolyte comprising an inorganic solid electrolyte and a polymer material for an electricity storage device using the inorganic solid electrolyte according to claims 1 to 5.

7. An electricity storage device comprising a polymer material for an electricity storage device using the inorganic solid electrolyte according to any one of claims 1 to 5.

8. An electricity storage device comprising the composite solid electrolyte according to claim 6.

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