Electrode mixture, secondary battery, and all-solid battery

Abstract

The purpose of the present invention is to provide an electrode mixture containing a dispersant with enhanced dispersibility of an electrode active material and / or a solid electrolyte. Specifically, an electrode mixture containing an electrode active material and / or a solid electrolyte and a dispersant, wherein the dispersant is a polyester represented by general formula (1-1) or (1-2) (where G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, X1 and X2 are each an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2-30 carbon atoms, p is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or the aromatic polybasic acid residue of X1, q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or the aromatic polybasic acid residue of X2, and n represents the number of repetitions).

Description

Electrode mixture, secondary battery and all-solid-state battery

[0001] The present invention relates to an electrode mixture, a secondary battery, and an all-solid-state battery.

[0002] In recent years, the introduction of electric vehicles has been progressing rapidly in various countries in order to reduce carbon dioxide emissions. High-energy-density lithium-ion batteries (LiBs) are being adopted as a driving power source, and the LiB market is expected to expand.

[0003] To extend the driving range of automobiles and further enhance user convenience, LiBs are required to have higher capacities and be more compact. LiBs typically consist of a laminated structure of a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet and the negative electrode sheet contain positive and negative electrode active materials, respectively. Battery performance can be improved by distributing the active materials evenly within the sheets.

[0004] All-solid-state batteries, which are being developed as next-generation batteries, typically have a laminated structure of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. Similar to LiBs, the electrode layer contains an active material, and battery performance can be improved by dispersing the active material well in the electrode layer without uneven distribution. Furthermore, because the electrolyte in all-solid-state batteries is solid, it is necessary to improve the dispersibility of the solid electrolyte in order to form good ion paths.

[0005] In order to improve the dispersibility of the active material and / or the solid electrolyte, Patent Document 1 proposes the addition of an amine-based dispersant.

[0006] Special Publication No. 2023-546207

[0007] The dispersant in Patent Document 1 is a low molecular weight compound containing nitrogen, and there is a risk of generating nitrogen gas and / or ammonia during use in a battery, which may compromise the safety of the battery.

[0008] The problem to be solved by the present invention is to provide an electrode mixture containing a dispersant that improves the dispersibility of an electrode active material and / or a solid electrolyte. Another problem to be solved by the present invention is to provide an all-solid-state battery that improves the dispersibility of an electrode active material and / or a solid electrolyte in a battery component. Another problem to be solved by the present invention is to provide a secondary battery that improves the dispersibility of an electrode active material and / or a solid electrolyte in a battery component.

[0009] As a result of intensive research to solve the above problems, the present inventors have found that a dispersant that is a specific polyester improves the dispersibility of an electrode active material and / or a solid electrolyte and improves battery performance, and have completed the present invention.

[0010] That is, the present invention relates to the following electrode mixtures, etc.: 1. An electrode mixture containing an electrode active material and / or a solid electrolyte and a dispersant, wherein the dispersant is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.) 2. The electrode mixture according to 1, wherein the acid value of the polyester is in the range of 3 to 400 mgKOH / g. 3. The electrode mixture according to 1 or 2, wherein G is a residue of an aliphatic diol having a branched structure and having 3 to 20 carbon atoms. 4. The electrode mixture according to any one of 1 to 3, wherein A is a residue of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms. 5. X １ and X２ are each independently a residue of an aliphatic dicarboxylic acid having 2 to 10 carbon atoms. 6. The electrode mixture according to any one of 1 to 5, wherein the polyester is a polyester represented by general formula (1-2), in which Z is a residue of an aliphatic monoalcohol having 2 to 30 carbon atoms. 7. The electrode mixture according to any one of 1 to 6, in which the number average molecular weight of the polyester is in the range of 1,500 to 5,000. 8. The electrode mixture according to any one of 1 to 7, in which the polyester is a liquid at room temperature. 9. The electrode mixture according to any one of 1 to 8, in which the electrode active material is one or more positive electrode active materials selected from lithium manganate, lithium cobaltate, lithium nickel manganese cobaltate, lithium nickel cobalt aluminate, lithium nickel cobaltate, lithium-containing olivine-type phosphate, titanium sulfide, molybdenum sulfide, iron sulfide, copper sulfide, nickel sulfide, niobium selenide, lithium iron phosphate, lithium manganese phosphate, lithium iron manganese phosphate, lithium cobalt phosphate, and lithium nickel phosphate. 10. The electrode mixture according to any one of 1 to 9, wherein the electrode active material is one or more negative electrode active materials selected from lithium, indium, aluminum, silicon, tin, lithium oxide, indium oxide, aluminum oxide, silicon oxide, and tin oxide. 11. The electrode mixture according to any one of 1 to 10, wherein the solid electrolyte is an oxide solid electrolyte containing lithium and oxygen and / or a sulfide solid electrolyte containing lithium and sulfur. 12. The electrode mixture according to any one of 1 to 11, wherein the dispersant is contained in an amount of 0.05 to 10 parts by mass relative to 100 parts by mass of the electrode active material and the solid electrolyte combined. 13. A secondary battery using the electrode mixture according to any one of 1 to 12. 14. An all-solid-state battery having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer in this order, wherein any one or more of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer contains a dispersant that is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ where n is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue of formula (1-1) or (1-2), and n represents the number of repetitions.) 15. A secondary battery having a positive electrode, a separator, and a negative electrode in this order, wherein the separator is a laminate in which the surface of a substrate is covered with a coating layer containing inorganic particles, and at least one of the positive electrode, the coating layer, and the negative electrode contains a dispersant which is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.

[0011] The present invention provides an electrode mixture containing a dispersant that enhances the dispersibility of an electrode active material and / or a solid electrolyte.The present invention provides an all-solid-state battery that enhances the dispersibility of an electrode active material and / or a solid electrolyte in a battery component.The present invention provides a secondary battery that enhances the dispersibility of an electrode active material and / or a solid electrolyte in a battery component.

[0012] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and can be carried out by making appropriate modifications within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources.

[0013] [Electrode Mixture] The electrode mix of the present invention is an electrode mix containing a solid electrolyte and / or an electrode active material and a dispersant, wherein the dispersant is a polyester having a specific structure. By including a dispersant that is a polyester having a specific structure in the electrode mix, uneven distribution of the solid electrolyte and / or the electrode active material in the battery components can be suppressed, thereby improving the performance of the resulting battery. Each component will be described below.

[0014] (Dispersant) The dispersant for the electrode mixture of the present invention is a polyester represented by the following general formula (1-1) or (1-2): Hereinafter, the polyester used as the dispersant may be referred to as the "polyester of the present invention."

[0015] (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.

[0016] It is believed that the polyester of the present invention improves the dispersibility of the electrode active material and the solid electrolyte by having the carboxyl group at one end adsorb to the solid electrolyte and / or the electrode active material, and by having the polyester chain including the other blocked end ensure compatibility in the electrode mixture.

[0017] In the present invention, "diol residue" and "alcohol residue" refer to the organic group remaining after removing the hydroxyl group from a diol or alcohol. In the present invention, "carboxylic acid residue" refers to the organic group remaining after removing the carboxyl group from a carboxylic acid. The number of carbon atoms in a carboxylic acid residue does not include the carbon atoms in the carboxyl group. In the present invention, "polybasic acid residue" refers to an organic group remaining after removing the basic acid functional group from a polybasic acid having two or more basic acid functional groups. For example, when the polybasic acid residue is a dicarboxylic acid residue, a tricarboxylic acid residue, or a tetracarboxylic acid residue, the dicarboxylic acid residue, the tricarboxylic acid residue, or the tetracarboxylic acid residue refers to the organic group remaining after removing the carboxyl group contained therein. The number of carbon atoms in a dicarboxylic acid residue, a tricarboxylic acid residue, or a tetracarboxylic acid residue does not include the carbon atoms in the carboxyl group.

[0018] The aliphatic chain of the aliphatic diol residue of G having 2 to 20 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond. In addition, the aliphatic chain of the aliphatic diol residue of G may be a saturated aliphatic chain or an unsaturated aliphatic chain having a carbon-carbon unsaturated bond.

[0019] The aliphatic diol residue G having 2 to 20 carbon atoms is preferably an aliphatic diol residue having a branched structure having 3 to 20 carbon atoms, and more preferably a diol represented by the following general formula (G-1). (In the general formula (G-1), p is an integer of 1 or more, q is an integer of 0 or more, r is an integer of 1 or more, R is a hydrogen atom or an alkyl group having 1 or more carbon atoms, at least one of the r R is an alkyl group having 1 or more carbon atoms, and the total number of carbon atoms of p, q, r, and R is an integer of 3 to 20.)

[0020] In the general formula (G-1), the alkyl group for R is preferably an alkyl group having 7 to 18 carbon atoms, and more preferably an alkyl group having 10 to 18 carbon atoms.

[0021] Examples of the aliphatic diol residue having 2 to 20 carbon atoms for G include an ethylene glycol residue, a 1,2-propylene glycol residue, a 1,3-propanediol residue, a 1,2-butanediol residue, a 1,3-butanediol residue, a 2-methyl-1,3-propanediol residue, a 1,4-butanediol residue, a 1,5-pentanediol residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane) residue, a 2-methyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane) residue, a 2-methyl-1,3-propanediol (neopentyl glycol) residue, a 2-methyl ... Examples of the alkyl group include n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) residue, 3-methyl-1,5-pentanediol residue, 1,6-hexanediol residue, 2,2,4-trimethyl-1,3-pentanediol residue, 2-ethyl-1,3-hexanediol residue, 2-methyl-1,8-octanediol residue, 1,9-nonanediol residue, 1,10-decanediol residue, 1,12-dodecanediol residue, 1,2-tetradecanediol residue, and 1,2-dodecanediol residue.

[0022] The aliphatic diol residue having 2 to 20 carbon atoms for G may contain an alicyclic structure, and examples of the aliphatic diol residue having 2 to 20 carbon atoms containing an alicyclic structure include a 1,3-cyclopentanediol residue, a 1,2-cyclohexanediol residue, a 1,3-cyclohexanediol residue, a 1,4-cyclohexanediol residue, a 1,2-cyclohexanedimethanol residue, and a 1,4-cyclohexanedimethanol residue.

[0023] The aliphatic diol residue having 2 to 20 carbon atoms for G may contain an ether bond (—O—), and examples of the aliphatic diol residue having 2 to 20 carbon atoms and containing an ether bond include a diethylene glycol residue, a triethylene glycol residue, a tetraethylene glycol residue, a dipropylene glycol residue, and a tripropylene glycol residue.

[0024] G is preferably an aliphatic diol residue having 2 to 14 carbon atoms, and more preferably an ethylene glycol residue, a diethylene glycol residue, a 1,2-propylene glycol residue, a 1,6-hexanediol residue, a 3-methyl-1,5-pentanediol residue, a 1,4-butanediol residue, a 1,3-butanediol residue, a 1,2-tetradecanediol residue, or a 1,2-dodecanediol residue.

[0025] The aliphatic chain of the aliphatic dicarboxylic acid residue of A may be linear or branched, and may contain an alicyclic structure and / or an ether bond. In addition, the aliphatic chain of the aliphatic dicarboxylic acid residue of A may be a saturated aliphatic chain or an unsaturated aliphatic chain having a carbon-carbon unsaturated bond.

[0026] Examples of the aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms for A include a malonic acid residue, a succinic acid residue, a glutaric acid residue, adipic acid residue, a pimelic acid residue, a suberic acid residue, an azelaic acid residue, a sebacic acid residue, a dodecanedicarboxylic acid residue, a maleic acid residue, a fumaric acid residue, a 1,2-dicarboxycyclohexane residue, and a 1,2-dicarboxycyclohexene residue, and are preferably a succinic acid residue, a glutaric acid residue, an adipic acid residue, or a sebacic acid residue.

[0027] The aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms for A is preferably an aliphatic dicarboxylic acid residue having 4 to 10 carbon atoms.

[0028] X １ and X ２ The aliphatic chain of the aliphatic polybasic acid residue having 2 to 10 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond.

[0029] X １ and X ２The aliphatic polybasic acid residue having 2 to 10 carbon atoms is preferably an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and examples of the aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms include succinic acid residue, glutaric acid residue, adipic acid residue, pimelic acid residue, suberic acid residue, azelaic acid residue, sebacic acid residue, dodecanedicarboxylic acid residue, maleic acid residue, fumaric acid residue, 1,2-dicarboxycyclohexane residue, and 1,2-dicarboxycyclohexene residue, and are preferably succinic acid residue, glutaric acid residue, adipic acid residue, sebacic acid residue, or dodecanedicarboxylic acid residue.

[0030] X １ and X ２ The aromatic polybasic acid residue having 6 to 15 carbon atoms is preferably an aromatic dicarboxylic acid residue having 6 to 15 carbon atoms, an aromatic tricarboxylic acid residue having 6 to 15 carbon atoms, or an aromatic tetracarboxylic acid residue having 6 to 15 carbon atoms, and specific examples thereof include a phthalic acid residue, a trimellitic acid residue, and a pyromellitic acid residue.

[0031] X １ and X ２ is preferably an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, more preferably an aliphatic dicarboxylic acid residue having 5 to 10 carbon atoms.

[0032] The monocarboxylic acid residue having 1 to 20 carbon atoms for Y may be, for example, either an aliphatic monocarboxylic acid residue having 1 to 20 carbon atoms or an aromatic monocarboxylic acid residue having 1 to 20 carbon atoms, and is preferably an aliphatic monocarboxylic acid residue having 1 to 20 carbon atoms.

[0033] When Y is a residue of an aliphatic monocarboxylic acid having 1 to 20 carbon atoms, the aliphatic chain of the residue of the aliphatic monocarboxylic acid having 1 to 20 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond. Furthermore, the aliphatic chain of the residue of the aliphatic monocarboxylic acid having 1 to 20 carbon atoms may be a saturated aliphatic chain or an unsaturated aliphatic chain having a carbon-carbon unsaturated bond.

[0034] Examples of the monocarboxylic acid residue having 1 to 20 carbon atoms represented by Y include acetic acid residue, propionic acid residue, butanoic acid residue, hexanoic acid residue, octanoic acid residue, octylic acid residue, benzoic acid residue, dimethylbenzoic acid residue, trimethylbenzoic acid residue, tetramethylbenzoic acid residue, ethylbenzoic acid residue, propylbenzoic acid residue, butylbenzoic acid residue, cumic acid residue, para-tert-butylbenzoic acid residue, orthotoluic acid residue, meta-toluic acid residue, para-toluic acid residue, ethoxybenzoic acid residue, propoxybenzoic acid residue, and anisic acid residue.

[0035] The monoalcohol residue of Z having 2 to 30 carbon atoms may be, for example, either an aliphatic monoalcohol residue having 2 to 30 carbon atoms or an aromatic monoalcohol residue having 6 to 30 carbon atoms, and is preferably an aliphatic monoalcohol residue having 2 to 30 carbon atoms.

[0036] When Z is a residue of an aliphatic monoalcohol having 2 to 30 carbon atoms, the aliphatic chain of the aliphatic monoalcohol residue having 2 to 30 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond. Furthermore, the aliphatic chain of the aliphatic monoalcohol residue having 2 to 30 carbon atoms may be a saturated aliphatic chain or an unsaturated aliphatic chain having a carbon-carbon unsaturated bond.

[0037] The monoalcohol residue of Z having 2 to 30 carbon atoms is preferably an alkyl alcohol residue having 2 to 10 carbon atoms or an alcohol residue of a polyalkylene glycol monoalkyl ether having 5 to 30 carbon atoms.

[0038] Examples of the alkyl alcohol residue having 2 to 10 carbon atoms represented by Z include an ethanol residue, a propanol residue, a butanol residue, a pentanol residue, a hexanol residue, a cyclohexanol residue, a heptanol residue, an octanol residue, a nonanol residue, and a decanol residue.

[0039] Examples of the alcohol residue of a polyalkylene glycol alkyl ether having 5 to 30 carbon atoms represented by Z include alcohol residues of polyethylene glycol alkyl ethers such as diethylene glycol monomethyl ether and triethylene glycol monomethyl ether; polypropylene glycol alkyl ethers such as polypropylene glycol monomethyl ether and polypropylene glycol monoethyl ether; and (polyethylene glycol-polypropylene glycol) monoalkyl ethers.

[0040] The average value of the repeat number of n is preferably in the range of 0 to 20, more preferably in the range of 0.2 to 15, and more preferably in the range of 0.5 to 10. The average value of the repeat number of n can be calculated from the number average molecular weight of the polyester of the present invention.

[0041] p is X １ is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue. １ and X ２ are each independently an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, X １ and X ２ The number of basic acid functional groups (carboxyl groups) possessed by each of the formulae (1-1) and (1-2) is 2, and p and q are each 1, so that the general formulae (1-1) and (1-2) are as follows:

[0042]

[0043] The polyester of the present invention may be any polyester that satisfies the above general formula (1-1) or (1-2), and may be used as a mixture of two or more polyesters having different structures.

[0044] The number average molecular weight (Mn) of the polyester of the present invention is, for example, in the range of 500 to 5,000, preferably in the range of 1,000 to 5,000, more preferably in the range of 1,500 to 5,000, and even more preferably in the range of 1,500 to 4,000. By setting the lower limit of the number average molecular weight to 1,500 or more, a particularly improved effect on dispersibility can be expected. The number average molecular weight (Mn) is a value calculated in terms of polystyrene based on gel permeation chromatography (GPC) measurement, and is measured by the method described in the Examples.

[0045] The acid value of the polyester of the present invention is in the range of 3 to 400 mgKOH / g, preferably in the range of 3 to 100 mgKOH / g, and more preferably in the range of 3 to 50 mgKOH / g. The acid value of the polyester is confirmed by the method described in the examples.

[0046] The properties of the polyester of the present invention vary depending on the number average molecular weight, composition, etc., but are preferably liquid at room temperature. Here, "liquid at room temperature" means that the polyester of the present invention exhibits fluidity at normal pressure and at a room temperature of 25°C.

[0047] The content of the dispersant in the electrode mixture is not particularly limited, but is, for example, in the range of 0.01 to 30 parts by mass of the dispersant per 100 parts by mass of the electrode active material, preferably in the range of 0.05 to 10 parts by mass of the dispersant per 100 parts by mass of the electrode active material, and more preferably in the range of 0.1 to 5.0 parts by mass of the dispersant per 100 parts by mass of the electrode active material.

[0048] The content of the dispersant in the electrode mixture is not particularly limited, but is, for example, in the range of 0.01 to 30 parts by mass of the dispersant per 100 parts by mass of the electrode active material and the solid electrolyte combined, preferably in the range of 0.05 to 10 parts by mass of the dispersant per 100 parts by mass of the electrode active material and the solid electrolyte combined, and more preferably in the range of 0.05 to 5.0 parts by mass of the dispersant per 100 parts by mass of the electrode active material and the solid electrolyte combined.

[0049] The polyester of the present invention can be obtained using reaction raw materials including an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monoalcohol and / or a monocarboxylic acid. Here, the reaction raw materials mean raw materials that constitute the polyester of the present invention, and do not include solvents or catalysts that do not constitute polyesters. The method for producing the polyester of the present invention is not particularly limited, and the polyester can be produced by known methods, including the production method described below.

[0050] The reaction raw materials for the polyester of the present invention may contain an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monoalcohol and / or a monocarboxylic acid, and may also contain other raw materials. The reaction raw materials for the polyester of the present invention preferably contain an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monoalcohol and / or a monocarboxylic acid in an amount of 90 mass% or more based on the total amount of the reaction raw materials, and more preferably consist of only an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monoalcohol and / or a monocarboxylic acid.

[0051] The aliphatic diol used in the production of the polyester of the present invention is an aliphatic diol corresponding to the aliphatic diol residue of G having 2 to 20 carbon atoms, and the aliphatic diol used may be used alone or in combination of two or more. The aliphatic dicarboxylic acid used in the production of the polyester of the present invention is an aliphatic dicarboxylic acid corresponding to the aliphatic dicarboxylic acid residue of A having 2 to 10 carbon atoms, and the aliphatic dicarboxylic acid used may be used alone or in combination of two or more. The aliphatic polybasic acid used in the production of the polyester of the present invention is an aliphatic dicarboxylic acid corresponding to the aliphatic dicarboxylic acid residue of A having 2 to 10 carbon atoms, and the aliphatic dicarboxylic acid used may be used alone or in combination of two or more. １ and X ２ The aliphatic polybasic acid used may be a single type or a combination of two or more types. １ and X ２The aromatic polybasic acid used may be a single aromatic polybasic acid corresponding to the aromatic polybasic acid residue having 6 to 15 carbon atoms of Y, or a combination of two or more aromatic polybasic acids. The monocarboxylic acid used in the production of the polyester of the present invention is a monocarboxylic acid corresponding to the monocarboxylic acid residue having 1 to 20 carbon atoms of Y, or a combination of two or more monocarboxylic acids. The monoalcohol used in the production of the polyester of the present invention is a monoalcohol corresponding to the monoalcohol residue having 2 to 30 carbon atoms of Z, or a combination of two or more monoalcohols.

[0052] When the polybasic acid (aliphatic polybasic acid and / or aromatic polybasic acid) used as the reaction raw material is an aliphatic dicarboxylic acid, the reaction raw materials may include an aliphatic diol, an aliphatic dicarboxylic acid, a monoalcohol and / or a monocarboxylic acid.

[0053] Hydrogenated vegetable oil fatty acids may be used as the monocarboxylic acid used in producing the polyester of the present invention. Examples of such hydrogenated vegetable oil fatty acids include hydrogenated coconut oil fatty acids, hydrogenated palm kernel oil fatty acids, hydrogenated palm oil fatty acids, hydrogenated olive oil fatty acids, hydrogenated castor oil fatty acids, and hydrogenated rapeseed oil fatty acids. These are obtained by hydrolyzing and hydrogenating oils obtained from coconut, palm kernel, palm, olive, castor, and rapeseed, respectively, and are all mixtures of two or more long-chain aliphatic monocarboxylic acids including an aliphatic monocarboxylic acid having 8 to 21 carbon atoms. The monocarboxylic acid used in producing the polyester of the present invention may be the above-mentioned vegetable oil fatty acids that have not been hydrogenated, as long as the effects of the present invention are not impaired. Furthermore, the vegetable oil fatty acids are not limited to those mentioned above.

[0054] When the polyester of the present invention is a polyester obtained by reacting an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a hydrogenated vegetable oil fatty acid as reaction raw materials, the resulting polyester is obtained as a mixture of two or more polyesters represented by the general formula (1-1).

[0055] The aliphatic diol, aliphatic dicarboxylic acid, aliphatic polybasic acid, aromatic polybasic acid, monoalcohol, and monocarboxylic acid used in the production of the polyester of the present invention can all be used as derivatives thereof. Examples of such derivatives include esters, acid chlorides, acid anhydrides, and cyclic esters. For example, since epoxy compounds undergo ring-opening to form diols when reacted with carboxylic acids, aliphatic epoxy compounds may be used as derivatives of the aliphatic diols used as reaction raw materials in the present invention.

[0056] The polyester represented by the general formula (1-1) can be produced, for example, by charging and reacting an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monocarboxylic acid all at once, with the equivalent weight of the carboxyl groups being greater than the equivalent weight of the hydroxyl groups. Alternatively, the polyester represented by the general formula (1-1) can be produced, for example, by reacting an aliphatic diol and an aliphatic dicarboxylic acid in any equivalent ratio, and then reacting the terminal hydroxyl groups of the resulting polyester with a monocarboxylic acid and an aliphatic polybasic acid and / or an aromatic polybasic acid, and capping the hydroxyl groups with a carboxylic acid residue.

[0057] The polyester represented by the general formula (1-2) can be produced, for example, by charging an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic polybasic acid and / or an aromatic polybasic acid, and a monoalcohol all at once and reacting them so that the equivalent weight of the carboxyl groups is greater than the equivalent weight of the hydroxyl groups. Alternatively, the polyester represented by the general formula (1-2) can be produced, for example, by reacting an aliphatic diol and an aliphatic dicarboxylic acid in any equivalent ratio, and then reacting the terminals of the resulting polyester with a monoalcohol and an aliphatic polybasic acid and / or an aromatic polybasic acid.

[0058] In the production of the polyester of the present invention, the reaction of the raw materials may be carried out as an esterification reaction, for example, in the presence of an esterification catalyst at a temperature of 170 to 250° C. for 10 to 25 hours. The conditions of the esterification reaction, such as the temperature and time, are not particularly limited and may be set appropriately.

[0059] Examples of the esterification catalyst include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; zinc-based catalysts such as zinc acetate; tin-based catalysts such as tin octoate and dibutyltin oxide; and organic sulfonic acid-based catalysts such as p-toluenesulfonic acid.

[0060] The amount of the esterification catalyst used may be appropriately determined, but is usually in the range of 0.0001 to 0.1 parts by mass per 100 parts by mass of the total amount of the reaction raw materials.

[0061] (Electrode Active Material) As the electrode active material, a positive electrode active material or a negative electrode active material is adopted depending on whether the electrode mixture is used for a positive electrode or a negative electrode.

[0062] Examples of the positive electrode active material include oxide-based positive electrode active materials and sulfide-based positive electrode active materials.

[0063] Examples of oxide-based positive electrode active materials include LMO (lithium manganese oxide), LCO (lithium cobalt oxide), NMC (lithium nickel manganese cobalt oxide), NCA (lithium nickel cobalt aluminate), LNCO (lithium nickel cobalt oxide), and lithium-containing olivine-type phosphate (LiMePO ４ , Me=Fe, Co, Ni, Mn) and the like.

[0064] Specific examples of oxide-based positive electrode active materials include LiCoO ２ , LiMnO ２ , LiNiO ２ , LiVO ２ , LiNi ｘ Co ｙ Mn ｚ O ２ Rock salt layered active materials such as LiMn ２ O ４ , Li ４ Ti ５ O １２ , Li(Ni ０．５ Mn １．５ ) O ４ Spinel-type active materials such as LiFePO ４ , LiMnPO ４ , LiNiPO ４ , LiCoPO４ , lithium manganese iron phosphate (LiMn ｘ Fe １－ｘ P.O. ４ ; 0<x<1) and the like.

[0065] As a sulfide-based positive electrode active material, titanium sulfide (TiS ２ ), molybdenum sulfide (MoS ２ ), iron sulfide (FeS, FeS ２ ), copper sulfide (CuS), nickel sulfide (Ni ３ S ２ ) and the like. Niobium selenide (NbSe ３ ) etc. can also be used.

[0066] The positive electrode active material may be used alone or in combination of two or more kinds.

[0067] Examples of the negative electrode active material include metallic lithium, metallic indium, metallic aluminum, metallic silicon, metallic tin, and other metallic lithium or metals capable of forming alloys with metallic lithium, oxides of these metals, and alloys of these metals with metallic lithium.

[0068] The electrode active material may be, for example, an electrode active material having a coating layer coated on its surface. Examples of materials for forming the coating layer include ion conductors such as nitrides of lithium atoms, oxides of lithium atoms, and composites thereof.

[0069] Specific examples of the coating layer material include Li ４－２ｘ Zn ｘ GeO ４ Conductors having a lysicone-type crystal structure such as Li ３ P.O. ４ For example, Li ４－ｘ Ge １－ｘ P ｘ S ４ Conductors having a thiolicon-type crystal structure such as La ２／３－ｘ Li ３ｘ TiO ３ Conductors having a perovskite crystal structure such as LiTi ２ (P.O. ４ ) ３Conductors having a NASICON type crystal structure such as Li ｙ Ti ３－ｙ O ４ (0<y<3), Li ４ Ti ５ O １２ Lithium titanate compounds such as (LTO), LiNbO ３ , LiTaO ３ Lithium metal oxide compounds of metals belonging to Group 5 of the periodic table, such as Li ２ Alumni ２ O ３ -P ２ O ５ system, Li ２ Alumni ２ O ３ -ZnO-based, Li ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -TiO ２ Also included are conductors of boron oxide / phosphorus oxide compounds such as the system.

[0070] The coating can be formed by a known method, for example, by depositing the electrode active material in a solution containing a material for forming a coating layer, and then baking the deposited electrode active material.

[0071] The coverage of the coating layer is preferably 90% or more, more preferably 95% or more, and even more preferably 100% based on the surface area of ​​the electrode active material, i.e., the entire surface is preferably covered. The thickness of the coating layer is preferably 1 nm or more, more preferably 2 nm or more, and the upper limit is preferably 30 nm or less, more preferably 25 nm or less. The thickness of the coating layer can be measured by cross-sectional observation using a transmission electron microscope (TEM), and the coverage can be calculated from the thickness of the coating layer, elemental analysis value, and BET specific surface area.

[0072] (Solid Electrolyte) Examples of the solid electrolyte include sulfide solid electrolytes and oxide solid electrolytes.

[0073] The sulfide solid electrolyte is a solid electrolyte containing a metal element (M) such as Li, Na, K, Mg, or Ca, and sulfur (S), preferably a sulfide solid electrolyte containing lithium and sulfur, and more preferably a sulfide solid electrolyte containing lithium, sulfur, and one or more elements selected from the group consisting of P, Si, Ge, Al, and B. The sulfide solid electrolyte may further contain a halogen element such as Cl, Br, or I, or O (oxygen), etc.

[0074] Specific examples of sulfide solid electrolytes include Li ２ S-P ２ S ５ , Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Li ２ O, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li ２ S-SiS ２ , Li ２ S-SiS ２ - LiI, Li ２ S-SiS ２ - LiBr, Li ２ S-SiS ２ -LiCl, Li ２ S-SiS ２ -B ２ S ３ - LiI, Li ２ S-SiS ２ -P ２ S ５ - LiI, Li ２ S-B ２ S ３ , Li ２ S-P ２ S ５ -Z ｍ S ｎ (where m and n are positive numbers, and Z is Ge, Zn, or Ga.), Li ２ S-GeS ２ , Li ２ S-SiS ２ -Li３ P.O. ４ , Li ２ S-SiS ２ -Li ｘ MO ｙ (where x and y are positive numbers, and M is any of P, Si, Ge, B, Al, Ga, and In.) ２ S-P ２ S ５ " is written by Li ２ S and P ２ S ５ The same applies to other descriptions.

[0075] The sulfide solid electrolyte may be either an amorphous sulfide solid electrolyte or a crystalline sulfide solid electrolyte. The amorphous sulfide solid electrolyte can be produced, for example, by mechanical milling the reaction raw materials. The crystalline sulfide solid electrolyte can be produced, for example, by heat treating the amorphous sulfide solid electrolyte at a temperature equal to or higher than the crystallization temperature.

[0076] Examples of oxide solid electrolytes include NASICON-type oxides, garnet-type oxides, and perovskite-type oxides. NASICON-type oxides include oxides containing Li, Al, Ti, P, and O (e.g., Li １．５ Al ０．５ Ti １．５ (P.O. ４ ) ３ Examples of garnet-type oxides include oxides containing Li, La, Zr, and O (e.g., Li ７ La ３ Zr ２ O １２ ), oxides containing Li, La, Zr, Ta and O (Li ７－ｘ La ３ Zr ２－ｘ Ta ｘ O １２ Examples of perovskite oxides include oxides containing Li, La, Ti, and O (e.g., LiLaTiO ３ ) can be mentioned.

[0077] When the electrode mixture contains both an electrode active material and a solid electrolyte, the mass ratio of the electrode active material to the solid electrolyte is, for example, in the range of electrode active material:solid electrolyte (mass ratio)=99.5:0.5 to 40:60, preferably in the range of electrode active material:solid electrolyte (mass ratio)=99:1 to 50:50, and more preferably in the range of electrode active material:solid electrolyte (mass ratio)=98:2 to 60:40.

[0078] (Other Components) The electrode mixture of the present invention only needs to contain an electrode active material and / or a solid electrolyte and a dispersant, and may contain other components other than these, such as a conductive material, a binder, etc., within a range that does not impair the effects of the present invention.

[0079] Examples of conductive materials include carbon-based materials such as artificial graphite, graphite carbon fiber, resin-burned carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads, furfuryl alcohol resin-burned carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, non-graphitizable carbon, and carbon nanotubes (multi-wall, single-wall).

[0080] When the electrode mixture of the present invention contains a conductive material, the content of the conductive material in the electrode mixture is not particularly limited, but in consideration of improving battery performance and production efficiency, the lower limit is preferably 0.5 mass % or more, more preferably 1 mass % or more, and even more preferably 1.5 mass % or more, and the upper limit is preferably 10 mass % or less, preferably 8 mass % or less, and even more preferably 5 mass % or less.

[0081] Examples of binders include fluorine-based polymers such as polytetrafluoroethylene and polyvinylidene fluoride, thermoplastic elastomers such as butylene rubber and styrene-butadiene rubber, and various resins such as acrylic resin, acrylic polyol resin, polyvinyl acetal resin, polyvinyl butyral resin, and silicone resin.

[0082] When the electrode mixture of the present invention contains a binder, the content of the binder in the electrode mixture is not particularly limited, but the lower limit is preferably 1 mass % or more, more preferably 3 mass % or more, and even more preferably 5 mass % or more, and the upper limit is preferably 20 mass % or less, preferably 15 mass % or less, and even more preferably 10 mass % or less.

[0083] The electrode mixture can be produced by mixing the solid electrolyte and / or electrode active material, the dispersant, and any other components by a known method.

[0084] [Secondary Battery] By using the electrode mixture of the present invention, a battery member for a secondary battery can be produced, and the secondary battery includes, for example, both an all-solid-state battery in which the electrolyte is solid and a lithium-ion battery in which the electrolyte is liquid.

[0085] [All-Solid-State Battery] The all-solid-state battery of the present invention is an all-solid-state battery having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer in this order, and at least one of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer contains a dispersant that is the polyester of the present invention. The electrode mixture of the present invention is suitable as a battery component for an all-solid-state battery. For example, when the electrode mixture of the present invention contains a positive electrode active material, it can form a positive electrode layer. For example, when the electrode mixture of the present invention contains a negative electrode active material, it can form a negative electrode layer. For example, when the electrode mixture of the present invention does not contain an electrode active material but contains a solid electrolyte, it can form a solid electrolyte layer. The positive electrode layer and the negative electrode layer may each contain a solid electrolyte.

[0086] The all-solid-state battery of the present invention is preferably configured to have a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector, in this order. Examples of the positive electrode current collector include a foil, plate, or porous material made of aluminum, aluminum alloy, stainless steel, nickel, iron, titanium, or the like. Examples of the negative electrode current collector include a foil, plate, or porous material made of nickel, copper, stainless steel, or the like.

[0087] The all-solid-state battery of the present invention can be produced by a known method. For example, the positive electrode layer and the negative electrode layer can each be produced by applying the electrode mixture slurry of the present invention onto a current collector and drying it.

[0088] Examples of the solvent for forming a slurry of the electrode mixture include ketone compounds such as methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, dibutyl ketone, and diisobutyl ketone; ether compounds such as diethylene glycol diethyl ether, cyclopentyl methyl ether, dibutyl ether, dipentyl ether, and anisole; and ester compounds such as ethyl butyrate, butyl butyrate, and 2-methylbutyl butyrate.

[0089] The electrode mixture slurry can be prepared by a known method, and the viscosity of the electrode mixture slurry may be set as desired.

[0090] The method for applying the electrode mixture slurry to the surface of the current collector is not particularly limited, and may be an inkjet method, screen printing method, CVD method, sputtering method, or a known application method such as a doctor blade. The total thickness of the electrode layer and current collector after drying (electrode thickness) is not particularly limited, but is, for example, in the range of 0.1 μm to 1 mm, and preferably in the range of 1 μm to 200 μm.

[0091] The solid electrolyte layer can be formed, for example, by pressing a solid electrolyte. Alternatively, the solid electrolyte layer can be formed by applying a slurry solution of the solid electrolyte, which is prepared by dispersing a solid electrolyte material in a solvent, to the surface of a substrate or an electrode. The thickness of the solid electrolyte layer is not particularly limited, but is, for example, 0.1 μm to 1 mm, and preferably 1 μm to 100 μm.

[0092] [Lithium-ion battery] The electrode mixture of the present invention can also be suitably used as a battery component for a lithium-ion battery using a liquid electrolyte. Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator sandwiched between the positive electrode and the negative electrode, and an electrolyte. The separator is, for example, a laminate formed by applying and drying a coating composition for a secondary battery separator containing inorganic particles and a binder resin onto a substrate.

[0093] (Inorganic Particles) The separator serves to prevent physical contact between the negative electrode and the positive electrode and to allow metal ions such as lithium ions to pass through its pores. However, if the separator is only a substrate (without a coating layer), there is a problem that the separator may be damaged by the electric charges of the metal particles that move between the separator during the charge / discharge process of the secondary battery. The inorganic particles are used to increase the strength of the separator.

[0094] Examples of inorganic particles contained in the coating composition for secondary battery separators include BaTiO ３ , Pb(Zr,Ti)O ３ , Pb １－ｘ La ｘ Zr １－ｙ TiyO ３ (0<x<1, 0<y<1), Pb(Mg １／３ Nb ２／３ ) O ３ -PbTiO ３ , HfO ２ , SrTiO ３ , SnO ２ , CeO ２ , MgO, NiO, CaO, ZnO, ZrO ２ , Y ２ O ３ , Al ２ O ３ , TiO ２ and SiC.

[0095] The inorganic particles are not limited to the above, and include lithium phosphate (Li ３ P.O. ４ ), lithium titanium phosphate (Li ｐ Tiｑ (P.O. ４ ) ３ , 0<p<2, 0<q<3), lithium aluminum titanium phosphate (Li ａ Al ｂ Ti ｃ (P.O. ４ ) ３ , 0<a<2, 0<b<1, 0<c<3), 14Li ２ O ９ Al ２ O ３ 38TiO ２ 39P ２ O ５ (LiAlTiP) etc. ｄ O ｅ Glass 0<d<4, 0<e<13), lithium lanthanum titanate (Li ｅ La ｆ TiO ３ , 0<e<2, 0<f<3), Li ３．２５ Ge ０．２５ P ０．７５ S ４ Lithium germanium thiophosphate (Li ｇ Ge ｈ P ｉ S ｊ , 0<g<4, 0<h<1, 0<i<1, 0<j<5), Li ３ Lithium nitride (LiN) ｋ N ｌ , 0<k<4, 0<l<2), Li ３ P.O. ４ -Li ２ S-SiS ２ SiS such as ２ Glass (Li ｍ Si ｎ S ｏ , 0<m<3, 0<n<2, 0<o<4), LiI-Li ２ S-P ２ S ５ P etc. ２ S ５ Inorganic particles having lithium ion conducting properties, such as glass, can also be used.

[0096] The particle size of the inorganic particles is not particularly limited, but is preferably D ５０is, for example, in the range of 0.1 to 10 μm, preferably in the range of 0.2 to 5 μm. Similarly, D ９０ is, for example, 30 μm or less, and preferably in the range of 10 to 25 μm.

[0097] The content of the inorganic particles may be, for example, in the range of 0.5 to 40 parts by mass, preferably in the range of 5 to 30 parts by mass, and more preferably in the range of 10 to 20 parts by mass, based on 100 parts by mass of the coating composition for a secondary battery separator.

[0098] The polyester of the present invention may be added as a dispersant to improve the dispersibility of inorganic particles. The content of the polyester of the present invention may be, for example, in the range of 0.1 to 10.0 parts by mass, preferably in the range of 0.1 to 5.0 parts by mass, more preferably in the range of 0.2 to 2.0 parts by mass, and even more preferably in the range of 0.8 to 1.8 parts by mass, relative to 100 parts by mass of inorganic particles.

[0099] (Binder Resin) The binder resin contained in the coating composition for a secondary battery separator may be, for example, one or more selected from the group consisting of an aliphatic conjugated diene / aromatic monovinyl copolymer, a (meth)acrylic polymer, a fluoropolymer, a (meth)acrylic acid / (meth)acrylamide copolymer, a (meth)acrylonitrile polymer, and an aromatic monovinyl / (meth)acrylic copolymer.

[0100] Specific examples of binder resins include polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylpyrrolidone, polyacrylonitrile, polyvinylidene fluoride-trichloroethylene, polyvinylidene fluoride-chlorotrifluoroethylene, polymethyl methacrylate, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, acrylonitrile-styrene-butadiene copolymer, and polyimide.

[0101] The content of the binder resin may be, for example, in the range of 10 to 50 parts by mass, preferably 15 to 45 parts by mass, and more preferably 20 to 40 parts by mass, per 100 parts by mass of the inorganic particles.

[0102] (Solvent) The solvent is used to ensure the coatability of the coating composition for a secondary battery separator of the present invention, and is not particularly limited as long as it can dissolve, for example, inorganic particles and binder resin to a certain level or more.

[0103] As the solvent, for example, one or more selected from the group consisting of acetone, tetrahydrofuran, acetonitrile, dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methylpyrrole, and water can be used.

[0104] The content of the solvent may be set so that the coating composition for a secondary battery separator is, for example, in a slurry state. For example, when the coating composition for a secondary battery separator is taken as 100 parts by mass, the content of the solvent may be, for example, in the range of 30 to 90 parts by mass, preferably in the range of 40 to 90 parts by mass, and more preferably in the range of 50 to 85 parts by mass.

[0105] The coating composition for a secondary battery separator may contain, for example, inorganic particles, a binder resin, a solvent, and any of the dispersants of the present invention, and may also contain other components such as a thickener, an antifoaming agent, a pH adjuster, a viscosity adjuster, and a redox shuttle agent.

[0106] The coating composition for a secondary battery separator may consist essentially of inorganic particles, a binder resin, a solvent, and any dispersant of the present invention, where "consist essentially of" means that the total of the inorganic particles, the binder resin, the solvent, and any dispersant of the present invention is 80% by weight or more, 90% by weight or more, 95% by weight or more, 99% by weight or more, or 100% by weight of the coating composition for a secondary battery separator.

[0107] The secondary battery separator is a laminate having a substrate and a coating layer formed from a coating composition for a secondary battery separator, and the coating layer may be disposed on at least one surface of the substrate.

[0108] The substrate serves to prevent physical contact between the negative electrode and the positive electrode and to allow metal ions such as lithium ions to pass through the pores. The substrate may be, for example, a porous polymer film made of one or more materials selected from the group consisting of polyolefin resin, fluororesin, polyester resin, polyacrylonitrile resin, and cellulose resin.

[0109] The substrate is preferably a porous polymer film made of one or more materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene terephthalate, and polybutylene terephthalate.

[0110] The lower limit of the thickness of the substrate is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.Similarly, the upper limit of the thickness of the substrate is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0111] The coating layer is formed by, for example, applying a coating composition for a secondary battery separator to a substrate and drying it, and may be formed by a known method. The lower limit of the thickness of the coating layer is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 3 μm or more. The upper limit of the thickness of the coating layer is preferably 10 μm or less, more preferably 8 μm or less.

[0112] The electrolyte solution may be an organic electrolyte solution containing a supporting electrolyte dissolved therein. Examples of the supporting electrolyte include LiPF ６ , LiAsF ６ , LiBF ４ , LiSbF ６ , LiAlCl ４ , LiClO ４ , C.F. ３ SO ３ Li, C４ F ９ SO ３ Li, CF ３ COOLi, (CF ３ CO) ２ NLi, (CF ３ SO ２ ) ２ NLi, (C ２ F ５ SO ２ ) NLi and the like.

[0113] Examples of organic solvents that dissolve the supporting electrolyte include carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), ethyl methyl carbonate (EMC), and vinylene carbonate (VC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; and sulfur-containing compounds such as sulfolane and dimethyl sulfoxide.

[0114] The positive electrode and negative electrode of the lithium ion battery may be any known material, and may be, for example, the same as those of an all-solid-state battery.

[0115] A lithium ion battery can be produced by, for example, stacking a positive electrode and a negative electrode with a separator between them, rolling or folding the stack as necessary, placing the stack in a battery container, injecting an electrolyte into the battery container, and sealing the container. If necessary, the battery container may contain an expanded metal, a fuse, an overcurrent prevention element such as a PTC element, a lead plate, or the like, to prevent pressure buildup within the battery and overcharging and discharging. Examples of the shape of the secondary battery include coin type, button type, sheet type, cylindrical type, prismatic type, and flat type.

[0116] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0117] In the examples of the present application, the acid value and hydroxyl value were evaluated by the following methods. [Method for measuring acid value] Measured by a method conforming to JIS K0070-1992. [Method for measuring hydroxyl value] Measured by a method conforming to JIS K0070-1992.

[0118] In the examples of the present application, the number average molecular weight of the polyester is a value calculated as polystyrene based on GPC measurement, and the measurement conditions are as follows. [GPC measurement conditions] Measurement apparatus: High-speed GPC apparatus "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSKGURDCOLUMNSuperHZ-L" manufactured by Tosoh Corporation + "TSKgelSuperHZM-M" manufactured by Tosoh Corporation + "TSKgelSuperHZM-M" manufactured by Tosoh Corporation + "TSKgelSuperHZ-2000" manufactured by Tosoh Corporation + "TSKgelSuperHZ-2000" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: "EcoSEC DataAnalysis version 1.07" manufactured by Tosoh Corporation Column temperature: 40°C Developing solvent: tetrahydrofuran Flow rate: 0.35 mL / min Measurement sample: 7.5 mg of sample was dissolved in 10 ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to prepare a measurement sample. Sample injection volume: 20 μl Standard sample: The following monodisperse polystyrene with known molecular weight was used in accordance with the measurement manual for the above-mentioned "HLC-8320GPC."

[0119] (Monodisperse polystyrene) "A-300" manufactured by Tosoh Corporation "A-500" manufactured by Tosoh Corporation "A-1000" manufactured by Tosoh Corporation "A-2500" manufactured by Tosoh Corporation "A-5000" manufactured by Tosoh Corporation "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation "F-10" manufactured by Tosoh Corporation "F-20" manufactured by Tosoh Corporation "F-40" manufactured by Tosoh Corporation "F-80" manufactured by Tosoh Corporation "F-128" manufactured by Tosoh Corporation "F-288" manufactured by Tosoh Corporation

[0120] (Synthesis Example 1: Preparation of Dispersant A) A 5-liter four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 676.3 g of 1,4-butylene glycol and 781.3 g of neopentyl glycol as glycol components, 2456.4 g of adipic acid as a dicarboxylic acid component, 259.7 g of isononyl alcohol as a monoalcohol component, and 0.13 g of tetraisopropyl titanate as a catalyst. Under a nitrogen stream, the temperature was raised stepwise to 220°C over 5 hours, and a condensation reaction was carried out at 220°C for 8 hours. After the reaction, unreacted raw materials and low-volatile components were removed at 200°C under reduced pressure to obtain a polyester, Dispersant A. The obtained Dispersant A was a viscous liquid at room temperature, had an acid value of 35.5 mgKOH / g, a hydroxyl value of 1.4 mgKOH / g, and a number average molecular weight of 2,320.

[0121] (Examples 1-4 and Comparative Examples 1-3: Preparation and Evaluation of Electrode Mixtures) The dispersants, positive electrode active materials, and solvents shown in Table 1 were mixed in the proportions shown in Table 1, and the mixture was stirred for 2 minutes at 1,000 rpm and 0.2 Pa using a planetary mixer (THINKYARV-310) to obtain paste-like electrode mixtures.

[0122] The positive electrode active materials used were as follows: NCM622: LiNi ０．６ Mn ０．２ Co ０．２ O ２ NCM811:LiNi ０．８ Co ０．１ Mn ０．１ O ２ LFP: LiFePO ４

[0123] (Viscosity) The viscosity of the prepared electrode mixture was measured at a predetermined shear rate [1 / S] using a rotational viscometer (RST-CPS manufactured by Eiko Seiki Co., Ltd.). Specifically, the electrode mixture was measured at a measurement temperature of 25°C and a shear rate of 50 [1 / S], and the value was read. The results are shown in Table 1.

[0124]

[0125] From the results in Table 1, it can be seen that the viscosity of the electrode mixture can be significantly reduced by adding a dispersant, and the positive electrode active material is well dispersed.

[0126] (Example 6: Production of all-solid-state battery) Positive electrode active material LiNi ０．６ Mn ０．２ Co ０．２ O ２ (NCM622) 6.7 g, dispersant A 0.1 g, solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２ A positive electrode slurry was prepared by adding butyl butyrate as a solvent to 3.0 g of the above, 0.2 g of acetylene black, and 1 g of a 10 mass % butyl butyrate solution of a styrene-butadiene rubber binder. This positive electrode slurry was applied to an aluminum foil current collector using an automatic bar coater and dried to produce a positive electrode layer containing dispersant A.

[0127] Solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２ A solid electrolyte slurry was prepared by mixing 9.9 g of the above and 1 g of a 10 mass % styrene-butadiene rubber binder butyl butyrate solution with butyl butyrate as a solvent. The obtained solid electrolyte slurry was applied to a PET film using an automatic bar coater, dried, and then the PET film was peeled off to obtain a solid electrolyte layer.

[0128] Using the produced positive electrode layer and solid electrolyte layer, a positive electrode layer, a solid electrolyte layer, and an indium-lithium alloy counter electrode, which had been punched into a circle with a diameter of 10 mm, were placed in a ceramic tube with an inner diameter of 10 mm, and the tube was press-molded to produce a positive electrode half-cell 1.

[0129] (Example 7: Production of all-solid-state battery) Positive electrode active material LiNi ０．６ Mn ０．２ Co ０．２ O ２ (NCM622) 6.7 g, solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２A positive electrode slurry was prepared by adding butyl butyrate as a solvent to 3.0 g of the above, 0.2 g of acetylene black, and 1 g of a 10% by mass styrene-butadiene rubber binder butyl butyrate solution using an automatic bar coater. The positive electrode slurry was applied to an aluminum foil current collector using an automatic bar coater and dried to produce a positive electrode layer.

[0130] Solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２ A solid electrolyte slurry was prepared by adding butyl butyrate as a solvent to 9.9 g of the above, 0.1 g of Dispersant A, and 1 g of a 10 mass % styrene-butadiene rubber binder butyl butyrate solution and mixing them. The obtained solid electrolyte slurry was applied to a PET film using an automatic bar coater, dried, and then the PET film was peeled off, thereby obtaining a solid electrolyte layer containing Dispersant A.

[0131] Using the produced positive electrode layer and solid electrolyte layer, a positive electrode layer, a solid electrolyte layer, and an indium-lithium alloy counter electrode, which had been punched into a circle with a diameter of 10 mm, were placed in a ceramic tube with an inner diameter of 10 mm, and the tube was press-molded to produce a positive electrode half-cell 2.

[0132] (Comparative Example 5: Production of all-solid-state battery) Positive electrode active material LiNi ０．６ Mn ０．２ Co ０．２ O ２ (NCM622) 6.7 g, solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２ A positive electrode slurry was prepared by adding butyl butyrate as a solvent to 3.0 g of the above, 0.2 g of acetylene black, and 1 g of a 10% by mass styrene-butadiene rubber binder butyl butyrate solution and mixing them. This positive electrode slurry was applied to an aluminum foil current collector using an automatic bar coater and dried to produce a positive electrode layer.

[0133] Solid electrolyte Li ６．６ La ３ Zr １．６ Ta ０．４ O １２A solid electrolyte slurry was prepared by mixing 9.9 g of the above and 1 g of a 10 mass % styrene-butadiene rubber binder butyl butyrate solution with butyl butyrate as a solvent. The obtained solid electrolyte slurry was applied to a PET film using an automatic bar coater, dried, and then the PET film was peeled off to obtain a solid electrolyte layer containing Dispersant A.

[0134] Using the produced positive electrode layer and solid electrolyte layer, a positive electrode layer, a solid electrolyte layer, and an indium-lithium alloy counter electrode punched into a circle with a diameter of 10 mm were placed in a ceramic tube with an inner diameter of 10 mm, and the tube was press-molded to produce a positive electrode half-cell 1′.

[0135] (Evaluation of all-solid-state batteries) The battery capacity [mAh / g] was measured for each of the produced cathode half-cell 1, cathode half-cell 2, and cathode half-cell 1'. The battery charge / discharge conditions were 25°C and a charge / discharge rate of 0.1 c. Charge / discharge cycles were repeated, and the discharge capacity of the fifth cycle was recorded as the battery capacity. When the battery capacity of cathode half-cell 1', which did not contain dispersant A in either the cathode layer or the solid electrolyte layer, was taken as 100, cathode half-cell 1, which contained dispersant A in the cathode layer, and cathode half-cell 2, which contained dispersant A in the solid electrolyte layer, both showed an improvement in battery capacity of 20% or more.

Claims

1. An electrode mixture containing an electrode active material and / or a solid electrolyte and a dispersant, wherein the dispersant is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.

2. The electrode mixture according to claim 1, wherein the acid value of the polyester is in the range of 3 to 400 mgKOH / g.

3. The electrode mixture according to claim 1, wherein G is a residue of an aliphatic diol having a branched structure and having 3 to 20 carbon atoms.

4. The electrode mixture according to claim 1, wherein A is a residue of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

5. X １ and X ２ The electrode mixture according to claim 1, wherein each of the groups independently represents an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms.

6. The electrode mixture according to claim 1, wherein the polyester is a polyester represented by the general formula (1-2) in which Z is an aliphatic monoalcohol residue having 2 to 30 carbon atoms.

7. The electrode mixture according to claim 1, wherein the number average molecular weight of the polyester is in the range of 1,500 to 5,000.

8. The electrode mixture of claim 1, wherein the polyester is a liquid at room temperature.

9. The electrode mixture according to claim 1, wherein the electrode active material is one or more positive electrode active materials selected from the group consisting of lithium manganese oxide, lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel cobalt aluminate, lithium nickel cobalt oxide, lithium-containing olivine-type phosphates, titanium sulfide, molybdenum sulfide, iron sulfide, copper sulfide, nickel sulfide, niobium selenide, lithium iron phosphate, lithium manganese phosphate, lithium iron manganese phosphate, lithium cobalt phosphate, and lithium nickel phosphate.

10. The electrode mixture according to claim 1, wherein the electrode active material is one or more negative electrode active materials selected from the group consisting of lithium, indium, aluminum, silicon, tin, lithium oxide, indium oxide, aluminum oxide, silicon oxide, and tin oxide.

11. The electrode mixture according to claim 1, wherein the solid electrolyte is an oxide solid electrolyte containing lithium and oxygen and / or a sulfide solid electrolyte containing lithium and sulfur.

12. The electrode mixture according to claim 1, wherein the dispersant is contained in an amount of 0.05 to 10 parts by mass per 100 parts by mass of the electrode active material and the solid electrolyte combined.

13. A secondary battery using the electrode mixture according to any one of claims 1 to 12.

14. An all-solid-state battery having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer in this order, wherein at least one of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer contains a dispersant that is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.

15. A secondary battery having a positive electrode, a separator, and a negative electrode in this order, wherein the separator is a laminate in which the surface of a substrate is covered with a coating layer containing inorganic particles, and at least one of the positive electrode, the coating layer, and the negative electrode contains a dispersant that is a polyester represented by the following general formula (1-1) or (1-2): (In the general formulas (1-1) and (1-2), G is an aliphatic diol residue having 2 to 20 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 10 carbon atoms, and X １ and X ２ are each independently an aliphatic polybasic acid residue having 2 to 10 carbon atoms or an aromatic polybasic acid residue having 6 to 15 carbon atoms, Y is a monocarboxylic acid residue having 1 to 20 carbon atoms, Z is a monoalcohol residue having 2 to 30 carbon atoms, and p is X １ q is an integer obtained by subtracting one from the number of basic acid functional groups of the aliphatic polybasic acid residue or aromatic polybasic acid residue of X ２ is an integer obtained by subtracting one from the number of basic acid functional groups in the aliphatic polybasic acid residue or aromatic polybasic acid residue, and n represents the number of repetitions.

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