Binder composition for all-solid-state secondary battery, slurry for all-solid-state secondary battery, solid electrolyte sheet for all-solid-state secondary battery and method for manufacturing same, and all-solid-state secondary battery and method for manufacturing same

Abstract

The present invention provides a binder composition for all-solid-state batteries, said binder composition exhibiting excellent storage stability for a long period of time, while having excellent lithium ion conductivity and achieving good cycle life characteristics even at high voltage.　A binder composition for all-solid-state batteries according to the present invention contains (A) a polymer that has an aromatic vinyl unit based on an aromatic vinyl compound and a conjugated diene unit based on a conjugated diene compound, (B) an anti-aging agent in an amount of from 200 ppm to 5,000 ppm relative to the total mass of this binder composition for all-solid-state batteries, and (C) a liquid medium.

Description

[Technical Field]

[0001] The present invention relates to a binder composition for an all-solid-state secondary battery, a slurry for an all-solid-state secondary battery containing the composition and a solid electrolyte, a solid electrolyte sheet for an all-solid-state secondary battery formed by applying the slurry to a substrate and drying it, a method for producing the same, and an all-solid-state secondary battery including the sheet and a method for producing the same. [Background technology]

[0002] Many lithium-ion secondary batteries, which are widely used as driving power sources for automobiles and home storage batteries, use liquid electrolytes. Currently, all-solid-state secondary batteries, which replace liquid electrolytes with solid electrolytes and use solid-state materials, are being developed as the ultimate battery that combines safety, high energy density, and long life.

[0003] All-solid-state secondary batteries use a solid electrolyte with high ionic conductivity, eliminating the risk of leakage or fire and offering excellent safety and reliability. All-solid-state secondary batteries are also suitable for achieving high energy density through electrode stacking. Specifically, they can be constructed with active material layers and solid electrolyte layers arranged in series. This eliminates the need for metal packaging to seal the battery cells and the copper wires and bus bars connecting the battery cells, significantly increasing the battery's energy density. Another advantage is their compatibility with positive electrode materials, which allow for higher potentials.

[0004] On the other hand, problems have also become apparent when manufacturing all-solid-state secondary batteries. Specifically, when a mixture of a solid electrolyte and an active material is pressure-molded to increase the contact area between them, the pressure-molded body becomes hard, brittle, and poorly processable. Furthermore, because the active material undergoes volume changes due to the absorption and desorption of lithium ions, the pressure-molded body has problems such as peeling of the active material with charge-discharge cycles, resulting in a significant decrease in capacity.

[0005] Therefore, in order to improve moldability, techniques have been investigated in which a binder component is further added to the mixture to improve moldability (see, for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-86899 [Patent Document 2] Special Publication No. 7-87045 [Patent Document 3] International Publication No. 2009 / 107784 [Patent Document 4] Patent No. 5120522 Summary of the Invention [Problem to be solved by the invention]

[0007] The compositions and slurries containing binder components disclosed in the above Patent Documents 1 to 4 have the problem that their storage stability is easily impaired due to deterioration over time of the polymer binder component. Furthermore, even when used in all-solid-state secondary batteries, the polymer deteriorates over time with repeated charge and discharge, which tends to inhibit ionic conduction between the solid electrolytes. In addition, the high-level cycle life characteristics under high voltages required for recent all-solid-state secondary batteries cannot be satisfied, and further improvement has been required.

[0008] Therefore, some aspects of the present invention provide a binder composition for an all-solid-state secondary battery that has excellent long-term storage stability, excellent lithium ion conductivity, and can achieve good cycle life characteristics even under high voltage. [Means for solving the problem]

[0009] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized as any of the following aspects.

[0010] One aspect of the binder composition for an all-solid-state secondary battery according to the present invention is a polymer (A) having an aromatic vinyl unit derived from an aromatic vinyl compound and a conjugated diene unit derived from a conjugated diene compound; The antioxidant (B) is 200 ppm or more and 5,000 ppm or less based on the total mass of the binder composition for an all-solid-state secondary battery, A liquid medium (C); Contains:

[0011] In one embodiment of the binder composition for an all-solid-state secondary battery, The antioxidant (B) may include at least one selected from the group consisting of phenol-based antioxidants and amine-based antioxidants.

[0012] In any one of the embodiments of the binder composition for an all-solid-state secondary battery, When the constituent ratios (molar ratios) of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) in the polymer (A) are p, q, r, and s, respectively, the value α represented by the following formula (i) may be less than 0.9. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ···(i) [ka]

[0013] In any one of the embodiments of the binder composition for an all-solid-state secondary battery, The polymer (A) may have a bound styrene content of 5 to 40%.

[0014] In any one of the embodiments of the binder composition for an all-solid-state secondary battery, The polymer (A) may have units based on a modifier containing at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, a silicon atom, a germanium atom and a tin atom.

[0015] In any one of the embodiments of the binder composition for an all-solid-state secondary battery, The liquid medium (C) may be at least one selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, esters, and ethers.

[0016] Any one of the embodiments of the binder composition for an all-solid-state secondary battery may include: The polymer (A) may be dissolved in the liquid medium (C).

[0017] One embodiment of the slurry for an all-solid-state secondary battery according to the present invention is The binder composition for an all-solid-state secondary battery according to any one of the above aspects and a solid electrolyte are contained.

[0018] In one embodiment of the slurry for the all-solid-state secondary battery, The solid electrolyte may contain a sulfide-based solid electrolyte or an oxide-based solid electrolyte.

[0019] One aspect of the all-solid-state secondary battery according to the present invention is The battery includes at least a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, At least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer formed by applying and drying the slurry for an all-solid-state secondary battery according to any one of the above aspects.

[0020] One aspect of the solid electrolyte sheet for an all-solid-state secondary battery according to the present invention is The all-solid-state secondary battery battery has a layer formed on a substrate by applying and drying the slurry for the all-solid-state secondary battery according to any one of the above aspects.

[0021] One aspect of the method for producing a solid electrolyte sheet for an all-solid-state secondary battery according to the present invention is to The method includes a step of applying the slurry for an all-solid-state secondary battery of any of the above aspects onto a substrate and drying it.

[0022] One aspect of the method for producing an all-solid-state secondary battery according to the present invention is to This is a method for producing an all-solid-state secondary battery through the method for producing a solid electrolyte sheet for an all-solid-state secondary battery of the above aspect. [Effects of the Invention]

[0023] The binder composition for an all-solid-state secondary battery according to the present invention improves the long-term storage stability of the polymer binder component. Furthermore, when used in an all-solid-state secondary battery, the binder composition can suppress the deterioration of the polymer over time due to repeated charge and discharge, thereby enabling the production of an all-solid-state secondary battery that has excellent lithium ion conductivity and can achieve good cycle life characteristics even under high voltage. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of the present invention will be described in detail below. The present invention is not limited to the embodiments described below, and should be understood to include various modifications that are implemented within the scope of the present invention. In this specification, "(meth)acrylic acid" is a concept that encompasses both "acrylic acid" and "methacrylic acid."

[0025] In this specification, a numerical range described as "A to B" is interpreted as including numerical value A as the lower limit and numerical value B as the upper limit.

[0026] 1. Binder composition for all-solid-state secondary batteries The binder composition for an all-solid-state secondary battery according to this embodiment contains a polymer (A) having aromatic vinyl units derived from an aromatic vinyl compound and conjugated diene units derived from a conjugated diene compound, an antioxidant (B) in an amount of 200 ppm to 5,000 ppm based on the total mass of the binder composition for an all-solid-state secondary battery, and a liquid medium (C). The binder composition for an all-solid-state secondary battery according to this embodiment may further contain optional components within a range that does not impair the effects of the present invention. Each component contained in the binder composition for an all-solid-state secondary battery according to this embodiment will be described in detail below.

[0027] 1.1. Polymer (A) The binder composition for an all-solid-state secondary battery according to this embodiment contains a polymer (A). The polymer (A) has aromatic vinyl units derived from an aromatic vinyl compound and conjugated diene units derived from a conjugated diene compound. In addition to the aromatic vinyl units and the conjugated diene units, the polymer (A) may also contain structural units derived from other monomers copolymerizable therewith. The order of arrangement of the structural units in the polymer (A) is not particularly limited. That is, the polymer (A) may be a block copolymer or a random copolymer.

[0028] Hereinafter, the production method of the polymer (A) and the physical properties of the polymer (A) will be described in that order.

[0029] 1.1.1. Production method of polymer (A) Polymer (A) can be produced, for example, by a method including a step of polymerizing an aromatic vinyl compound and a conjugated diene compound to obtain a conjugated diene copolymer having an active terminal (polymerization step), a step of modifying the terminal of the obtained conjugated diene copolymer (modification step), and a step of hydrogenating the conjugated diene copolymer (hydrogenation step). Specifically, polymer (A) can be produced according to the method described in WO 2014 / 133097, with appropriate adjustments made to the molecular weight, amount of aromatic vinyl compound, vinyl bond content, hydrogenation rate, type of modifier, etc., to suit the intended use. The production method of polymer (A) is described in detail below.

[0030] <Polymerization process> The polymerization step is a step of polymerizing a monomer containing an aromatic vinyl compound and a conjugated diene compound to obtain a conjugated diene copolymer having an active terminal. The polymerization method for obtaining the conjugated diene copolymer may be any of solution polymerization, gas phase polymerization, and bulk polymerization, with solution polymerization being particularly preferred. The polymerization method may be either batch or continuous. When using solution polymerization, a specific example of the polymerization method is to polymerize a monomer containing an aromatic vinyl compound and a conjugated diene compound in an organic solvent in the presence of a polymerization initiator and, if necessary, a vinyl control agent (hereinafter also referred to as a "randomizer").

[0031] Examples of aromatic vinyl compounds include styrene, divinylbenzene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, N,N-dimethylaminoethylstyrene, and diphenylethylene. Among these, the aromatic vinyl compound is particularly preferably one or more compounds selected from styrene and divinylbenzene. The aromatic vinyl compounds may be used alone or in combination.

[0032] As the conjugated diene compound, in addition to 1,3-butadiene, conjugated diene compounds other than 1,3-butadiene may be used. Such conjugated diene compounds are not particularly limited as long as they are copolymerizable with 1,3-butadiene and aromatic vinyl compounds, and examples thereof include isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. Among these, isoprene is preferred as the conjugated diene compound other than 1,3-butadiene. Note that the conjugated diene compounds may be used alone or in combination of two or more.

[0033] The conjugated diene copolymer obtained by the polymerization step may be a copolymer of 1,3-butadiene and an aromatic vinyl compound, or a copolymer of 1,3-butadiene and a conjugated diene compound other than 1,3-butadiene and an aromatic vinyl compound. From the viewpoint of high living property in anionic polymerization, the conjugated diene copolymer is preferably a copolymer using 1,3-butadiene and styrene.

[0034] In the conjugated diene copolymer obtained by the polymerization step, the content of the aromatic vinyl compound is preferably 5 to 40 mass%, more preferably 8 to 30 mass%, and particularly preferably 10 to 27 mass%, relative to the total amount of monomers used in the polymerization. Furthermore, by setting the content of the aromatic vinyl compound within the above range, it is possible to achieve both adhesion and flexibility of the electrode. The monomers used to produce the conjugated diene copolymer before hydrogenation preferably contain 60 to 95 parts by mass of butadiene, 5 to 40 parts by mass of an aromatic vinyl compound, and 0 to 35 parts by mass of a conjugated diene compound other than butadiene. These blending amounts are preferred in that they allow for both adhesion and flexibility of the electrode.

[0035] In the polymerization, other monomers can be used in addition to the aromatic vinyl compound and the conjugated diene compound. Examples of the other monomers include acrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate. The amount of the other monomers used is preferably 20% by mass or less, more preferably 18% by mass or less, and particularly preferably 15% by mass or less, based on the total amount of the monomers used in the polymerization.

[0036] As the polymerization initiator, at least one of an alkali metal compound and an alkaline earth metal compound can be used. As the alkali metal compound and alkaline earth metal compound, those commonly used as initiators for anionic polymerization can be used, such as alkyllithiums such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and tert-butyllithium; 1,4-dilithiobutane, phenyllithium, stilbenelithium, naphthyllithium, naphthylsodium, naphthylpotassium, di-n-butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, and calcium stearate. Among these, lithium compounds are preferred.

[0037] The polymerization reaction is carried out by polymerizing at least one of the above alkali metal compounds and alkaline earth metal compounds. meeting and opening The polymerization may be carried out in the presence of a compound (hereinafter also referred to as "compound (R)") obtained by mixing a compound (hereinafter also referred to as "compound (C1)") that introduces a functional group that interacts with a current collector, solid electrolyte, etc., at the initiation terminal of the conjugated diene copolymer. By carrying out the polymerization in the presence of compound (R), a functional group that interacts with a current collector, solid electrolyte, etc. can be introduced at the polymerization initiation terminal of the conjugated diene copolymer. In this specification, "interaction" refers to the formation of a covalent bond between molecules or the formation of an intermolecular force weaker than a covalent bond (e.g., an electromagnetic force acting between molecules such as an ion-dipole interaction, a dipole-dipole interaction, a hydrogen bond, or a van der Waals force). In addition, the "functional group that interacts with a current collector, solid electrolyte, etc." refers to a group having at least one atom such as a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom, or a phosphorus atom.

[0038] The compound (C1) may contain a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom, , or Phosphorus and hydrogen atoms andThere are no particular limitations on the compound (C1) as long as it has a partial structure in which the groups are directly bonded. Examples of compounds that can be used as compound (C1) include nitrogen-containing compounds such as secondary amines, compounds having a hydroxyl group, silicon-containing compounds such as tertiary silanes, compounds having a thiol group, and secondary phosphines. Among these, nitrogen-containing compounds such as secondary amine compounds are preferred. Specific examples of the nitrogen-containing compound include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dioctylamine, dihexylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, 3,3-dimethylpiperidine, 2,6-dimethylpiperidine, 1-methyl-4-(methylamino)piperidine, 2,2,6,6-tetramethylpiperidine, pyrrolidine, piperazine, 2,6-dimethylpiperazine, 1-ethylpiperazine, 2-methylpiperazine, 1-benzylpiperazine, 2,6-dimethylmorpholine, hexamethyleneimine, heptamethyleneimine, and dicyclohexylamine. , N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, N'-[2-N,N-bis(trimethylsilyl)aminoethyl]piperazine, 1,3-ditrimethylsilyl-1,3,5-triazinane, 5-benzyloxyindole, 3-azaspiro[5,5]undecane, and the like.

[0039] The compound (R) is preferably a reaction product of a lithium compound such as an alkyllithium with the compound (C1). When polymerization is carried out in the presence of the compound (R), the compound (R) may be prepared by premixing an alkali metal compound or alkaline earth metal compound with the compound (C1), and the prepared compound (R) may be added to the polymerization system to carry out polymerization. Alternatively, the alkali metal compound or alkaline earth metal compound and the compound (C1) may be added to the polymerization system, and the two may be mixed in the polymerization system to prepare the compound (R), and then polymerization may be carried out.

[0040] The randomizer can be used for the purpose of adjusting the content of vinyl bonds (vinyl bond content), etc. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(tetrahydrofuryl)propane, 2-(2-ethoxyethoxy)-2-methylpropane, triethylamine, pyridine, N-methylmorpholine, and tetramethylethylenediamine. These can be used alone or in combination of two or more.

[0041] The organic solvent used in the polymerization may be any organic solvent inert to the reaction, and may include, for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, etc. Among these, hydrocarbons having 3 to 8 carbon atoms are preferred, and specific examples thereof include n-pentane, isopentane, n-hexane, n-heptane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, cis-2-butene, 1-pentyne, 2-pentyne, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, cyclopentane, methylcyclopentane, methylcyclohexane, 1-pentene, 2-pentene, cyclohexene, etc. The organic solvent may be used alone or in combination of two or more.

[0042] When solution polymerization is used, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, in order to maintain a balance between productivity and ease of polymerization control. The temperature of the polymerization reaction is preferably -20 to 150°C, more preferably 0 to 120°C, and particularly preferably 20 to 100°C. The polymerization reaction is preferably carried out under a pressure sufficient to maintain the monomers substantially in a liquid phase. Such a pressure can be obtained by, for example, pressurizing the reactor with a gas inert to the polymerization reaction.

[0043] In the conjugated diene copolymer obtained by the above polymerization, the 1,2-vinyl bond content in the structural units derived from butadiene is preferably 5 to 70 mass%, more preferably 10 to 65 mass%, and particularly preferably 20 to 60 mass%. When the 1,2-vinyl bond content is 5 mass% or more, adhesion tends to be improved, and when it is 70 mass% or less, lithium ion conductivity and cycle life characteristics tend to be easily improved. The 1,2-vinyl bond content is 1 The values ​​were measured by H-NMR.

[0044] The conjugated diene copolymer before hydrogenation preferably has a random copolymerization portion of a structural unit derived from butadiene and a structural unit derived from an aromatic vinyl compound, which is advantageous in that it can improve the dispersibility of the active material and the solid electrolyte.

[0045] <Denaturation process> The modification step is a step of reacting the active terminal of the conjugated diene copolymer obtained by the polymerization step with a compound (hereinafter also referred to as "compound (C2)") that introduces a functional group that interacts with a current collector, a solid electrolyte, etc., at the polymerization terminal. This step allows the introduction of a functional group that interacts with a current collector, a solid electrolyte, etc., at the polymerization terminal of the conjugated diene copolymer. In this specification, the active terminal refers to the portion (more specifically, a carbon anion) that is present at the end of the molecular chain and is not derived from a monomer having a carbon-carbon double bond.

[0046] The conjugated diene copolymer used in this modification reaction (hereinafter also referred to as "terminal modification reaction") may have an unmodified or modified polymerization initiation terminal, as long as it has an active terminal. Compound (C2) is not particularly limited as long as it is a compound capable of reacting with the active terminal of the conjugated diene copolymer. However, it is preferred that the compound (C2) has one or more functional groups selected from the group consisting of an amino group, a group having a carbon-nitrogen double bond, a nitrogen-containing heterocyclic group, a phosphino group, an epoxy group, a thioepoxy group, a protected hydroxyl group, a protected thiol group, and a hydrocarbyloxysilyl group, and is capable of reacting with the active polymerization terminal. Specifically, at least one compound selected from the group consisting of compounds represented by the following general formula (5) and compounds represented by the following general formula (6) can be preferably used as compound (C2).

[0047] [ka] (In formula (5), A 1 has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, and R 5 R is a monovalent functional group bonded to R via a nitrogen atom, phosphorus atom, oxygen atom, sulfur atom, silicon atom, or a carbon atom contained in a carbonyl group, or is a (thio)epoxy group. 3 and R 4 is a hydrocarbyl group, and R 5 is a hydrocarbylene group, and r is an integer of 0 to 2. 3 or R 4 If there are multiple R 3 or R 4 may be the same or different.)

[0048] [ka] (In formula (6), A 2 has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, does not have active hydrogen, and R9 is a monovalent functional group bonded to R via a nitrogen atom, phosphorus atom, oxygen atom, sulfur atom, or silicon atom. 6 and R 7 are each independently a hydrocarbyl group, and R 8 and R 9 are each independently a hydrocarbylene group, and m is 0 or 1. 7 If there are multiple R 7 may be the same or different.)

[0049] In the above formulas (5) and (6), R 3 , R 4 , R 6 and R 7 The hydrocarbyl group in R is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. 5 , R 8 and R 9 The hydrocarbylene group is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms. r and m are preferably 0 or 1 because this increases the reactivity with the active terminal.

[0050] A 1 When A is the monovalent functional group, 1 At least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur and silicon contained in A is preferably not bonded to an active hydrogen but is protected by a protecting group (for example, a tri-substituted hydrocarbylsilyl group). 2 At least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur and silicon contained in A is preferably not bonded to active hydrogen but is protected by a protecting group (for example, a tri-substituted hydrocarbylsilyl group, etc.). In this specification, "active hydrogen" refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably refers to one having a bond energy lower than that of the carbon-hydrogen bond of polymethylene. The protecting group is a group selected from the group consisting of A, ... 1 , A2 The (thio)epoxy group is a functional group that converts the (thio)epoxy group into an inactive functional group at the polymerization active terminal.

[0051] A 1 may be a group that can be converted into an onium ion by an onium salt generating agent. 1 ) can provide excellent adhesion to the conjugated diene copolymer. 1 Specific examples include a nitrogen-containing group in which two hydrogen atoms of a primary amino group are substituted with two protecting groups, a nitrogen-containing group in which one hydrogen atom of a secondary amino group is substituted with one protecting group, a tertiary amino group, an imino group, a pyridyl group, a phosphorus-containing group in which two hydrogen atoms of a primary phosphino group are substituted with two protecting groups, a phosphorus-containing group in which one hydrogen atom of a secondary phosphino group is substituted with one protecting group, a tertiary phosphino group, an epoxy group, a group in which the hydrogen atom of a hydroxyl group is protected with a protecting group, a thioepoxy group, a sulfur-containing group in which the hydrogen atom of a thiol group is substituted with a protecting group, a hydrocarbyloxycarbonyl group, etc. Among these, a group having a nitrogen atom is preferred because of its good affinity with solid electrolytes and active materials, and a tertiary amino group or a nitrogen-containing group in which two hydrogen atoms of a primary amino group are substituted with two protecting groups is more preferred.

[0052] Preferred specific examples of compound (C2) include dibutyldichlorosilicon, methyltrichlorosilicon, dimethyldichlorosilicon, tetrachlorosilicon, triethoxymethylsilane, triphenoxymethylsilane, trimethoxysilane, methyltriethoxysilane, the compound represented by the above general formula (5), and the compound represented by the above general formula (6). Examples of the compound represented by the general formula (5) include N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N-trimethylsilyl-N-methylaminopropylmethyldiethoxysilane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of the compound represented by the general formula (6) include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1,2-azasilolidine, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl-1,2-azasilolidine, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, etc. Compound (C2) can be used either alone or in combination of two or more.

[0053] In addition to the compound (C2), germane compounds, stannane compounds, and the like can also be suitably used in the modification step. By using these compounds, germanium atoms and tin atoms can be introduced into the polymer (A). In this specification, the group consisting of the compound (R), the compound (C2), the germane compounds, and the stannane compounds is also referred to as a "modifier."

[0054] Examples of the germane compounds include alkoxy germane compounds such as monoalkoxy germane compounds, dialkoxy germane compounds, trialkoxy germane compounds, and tetraalkoxy germane compounds; halogenated triorgano germane compounds, dihalogenated diorgano germane compounds, trihalogenated organo germane compounds, and tetrahalogenated germane compounds.Furthermore, examples of the germane compounds include compounds similar to those exemplified as the silane compounds, but having a germanium atom instead of a silicon atom.

[0055] Examples of the stannane compound include alkoxystannane compounds such as monoalkoxystannane compounds, dialkoxystannane compounds, trialkoxystannane compounds, and tetraalkoxystannane compounds; halogenated triorganostannane compounds, dihalogenated diorganostannane compounds, trihalogenated organostannane compounds, and tetrahalogenated stannane compounds.Further, examples of the stannane compound include the same compounds as those exemplified as the silane compound, and compounds having a tin atom instead of a silicon atom.

[0056] Specific examples of these stannane compounds include tetrachlorotin, tetrabromotin, trichlorobutyltin, trichloromethyltin, trichlorooctyltin, dibromodimethyltin, dichlorodimethyltin, dichlorodibutyltin, dichlorodioctyltin, 1,2-bis(trichlorostannyl)ethane, 1,2-bis(methyldichlorostannyl)ethane, 1,4-bis(trichlorostannyl)butane, 1,4-bis(methyldichlorostannyl)butane, ethyltin tristearate, butyltin trisoctanoate, butyltin tristearate, butyltin trislaurate, dibutyltin bisoctanoate, dibutyltin bisstearate, dibutyltin bislaurate, etc. Among these, tetrachlorotin (SnCl4) is particularly preferred.

[0057] The terminal modification reaction can be carried out, for example, as a solution reaction. This solution reaction may be carried out using a solution containing unreacted monomers after the polymerization reaction in the polymerization step. Alternatively, the conjugated diene copolymer contained in the solution may be isolated and dissolved in a suitable solvent such as cyclohexane before the reaction. The terminal modification reaction may be carried out either batchwise or continuously. In this case, the method of adding the compound (C2), the germane compound, or the stannane compound is not particularly limited, and examples thereof include a method of adding them all at once, a method of adding them in portions, and a method of adding them continuously.

[0058] The amount of compound (C2), germane compound, or stannane compound used in the terminal modification reaction may be appropriately determined depending on the type of compound used in the reaction, but is preferably 0.1 molar equivalents or more, more preferably 0.3 molar equivalents or more, relative to the metal atoms involved in the polymerization reaction in the polymerization initiator. By using an amount of 0.1 molar equivalents or more, the modification reaction can be sufficiently promoted and the dispersion stability of the slurry can be suitably improved.

[0059] The temperature of the terminal modification reaction is usually the same as the temperature of the polymerization reaction, and is preferably -20 to 150°C, more preferably 0 to 120°C, and particularly preferably 20 to 100°C. If the temperature of the modification reaction is low, the viscosity of the modified conjugated diene copolymer tends to increase. On the other hand, if the temperature of the modification reaction is high, the active polymerization terminals are likely to be deactivated. The reaction time of the modification reaction is preferably 1 minute to 5 hours, and more preferably 2 minutes to 1 hour.

[0060] As described above, the polymer (A) preferably has units based on a modifier containing at least one atom selected from the group consisting of nitrogen atoms, oxygen atoms, silicon atoms, germanium atoms, and tin atoms.

[0061] <Hydrogenation reaction> The polymer (A) may be a product obtained by hydrogenating the modified or unmodified conjugated diene copolymer obtained above. Any method and conditions for the hydrogenation reaction can be used as long as a conjugated diene copolymer with the desired hydrogenation rate is obtained. Examples of such hydrogenation methods include a method using a catalyst containing an organometallic compound of titanium as the main component as a hydrogenation catalyst; a method using a catalyst composed of an organic compound of iron, nickel, or cobalt and an organometallic compound such as an alkylaluminum; a method using an organic complex of an organometallic compound such as ruthenium or rhodium; and a method using a catalyst in which a metal such as palladium, platinum, ruthenium, cobalt, or nickel is supported on a support such as carbon, silica, or alumina. Among the various methods, a method in which hydrogenation is carried out under mild conditions of low pressure and low temperature using a homogeneous catalyst comprising a titanium organometallic compound alone or a titanium organometallic compound together with an organometallic compound of lithium, magnesium, or aluminum (JP-B Nos. 63-4841, 1-37970, and 2000-37632) is industrially preferred, and also has high hydrogenation selectivity to the double bond of butadiene, making it suitable for the object of the present invention.

[0062] The hydrogenation reaction of the modified conjugated diene copolymer is carried out in a solvent that is inert to the catalyst and that the conjugated diene copolymer is soluble in. Preferred solvents include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane, alicyclic hydrocarbons such as cyclohexane and cycloheptane, aromatic hydrocarbons such as benzene and toluene, and ethers such as diethyl ether and tetrahydrofuran, either alone or as a mixture containing these as the main components.

[0063] The hydrogenation reaction is generally carried out by maintaining the conjugated diene copolymer at a predetermined temperature in a hydrogen or inert atmosphere, adding a hydrogenation catalyst with or without stirring, and then introducing hydrogen gas to pressurize to a predetermined pressure. An inert atmosphere refers to an atmosphere that does not react with the participants in the hydrogenation reaction, and examples include helium, neon, and argon. Air and oxygen are undesirable because they oxidize the catalyst and cause catalyst deactivation. Nitrogen is also undesirable because it acts as a catalyst poison during the hydrogenation reaction and reduces hydrogenation activity. In particular, it is most suitable for the hydrogenation reactor to have an atmosphere of hydrogen gas alone.

[0064] The hydrogenation reaction process for obtaining a hydrogenated conjugated diene copolymer can be a batch process, a continuous process, or a combination thereof. When a titanocene diaryl compound is used as the hydrogenation catalyst, it may be added to the reaction solution either directly or as a solution in an inert organic solvent. When the catalyst is used as a solution, various solvents that do not react with the participants in the hydrogenation reaction can be used as the inert organic solvent. The solvent is preferably the same as the solvent used in the hydrogenation reaction. The amount of catalyst added is 0.02 to 20 mmol per 100 g of the conjugated diene copolymer before hydrogenation.

[0065] In addition, when the constituent ratios (molar ratios) of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) in the polymer (A) are p, q, r, and s, respectively, the value α represented by the following formula (i) is preferably less than 0.9. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ···(i) [ka] By setting α to less than 0.9, it is possible to achieve excellent dispersion stability of the slurry and flexibility of the electrode, as well as high lithium ion conductivity and good cycle life characteristics. For these reasons, α is preferably less than 0.9, more preferably less than 0.8, and particularly preferably less than 0.7. Note that α in the above formula (i) corresponds to the hydrogenation rate of the conjugated diene copolymer. For example, when α is 0.6, the hydrogenation rate of the conjugated diene copolymer is 60%. α may also be 0. The hydrogenation rate in the conjugated diene copolymer can be adjusted by the hydrogenation reaction time, the amount of hydrogen supplied, etc. This hydrogenation rate is 1 It can be measured by H-NMR.

[0066] After the modification step or hydrogenation step, an antioxidant (B) may be added. Addition of the antioxidant (B) can prevent gelation and deterioration of the polymer (A) due to heat, light, and oxidation during the desolvation step by steam stripping or the drying step using a heated roll, which are carried out after the synthesis of the polymer (A), and during subsequent long-term storage in a bale state.

[0067] Examples of the antioxidant include those described in the section "1.2. Antiaging Agent (B)" below.

[0068] The anti-aging agent (B) can be added in a solid state, a molten state, or a solution state in which it is dissolved in a solvent that dissolves the anti-aging agent (B). When the anti-aging agent (B) is added, the polymer (A) may be in either a solid state or a solution state, but is preferably in a solution state from the viewpoint of dispersibility of the anti-aging agent (B).

[0069] When the polymer (A) contains an antioxidant, the lower limit of the content of the antioxidant is preferably 0.05 parts by mass, more preferably 0.1 parts by mass, and particularly preferably 0.2 parts by mass, relative to 100 parts by mass of the polymer (A), and the upper limit of the content of the antioxidant is preferably 2 parts by mass, more preferably 1.5 parts by mass, and particularly preferably 1.2 parts by mass.

[0070] A suitable method for obtaining polymer (A) is to solution polymerize a butadiene-containing monomer in the presence of an alkali metal compound, and then use the resulting polymer solution as is to carry out the modification step, which is industrially useful. The polymer (A) is If necessary, the resulting solution may be subjected to a hydrogenation step. In these cases, the polymer (A) is obtained by removing the solvent from the solution obtained above and isolating the polymer (A). The polymer (A) can be isolated by a known solvent removal method such as steam stripping or by a drying procedure such as heat treatment.

[0071] In order to improve the dispersion stability of the slurry and the adhesion of the electrode, the polymer (A) preferably has one or more functional groups selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, a phosphino group, a hydroxyl group, a thiol group, and a hydrocarbyloxysilyl group, and more preferably has one or more functional groups selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, and a hydrocarbyloxysilyl group. It is particularly preferred that these functional groups are introduced into the terminals of the polymer (A).

[0072] 1.1.2. Physical properties of polymer (A) <Bound styrene content> The bound styrene content of the polymer (A) is preferably 5 to 40%, more preferably 8 to 30%, and particularly preferably 10 to 27%. When the bound styrene content of the polymer (A) is within the above range, both adhesion and flexibility of the electrode can be achieved. The bound styrene content is 1 It can be measured by H-NMR measurement.

[0073] <Weight average molecular weight> The weight average molecular weight (Mw) of the polymer (A) is preferably 1.0×10 5 ~2.0×10 6 and more preferably 1.0 × 10 5 ~1.5×10 6 and particularly preferably 1.5 × 10 5 ~1.0×106 When the weight-average molecular weight (Mw) is equal to or greater than the lower limit, the adhesion of the electrode tends to be improved. When the weight-average molecular weight (Mw) is equal to or less than the upper limit, the flexibility of the electrode tends to be maintained. In this specification, the "weight-average molecular weight (Mw)" refers to the weight-average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0074] <Solubility> The polymer (A) is preferably in a state of being dissolved in the liquid medium (C) described below. The phrase "the polymer (A) dissolves in the liquid medium (C)" means that the solubility of the polymer (A) in the liquid medium (C) is 1 g or more per 100 g of the liquid medium (C). The polymer (A) being dissolved in the liquid medium (C) facilitates coating of the surface of the active material with the polymer (A), which has excellent flexibility and adhesiveness. This effectively prevents the active material from falling off due to expansion and contraction during charge and discharge, facilitating the production of an all-solid-state secondary battery exhibiting good charge and discharge durability. This is also preferred because it improves the stability of the slurry and improves the applicability of the slurry to the current collector.

[0075] 1.2. Antioxidant (B) The binder composition for an all-solid-state secondary battery according to this embodiment contains an antioxidant (B) in an amount of 200 ppm to 5,000 ppm based on the total mass of the binder composition. By containing the antioxidant (B) within this concentration range, deterioration of the polymer (A) in the binder composition can be suppressed.

[0076] When using polymer (A) as a binder for all-solid-state secondary batteries, it is typically dissolved. However, because the antioxidant contained in polymer (A) is consumed by heating during the solution process and its concentration is diluted during solution formation, it is necessary to control the antioxidant concentration. Without concentration control, microgels may form during storage of the polymer (A) solution, resulting in the formation of protrusions and craters in the coating film of the slurry containing polymer (A). Furthermore, if the antioxidant is not added at a concentration above the minimum limit, the slurry stability will be poor, and polymer (A) will deteriorate during drying of the electrode plate and during battery charge / discharge, resulting in poor battery performance. In particular, the binder for the anode and solid electrolyte layer must adapt to the volume changes (expansion / contraction) of the anode active material during charge / discharge. Poor adaptability will prevent the lithium ion conduction path from being maintained, resulting in reduced lithium ion conductivity and increased resistance.

[0077] On the other hand, adding an antioxidant within the above concentration range suppresses deterioration of the polymer (A), thereby improving the storage stability of the polymer solution or slurry and further improving the characteristics of the electricity storage device. Furthermore, adding an antioxidant within the above concentration range also suppresses bleeding out of the antioxidant (B) after coating the slurry due to the interaction between the polymer (A) and the antioxidant (B). As a result, it is possible to suppress the reaction of the antioxidant (B) with the solid electrolyte, which would otherwise cause deterioration in battery performance.

[0078] Examples of the antioxidant (B) include phenol-based antioxidants, amine-based antioxidants, quinone-based antioxidants, organophosphorus-based antioxidants, sulfur-based antioxidants, phenothiazine-based antioxidants, etc. Among these, at least one selected from the group consisting of phenol-based antioxidants and amine-based antioxidants is preferred.

[0079] Examples of phenolic antioxidants include p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, phenol, hydroquinone, p-cresol, butylhydroxyanisole, propyl gallate, chlorogenic acid, catechin, caffeic acid, genkwanin, luteolin, tocopherol, catechol, resorcinol, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, pyrogallol, 4,4'-butylidenebis(6-tert-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(6-tert-butyl-4-ethyl phenol), 4,4'-thiobis(6-tert-butyl-m-cresol), 2,5-di-tert-amylhydroquinone, styrenated phenol, 2,5-di-tert-butylhydroquinone, 2-methyl-4,6-bis[(n-octylthio)methyl]phenol, 2,4-bis(dodecylthiomethyl)-6-methylphenol, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and the like.

[0080] Examples of amine-based antiaging agents include aromatic amines such as 1-naphthylamine, 2-naphthylamine, phenylenediamine, 4,4'-diaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, N-isopropyl-N'-phenylbenzene-1,4-diamine, N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline. Other suitable amine-based antiaging agents include light stabilizers (HALS), hindered amine compounds, and nitroxyl radicals (2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)).

[0081] Examples of phosphorus-based antioxidants include phosphite compounds, and examples of sulfur-based antioxidants include thiol compounds and sulfide compounds such as pentaerythrityl tetrakis(3-laurylthiopropionate).

[0082] The lower limit of the concentration of the antioxidant (B) is 200 ppm, preferably 300 ppm, and more preferably 400 ppm, relative to the total mass of the binder composition for an all-solid-state secondary battery. The upper limit of the concentration of the antioxidant (B) is 5,000 ppm, preferably 4,500 ppm, and more preferably 4,200 ppm, relative to the total mass of the binder composition for an all-solid-state secondary battery. Adding the antioxidant (B) within the above concentration range suppresses deterioration of the polymer (A), thereby improving the storage stability of the polymer solution or slurry and further improving the characteristics of the power storage device. Furthermore, the interaction between the polymer (A) and the antioxidant (B) can also suppress bleeding out of the antioxidant (B) after coating the slurry. As a result, deterioration of battery performance due to reaction of the antioxidant (B) with the solid electrolyte can be suppressed.

[0083] The lower limit of the content of the antioxidant (B) is preferably 2,000 ppm, more preferably 3,000 ppm, and particularly preferably 4,000 ppm, per 100 parts by mass of the polymer (A). The upper limit of the content of the antioxidant (B) is preferably 50,000 ppm, more preferably 45,000 ppm, and particularly preferably 42,000 ppm, per 100 parts by mass of the polymer (A). By keeping the content of the antioxidant (B) within the above range, deterioration of the polymer (A) is suppressed, thereby improving the storage stability of the polymer solution or slurry and further improving the characteristics of the electricity storage device. Furthermore, the interaction between the polymer (A) and the antioxidant (B) can also suppress bleeding out of the antioxidant (B) after coating the slurry. As a result, deterioration of battery performance due to reaction of the antioxidant (B) with the solid electrolyte can be suppressed.

[0084] 1.3. Liquid Medium (C) The liquid medium (C) is not particularly limited, but examples thereof include aliphatic hydrocarbons such as hexane, heptane, octane, decane, and dodecane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, and cyclodecane; aromatic hydrocarbons such as toluene, xylene, mesitylene, naphthalene, and tetralin; ketones such as 3-pentanone, 4-heptanone, methylhexyl ketone, and diisobutyl ketone; esters such as butyl acetate, butyl butyrate, methyl butanoate, butyl pentanoate, butyl hexanoate, pentyl butyrate, pentyl pentanoate, pentyl hexanoate, hexyl butyrate, hexyl pentanoate, and hexyl hexanoate; and ethers such as dibutyl ether, tetrahydrofuran, and anisole. These solvents can be used alone or in combination of two or more.

[0085] The content of the liquid medium (C) is preferably 100 to 10,000 parts by mass, more preferably 150 to 5,000 parts by mass, still more preferably 200 to 4,000 parts by mass, and particularly preferably 300 to 3,000 parts by mass, relative to 100 parts by mass of the polymer (A). By setting the content of the liquid medium (C) within the above range, it is possible to improve the workability when using the binder composition for an all-solid-state secondary battery and the slurry for an all-solid-state secondary battery obtained therefrom.

[0086] 1.4. Other additives The binder composition for an all-solid-state secondary battery according to this embodiment may contain additives such as a thickener, if necessary.

[0087] <Thickener> The binder composition for an all-solid-state secondary battery according to this embodiment By including a thickener, Obtained slurry for all-solid-state secondary battery In some cases, the coating properties of the resulting all-solid-state secondary battery and the charge-discharge characteristics of the resulting all-solid-state secondary battery can be further improved.

[0088] Examples of thickeners include cellulose-based polymers such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, and hydroxypropyl cellulose; poly(meth)acrylic acid; ammonium salts or alkali metal salts of the above-mentioned cellulose compounds or poly(meth)acrylic acid; modified polyvinyl alcohol, polyethylene oxide; polyvinylpyrrolidone, polycarboxylic acid, oxidized starch, starch phosphate, casein, various modified starches, chitin, and chitosan derivatives. Among these, cellulose-based polymers are preferred.

[0089] When the binder composition for an all-solid-state secondary battery according to this embodiment contains a thickener, the content of the thickener is preferably 5 parts by mass or less, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the total solid content of the binder composition for an all-solid-state secondary battery.

[0090] 1.5. Method for preparing binder composition for all-solid-state secondary battery The binder composition for an all-solid-state secondary battery according to this embodiment can be prepared by a process of adding an antioxidant (B) and a liquid medium (C) to a polymer (A), further adding other additives as necessary, and appropriately stirring the mixture to dissolve the polymer (A) and the antioxidant (B) in the liquid medium (C).

[0091] The binder composition for an all-solid-state secondary battery according to the present embodiment can form a binder having high adhesion not only to the current collector of the electrode but also to the solid electrolyte material, and can improve the conductivity of the solid electrolyte layer while reducing the amount used, and therefore can be suitably used for all-solid-state batteries.

[0092] The method for preparing the binder composition for an all-solid-state secondary battery according to this embodiment may include a step of removing particulate metal components from the binder composition (hereinafter also referred to as a "particulate metal removing step"). In the particulate metal removing step, the "particulate metal components" refer to those present in particulate form in the binder composition, and do not include those present in the dissolved state of metal ions.

[0093] In the particulate metal removal step, the method for removing particulate metal components from the binder composition for an all-solid-state secondary battery is not particularly limited, and examples thereof include a method of removing by filtration using a filter, a method of removing by a vibrating sieve, a method of removing by centrifugation, a method of removing by magnetic force, etc. Among these, the method of removing by magnetic force is preferred because the target to be removed is a metal component.

[0094] The method of removing the metal components by magnetic force is not particularly limited as long as it is a method that can remove the metal components. However, in consideration of productivity and removal efficiency, a method of removing the metal components by passing a polymer solution through a magnetic filter disposed in a production line of the binder composition for an all-solid-state secondary battery is preferred.

[0095] The process of removing particulate metal components from a polymer solution using a magnetic filter is carried out using a magnetic flux density of 100 gauss or more. degree This is preferably done by passing the material through a magnetic filter that generates a magnetic field. Since a low magnetic flux density reduces the efficiency of removing metal components, the magnetic flux density is preferably 1000 gauss or more, more preferably 2000 gauss or more in consideration of removing stainless steel, which has weak magnetic properties, and most preferably 5000 gauss or more.

[0096] When a magnetic filter is installed in a production line, it is preferable to include a process for removing coarse foreign matter or metal particles using a filter such as a cartridge filter upstream of the magnetic filter, since coarse metal particles may pass through the magnetic filter depending on the filtration flow rate.

[0097] Although the magnetic filter is effective even if it is used for a single filtration, it is more preferable to use a circulating type filter, since this improves the efficiency of removing metal particles.

[0098] When a magnetic filter is placed in a production line for the binder composition for an all-solid-state secondary battery, the location of the magnetic filter is not particularly limited, but it is preferably placed immediately before filling the binder composition for an all-solid-state secondary battery into a container, or before the filter if a filtration step using a filtration filter is performed before filling the binder composition into a container. This is to prevent metal components from being mixed into the product if they are desorbed from the magnetic filter.

[0099] Specific examples of particulate metal components include metals such as Fe, Ni, and Cr, or compounds of these metals. The above-mentioned particulate metal components may remain in the binder composition for an all-solid-state secondary battery according to this embodiment. However, it is preferable to remove the particulate metal components so that the content of particulate metal components having a particle size of 20 μm or more is 10 ppm or less by a particulate metal removal step. The content of particulate metal components having a particle size of 20 μm or more can be determined by filtering the obtained binder composition for an all-solid-state secondary battery through a mesh with an opening equivalent to 20 μm, performing elemental analysis of the elements of the meshed metal particles using an X-ray microanalyzer (EPMA), and then dissolving the metal in an acid capable of dissolving the metal, and measuring the content using ICP (Inductively Coupled Plasma).

[0100] 2. Slurry for all-solid-state secondary batteries The slurry for an all-solid-state secondary battery according to this embodiment contains the binder composition for an all-solid-state secondary battery described above and a solid electrolyte. The slurry for an all-solid-state secondary battery according to this embodiment can be used as a material for forming either a positive electrode active material layer or a negative electrode active material layer, and can also be used as a material for forming a solid electrolyte layer.

[0101] The all-solid-state secondary battery slurry for forming the positive electrode active material layer contains the above-mentioned binder composition for the all-solid-state secondary battery, a solid electrolyte, and a positive electrode active material (hereinafter also simply referred to as "positive electrode active material"). The all-solid-state secondary battery slurry for forming the negative electrode active material layer contains the above-mentioned binder composition for the all-solid-state secondary battery, a solid electrolyte, and a negative electrode active material (hereinafter also simply referred to as "negative electrode active material"). The all-solid-state secondary battery slurry for forming the solid electrolyte layer contains the above-mentioned binder composition for the all-solid-state secondary battery and a solid electrolyte. Components that can be contained in the all-solid-state secondary battery slurry according to this embodiment will be described below.

[0102] 2.1.Active material <Cathode active material> Examples of the positive electrode active material include MnO2, MoO3, V2O5, and V6O 13 , Fe2O3, Fe3O4, Li (1-x) CoO2, Li (1-x) NiO2, Li x Co y Sn z O2, Li (1-x) Co (1-y) Ni y O2, Li (1+x) Ni 1 / 3 Co 1 / 3 Mn 1 / 3 Examples of usable positive electrode active materials include inorganic compounds such as O2, TiS2, TiS3, MoS3, FeS2, CuF2, and NiF2; carbon materials such as carbon fluoride, graphite, vapor-grown carbon fiber and / or its pulverized product, PAN-based carbon fiber and / or its pulverized product, and pitch-based carbon fiber and / or its pulverized product; and conductive polymers such as polyacetylene and poly-p-phenylene. These positive electrode active materials may be used alone or in combination of two or more.

[0103] The average particle size of the positive electrode active material is not particularly limited, but is preferably 0.1 μm to 50 μm because it can increase the contact area of ​​the solid-solid interface. To adjust the positive electrode active material to a predetermined average particle size, a grinder such as a mortar, ball mill, sand mill, vibration ball mill, satellite ball mill, or swirling airflow jet mill, or a classifier such as a sieve or wind classifier, may be used. During grinding, wet grinding may be performed in the presence of a solvent such as water or methanol, if necessary. Classification may be performed by either a dry or wet method. The positive electrode active material obtained by the calcination method may be used after washing with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

[0104] The average particle size of the active material refers to the volume-average particle size measured using a particle size distribution analyzer that employs laser diffraction as its measurement principle. Examples of such laser diffraction particle size distribution analyzers include the HORIBA LA-300 series and HORIBA LA-920 series (both manufactured by HORIBA, Ltd.).

[0105] In the slurry for an all-solid-state secondary battery for forming a positive electrode active material layer, the content of the positive electrode active material is preferably 20 to 90 parts by mass, and more preferably 40 to 80 parts by mass, when the total solid components are taken as 100 parts by mass.

[0106] <Negative electrode active material> The negative electrode active material is not particularly limited as long as it can reversibly absorb and release lithium ions, and examples thereof include carbonaceous materials, metal oxides such as tin oxide and silicon oxide, elemental lithium, lithium alloys such as lithium-aluminum alloys, and metals capable of forming alloys with lithium, such as Sn, Si, or In. Of these, carbonaceous materials are preferably used from the viewpoint of reliability, and silicon-containing materials are preferably used from the viewpoint of increasing battery capacity.

[0107] The carbonaceous material is not particularly limited as long as it is a material substantially composed of carbon, and examples thereof include petroleum pitch, natural graphite, artificial graphite such as vapor-grown graphite, and carbonaceous materials obtained by burning various synthetic resins such as PAN-based resins and furfuryl alcohol resins. Further examples include various carbon fibers such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA-based carbon fibers, lignin carbon fibers, glassy carbon fibers, and activated carbon fibers, as well as mesophase microspheres, graphite whiskers, and tabular graphite.

[0108] Silicon-containing materials can absorb more lithium ions than commonly used graphite and acetylene black. This increases the amount of lithium ions absorbed per unit weight, thereby increasing battery capacity. As a result, they offer the advantage of extending battery life, making their use in automotive batteries and other applications anticipated. However, silicon-containing materials are known to undergo large volumetric changes upon absorption and desorption of lithium ions. While graphite and acetylene black experience a volumetric expansion of approximately 1.2 to 1.5 times upon absorption of lithium ions, silicon-containing negative electrode active materials can experience a volumetric expansion of up to approximately 3 times. Repeated expansion and contraction (charge and discharge) can lead to insufficient durability of the negative electrode active material layer, resulting in poor contact and shortened cycle life (battery life). The negative electrode active material layer formed using the slurry for an all-solid-state secondary battery according to this embodiment exhibits high durability (strength) due to the binder component's ability to withstand repeated expansion and contraction, thereby achieving excellent cycle life characteristics even under high voltages.

[0109] The average particle size of the negative electrode active material is not particularly limited, but is preferably 0.1 μm to 60 μm in order to increase the contact area of ​​the solid-solid interface. In order to adjust the negative electrode active material to a predetermined average particle size, the above-mentioned pulverizers and classifiers can be used.

[0110] In the slurry for an all-solid-state secondary battery for forming the negative electrode active material layer, the content of the negative electrode active material is preferably 20 to 90 parts by mass, and more preferably 40 to 80 parts by mass, when the total solid components are taken as 100 parts by mass.

[0111] 2.2.Solid electrolyte The slurry for an all-solid-state secondary battery according to this embodiment contains a solid electrolyte. The solid electrolyte may be appropriately selected from solid electrolytes generally used in all-solid-state secondary batteries, but is preferably a sulfide-based solid electrolyte or an oxide-based solid electrolyte.

[0112] The lower limit of the average particle size of the solid electrolyte is preferably 0.01 μm, more preferably 0.1 μm, and the upper limit of the average particle size of the solid electrolyte is preferably 100 μm, more preferably 50 μm.

[0113] In the slurry for an all-solid-state secondary battery according to this embodiment, the lower limit of the solid electrolyte content is preferably 50 parts by mass, more preferably 70 parts by mass, and particularly preferably 90 parts by mass, per 100 parts by mass of the total solid components, because this allows both battery performance and the effect of reducing and maintaining interfacial resistance to be achieved. Due to the same effect, the upper limit of the solid electrolyte content is preferably 99.9 parts by mass, more preferably 99.5 parts by mass, and particularly preferably 99.0 parts by mass, per 100 parts by mass of the total solid components. However, when used together with the positive electrode active material or the negative electrode active material, it is preferable that the total concentration thereof be within the above-mentioned concentration range.

[0114] <Sulfide solid electrolyte> The sulfide-based solid electrolyte preferably contains a sulfur atom (S) and a metal element of Group 1 or 2 of the periodic table, and has ionic conductivity and electronic insulation. Examples of such sulfide-based solid electrolytes include sulfide-based solid electrolytes having a composition formula represented by the following general formula (7): Li a M b P cS d ·····(7) (In formula (7), M represents an element selected from B, Zn, Si, Cu, Ga, and Ge. a to d represent the composition ratio of each element, and a:b:c:d=1-12:0-1:1:2-9 is satisfied.)

[0115] In the general formula (7), the composition ratio of Li, M, P, and S is preferably b=0. More preferably, b=0 and a:c:d=1-9:1:3-7. Even more preferably, b=0 and a:c:d=1.5-4:1:3.25-4.5. The composition ratio of each element can be controlled by adjusting the blending amounts of raw material compounds when producing a sulfide-based solid electrolyte, as described below.

[0116] The sulfide-based solid electrolyte may be amorphous (glass), crystalline (glass ceramic), or only partially crystallized.

[0117] In the Li-PS-based glass and Li-PS-based glass ceramics, the ratio of Li2S to P2S5 is preferably 65:35 to 85:15, more preferably 68:32 to 80:20, in terms of the molar ratio of Li2S:P2S5. By setting the ratio of Li2S to P2S5 within this range, the lithium ion conductivity can be increased. The lithium ion conductivity of the sulfide-based solid electrolyte is 1×10 -4 S / cm or more is preferable, and 1×10 -3 S / cm or more is more preferable.

[0118] Such compounds include, for example, those obtained using a raw material composition containing Li2S and sulfides of elements of groups 13 to 15. Specific examples include Li2S-P2S5, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-LiI, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li 10 GeP2S 12 Among these, crystalline and / or amorphous raw material compositions consisting of Li2S-P2S5, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-SiS2-P2S5, Li2S-SiS2-Li4SiO4, and Li2S-SiS2-Li3PO4 are preferred because they have high lithium ion conductivity.

[0119] Examples of methods for synthesizing a sulfide-based solid electrolyte using such a raw material composition include an amorphization method. Examples of amorphization methods include a mechanical milling method and a melt quenching method. Among these, the mechanical milling method is preferred because it allows processing at room temperature and simplifies the manufacturing process.

[0120] The sulfide-based solid electrolyte can be synthesized with reference to literature such as T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp. 231-235 or A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp. 872-873.

[0121] <Oxide solid electrolyte> The oxide-based solid electrolyte preferably contains oxygen atoms (O) and a metal element of Group 1 or 2 of the periodic table, and has ionic conductivity and electronic insulation. Examples of such oxide-based solid electrolytes include Li xa La ya TiO3 [xa=0.3~0.7, ya=0.3~0.7] (LLT), Li7La3Zr2O 12 (LLZ), LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4, LiTi2P3O with NASICON (sodium super ionic conductor) type crystal structure 12 , Li (1+xb+yb) (Al,Ga) xb (Ti,Ge) (2-xb) Si yb P (3-yb) O 12 (where 0≦xb≦1, 0≦yb≦1), Li7La3Zr2O with a garnet-type crystal structure 12 Examples include:

[0122] Also preferred as oxide-based solid electrolytes are phosphorus compounds containing Li, P, and O. Examples include lithium phosphate (Li3PO4), LiPON, in which some of the oxygen atoms in lithium phosphate have been replaced with nitrogen atoms, and LiPOD (where D represents at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au). Also preferred are LiAON (where A represents at least one selected from Si, B, Ge, Al, C, and Ga).

[0123] Among these, Li (1+xb+yb) (Al,Ga) xb (Ti,Ge) (2-xb) Si yb P (3-yb) O 12(where 0≦xb≦1, 0≦yb≦1) are preferred because they have high lithium ion conductivity, are chemically stable, and are easy to handle. These may be used alone or in combination of two or more.

[0124] The lithium ion conductivity of oxide-based solid electrolytes is 1×10 -6 S / cm or more is preferable, and 1×10 -5 S / cm or more is more preferable, 5×10 -5 S / cm or more is particularly preferred.

[0125] 2.3. Other additives The slurry for an all-solid-state secondary battery according to this embodiment may contain other additives as needed in addition to the above-mentioned components, such as a conductivity imparting agent, a thickener, a liquid medium (excluding the amount carried over from the binder composition for an all-solid-state secondary battery), etc.

[0126] <Conductivity imparting agent> The conductivity-imparting agent has the effect of improving the conductivity of electrons and is therefore added to the slurry for an all-solid-state secondary battery for forming a positive electrode active material layer or a negative electrode active material layer. Specific examples of the conductivity-imparting agent include activated carbon, acetylene black, ketjen black, furnace black, graphite, carbon fiber, fullerene, and other carbons. Among these, acetylene black and furnace black are preferred. When the slurry for an all-solid-state secondary battery according to this embodiment contains the conductivity-imparting agent, the content of the conductivity-imparting agent is preferably 20 parts by mass or less, more preferably 1 to 15 parts by mass, and particularly preferably 2 to 10 parts by mass, relative to 100 parts by mass of the active material.

[0127] <Thickener> Specific examples of the thickener include the thickeners exemplified in the section <Thickener> of "1.4. Other Additives" above. When the slurry for an all-solid-state secondary battery according to this embodiment contains a thickener, the content of the thickener is preferably 5 parts by mass or less, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the total solid content of the slurry for an all-solid-state secondary battery.

[0128] <Liquid medium> Specific examples of the liquid medium include the same liquid medium as the liquid medium (C) exemplified in the above section "1.3. Liquid medium (C)." When a liquid medium is added to the slurry for an all-solid-state secondary battery according to this embodiment, the liquid medium may be the same as the liquid medium (C) contained in the binder composition for an all-solid-state secondary battery, or a different liquid medium may be added, but it is preferable to add the same liquid medium. The content ratio of the liquid medium in the slurry for an all-solid-state secondary battery according to this embodiment can be adjusted to any ratio in order to improve the coatability and to suppress the concentration gradient of the polymer (A) and the active material during the drying treatment after coating.

[0129] 2.4. Method for preparing slurry for all-solid-state secondary batteries The slurry for an all-solid-state secondary battery according to this embodiment may be produced by any method as long as it contains the above-mentioned binder composition for an all-solid-state secondary battery and a solid electrolyte.

[0130] However, in order to produce a slurry having better dispersibility and stability more efficiently and inexpensively, it is preferable to produce the slurry by adding the solid electrolyte and optional additive components used as needed to the binder composition for an all-solid-state secondary battery described above and mixing them. Mixing the binder composition for an all-solid-state secondary battery with other components can be carried out by stirring using a known method.

[0131] The mixing and stirring means for producing a slurry for an all-solid-state secondary battery must be a mixer that can stir the solid electrolyte particles to an extent that no agglomerates remain in the slurry, and must provide the necessary and sufficient dispersion conditions. The degree of dispersion can be measured using a particle gauge, but it is preferable to mix and disperse the particles so that no agglomerates larger than 100 μm remain. Examples of mixers that meet these conditions include ball mills, bead mills, sand mills, defoamers, pigment dispersers, crushers, ultrasonic dispersers, homogenizers, planetary mixers, and Hobart mixers.

[0132] It is preferable that at least a part of the preparation of the slurry for the all-solid-state secondary battery (mixing operation of each component) is carried out under reduced pressure. This can prevent the formation of bubbles in the obtained positive electrode active material layer, negative electrode active material layer, or solid electrolyte layer. The degree of reduced pressure is 5.0 × 10 absolute pressure. 3 ~5.0×10 5 It is preferable to set the pressure to about Pa.

[0133] 3.Solid electrolyte sheet The solid electrolyte sheet according to this embodiment has a layer formed by applying the above-mentioned slurry for an all-solid-state secondary battery onto a substrate and drying it.

[0134] The solid electrolyte sheet according to this embodiment can be produced by applying the slurry for an all-solid-state secondary battery described above onto a substrate film by a blade method (e.g., a doctor blade method), a calendar method, a spin coating method, a dip coating method, an inkjet method, an offset method, a die coating method, a spray method, or the like, drying the applied layer, and then peeling off the film. As such a film, a common film such as a release-treated PET film can be used.

[0135] Alternatively, a solid electrolyte sheet can be formed by directly applying a slurry for an all-solid-state secondary battery containing a solid electrolyte to the surface of a green sheet to be laminated with the solid electrolyte sheet or other constituent member of the all-solid-state secondary battery, followed by drying.

[0136] The solid electrolyte sheet according to this embodiment is preferably coated with the above-described slurry for an all-solid-state secondary battery so that the layer thickness is preferably in the range of 1 to 500 μm, more preferably 1 to 100 μm. When the layer thickness is within this range, conductive ions such as lithium ions can easily move, thereby increasing the battery output. Furthermore, when the layer thickness is within this range, the entire battery can be made thinner, thereby increasing the capacity per unit volume.

[0137] The drying of the slurry for an all-solid-state secondary battery is not particularly limited, and any means can be used, such as heat drying, reduced-pressure drying, heat-reduced-pressure drying, etc. The drying atmosphere is not particularly limited, and can be, for example, air atmosphere.

[0138] When the solid electrolyte sheet contains a positive electrode active material and a solid electrolyte, the solid electrolyte sheet functions as a positive electrode active material layer. When the solid electrolyte sheet contains a negative electrode active material and a solid electrolyte, the solid electrolyte sheet functions as a negative electrode active material layer. When the solid electrolyte sheet does not contain a positive electrode active material or a negative electrode active material but contains a solid electrolyte, the solid electrolyte sheet functions as a solid electrolyte layer.

[0139] 4. Electrodes for all-solid-state secondary batteries and all-solid-state secondary batteries The electrode for an all-solid-state secondary battery according to this embodiment comprises a current collector and an active material layer formed by applying and drying the above-described all-solid-state secondary battery slurry on the surface of the current collector. Such an electrode for an all-solid-state secondary battery can be produced by applying the above-described all-solid-state secondary battery slurry to the surface of a current collector such as a metal foil to form a coating film, and then drying the coating film to form an active material layer. The electrode for an all-solid-state secondary battery produced in this manner comprises an active material layer bound to the current collector, the active material layer containing the above-described polymer (A), antioxidant (B), solid electrolyte, and active material, and further optional components added as necessary, and therefore exhibits excellent flexibility, abrasion resistance, and powder-fall resistance, as well as good charge / discharge durability.

[0140] The positive and negative electrode current collectors are preferably made of an electron conductor that does not undergo chemical change. The positive electrode current collector is preferably made of aluminum, stainless steel, nickel, titanium, or an alloy thereof, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, or silver, with aluminum and aluminum alloys being more preferred. The negative electrode current collector is preferably made of aluminum, copper, stainless steel, nickel, titanium, or an alloy thereof, with aluminum, copper, or a copper alloy being more preferred.

[0141] The current collector is usually in the form of a film sheet, but nets, punched materials, laths, porous materials, foams, and molded fibers can also be used. The thickness of the current collector is not particularly limited, but is preferably 1 μm to 500 μm. It is also preferable to roughen the surface of the current collector by surface treatment.

[0142] The slurry for an all-solid-state secondary battery can be applied to a current collector by a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, etc. Conditions for the drying treatment of the coating film of the slurry for an all-solid-state secondary battery include a treatment temperature of preferably 20 to 250°C, more preferably 50 to 150°C, and a treatment time of preferably 1 to 120 minutes, more preferably 5 to 60 minutes.

[0143] Alternatively, the active material layer formed on the current collector may be compressed by pressing. As a pressing means, a high-pressure super press, a soft calender, a 1-ton press, or the like can be used. The pressing conditions can be set appropriately depending on the processing machine used.

[0144] The active material layer thus formed on the current collector has a thickness of, for example, 40 to 100 μm and a density of 1.3 to 2.0 g / cm 3 is.

[0145] The electrode for an all-solid-state secondary battery produced in this manner is suitably used as an electrode in an all-solid-state secondary battery configured by sandwiching a solid electrolyte layer between a pair of electrodes, specifically as a positive electrode and / or a negative electrode for the all-solid-state secondary battery. Also, the solid electrolyte layer formed using the above-mentioned slurry for an all-solid-state secondary battery is suitably used as a solid electrolyte layer for the all-solid-state secondary battery.

[0146] The all-solid-state secondary battery according to this embodiment can be manufactured by a known method. Specifically, the following manufacturing method can be used.

[0147] First, a slurry for an all-solid-state secondary battery positive electrode containing a solid electrolyte and a positive electrode active material is applied to a current collector and dried to form a positive electrode active material layer, thereby producing a positive electrode for an all-solid-state secondary battery. Next, a slurry for an all-solid-state secondary battery solid electrolyte layer containing a solid electrolyte is applied to the surface of the positive electrode active material layer of the all-solid-state secondary battery positive electrode and dried to form a solid electrolyte layer. Similarly, a slurry for an all-solid-state secondary battery negative electrode containing a solid electrolyte and a negative electrode active material is applied to the surface of the solid electrolyte layer and dried to form a negative electrode active material layer. Finally, a negative electrode side current collector (metal foil) is placed on the surface of the negative electrode active material layer, thereby obtaining the desired all-solid-state secondary battery structure.

[0148] Alternatively, a solid electrolyte sheet may be prepared on a release PET film and then bonded to a previously prepared positive electrode or negative electrode for an all-solid-state secondary battery. The release PET film may then be peeled off to obtain the desired all-solid-state secondary battery structure. The above compositions may be applied by conventional methods. After each application of the slurry for the positive electrode of an all-solid-state secondary battery, the slurry for the solid electrolyte layer of an all-solid-state secondary battery, and the slurry for the negative electrode of an all-solid-state secondary battery, it is preferable to subject each to a heat treatment. The heating temperature is preferably equal to or higher than the glass transition temperature of the polymer (A). Specifically, it is preferably 30°C or higher, more preferably 60°C or higher, and most preferably 100°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower. Heating within this temperature range allows the polymer (A) to soften and maintain its shape. This allows for good adhesion and lithium ion conductivity to be obtained in the all-solid-state secondary battery.

[0149] It is also preferable to apply pressure while heating. 2 More than 10kN / cm is preferable. 2 More preferably, 20 kN / cm or more 2 In this specification, the discharge capacity refers to the value per weight of the active material of the electrode, and in the case of a half cell, refers to the value per weight of the active material of the negative electrode.

[0150] 5. Working Example The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0151] 5.1.Measuring methods for each physical property In the following examples and comparative examples, the methods for measuring the various physical properties are as follows.

[0152] (1) Measurement of 1,2-vinyl bond content The 1,2-vinyl bond content (unit: mol%) in the polymer was measured using deuterated chloroform as a solvent and a 500 MHz 1 The carbon number was determined by H-NMR.

[0153] (2) Bound styrene content The bound styrene content (unit: %) in the polymer was measured using deuterated chloroform as a solvent and a 500 MHz 1 The carbon number was determined by H-NMR.

[0154] (3) Weight average molecular weight (Mw) The polystyrene equivalent was determined from the retention time corresponding to the apex of the maximum peak in a GPC curve obtained using gel permeation chromatography (GPC) (trade name "HLC-8120GPC", manufactured by Tosoh Corporation). (GPC conditions) Column: 2 "GMHXL" (Tosoh Corporation) Column temperature: 40℃ Mobile phase: Tetrahydrofuran ·Flow rate: 1.0ml / min Sample concentration: 10mg / 20ml

[0155] (4) Hydrogenation rate The hydrogenation rate of the double bonds in the polymer was measured using deuterated chloroform as a solvent at 500 MHz. 1 H-NMR was measured, and the value was calculated from the peak area of ​​the obtained spectrum based on the formula for α, which was taken as the hydrogenation rate.

[0156] (5) Quantitative determination of antioxidants 10 g of the binder composition for an all-solid-state secondary battery obtained as described below was poured into 100 mL of stirred methanol to precipitate a polymer. The precipitated polymer was filtered off using a stainless steel mesh, and the obtained filtrate was analyzed by liquid chromatography (HPLC). A liquid chromatograph manufactured by Shimadzu Corporation under the trade name "CBM-20A" was used for the liquid chromatography. The HPLC conditions were as follows: (HPLC conditions) ·Flow rate: 1mL / min Column oven temperature: 40℃ Detector: Absorbance detector (measures absorbance at 280 nm) Eluent: A mixture of methanol (MeOH) and water (MeOH / water = 9 / 1)

[0157] 5.2. Polymer synthesis example <Synthesis Example 1> A 50-liter autoclave reactor with a nitrogen-purged atmosphere was charged with 25 kg of cyclohexane as a hydrocarbon solvent, 75 g of tetrahydrofuran as a vinyl control agent, 600 g of styrene, and 1,800 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 10°C, and 27.4 mmol of n-butyllithium as a polymerization initiator was added to initiate polymerization. The polymerization was carried out under adiabatic conditions, with a maximum temperature of 85°C. When the polymerization conversion reached 99% (26 minutes after the start of polymerization), 100 g of 1,3-butadiene was added over 2 minutes. After an additional 3 minutes of polymerization, 4 mmol of tin tetrachloride was added and the reaction was continued for 30 minutes. Finally, 11.4 mmol of N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane (BTADS) was added and the reaction was continued for 30 minutes, yielding a polymer solution containing a modified conjugated diene copolymer.

[0158] To the resulting polymer solution, 7.5 g of 2,6-di-tert-butyl-p-cresol was added, and then the solvent was removed by steam stripping using hot water adjusted to pH 9 with sodium hydroxide, yielding a rubbery modified conjugated diene copolymer. The modified conjugated diene copolymer was then dried using a heated roll adjusted to 110°C, yielding polymer (A-1). The weight average molecular weight (Mw) of polymer (A-1) was 527 x 10 3 The 1,2-vinyl bond content was 41 mol %.

[0159] <Synthesis Example 2> A 50-liter autoclave reactor with a nitrogen-purged atmosphere was charged with 25 kg of cyclohexane as a hydrocarbon solvent, 30 g of tetrahydrofuran as a vinyl control agent, 600 g of styrene, and 1,800 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 10°C, and 27.4 mmol of n-butyllithium as a polymerization initiator was added to initiate polymerization. The polymerization was carried out under adiabatic conditions, with a maximum temperature of 85°C. When the polymerization conversion reached 99% (26 minutes after the start of polymerization), 100 g of 1,3-butadiene was added over 2 minutes. After an additional 3 minutes of polymerization, 2 mmol of tin tetrachloride was added and the reaction was continued for 30 minutes. Finally, 19.4 mmol of N-trimethylsilyl-N-methylaminopropylmethyldiethoxysilane (TMADS) was added and the reaction was continued for 30 minutes, yielding a polymer solution containing a modified conjugated diene copolymer.

[0160] The hydrogen gas supply pressure was then increased to 0.7 MPa (gauge pressure), the reaction solution was heated to 90°C, and a titanocene dichloride-based hydrogenation catalyst was added to initiate the hydrogenation reaction. When the hydrogen absorption by the modified conjugated diene copolymer reached the target hydrogenation rate (85 mol%), the atmosphere in the reaction vessel was replaced with nitrogen to obtain a polymer solution containing a hydrogenated modified conjugated diene copolymer. 7.5 g of 2,6-di-tert-butyl-p-cresol was added to the polymer solution, and the solvent was removed by steam stripping using hot water adjusted to pH 9 with sodium hydroxide, yielding a rubbery hydrogenated modified conjugated diene copolymer. The hydrogenated modified conjugated diene copolymer was then dried using a heated roll heated to 110°C to obtain Polymer (A-2). The weight-average molecular weight (Mw) of Polymer (A-2) was 324 x 10 3 The 1,2-vinyl bond content was 31 mol %, and the hydrogenation rate was 85 mol %.

[0161] <Synthesis Example 3> Polymer (A-3) was synthesized by appropriately applying the synthesis method of Synthesis Example 1 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-3) was 331 × 10 3 The 1,2-vinyl bond content was 62 mol %.

[0162] <Synthesis Example 4> Polymer (A-4) was synthesized by appropriately applying the synthesis method of Synthesis Example 1 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-4) was 284 × 10 3 The 1,2-vinyl bond content was 40 mol %.

[0163] <Synthesis Example 5> Polymer (A-5) was synthesized by appropriately applying the synthesis method of Synthesis Example 2 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-5) was 278 × 10 3The 1,2-vinyl bond content was 42 mol %, and the hydrogenation rate was 80 mol %.

[0164] <Synthesis Example 6> Polymer (A-6) was synthesized by appropriately applying the synthesis method of Synthesis Example 2 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-6) was 354 × 10 3 The 1,2-vinyl bond content was 41 mol %, and the hydrogenation rate was 81 mol %.

[0165] <Synthesis Example 7> Polymer (A-7) was synthesized by appropriately applying the synthesis method of Synthesis Example 1 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-7) was 311 × 10 3 The 1,2-vinyl bond content was 42 mol %.

[0166] <Synthesis Example 8> Polymer (A-8) was synthesized by appropriately applying the synthesis method of Synthesis Example 2 above, except that the types and amounts of the components used were as shown in Table 1. The weight-average molecular weight (Mw) of polymer (A-8) was 299 × 10 3 The 1,2-vinyl bond content was 43 mol %, and the hydrogenation rate was 85 mol %.

[0167] <Synthesis Example 9> Polymer (A-9) was synthesized by appropriately applying the synthesis method of Synthesis Example 1 above, except that the types and amounts of the components used were as shown in Table 1. The weight average molecular weight (Mw) of polymer (A-9) was 387 × 10 3 The 1,2-vinyl bond content was 41 mol %.

[0168] <Synthesis Example 10> Polymer (A-10) was synthesized by appropriately applying the synthesis method of Synthesis Example 2 above, except that the types and amounts of the components used were as shown in Table 1. The weight-average molecular weight (Mw) of polymer (A-10) was 349 × 10 3The 1,2-vinyl bond content was 41 mol %, and the hydrogenation rate was 86 mol %.

[0169] <Synthesis Example 11> A 50-liter autoclave reactor purged with nitrogen was charged with 25 kg of cyclohexane as a hydrocarbon solvent, 75 g of tetrahydrofuran as a vinyl control agent, 400 g of styrene, and 2,000 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 10°C, and 27.4 mmol of n-butyllithium as a polymerization initiator was added to initiate polymerization. The polymerization was carried out under adiabatic conditions, with a maximum temperature of 85°C. When the polymerization conversion reached 99% (26 minutes after the start of polymerization), 100 g of 1,3-butadiene was added over 2 minutes, and polymerization was continued for an additional 3 minutes to obtain a polymer solution containing a conjugated diene copolymer.

[0170] To the resulting polymer solution, 7.5 g of 2,6-di-tert-butyl-p-cresol was added, and then the solvent was removed by steam stripping using hot water adjusted to pH 9 with sodium hydroxide, yielding a conjugated diene copolymer. The conjugated diene copolymer was then dried using a heated roll adjusted to 110°C, yielding polymer (A-11). The weight average molecular weight (Mw) of polymer (A-11) was 223 x 10 3 The 1,2-vinyl bond content was 43 mol %.

[0171] <Synthesis Example 12> Polymer (A-12) was synthesized by appropriately applying the synthesis method of Synthesis Example 1 above, except that the types and amounts of the components used were as shown in Table 1. The weight-average molecular weight (Mw) of polymer (A-12) was 342 × 10 3 The 1,2-vinyl bond content was 61 mol %.

[0172] <Synthesis Example 13> Polymer (A-13) was synthesized by appropriately applying the synthesis method of Synthesis Example 2 above, except that the types and amounts of the components used were as shown in Table 1. The weight-average molecular weight (Mw) of polymer (A-13) was 505 × 10 3The 1,2-vinyl bond content was 41 mol %, and the hydrogenation rate was 95 mol %.

[0173] <Synthesis Example 14> An autoclave reactor equipped with a stirrer was charged with 240 parts of ion-exchanged water, 2.5 parts of sodium alkylbenzenesulfonate as an emulsifier, 35 parts of acrylonitrile as a nitrile group-containing monomer, and 0.25 parts of tert-dodecyl mercaptan as a chain transfer agent, in that order. After the interior was purged with nitrogen, 65 parts of 1,3-butadiene as a conjugated diene monomer was added under pressure, and 0.25 parts of ammonium persulfate as a polymerization initiator was added. Polymer (A-14), a copolymer of acrylonitrile and 1,3-butadiene, was obtained. The polymerization conversion was 85%. The resulting aqueous dispersion of the copolymer was subjected to steam stripping to remove unreacted monomers, and then concentrated under reduced pressure to adjust the total solids concentration to 40%. Next, 1500 parts of mesitylene was added to the aqueous dispersion of the copolymer and concentrated under reduced pressure to replace the solvent, and 1500 ppm of Sumilizer GM and 1500 ppm of IPPD were added to obtain a 10.1% mesitylene solution of polymer (A-14). The weight average molecular weight (Mw) of polymer (A-14) was 214 × 10 3 The 1,2-vinyl bond content was 9 mol %.

[0174] <Synthesis Example 15> A 200 mL three-neck flask was charged with 13.2 g of dicyclohexylmethane-4,4'-diisocyanate, 0.9 g of 1,4-butanediol, 24 g of DURANOLT5650J (Asahi Kasei Corporation, mass-average molecular weight 800), and 1.5 g of 2,2-(bishydroxymethyl)butanoic acid. 56 g of tetrahydrofuran was then added and dissolved by heating at 60°C. 50 mg of Neostan U-600 (trade name, Nitto Kasei Corporation, inorganic bismuth) catalyst was added over 10 minutes, and the mixture was heated and stirred at 60°C for 5 hours. 10 mL of methanol was added to the resulting polymer solution, and the mixture was stirred at 60°C for 1 hour to terminate the polymerization. This polymer solution was crystallized in 1 L of methanol, and the polymer solid was vacuum dried at 80°C for 6 hours. The resulting polymer (A-15) had a weight-average molecular weight of 38,000 and a glass transition temperature of 25°C. This was redissolved in THF, and 1500 ppm of 2,6-di-tert-butyl-p-cresol and 1500 ppm of Sumilizer GS were added to prepare a 10.1% THF solution.

[0175] The obtained polymer (A-15) was a polyurethane (H12MDI / BG / DMBA / DURANOLT5650J=50 / 10 / 10 / 30 mol %) represented by the following formula (8). [ka]

[0176] <Synthesis Example 16> Polymerization was carried out by stirring at 60°C for 1 hour in the same manner as in Synthesis Example 15, except that 1.9 g of EPOL (registered trademark, manufactured by Idemitsu Kosan Co., Ltd.) was used instead of 10 mL of methanol. The resulting polymer solution was added dropwise to 500 mL of octane and dispersed. After concentrating the solution under reduced pressure, 1500 ppm of 2,6-di-tert-butyl-p-cresol and 1500 ppm of Sumilizer GS were added to obtain a 10.2% polyurethane latex dispersed in octane. The resulting polymer (A-16) had a weight-average molecular weight of 17,000, a glass transition temperature of 15°C, and an average particle size of 190 nm.

[0177] The obtained polymer (A-16) is a polyurethane latex (H12MDI / BG / DMBA / DURANOL5650J / EPOL=50 / 10 / 10 / 27 / 3 mol %) represented by the following formula (9). [ka]

[0178] 5.3. Example 1 <Preparation of Binder Composition> The polymer (A-1) obtained in Synthesis Example 1 and 2,6-di-tert-butyl-p-cresol as the antioxidant (B) (400 ppm relative to the binder composition immediately after preparation) were added to anisole, a liquid medium (C), and stirred at 90°C for 3 hours to dissolve the polymer (A-1) and the antioxidant (B) in the anisole, thereby preparing a binder composition. This binder composition was then passed through a cartridge filter (manufactured by Advantec Co., Ltd., all-fluororesin cartridge filter, product name "TCF-300-H5MF") having a filter membrane with an average pore size of 3.00 μm, and then passed through a magnetic filter (manufactured by Toc Engineering Co., Ltd., magnetic flux density 8000 Gauss). The total solids content of this binder composition was 10.1% when the entire binder composition was taken as 100% by mass. The concentration of the antioxidant immediately after preparation of the binder composition was measured using the method described above and found to be 600 ppm.

[0179] <Viscosity of binder composition> The viscosity of the binder composition obtained above was measured at 25° C. within 5 minutes after preparation using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 50 rpm.

[0180] <Storage stability of binder composition> 500 g of the binder composition prepared above (hereinafter also referred to as "binder composition immediately after preparation") was filled into a 1 L Clean Barrier (registered trademark) bottle (a barrier container for ultra-high purity solvents) commercially available from Aicello Chemical Co., Ltd. and stored in a thermostatic chamber set at 40°C for 6 months. The weight-average molecular weight (Mw1) of the binder composition after 6 months of storage (hereinafter also referred to as "binder composition after long-term storage") was measured by gel permeation chromatography (GPC: temperature condition: 50°C, column: Tosoh Corporation "GMHHR-H", polystyrene equivalent). The rate of change between the weight-average molecular weight before storage (Mw0) and the weight-average molecular weight after storage (Mw1) was calculated as ΔMw (%) = (Mw1 / Mw0) × 100 and evaluated according to the following criteria. The smaller the rate of change ΔMw of the weight-average molecular weight, the better the storage stability of the binder composition. (Evaluation criteria) A: ΔMw is 97% or more and less than 103%. B: ΔMw is 95% or more and less than 97% or 103% or more and less than 105%. C: ΔMw is less than 95% or more than 105%.

[0181] In the operations of the following examples, the term "binder composition" refers to either the "binder composition immediately after preparation" or the "binder composition after long-term storage." In Table 1 below, the results showing the characteristics of an all-solid-state secondary battery produced using a binder composition immediately after preparation ("Electricity storage device characteristics (immediately after production)" in Table 1 below) and the results showing the characteristics of an all-solid-state secondary battery produced using a binder composition after long-term storage ("Electricity storage device characteristics (after long-term storage)" in Table 1 below) are shown separately.

[0182] <Preparation of slurry for positive electrodes of all-solid-state secondary batteries> A mixture of 70 parts by mass of LiCoO (average particle size: 10 μm) as the positive electrode active material, 30 parts by mass of sulfide glass composed of LiS and P2S5 (Li2S / P2S5 = 75 mol% / 25 mol%, average particle size 5 μm) as the solid electrolyte, 2 parts by mass of acetylene black as the conductive additive, and 2 parts by mass (solid content equivalent) of the binder composition prepared above was mixed, and anisole was further added as a liquid medium to adjust the solid content to 75%, followed by mixing for 10 minutes in a planetary centrifugal mixer (THINKY Corporation, Awatori Rentaro ARV-310) to prepare a slurry for the positive electrode of an all-solid-state secondary battery.

[0183] <Preparation of slurry for solid electrolyte layer of all-solid-state secondary battery> 100 parts by mass of sulfide glass composed of LiS and P2S5 (Li2S / P2S5 = 75 mol% / 25 mol%, average particle size 5 μm) as a solid electrolyte was mixed with 2 parts by mass of the binder composition prepared above in terms of solid content, and anisole was further added as a liquid medium to adjust the solid content concentration to 55%, followed by mixing for 10 minutes with a planetary centrifugal mixer (THINKY Corporation, Awatori Rentaro ARV-310) to prepare a slurry for a solid electrolyte layer of an all-solid-state secondary battery.

[0184] <Preparation of slurry for negative electrodes of all-solid-state secondary batteries> 65 parts by mass of artificial graphite (average particle size: 20 μm) as the negative electrode active material, 35 parts by mass of sulfide glass composed of LiS and P2S5 (Li2S / P2S5=75 mol% / 25 mol%, average particle size: 5 μm) as the solid electrolyte, and 2 parts by mass of the binder composition prepared above in terms of solid content were mixed together, and anisole was further added as a liquid medium to adjust the solid content concentration to 65%, and the mixture was then mixed for 10 minutes in a planetary centrifugal mixer (THINKY Corporation, Awatori Rentaro ARV-310) to prepare a slurry for an all-solid-state secondary battery negative electrode.

[0185] <Evaluation of slurry stability> The viscosity of the slurry for the solid electrolyte layer of an all-solid-state secondary battery obtained above was measured at 25°C within 5 minutes after preparation using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.) at 50 rpm, and the viscosity was defined as η0. This slurry for the solid electrolyte layer of an all-solid-state secondary battery was stored in a 25°C thermostatic chamber for 48 hours, and after storage, the viscosity η1 was calculated using a Brookfield viscometer at 50 rpm. The measurement temperature was also set at 25°C. The viscosity change rate Δη (%) = (η1 / η0) × 100 was calculated and evaluated according to the following criteria. The smaller the viscosity change rate Δη, the better the slurry stability. (Evaluation criteria) AA: Δη is 80% or more and less than 120%. A: Δη is 70% or more and less than 80% or 120% or more and less than 130%. B: Δη is 60% or more and less than 70% or 130% or more and less than 140%. C: Δη is less than 60% or 140% or more.

[0186] <Preparation of positive and negative electrodes and solid electrolyte layers> The slurry for the positive electrode of an all-solid-state secondary battery prepared above was applied onto an aluminum foil by a doctor blade method, and the anisole was evaporated under reduced pressure at 120°C, followed by drying for 3 hours, thereby producing a positive electrode of an all-solid-state secondary battery on which a positive electrode active material layer with a thickness of 0.1 mm was formed. The slurry for solid electrolyte of all-solid-state secondary batteries prepared above was applied onto a release PET film by the doctor blade method, and the anisole was evaporated under reduced pressure at 120°C, followed by drying for 3 hours to produce a solid electrolyte layer with a thickness of 0.1 mm. The slurry for the negative electrode of an all-solid-state secondary battery prepared above was applied onto a stainless steel foil by a doctor blade method, and the anisole was evaporated under reduced pressure at 120°C, followed by drying for 3 hours, thereby producing a negative electrode of an all-solid-state secondary battery on which a negative electrode active material layer with a thickness of 0.1 mm was formed.

[0187] <Peel strength test of positive electrodes of all-solid-state secondary batteries> For the positive electrode active material layer formed on the aluminum foil of the all-solid-state secondary battery positive electrode obtained above, a 20 mm wide tape was attached to the positive electrode active material layer, and the peel strength was measured when it was peeled off at a peel angle of 90° and a peel speed of 50 mm / min. The evaluation criteria were as follows. The results are shown in Table 1. (Evaluation criteria) AA: Peel strength is 20N / m or more. A: Peel strength is 10N / m or more but less than 20N / m. B: Peel strength is 5N / m or more and less than 10N / m. C: Peel strength is less than 5N / m.

[0188] <Flexibility test of positive electrodes for all-solid-state secondary batteries> The aluminum foil side of the positive electrode test piece was placed along a metal rod with a diameter of 1.0 mm, and the positive electrode test piece was wrapped around this metal rod to evaluate whether the positive electrode active material layer cracked or whether there was any damage to the wound end. The evaluation criteria were as follows. The results are shown in Table 1. Test pieces with no visible damage to the positive electrode active material layer indicate that the test piece is highly flexible and has good process suitability for assembling all-solid-state secondary batteries. (Evaluation criteria) A: No cracks in the positive electrode active material layer, no damage to the winding edge. B: No cracks in the positive electrode active material layer, but damage to the winding end. C: Cracks in the positive electrode active material layer.

[0189] <Lithium ion conductivity measurement of solid electrolyte layer> The solid electrolyte layer peeled from the PET film was sandwiched between two stainless steel flat plates and measured using an impedance analyzer. The lithium ion conductivity was calculated from the Nyquist plot. The evaluation criteria are as follows. The results are shown in Table 1. The higher the lithium ion conductivity, the better the battery performance of the resulting all-solid-state secondary battery. (Evaluation criteria) AA: Lithium ion conductivity is 0.8×10 -4 S / cm or more 1.0×10 -4 Less than S / cm. A: Lithium ion conductivity is 0.5 × 10 -4S / cm or more 0.8×10 -4 Less than S / cm. B: Lithium ion conductivity is 0.2 × 10 -4 S / cm or more 0.5×10 -4 Less than S / cm. C: Lithium ion conductivity is 0.2 × 10 -4 Less than S / cm.

[0190] <Creating all-solid-state secondary batteries> The all-solid-state secondary battery positive electrode prepared above was cut into a 13 mm diameter disk, and the all-solid-state secondary battery negative electrode and the solid electrolyte layer peeled from the PET film were cut into a 15 mm diameter disk. Next, the cut-out all-solid-state secondary battery positive electrode was bonded to one side of the cut-out solid electrolyte layer so that the surface of the positive electrode active material layer of the all-solid-state secondary battery positive electrode was in contact with the solid electrolyte layer. The cut-out all-solid-state secondary battery negative electrode was bonded to the other side of the cut-out solid electrolyte layer so that the surface of the negative electrode active material layer of the all-solid-state secondary battery negative electrode was in contact with the solid electrolyte layer. Using a heat press, the all-solid-state secondary battery laminate was heated (120 °C) and pressed (600 MPa, 1 minute) to produce an all-solid-state secondary battery laminate having a laminated structure of aluminum foil / positive electrode active material layer / solid electrolyte layer / negative electrode active material layer / stainless steel foil. Next, the all-solid-state secondary battery laminate prepared in this way was placed in a stainless steel 2032-type coin case incorporating a spacer and a washer, and the 2032-type coin case was crimped to produce an all-solid-state secondary battery.

[0191] <Cycle life characteristics (capacity retention rate)> A charge-discharge test was carried out in an environment of 30°C using the all-solid-state secondary battery prepared above. Charge-discharge measurements were performed at a 0.1C rate in the potential range of 4.2V to 3.0V. This 0.1C rate charge-discharge was repeated, and the capacity retention rate after 20 cycles was calculated using the following formula, where A (mAh / g) is the discharge capacity at the first cycle and B (mAh / g) is the discharge capacity at the 20th cycle. The evaluation criteria were as follows. The results are shown in Table 1. Capacity retention rate after 20 cycles (%) = (B / A) x 100 The C in C rate stands for time rate, and is defined as (1 / X)C = rated capacity (Ah) / X (h). X represents the time it takes to charge or discharge the rated capacity. For example, 0.1C means that the current value is rated capacity (Ah) / 10 (h). (Evaluation criteria) AA: Capacity retention rate is between 95% and 100%. A: Capacity retention rate is between 90% and 95%. B: Capacity retention rate is 85% or more but less than 90%. C: Capacity retention rate is less than 85%.

[0192] <Good product rate> The all-solid-state secondary battery prepared above was subjected to 20 cycles of charge and discharge at a 0.1 C rate in a potential range of 4.2 V to 3.0 V in a 30°C environment. The battery was then charged to 4.2 V at a 0.1 C rate in a 0°C environment, and then discharged to 3.0 V at a 0.1 C rate in a 30°C environment. The battery was evaluated for abnormalities according to the following criteria. The results are shown in Table 1. "Abnormal" means that the battery voltage dropped by 0.1 V or more during charging or discharging. (Evaluation criteria) AA: Of the 10 all-solid-state secondary batteries, 9 to 10 were charged and discharged without any abnormalities. A: Of the 10 all-solid-state secondary batteries, 7 to 8 were charged and discharged without any problems. B: Of the 10 all-solid-state secondary batteries, 4 to 6 were charged and discharged without any abnormalities. C: Of the 10 all-solid-state secondary batteries, 0 to 3 were charged and discharged without any abnormalities.

[0193] 5.4. Examples 2 to 10 and Comparative Examples 1 to 6 Except for using the polymers shown in Table 1, binder compositions for all-solid-state secondary batteries were obtained in the same manner as in Example 1 above, and slurries for all-solid-state secondary batteries, all-solid-state secondary battery electrodes, and all-solid-state secondary batteries were produced and evaluated in the same manner as in Example 1 above. The respective results are shown in Table 1.

[0194] 5.5.Evaluation Results Table 1 below shows the polymer compositions, physical properties, and evaluation results used in Examples 1 to 10 and Comparative Examples 1 to 6.

[0195] [Table 1]

[0196] The abbreviations or product names in Table 1 above represent the following compounds. <Polymerization initiator> Piperazine derivative a: N-trimethylsilylpiperazine Piperazine derivative b: N'-[2-N,N-bis(trimethylsilyl)aminoethyl]piperazine <Denaturant> BTADS: N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane TMADS: N-trimethylsilyl-N-methylaminopropylmethyldiethoxysilane DATMS: [3-(N,N-dimethylamino)propyl]trimethoxysilane <Anti-aging agent> BHT: 2,6-di-tert-butyl-p-cresol MBMTBP: 2,2'-methylenebis(4-methyl-6-tert-butylphenol) Sumilizer GM: 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate Sumilizer GS: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate IPPD: N-isopropyl-N'-phenylbenzene-1,4-diamine TMDQ: 2,2,4-trimethyl-1,2-dihydroquinoline polymer ETMDQ: 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline <Liquid medium (C)> DIBK: Diisobutyl ketone THF: Tetrahydrofuran

[0197] The results in Table 1 confirm that the binder compositions for all solid state secondary batteries of Examples 1 to 10 have excellent long-term storage stability. Furthermore, the results in Table 1 confirm that when any of the binder compositions of Examples 1 to 10, immediately after preparation or after long-term storage, is used, it is possible to prepare an all solid state secondary battery that has excellent lithium ion conductivity and can achieve good cycle life characteristics even under high voltage.

[0198] Furthermore, in Examples 1 to 10, an active material and a solid electrolyte were contained in an all-solid-state secondary battery binder composition as the slurry for an all-solid-state secondary battery electrode. It was confirmed that, in the active material layer formed using this slurry, the active material layer itself did not become brittle during peel strength measurement, causing the active material or solid electrolyte to fall off or cracks, and sufficient polymer binding strength was obtained between both the active material and the solid electrolyte. Therefore, it is presumed that the active material layer formed using the binder composition for an all-solid-state secondary battery according to the present invention has sufficient adhesion to the solid electrolyte layer, and that high workability is achieved even when a solid electrolyte layer is formed using the binder composition for an all-solid-state secondary battery according to the present invention, and that the formed solid electrolyte has sufficient adhesion to the active material layer.

[0199] The present invention is not limited to the above-described embodiments, and various modifications are possible. The present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations with the same function, method, and result, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the above embodiments are replaced with other configurations. Furthermore, the present invention also includes configurations that achieve the same effects or purposes as the configurations described in the above embodiments. Furthermore, the present invention also includes configurations in which publicly known technology is added to the configurations described in the above embodiments.

Claims

1. a polymer (A) having 5 to 40 parts by mass of aromatic vinyl units derived from an aromatic vinyl compound and 60 to 95 parts by mass of conjugated diene units derived from a conjugated diene compound; The antioxidant (B) is contained in an amount of 200 ppm or more and 5,000 ppm or less based on the total mass of the binder composition for an all-solid-state secondary battery, A liquid medium (C), Contains The binder composition for an all-solid-state secondary battery, wherein the polymer (A) has a value α represented by the following formula (i) of less than 0.9, where p, q, r, and s are constituent ratios (molar ratios) in the polymer of a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4), respectively: α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ・・・(i) 【Chemistry 1】

2. 2. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the antioxidant (B) comprises at least one selected from the group consisting of phenol-based antioxidants and amine-based antioxidants.

3. 3. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the polymer (A) has a bound styrene content of 5 to 40%.

4. 4. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the polymer (A) has a unit based on a modifier containing at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, a silicon atom, a germanium atom, and a tin atom.

5. 5. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the liquid medium (C) is at least one selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, esters, and ethers.

6. The binder composition for an all-solid-state secondary battery according to claim 1 , wherein the polymer (A) is dissolved in the liquid medium (C).

7. A slurry for an all-solid-state secondary battery, comprising the binder composition for an all-solid-state secondary battery according to claim 1 and a solid electrolyte.

8. The slurry for an all-solid-state secondary battery according to claim 7 , wherein the solid electrolyte is a sulfide-based solid electrolyte or an oxide-based solid electrolyte.

9. An all-solid-state secondary battery including at least a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, 9. An all-solid-state secondary battery, wherein at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer formed by applying and drying the slurry for an all-solid-state secondary battery according to claim 7 or 8.

10. A solid electrolyte sheet for an all-solid-state secondary battery, comprising a layer formed by applying the slurry for an all-solid-state secondary battery according to claim 7 or 8 onto a substrate and drying the applied layer.

11. A method for producing a solid electrolyte sheet for an all-solid-state secondary battery, comprising the steps of applying the slurry for an all-solid-state secondary battery according to claim 7 or 8 onto a substrate and drying the applied slurry.

12. A method for producing an all-solid-state secondary battery, comprising producing an all-solid-state secondary battery by the method for producing a solid electrolyte sheet for an all-solid-state secondary battery according to claim 11.

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