Binder for all-solid-state secondary battery, 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 the same, and all-solid-state secondary battery and method for manufacturing the same

Abstract

The present invention provides: a binder for all-solid-state secondary batteries, the binder having excellent adhesion, excellent flexibility and good cycle life characteristics, while achieving a high rate of acceptable products; and a binder composition for all-solid-state secondary batteries, the binder composition containing the above-described binder.　A binder for all-solid-state secondary batteries according to the present invention contains a conjugated diene copolymer (A) which comprises an aromatic vinyl unit based on an aromatic vinyl compound and a conjugated diene unit based on a conjugated diene compound, while having a storage elastic modulus (G') of 4.0 × 104 Pa to 2.0 × 105 Pa and a loss tangent (tanδ) of 0.10 to 0.80 as determined at a measurement temperature of 25°C, at a frequency of 0.1 Hz and at a strain of 0.1% with use of a dynamic viscoelasticity measurement device.

Description

[Technical Field]

[0001] The present invention relates to a binder for an all-solid-state secondary battery, a binder composition for an all-solid-state secondary battery containing the binder, 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, a technique for improving moldability by further adding a binder component made of a polymer compound to the mixture has been investigated (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] Due to improvements in formability, solid electrolyte-containing sheets (sheets having a solid electrolyte layer and an electrode active material layer) can now be manufactured using a highly productive roll-to-roll method instead of the conventional sheet-fed method, and development toward industrial production is underway.

[0008] However, with conventional binders, powder falling or cracking may occur in the process of winding the solid electrolyte-containing sheet or in the process of storing or transporting the wound solid electrolyte-containing sheet, and there is a risk that an all-solid-state secondary battery having the desired performance and yield rate may not be obtained, and further improvement has been required.

[0009] Some aspects of the present invention provide a binder for an all-solid-state secondary battery that is excellent in adhesion and flexibility, has good cycle life characteristics, and can achieve a high yield rate, and a binder composition for an all-solid-state secondary battery that contains the binder. [Means for solving the problem]

[0010] 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.

[0011] One aspect of the binder for an all-solid-state secondary battery according to the present invention is having aromatic vinyl units derived from an aromatic vinyl compound and conjugated diene units derived from a conjugated diene compound, The storage modulus (G') measured using a dynamic viscoelasticity measuring device under the conditions of a measurement temperature of 25°C, a frequency of 0.1 Hz, and a strain of 1% was 4.0 x 10 4 Pa or more 2.0×10 5 The polymer contains a conjugated diene copolymer (A) having a viscosity of 100 Pa or less and a loss tangent (tan δ) of 0.10 or more and 0.80 or less.

[0012] In one embodiment of the binder for an all-solid-state secondary battery, In the conjugated diene copolymer (A), when the constituent ratios (molar ratios) in the polymer 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) are p, q, r, and s, respectively, the value α represented by the following formula (i) may be less than 0.7. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ···(i) [ka]

[0013] In any one of the embodiments of the binder for an all-solid-state secondary battery, The conjugated diene copolymer (A) may have a bound styrene content of 5 to 45%.

[0014] In any one of the embodiments of the binder for an all-solid-state secondary battery, The conjugated diene copolymer (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] One aspect of the binder composition for an all-solid-state secondary battery according to the present invention is The binder for an all-solid-state secondary battery according to any one of the above embodiments and a liquid medium (B) are contained.

[0016] In one embodiment of the binder composition for an all-solid-state secondary battery, The liquid medium (B) may be at least one selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, esters, and ethers.

[0017] In any one of the embodiments of the binder composition for an all-solid-state secondary battery, The conjugated diene copolymer (A) may be dissolved in the liquid medium (B).

[0018] 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.

[0019] 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.

[0020] One aspect of the all-solid-state secondary battery according to the present invention is 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, 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.

[0021] 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.

[0022] 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.

[0023] One aspect of the method for producing an all-solid-state secondary battery according to the present invention is to An all-solid-state secondary battery is manufactured by the method for manufacturing a solid electrolyte sheet for an all-solid-state secondary battery of the above aspect. [Effects of the Invention]

[0024] The binder for an all-solid-state secondary battery according to the present invention can sufficiently enhance adhesion and flexibility when used as a material for the solid electrolyte layer and / or active material layer of an all-solid-state secondary battery, thereby improving moldability in pressure molding, thereby providing an all-solid-state secondary battery having excellent lithium ion conductivity and good cycle life characteristics, and achieving the excellent effect of realizing a high yield rate. DETAILED DESCRIPTION OF THE INVENTION

[0025] 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."

[0026] In this specification, a numerical range described as "X to Y" is interpreted as including the numerical value X as the lower limit and the numerical value Y as the upper limit.

[0027] 1. Binders for all-solid-state secondary batteries The binder for an all-solid-state secondary battery according to one embodiment of the present invention has an aromatic vinyl unit based on an aromatic vinyl compound and a conjugated diene unit based on a conjugated diene compound, and has a storage modulus (G') of 4.0 × 10 measured using a dynamic viscoelasticity measuring device under conditions of a measurement temperature of 25°C, a frequency of 0.1 Hz, and a strain of 1%. 4 Pa or more 2.0×10 5 The polymer contains a conjugated diene copolymer (A) having a viscosity of 100 Pa or less and a loss tangent (tan δ) of 0.10 or more and 0.80 or less.

[0028] In addition, the conjugated diene copolymer (A) may contain, in addition to the aromatic vinyl unit and the conjugated diene unit, structural units based on other monomers copolymerizable therewith. The order of the structural units in the conjugated diene copolymer (A) is not particularly limited. That is, the conjugated diene copolymer (A) may be a block copolymer or a random copolymer.

[0029] Hereinafter, the production method of the conjugated diene copolymer (A) and the physical properties of the conjugated diene copolymer (A) will be described in that order.

[0030] 1.1. Method for producing conjugated diene copolymer (A) The conjugated diene copolymer (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 active terminals (polymerization step), and a step of modifying the terminals of the resulting conjugated diene copolymer (modification step). The method may also include a step of hydrogenating the conjugated diene copolymer (hydrogenation step). Specifically, the conjugated diene copolymer (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, and the like, depending on the intended use. The method for producing the conjugated diene copolymer (A) is described in detail below.

[0031] <Polymerization process> The polymerization step is a step in which a monomer containing an aromatic vinyl compound and a conjugated diene compound is polymerized to obtain a conjugated diene copolymer having an active terminal.

[0032] The polymerization method for obtaining a 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 batchwise 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").

[0033] 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.

[0034] 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.

[0035] The conjugated diene copolymer (A) 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 (A) is preferably a copolymer using 1,3-butadiene and styrene.

[0036] In the conjugated diene copolymer obtained by the polymerization step, the content of the aromatic vinyl compound is preferably 5 to 45 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, both the adhesion and flexibility of the electrode may be improved. The monomers used to produce the conjugated diene copolymer before hydrogenation preferably contain 55 to 95 mass% butadiene, 5 to 45 mass% aromatic vinyl compound, and 0 to 40 mass% conjugated diene compound other than butadiene. These blending amounts are preferred in that they allow for both adhesion and flexibility of the electrode to be achieved.

[0037] In the polymerization, other monomers can be used in addition to the conjugated diene compound and the aromatic vinyl 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.

[0038] 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 alkyl lithium such as methyl lithium, ethyl lithium, n-propyl lithium, n-butyl lithium, sec-butyl lithium, and tert-butyl lithium; 1,4-dilithiobutane, phenyl lithium, stilbene lithium, naphthyl lithium, naphthyl sodium, naphthyl potassium, di-n-butyl magnesium, di-n-hexyl magnesium, ethoxy potassium, and calcium stearate. Among these, lithium compounds are preferred.

[0039] The polymerization reaction may also be carried out in the presence of a compound (hereinafter also referred to as "compound (R)") obtained by mixing at least one of the alkali metal compounds and alkaline earth metal compounds described above with 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 polymerization initiation terminal. By carrying out 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). Furthermore, 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.

[0040] The compound (C1) is not particularly limited as long as it has a partial structure in which a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom, or a phosphorus atom is directly bonded to a hydrogen atom. Examples of the compound (C1) that can be used 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, dihexylamine, dioctylamine, 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, and 2-methylpiperazine. , 1-benzylpiperazine, 2,6-dimethylmorpholine, hexamethyleneimine, heptamethyleneimine, 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.

[0041] 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.

[0042] The randomizer can be used for the purpose of adjusting the vinyl bond content (1,2-vinyl bond content), etc. Examples of the randomizer 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.

[0043] The organic solvent used in the polymerization may be any organic solvent inert to the reaction, and examples thereof include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. 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, and cyclohexene. The organic solvent may be used alone or in combination of two or more.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] <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.

[0048] 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).

[0049] [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 and R4 If there are multiple R 3 and R 4 may be the same or different.)

[0050] [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 R 9 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.)

[0051] 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.

[0052] A 1 When A is the monovalent functional group, 1At 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 , A 2 The (thio)epoxy group is a functional group that converts the (thio)epoxy group into an inactive functional group at the polymerization active terminal.

[0053] A 1 may be a group that can be converted into an onium ion by an onium 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.

[0054] 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-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.

[0055] In addition to the compound (C2), germanium 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 conjugated diene copolymer (A). In this specification, the group consisting of the compound (R), the compound (C2), the germanium compounds, and the stannane compounds is also referred to as a "modifier."

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 atom 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.

[0061] The temperature of the terminal modification reaction is usually the same as the temperature of the above-mentioned 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 polymerization active 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.

[0062] As described above, the conjugated diene copolymer (A) preferably contains units derived from a modifier containing at least one atom selected from the group consisting of nitrogen, oxygen, silicon, germanium, and tin. The conjugated diene copolymer (A) contains units derived from such a modifier, which improves the dispersion stability of the slurry and improves the moldability of the pressure-molded all-solid-state secondary battery. This allows for the production of an all-solid-state secondary battery with excellent lithium ion conductivity and good cycle life characteristics.

[0063] <Onium generating agent addition process> When the conjugated diene copolymer (A) has units based on a nitrogen-containing modifier, a step of adding an onium-forming agent may be performed after the modification step. The addition of the onium-forming agent can impart shape stability to the conjugated diene copolymer (A). In addition, increasing the amount of the onium-forming agent tends to increase the storage modulus (G') of the conjugated diene copolymer (A).

[0064] Examples of the onium generating agent include metal halides such as silicon halide compounds, tin halide compounds, aluminum halide compounds, titanium halide compounds, zirconium halide compounds, germanium halide compounds, gallium halide compounds, and zinc halide compounds; inorganic acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, iodic acid, sulfuric acid, nitric acid, carbonic acid, and phosphoric acid; inorganic acid salts such as potassium fluoride, tetramethylammonium fluoride, and tetra-n-butylammonium fluoride; and organic acids such as carboxylic acids, sulfonic acids, sulfates, phosphates, carbonates, and nitrates.

[0065] Examples of the onium generating agent compound include metal halides such as silicon tetrachloride, tin tetrachloride, trimethylsilyl chloride, dimethyldichlorosilane, methyltrichlorosilane, methyldichlorosilane, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, titanium tetrachloride, titanocene dichloride, zirconium tetrachloride, zirconocene dichloride, germanium tetrachloride, gallium trichloride, and zinc chloride. Examples of other onium generating agent compounds include diethyl sulfate, dimethyl sulfate, magnesium laureth sulfate, magnesium lauryl sulfate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, 2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, nitrocellulose, nitroglycerin, nitroglycerin, formic acid, acetic acid, oxalic acid, maleic acid, citric acid, malic acid, fumaric acid, malonic acid, acrylic acid, crotonic acid, succinic acid, glutaric acid, itaconic acid, tartaric acid, sebacic acid, terephthalic acid, isophthalic acid, β-mercaptopropionic acid, benzenesulfonic acid, p-toluenesulfonic acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, iodic acid, sulfuric acid, nitric acid, carbonic acid, phosphoric acid, potassium fluoride, tetramethylammonium fluoride, and tetra-n-butylammonium fluoride. These onium generators all have the same effect from the viewpoint of being capable of oniumizing units based on a modifier containing a nitrogen atom, and even those not described in the examples described later can be used in the present invention.

[0066] The modified conjugated diene copolymer obtained in the modification step and the onium-forming agent can be mixed, for example, in a solution. The mixing method is not particularly limited, and the mixture may be performed using a batch mixer or a continuous mixer such as a multistage continuous mixer or an in-line mixer.

[0067] The amount of acid component that can be generated from the onium-forming agent is preferably 1.0 molar equivalent or more, more preferably 1.5 molar equivalent or more, relative to the active sites of the conjugated diene copolymer obtained by anionic polymerization. If the amount is less than 1.0 molar equivalent, the onium formation does not proceed sufficiently, and the shape retention of the rubber may be poor.

[0068] Here, the amount of acid component that can be generated from the onium generating agent refers to the following. When the onium generator has hydrogen atoms with a pka of 7 or less as measured in water at 25°C: The amount of hydrogen atoms with a pka of 7 or less as measured in water at 25°C present in the onium generator. When the onium generator does not contain hydrogen atoms and generates hydrogen ions when it comes into contact with water, the amount of hydrogen ions generated when 100 mol of water is added to the onium generator and the reaction is allowed to proceed at 25°C for a sufficient period of time. - When the onium generator does not have a hydrogen atom with a pka of 7 or less when measured in water at 25°C and does not release a hydrogen ion when in contact with water: the amount of substance of the onium generator.

[0069] The method for adding the onium generating agent is not particularly limited, and examples thereof include a method of adding it all at once, a method of adding it in portions, or a method of adding it continuously, but a method of adding it all at once is preferred.The onium generating agent may also be added as a solution using a hydrocarbon solvent such as an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon, or a randomizer, which are exemplified as the organic solvent to be used in the polymerization in the polymerization step.

[0070] The temperature at which the modified conjugated diene copolymer obtained in the modification step and the onium-forming agent are mixed can be the same as the polymerization temperature used in the polymerization step. Specifically, the temperature is preferably 0 to 120°C, and more preferably 20 to 100°C. Lower temperatures tend to increase the viscosity of the polymer, while higher temperatures tend to cause the active polymerization terminals to degrade. Therefore, temperatures outside the above ranges are not preferred. The mixing time is preferably 1 minute to 5 hours, and more preferably 2 minutes to 1 hour.

[0071] <Anti-aging agent addition process> A step of adding an antioxidant may be carried out after the modification step or the step of adding an onium-forming agent. The addition of the antioxidant can prevent gelation and deterioration of the conjugated diene copolymer (A) due to heat, light, and oxidative degradation in the desolvation step by steam stripping or the drying step with a heated roll, which are carried out after the synthesis of the conjugated diene copolymer (A), and in the subsequent long-term storage in a bale state.

[0072] Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, quinone-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and phenothiazine-based antioxidants. Among these, phenol-based antioxidants and amine-based antioxidants are preferred. These antioxidants may be used alone or in combination of two or more.

[0073] 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- 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.

[0074] 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. Furthermore, light stabilizers (HALS), hindered amine compounds, and nitroxyl radicals (2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)) can also be suitably used as amine-based antiaging agents.

[0075] Examples of phosphorus-based anti-aging agents include phosphite compounds, and examples of sulfur-based anti-aging agents include thiol compounds and sulfide compounds such as pentaerythrityl tetrakis(3-laurylthiopropionate).

[0076] The above-mentioned antiaging agent can be added in any of a solid state, a molten state, or a solution state in which the antiaging agent is dissolved in a solvent that the antiaging agent is dissolved in. When the antiaging agent is added, the conjugated diene copolymer (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 antiaging agent.

[0077] When the conjugated diene copolymer (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 conjugated diene copolymer (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.

[0078] <Hydrogenation process> The conjugated diene copolymer (A) may be 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 (catalysts described in JP-B-63-4841, JP-B-1-37970, JP-A-2000-037632, etc.) 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.

[0079] 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 main components.

[0080] 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.

[0081] 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.

[0082] A suitable method for obtaining the conjugated diene copolymer (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 a modification step, which is industrially useful. A hydrogenation step may also be included after the modification step. In this case, the conjugated diene copolymer (A) is obtained by removing the solvent from the resulting solution and isolating the conjugated diene copolymer (A). The conjugated diene copolymer (A) can be isolated by known solvent removal methods such as steam stripping and drying procedures such as heat treatment.

[0083] In order to improve the dispersion stability of the slurry and the adhesion of the electrode, the conjugated diene copolymer (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 conjugated diene copolymer (A).

[0084] 1.2. Physical properties of conjugated diene copolymer (A) <Storage modulus (G') and loss tangent (tanδ)> The storage modulus (G') of the conjugated diene copolymer (A) is 4.0 × 10 4 Pa or more 2.0×10 5 The lower limit of the storage modulus (G') of the conjugated diene copolymer (A) is preferably 4.5 × 10 4 Pa, and more preferably 5.0×10 4 Pa, and particularly preferably 5.5 × 10 4 The upper limit of the storage modulus (G') of the conjugated diene copolymer (A) is preferably 1.9 × 10 5 Pa, more preferably 1.8×10 5 Pa, and particularly preferably 1.7 × 10 5 Pa. When the storage modulus (G') of the conjugated diene copolymer (A) is equal to or greater than the lower limit, the strength of the electrode is improved, and a good electrode can be obtained. Furthermore, by setting the storage modulus (G') of the conjugated diene copolymer (A) within the above range, the obtained electrode has appropriate flexibility, making it less likely to powder or crack after application or pressing. Furthermore, the electrode has good adhesion and exhibits good electrical storage device properties.

[0085] The loss tangent (tanδ) of the conjugated diene copolymer (A) is 0.10 or more and 0.80 or less. The lower limit of the loss tangent (tanδ) of the conjugated diene copolymer (A) is preferably 0.12, more preferably 0.14, and particularly preferably 0.16. The upper limit of the loss tangent (tanδ) of the conjugated diene copolymer (A) is preferably 0.78, more preferably 0.76, and particularly preferably 0.74. When the loss tangent (tanδ) of the conjugated diene copolymer (A) is equal to or greater than the lower limit, the adhesion of the resulting electrode is improved, and powdering and cracking after coating or pressing are less likely to occur. Furthermore, by setting the loss tangent (tanδ) of the conjugated diene copolymer (A) within the above range, an increase in electrode resistance can be suppressed, and an electrode with excellent electrical storage device properties can be obtained.

[0086] The storage modulus and loss tangent of the conjugated diene copolymer (A) can be measured as follows. First, the conjugated diene copolymer (A) is dissolved in a desired organic solvent, and the solution is dried to prepare a uniform film with a thickness of 1.0±0.3 mm. This film is further dried and cut into 10 mm × 10 mm strips to serve as measurement samples. Next, using a dynamic viscoelasticity measuring device (e.g., Anton Paar, model "MCR 301"), the measurement sample is fixed with parallel plates, and dynamic viscoelasticity is measured under the conditions of shear mode, measurement temperature 25°C, frequency 0.1 Hz, and strain 1%, to obtain the storage modulus and loss tangent values.

[0087] The storage modulus (G') and loss tangent (tanδ) of the conjugated diene copolymer (A) can be adjusted by, for example, changing the composition, microstructure, molecular weight, and terminal functional groups (polymerization initiation end, polymerization termination end) of the conjugated diene copolymer (A). Specifically, the storage modulus (G') of the conjugated diene copolymer (A) decreases when the bound styrene content is reduced, and increases when the polymerization termination end is functionally modified. Furthermore, the loss tangent (tanδ) decreases when the polymerization termination end is functionally modified.

[0088] <Bound styrene content> The lower limit of the bound styrene content of the conjugated diene copolymer (A) is preferably 5%, more preferably 8%, and particularly preferably 10%. The upper limit of the bound styrene content of the conjugated diene copolymer (A) is preferably 45%, more preferably 30%, and particularly preferably 27%. When the bound styrene content of the conjugated diene copolymer (A) is within the above range, both good adhesion and flexibility of the electrode can be achieved. The bound styrene content is 1 It can be measured by H-NMR measurement.

[0089] <Weight average molecular weight> The weight average molecular weight (Mw) of the conjugated diene copolymer (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 ~1.0×10 6 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).

[0090] <Hydrogenation rate> As mentioned above, the conjugated diene copolymer (A) may be hydrogenated. In such a case, the conjugated diene copolymer (A) has at least one structural unit selected from the structural units represented by the following formula (1), the structural units represented by the following formula (2), the structural units represented by the following formula (3), and the structural units represented by the following formula (4), and when the constituent ratios (molar ratios) in the polymer are p, q, r, and s, respectively, the value α represented by the following mathematical formula (i) corresponds to the hydrogenation rate of the conjugated diene copolymer. For example, when α in the following mathematical formula (i) is 0.7, the hydrogenation rate of the conjugated diene copolymer is 70%. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ···(i) [ka]

[0091] Although α may take any value, by making it less than 0.7, excellent dispersion stability of the slurry and flexibility of the electrode can be obtained, and high lithium ion conductivity and good cycle life characteristics can be realized. For these reasons, α is preferably less than 0.7, more preferably less than 0.6, and particularly preferably less than 0.5. The hydrogenation rate in the conjugated diene copolymer can be adjusted by the hydrogenation reaction time or the amount of hydrogen supplied, etc. This hydrogenation rate 1 It can be measured by H-NMR.

[0092] 2. Binder composition for all-solid-state secondary batteries The binder composition for an all-solid-state secondary battery according to one embodiment of the present invention contains the above-mentioned binder for an all-solid-state secondary battery and a liquid medium (B). Hereinafter, each component contained in the binder composition for an all-solid-state secondary battery according to this embodiment will be described in detail. Note that the binder for an all-solid-state secondary battery has been described above, so a detailed description thereof will be omitted.

[0093] 2.1. Liquid Medium (B) The liquid medium (B) 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.

[0094] The content of the liquid medium (B) 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 conjugated diene copolymer (A). By setting the content of the liquid medium (B) 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.

[0095] <Solubility> In the binder composition for an all-solid-state secondary battery according to this embodiment, the conjugated diene copolymer (A) is preferably dissolved in the liquid medium (B). The phrase "the conjugated diene copolymer (A) is soluble in the liquid medium (B)" means that the solubility of the conjugated diene copolymer (A) in the liquid medium (B) is 1 g or more per 100 g of the liquid medium (B). The conjugated diene copolymer (A) dissolved in the liquid medium (B) facilitates coating of the surface of the active material with the conjugated diene copolymer (A), which has excellent flexibility and adhesion. 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 excellent charge and discharge durability. This is also preferable because it improves the stability of the slurry and improves the applicability of the slurry to the current collector.

[0096] 2.2. Other additives The binder composition for an all-solid-state secondary battery according to this embodiment may contain additives such as an antioxidant and a thickener, if necessary.

[0097] <Anti-aging agent> Examples of the antioxidant include the various antioxidants described in the section <Antiaging Agent Addition Step> of "1.1. Production Method of Conjugated Diene Copolymer (A)" above.

[0098] When the binder composition for an all-solid-state secondary battery according to this embodiment contains an antioxidant, the content of the antioxidant is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 1 part by mass, and particularly preferably 0.2 to 0.8 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.

[0099] <Thickener> By including a thickener, the coating properties and the charge / discharge characteristics of the resulting all-solid-state secondary battery can be further improved in some cases.

[0100] 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.

[0101] 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.

[0102] 2.3. 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 adding a liquid medium (B) to a conjugated diene-based copolymer (A), further adding other additives as necessary, and appropriately stirring the mixture to dissolve or disperse the conjugated diene-based copolymer (A) in the liquid medium (B).

[0103] 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.

[0104] 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.

[0105] 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.

[0106] The method of removing metal components by magnetic force is not particularly limited as long as it is a method that can remove metal components. However, in consideration of productivity and removal efficiency, a method of removing metal components by passing a polymer solution through a magnetic filter disposed in a production line of a binder composition for an all-solid-state secondary battery is preferred.

[0107] The step of removing particulate metal components from a polymer solution using a magnetic filter is preferably carried out by passing the polymer solution through a magnetic filter that forms a magnetic field with a magnetic flux density of 100 gauss or more. Because 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 low magnetic properties, and most preferably 5000 gauss or more.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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).

[0112] 3. Slurry for all-solid-state secondary batteries A slurry for an all-solid-state secondary battery according to one embodiment of the present invention contains the above-mentioned binder composition for an all-solid-state secondary battery 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.

[0113] 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.

[0114] 3.1.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.

[0115] 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.

[0116] 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.).

[0117] 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.

[0118] <Negative electrode active material> The negative electrode active material is not particularly limited as long as it can reversibly absorb and release lithium ions, etc., and examples thereof include carbonaceous materials, metal oxides such as tin oxide and silicon oxide, elemental lithium, lithium alloys such as lithium-aluminum alloys, metals capable of forming alloys with lithium such as Sn, Si, or In, etc. Among 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.

[0119] 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.

[0120] Silicon-containing materials can absorb more lithium ions than commonly used graphite or 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 volume changes upon absorption and desorption of lithium ions. While graphite and acetylene black experience a volume expansion of approximately 1.2 to 1.5 times upon absorption of lithium ions, silicon-containing negative electrode active materials can experience a volume 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, for example, poor contact and a 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.

[0121] 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.

[0122] 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.

[0123] 3.2.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.

[0124] 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.

[0125] 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.

[0126] <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 c S 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.)

[0127] 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.

[0128] The sulfide-based solid electrolyte may be amorphous (glass), crystalline (glass ceramic), or only partially crystallized.

[0129] In the Li-PS glass and Li-PS 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.

[0130] 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 12Among 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.

[0131] 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.

[0132] 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.

[0133] <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:

[0134] 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).

[0135] 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.

[0136] 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.

[0137] 3.3. 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.

[0138] <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.

[0139] <Thickener> Specific examples of the thickener include the thickeners exemplified in the section <Thickener> of "2.2. 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.

[0140] <Liquid medium> Specific examples of the liquid medium include the liquid medium exemplified in the above section "2.1. Liquid Medium (B)". 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 (B) 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 conjugated diene copolymer (A) and the active material during the drying treatment after coating.

[0141] 3.4. 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 4.Solid electrolyte sheet A solid electrolyte sheet according to one embodiment of the present invention has a layer formed by applying the above-mentioned slurry for an all-solid-state secondary battery onto a substrate and drying it.

[0146] The solid electrolyte sheet according to this embodiment can be produced by applying the slurry for an all-solid-state secondary battery described above to 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 5. Electrodes for all-solid-state secondary batteries and all-solid-state secondary batteries An electrode for an all-solid-state secondary battery according to one embodiment of the present invention comprises a current collector and an active material layer formed by coating 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 coating the surface of a current collector such as a metal foil with the above-described all-solid-state secondary battery slurry to form a coating film, and then drying the coating 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 conjugated diene copolymer (A), a solid electrolyte, and an 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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 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.

[0160] 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 conjugated diene copolymer (A). Specifically, a temperature of 30°C or higher is preferred, 60°C or higher is more preferred, and 100°C or higher is most preferred. The upper limit is preferably 300°C or lower, more preferably 250°C or lower. Heating within this temperature range softens the conjugated diene copolymer (A) while maintaining its shape. This allows for good adhesion and lithium ion conductivity in the all-solid-state secondary battery.

[0161] It is also preferable to apply pressure while heating. 2 More than 10kN / cm is preferable. 2 More preferably, it is 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.

[0162] 6. 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.

[0163] 6.1.Measuring methods for each physical property In the following examples and comparative examples, the methods for measuring the various physical properties are as follows.

[0164] (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.

[0165] (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.

[0166] (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

[0167] (4) Hydrogenation rate (%) and [α] The hydrogenation rate (%) and [α] of the polymer were measured using deuterated chloroform as a solvent and a 500 MHz 1 It was determined by H-NMR, where [α] is the value represented by the above formula (i).

[0168] (5) Storage modulus (G') and loss tangent (tanδ) The polymer was dissolved in xylene and then dried at 40°C for 24 hours to produce a uniform film with a thickness of 1.0±0.3 mm. This film was then dried in a vacuum dryer at 160°C for 30 minutes. The film was removed from the vacuum dryer and cut into 10 mm x 10 mm strips to serve as measurement samples. Next, using a dynamic viscoelasticity measuring device (manufactured by Anton Paar, model "MCR 301"), the measurement sample was fixed on a parallel plate (product name "PP-12") and dynamic viscoelasticity was measured under the conditions of shear mode, measurement temperature 25°C, frequency 0.1 Hz, and strain 1%, to obtain the storage modulus and loss tangent.

[0169] 6.2. Synthesis example of conjugated diene copolymer <Synthesis of hydrogenation catalyst E> Hydrogenation catalyst E used in the following Synthesis Examples 9 and 10 was synthesized as follows. A 1 L three-necked flask equipped with a stirrer and a dropping funnel was purged with dry nitrogen, and 200 ml of anhydrous tetrahydrofuran and 0.2 mol of tetrahydrofurfuryl alcohol were added. Then, an n-butyllithium / cyclohexane solution (0.2 mol) was added dropwise to the three-necked flask at 15°C to carry out a reaction, thereby obtaining a tetrahydrofurfuryloxylithium tetrahydrofuran solution. Next, a 1 L three-necked flask equipped with a stirrer and a dropping funnel was purged with dry nitrogen, and 49.8 g (0.2 mol) of bis(η5-cyclopentadienyl)titanium dichloride and 250 ml of anhydrous tetrahydrofuran were added. Then, the tetrahydrofuran solution of tetrahydrofurfuryloxylithium obtained by the method described above was added dropwise to the flask over approximately 1 hour with stirring at room temperature. After approximately 2 hours, the reddish-brown liquid was filtered, and the insoluble portion was washed with dichloromethane. The filtrate and washings were then combined and the solvent was removed under reduced pressure to obtain hydrogenation catalyst E [bis(η5-cyclopentadienyl)titanium(tetrahydrofurfuryloxy)chloride] (also referred to as "chlorobis(2,4-cyclopentadienyl)titanium(IV) tetrahydrofurfurylalkoxide"). The yield was 95%.

[0170] <Synthesis Example 1> A 50-liter autoclave reactor with a nitrogen-purged atmosphere was charged with 25 kg of cyclohexane as a hydrocarbon solvent, 500 g of tetrahydrofuran as a vinyl control agent, 1000 g of styrene, 3850 g of 1,3-butadiene, and 0.55 g of divinylbenzene (55% purity by mass) (as m-, p-divinylbenzene). The temperature of the reactor contents was adjusted to 10°C, and 50 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 reaching 85°C. When the polymerization conversion reached 99% (26 minutes after the start of polymerization), an additional 150 g of 1,3-butadiene was added and the polymerization was continued for another 3 minutes. After that, 2.5 mmol of tin tetrachloride was added and the reaction was continued for 30 minutes. 44 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.

[0171] To the resulting polymer solution, 15 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 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 1,2-vinyl bond content of polymer (A-1) was 56 mol%, the bound styrene content was 20%, and the weight average molecular weight (Mw) was 303 x 10 3 and the storage modulus (G') is 130×10 3 Pa and loss tangent (tan δ) were 0.198.

[0172] <Synthesis Examples 2 to 8, 11, and 12> Polymers (A-2) to (A-8), polymer (A-11) and polymer (A-12) were synthesized according to the synthesis method of Synthesis Example 1, except that the types and amounts of raw materials used were as shown in Table 1. The physical properties of each polymer measured by the above methods are also shown in Table 1.

[0173] <Synthesis Example 9> (Process 1) A 50-liter autoclave reactor with nitrogen purging was charged with 26 kg of cyclohexane as a hydrocarbon solvent, 60 g of tetrahydrofuran, 370 g of styrene, and 3264 g of 1,3-butadiene. After adjusting the temperature of the reactor contents to 45°C, a cyclohexane solution containing n-butyllithium (39 mmol) was added to initiate polymerization. The polymerization was carried out under adiabatic conditions, with the maximum temperature reaching 80°C. After confirming that the polymerization conversion had reached 99%, 111 g of butadiene was added and the polymerization was continued for an additional 5 minutes. Then, 2 mmol of tin tetrachloride was added and the reaction was continued for 10 minutes. Then, 28 mmol of N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane (BTADS) was added and the reaction was continued for 20 minutes.

[0174] (Process 2) The reaction solution obtained in step 1 was heated to 80°C or higher and hydrogen was introduced into the system, followed by the addition of 3.2 g of diethylaluminum chloride, 2.4 g of hydrogenation catalyst E, and 15 mmol of n-butyllithium. Hydrogen was supplied to the system while maintaining a hydrogen pressure of 0.7 MPa or higher until a predetermined integrated hydrogen value was reached, allowing the reaction to proceed. The reaction solution was then returned to room temperature and pressure and withdrawn from the reactor to obtain a polymer solution. 15 g of 2,6-di-tert-butyl-p-cresol was added to the resulting polymer solution containing the hydrogenated conjugated diene copolymer. Next, an aqueous solution (temperature: 80°C) adjusted to pH 8.5 (pH at 80°C by glass electrode method) with ammonia as a pH adjuster was placed in a desolvation tank, and the polymer solution was added (1000 parts by mass of the aqueous solution per 100 parts by mass of the polymer solution). The solvent was removed by steam stripping (steam temperature: 190°C) for 2 hours at a liquid phase temperature of 95°C in the desolvation tank, and the mixture was dried using a heated roll heated to 110°C to obtain polymer (A-9). The hydrogenation rate of polymer (A-9) was 60% (α = 0.60), and other physical properties are shown in Table 1.

[0175] <Synthesis Example 10> Polymerization and desolvation were carried out in the same manner as in Synthesis Example 9, except that the amount of hydrogen supplied in step 2 was changed, to obtain a polymer (A- 10 The polymer (A- 10 The hydrogenation rate of ) was 88% (α=0.88), and other physical properties were as shown in Table 1.

[0176] <Synthesis Example 13> A 50-liter autoclave reactor purged with nitrogen was charged with 25 kg of cyclohexane as a hydrocarbon solvent, 500 g of tetrahydrofuran as a vinyl control agent, 1,000 g of styrene, and 3,900 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 10°C, and polymerization was initiated by adding 50 mmol of n-butyllithium and 44 mmol of N-trimethylsilylpiperazine as polymerization initiators. The polymerization was carried out under adiabatic conditions, with a maximum temperature reaching 85°C. When the polymerization conversion reached 99% (26 minutes after the start of polymerization), an additional 100 g of 1,3-butadiene was added and polymerization was continued for another 3 minutes. After this, 44 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.

[0177] To the resulting polymer solution, 42.3 mmol of silicon tetrachloride was added as an onium generating agent and stirred for an additional 10 minutes. 15 g of 2,6-di-tert-butyl-p-cresol was added, and then the solvent was removed by steam stripping using hot water to obtain a modified conjugated diene copolymer. The modified conjugated diene copolymer was then dried using a heated roll adjusted to 110°C to obtain polymer (A-13). The 1,2-vinyl bond content of polymer (A-13) was 56 mol%, the bound styrene content was 20%, and the weight average molecular weight (Mw) was 297 x 10 3 and the storage modulus (G') is 221 × 10 3 Pa and loss tangent (tan δ) were 0.083.

[0178] Example 1 6.3.1. Preparation of the Binder Composition The polymer (A-1) obtained in Synthesis Example 1 above and 400 ppm of IRGANOX 1520L and 200 ppm of Sumilizer TP-D as antioxidants were added to anisole, which was the liquid medium (B), and the mixture was stirred at 90°C for 3 hours to dissolve the polymer (A-1) and the antioxidant in the anisole. The binder composition was then transferred to a three-neck flask, and while maintaining a reduced pressure of 100 Torr, dry nitrogen gas with a water vapor content of 25.0 mg / L or less was bubbled through at 90°C for 4 hours to prepare a binder composition with a residual water content reduced to 43 ppm. This binder composition was then passed through a cartridge filter (Advantec Co., Ltd., all-fluororesin cartridge filter, product name "TCF-300-H5MF") with a filter membrane having an average pore size of 3.00 μm, and then through a magnetic filter (Tok Engineering Co., Ltd., magnetic flux density 8000 Gauss), after which it was filled into a 1 L Hyper Pure bottle (a multilayer barrier container for ultra-high purity solvents) commercially available from Kodama Resin Industry Co., Ltd. The total solids content was 10.3% when the entire binder composition was taken as 100% by mass. This preparation work was carried out in a dry room at a room temperature of 25°C, cleanliness class 7 according to ISO 14644-1, and an indoor dew point of -40°C DP or less.

[0179] 6.3.2. Preparation of Slurry for All-Solid-State Secondary Batteries <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.

[0180] <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.

[0181] <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.

[0182] 6.3.3. Preparation and evaluation of positive and negative electrodes and solid electrolyte layers for all-solid-state secondary batteries <Preparation of positive electrodes for all-solid-state secondary batteries> 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.

[0183] <Preparation of solid electrolyte layer> 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.

[0184] <Fabrication of negative electrodes for all-solid-state secondary batteries> 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.

[0185] <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 below. (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.

[0186] <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 below. 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.

[0187] <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 below. 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 -4 S / 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.

[0188] 6.3.4. Fabrication and Evaluation of All-Solid-State Secondary Batteries <Fabrication of 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 all-solid-state secondary battery positive electrode was bonded to one side of the 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 all-solid-state secondary battery negative electrode was bonded to the other side of the 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. The all-solid-state secondary battery laminate thus prepared was then placed in a stainless steel 2032-type coin case incorporating a spacer and washer, and the 2032-type coin case was crimped to produce an all-solid-state secondary battery.

[0189] <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 produced 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 below. 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%.

[0190] <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. Subsequently, the battery was 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 below. "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 able to charge and discharge without any problems. A: Of the 10 all-solid-state secondary batteries, 7 to 8 were able to charge and discharge without any problems. B: Of the 10 all-solid-state secondary batteries, 4 to 6 were able to charge and discharge without any problems. C: Of the 10 all-solid-state secondary batteries, 0 to 3 were able to charge and discharge without any abnormalities.

[0191] 6.4. Example 2 10 , Comparative Example 1~ 3 A binder composition, a slurry for an all-solid-state secondary battery, a positive electrode / negative electrode / solid electrolyte layer for an all-solid-state secondary battery, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1 above, except that the types and amounts of the components used were as shown in Table 1 below.

[0192] 6.5.Evaluation Results Table 1 below shows Examples 1 to 10 and Comparative Examples 1 to 3 The composition of the polymer used, its properties, and the evaluation results are summarized below.

[0193] [Table 1]

[0194] The abbreviations or product names in Table 1 above represent the following compounds. <Denaturant> BTADS: N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane <Anti-aging agent> BHT: 2,6-di-tert-butyl-p-cresol IRGANOX 1520L: BASF Japan, 2-methyl-4,6-bis[(n-octylthio)methyl]phenol Sumilizer TP-D: Sumitomo Chemical Co., Ltd., pentaerythritol tetra(3-dodecylthiopropionate) <Liquid medium (B)> DIBK: Diisobutyl ketone

[0195] From the results in Table 1 above, Examples 1 to 10It has been confirmed that when the binder and the binder composition containing the binder are used, an electrode having excellent adhesion and flexibility can be obtained, and an all-solid-state secondary battery having excellent lithium ion conductivity and cycle life characteristics and a high yield can be fabricated.

[0196] In addition, Examples 1 to 10 In the publication, a slurry for an all-solid-state secondary battery electrode is used that contains a binder composition for an all-solid-state secondary battery, an active material, and a solid electrolyte. It was confirmed that, in an active material layer formed using this slurry, the active material layer itself does not become brittle during peel strength measurement, causing the active material or solid electrolyte to fall off or cracks, and sufficient polymer binding strength is obtained between both the active material and the solid electrolyte. Therefore, it is presumed that an active material layer formed using the binder composition for an all-solid-state secondary battery according to the present invention has sufficient adhesion to a solid electrolyte layer, and that when a solid electrolyte layer is formed using the binder composition for an all-solid-state secondary battery according to the present invention, high workability is achieved, and the formed solid electrolyte layer has sufficient adhesion to the active material layer.

[0197] 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. having aromatic vinyl units derived from an aromatic vinyl compound and conjugated diene units derived from a conjugated diene compound, The storage modulus (G') measured using a dynamic viscoelasticity measuring device under the conditions of a measurement temperature of 25°C, a frequency of 0.1 Hz, and a strain of 1% is 4.0 x 10 ４ Pa or more 2.0×10 ５ Pa or less and a loss tangent (tanδ) of 0.10 or more and 0.80 or less, a binder for an all-solid-state secondary battery, wherein the conjugated diene copolymer (A) has 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.

2. 2. The binder for an all-solid-state secondary battery according to claim 1, wherein, when the constituent ratios (molar ratios) in the polymer 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 conjugated diene-based copolymer (A) are p, q, r, and s, respectively, the value α represented by the following formula (i) is less than 0.7: α=(p+(0.5×r)) / (p+q+(0.5×r)+s) ・・・(i) 【Chemistry 1】

3. 10. The method according to claim 1, wherein the conjugated diene copolymer (A) has a bound styrene content of 5 to 45%.

3. The binder for an all-solid-state secondary battery according to claim 2.

4. A binder composition for an all-solid-state secondary battery, comprising the binder for an all-solid-state secondary battery according to any one of claims 1 to 3 and a liquid medium (B).

5. 5. The binder composition for an all-solid-state secondary battery according to claim 4, wherein the liquid medium (B) 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 4 or 5, wherein the conjugated diene copolymer (A) is dissolved in the liquid medium (B).

7. A slurry for an all-solid-state secondary battery, comprising the binder composition for an all-solid-state secondary battery according to any one of claims 4 to 6 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 slurry.

11. 9. 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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