Binder composition for all-solid-state secondary battery, slurry composition for all-solid-state secondary battery, solid electrolyte-containing layer and all-solid-state secondary battery

Abstract

The purpose of the present invention is to provide a binder composition which enables the preparation of a slurry composition that exhibits excellent dispersibility, and which is capable of forming a solid electrolyte-containing layer that enables an all-solid-state secondary battery to exhibit excellent cycle characteristics. A binder composition according to the present invention contains a polymer and an aromatic halide. The polymer contains a nitrile group-containing monomer unit at a ratio of from 10% by mass to 35% by mass, while containing a (meth)acrylic acid ester monomer unit at a ratio of from 15% by mass to 40% by mass. The aromatic halide has a structure wherein from 2 to 4 halogen atoms are directly bonded to an aromatic ring; and the content of the aromatic halide in the binder composition is from 5 ppm by mass to 3,000 ppm by mass relative to the content of the polymer.

Description

[Technical Field]

[0001] The present invention relates to a binder composition for an all-solid-state secondary battery, a slurry composition for an all-solid-state secondary battery, a solid electrolyte-containing layer, and an all-solid-state secondary battery. [Background technology]

[0002] In recent years, demand for secondary batteries such as lithium-ion secondary batteries has been increasing for a variety of applications, including not only portable terminals such as personal digital assistants and portable electronic devices, but also small-sized home power storage devices, motorcycles, electric vehicles, hybrid electric vehicles, etc. As the range of applications expands, further improvements in the safety of secondary batteries are being demanded.

[0003] Therefore, as a highly safe secondary battery, all-solid-state secondary batteries using solid electrolytes instead of organic solvent electrolytes, which are highly flammable and have a high risk of catching fire when leaking, have attracted attention. The solid electrolyte is contained in the all-solid-state secondary battery, for example, as a solid electrolyte-containing layer (electrode mixture layer, solid electrolyte layer) in which components such as the solid electrolyte are bound to each other by a binder. Here, to form the solid electrolyte-containing layer, a slurry composition for the solid electrolyte-containing layer is used, which is prepared using a binder composition containing a polymer as a binding material.

[0004] In order to improve the performance of all-solid-state secondary batteries, improvements have been made to polymers used as binders and binder compositions containing such polymers (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 125716 [Patent Document 2] International Publication No. 2012 / 026583 [Patent Document 3] International Publication No. 2019 / 007875 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional binder compositions described above have room for improvement in terms of increasing the dispersibility of the slurry composition and enabling the all-solid-state secondary battery to exhibit excellent cycle characteristics.

[0007] Therefore, an object of the present invention is to provide a binder composition for an all-solid-state secondary battery, which can prepare a slurry composition for an all-solid-state secondary battery having excellent dispersibility and can form a solid electrolyte-containing layer that can cause the all-solid-state secondary battery to exhibit excellent cycle characteristics. Another object of the present invention is to provide a slurry composition for an all-solid-state secondary battery that has excellent dispersibility and is capable of forming a solid electrolyte-containing layer that can enable the all-solid-state secondary battery to exhibit excellent cycle characteristics. Another object of the present invention is to provide a solid electrolyte-containing layer that can enable an all-solid-state secondary battery to exhibit excellent cycle characteristics, and an all-solid-state secondary battery that has excellent cycle characteristics. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and have newly discovered that by using a binder composition containing a predetermined polymer and a predetermined aromatic halide, in which the content of the aromatic halide relative to the content of the polymer is within a predetermined range, it is possible to ensure sufficient dispersibility of the slurry composition while allowing an all-solid-state secondary battery to exhibit excellent cycle characteristics, and have completed the present invention.

[0009] The present invention aims to advantageously solve the above-mentioned problems, and provides a binder composition for an all-solid-state secondary battery, comprising a polymer and an aromatic halide, wherein the polymer contains nitrile group-containing monomer units in a proportion of 10% to 35% by mass and (meth)acrylic acid ester monomer units in a proportion of 15% to 40% by mass, the aromatic halide has a structure in which two to four halogen atoms are directly bonded to an aromatic ring, and the content of the aromatic halide is 5 ppm by mass to 3,000 ppm by mass relative to the content of the polymer. By using a binder composition containing the polymer and the aromatic halide having the predetermined structure, where the ratio of the polymer to the aromatic halide content is within the above range, a slurry composition with excellent dispersibility and a solid electrolyte-containing layer that can provide an all-solid-state secondary battery with excellent cycle characteristics can be obtained. In the present invention, the content of aromatic halides can be measured by gas chromatography. In the present invention, the term "(meth)acrylic" means acrylic and / or methacrylic. In the present invention, "containing a monomer unit" means that "a polymer obtained using the monomer contains a structural unit derived from the monomer." In addition, in the present invention, the content (mass %) of the "structural unit" (including the "monomer unit") in the polymer is 1 It can be measured using nuclear magnetic resonance (NMR) techniques such as H-NMR.

[0010] Here, the binder composition for an all-solid-state secondary battery of the present invention preferably contains a metal belonging to Period 5 of the periodic table and Groups 3 to 14 of the periodic table in an amount of 0.5 ppm by mass to 200 ppm by mass, based on the content of the polymer. If the binder composition contains a metal belonging to Period 5 of the periodic table and Groups 3 to 14 of the periodic table (hereinafter sometimes abbreviated as "Period 5 metal") in an amount within the above range, the cycle characteristics of the all-solid-state secondary battery can be further improved, while the output characteristics can be increased. In the present invention, the contents of various metals contained in the binder composition can be measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Specifically, the contents can be measured using the method described in the examples.

[0011] In addition, the binder composition for an all-solid-state secondary battery of the present invention preferably contains a metal belonging to Group 1 or Group 2 of the periodic table in an amount of 5 ppm by mass to 3,000 ppm by mass, based on the content of the polymer. If the binder composition contains a metal belonging to Group 1 or Group 2 of the periodic table (hereinafter sometimes abbreviated as "Group 1-2 metal") in an amount within the above range, the dispersibility of the slurry composition can be further improved while ensuring the water resistance of the solid electrolyte, thereby improving the cell characteristics of the all-solid-state secondary battery (i.e., improving the cycle characteristics and output characteristics while reducing the IV resistance of the all-solid-state secondary battery).

[0012] In the binder composition for an all-solid-state secondary battery of the present invention, the iodine value of the polymer is preferably 0.5 mg / 100 mg or more and 20 mg / 100 mg or less. When the iodine value of the polymer is within the above range, the adhesion of the solid electrolyte-containing layer can be improved while suppressing oxidative degradation of the electrode active material (particularly the positive electrode active material), thereby further improving the cycle characteristics of the all-solid-state secondary battery. In the present invention, the "iodine value" of the polymer can be measured by the method described in the examples.

[0013] Here, in the binder composition for an all-solid-state secondary battery of the present invention, the number of carbon atoms constituting the alkyl group bonded to the non-carbonyl oxygen atom possessed by the (meth)acrylic acid ester monomer unit is preferably 4 or more and 9 or less. If a structural unit derived from a (meth)acrylic acid ester monomer in which the number of carbon atoms constituting the alkyl group bonded to the non-carbonyl oxygen atom is 4 or more and 9 or less is used as the (meth)acrylic acid ester monomer unit, the dispersibility of the slurry composition and the cycle characteristics of the all-solid-state secondary battery can be further improved.

[0014] The binder composition for an all-solid-state secondary battery of the present invention can further contain a solvent. In the present invention, the above aromatic halides having a structure in which two or more and four or less halogen atoms are directly bonded to an aromatic ring are not included in the "solvent".

[0015] The present invention also aims to advantageously solve the above-mentioned problems, and provides a slurry composition for an all-solid-state secondary battery, characterized in that it contains the binder composition for an all-solid-state secondary battery, which contains a solid electrolyte and a solvent. A slurry composition containing a solid electrolyte, the polymer, the aromatic halide, and a solvent, and in which the ratio of the polymer content to the aromatic halide content is within the above-mentioned range, has excellent dispersibility, and by using this slurry composition, it is possible to form a solid electrolyte-containing layer that can provide an all-solid-state secondary battery with excellent cycle characteristics.

[0016] The slurry composition for an all-solid-state secondary battery of the present invention can further contain an electrode active material. The slurry composition for an all-solid-state secondary battery containing the electrode active material can be used as a slurry composition for an electrode mixture layer.

[0017] In addition, the slurry composition for an all-solid-state secondary battery of the present invention containing an electrode active material preferably further contains carbon nanotubes. Use of a slurry composition for an electrode mixture layer containing carbon nanotubes (hereinafter sometimes abbreviated as "CNTs") can further improve the cell characteristics of the all-solid-state secondary battery.

[0018] The present invention also aims to advantageously solve the above-mentioned problems, and provides a solid electrolyte-containing layer formed using any of the above-mentioned slurry compositions for an all-solid-state secondary battery. The solid electrolyte-containing layer formed using any of the above-mentioned slurry compositions can enable the all-solid-state secondary battery to exhibit excellent cycle characteristics.

[0019] The present invention has an object to advantageously solve the above-mentioned problems, and provides an all-solid-state secondary battery comprising the above-mentioned solid electrolyte-containing layer. The all-solid-state secondary battery comprising the above-mentioned solid electrolyte-containing layer has excellent cell characteristics such as cycle characteristics. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a binder composition for an all-solid-state secondary battery, which can prepare a slurry composition for an all-solid-state secondary battery having excellent dispersibility and can form a solid electrolyte-containing layer that can cause the all-solid-state secondary battery to exhibit excellent cycle characteristics. Furthermore, according to the present invention, it is possible to provide a slurry composition for an all-solid-state secondary battery that has excellent dispersibility and is capable of forming a solid electrolyte-containing layer that can cause the all-solid-state secondary battery to exhibit excellent cycle characteristics. Furthermore, according to the present invention, it is possible to provide a solid electrolyte-containing layer that can enable an all-solid-state secondary battery to exhibit excellent cycle characteristics, and an all-solid-state secondary battery that has excellent cycle characteristics. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail. The binder composition for an all-solid-state secondary battery of the present invention is used in preparing a slurry composition for an all-solid-state secondary battery. Here, the slurry composition for an all-solid-state secondary battery of the present invention is used when forming a solid electrolyte-containing layer such as an electrode mixture layer or a solid electrolyte layer used in an all-solid-state secondary battery such as an all-solid-state lithium-ion secondary battery. That is, the slurry composition for an all-solid-state secondary battery of the present invention can be used as a slurry composition for an electrode mixture layer or a slurry composition for a solid electrolyte layer. Furthermore, the solid electrolyte-containing layer of the present invention is formed using the slurry composition for an all-solid-state secondary battery of the present invention. Furthermore, the all-solid-state secondary battery of the present invention comprises the solid electrolyte-containing layer of the present invention.

[0022] (Binder composition for all-solid-state secondary battery) The binder composition of the present invention contains a polymer and an aromatic halide in which two or more and four or less halogen atoms are directly bonded to an aromatic ring, and may optionally further contain at least one selected from the group consisting of period 5 metals, group 1-2 metals, solvents, and other components. Here, the binder composition of the present invention is characterized in that the polymer contains nitrile group-containing monomer units in a proportion of 10% by mass to 35% by mass and (meth)acrylic acid ester monomer units in a proportion of 15% by mass to 40% by mass, and the content of the aromatic halide relative to the polymer is 5 ppm by mass to 3,000 ppm by mass.

[0023] Furthermore, in the binder composition of the present invention, the content ratios of the nitrile group-containing monomer unit and the (meth)acrylic acid ester monomer unit in the polymer are each within the above-mentioned ranges, and the content of the aromatic halide relative to the polymer is within the above-mentioned range. Therefore, by using this binder composition, it is possible to obtain a slurry composition having excellent dispersibility and a solid electrolyte-containing layer that can enable an all-solid-state secondary battery to exhibit excellent cycle characteristics.

[0024] <Polymer> The polymer functions as a binder that binds components such as the solid electrolyte together in the solid electrolyte-containing layer formed from the slurry composition prepared using the binder composition.

[0025] <<Composition>> Here, the polymer must contain nitrile group-containing monomer units in a proportion of 10% by mass to 35% by mass and (meth)acrylic acid ester monomer units in a proportion of 15% by mass to 40% by mass. The polymer may contain structural units (other structural units) other than the nitrile group-containing monomer units and the (meth)acrylic acid ester monomer units.

[0026] [Nitrile group-containing monomer unit] Examples of nitrile group-containing monomers that can form nitrile group-containing monomer units include acrylonitrile; α-halogenoacrylonitriles such as α-chloroacrylonitrile and α-bromoacrylonitrile; and α-alkylacrylonitriles such as methacrylonitrile and α-ethylacrylonitrile. These may be used alone or in combination of two or more. Among these, acrylonitrile is preferred.

[0027] Here, the proportion of nitrile group-containing monomer units among all structural units contained in the polymer, assuming all structural units to be 100% by mass, must be 10% by mass or more and 35% by mass or less, as described above, preferably 12% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 30% by mass or less, more preferably 28.5% by mass or less, and even more preferably 27% by mass or less. If the proportion of nitrile group-containing monomer units among all structural units of the polymer is less than 10% by mass, the polymer cannot be sufficiently adsorbed to the solid electrolyte, and the solid electrolyte cannot be well dispersed in the slurry composition. This results in a decrease in dispersibility of the slurry composition. On the other hand, if the proportion of nitrile group-containing monomer units among all structural units of the polymer is more than 35% by mass, the solubility in the solvent contained in the slurry composition decreases, resulting in a decrease in dispersibility of the slurry composition. When the proportion of the nitrile group-containing monomer units in the total structural units of the polymer is 10% by mass or more and 35% by mass or less, it is possible to prepare a slurry composition with excellent dispersibility and improve the cell characteristics (such as cycle characteristics) of the all-solid-state secondary battery.

[0028] [(Meth)acrylic acid ester monomer unit] Examples of (meth)acrylic acid ester monomers that can form (meth)acrylic acid ester monomer units include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate; acrylic acid alkoxy esters such as 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate; and 2-(perfluoroalkyl)ethyl acrylates such as 2-(perfluorobutyl)ethyl acrylate and 2-(perfluoropentyl)ethyl acrylate. methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, n-tetradecyl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate; methacrylic acid alkoxy esters such as 2-methoxyethyl methacrylate and 2-ethoxyethyl methacrylate; and 2-(perfluoroalkyl)ethyl methacrylates such as 2-(perfluorobutyl)ethyl methacrylate and 2-(perfluoropentyl)ethyl methacrylate. These may be used alone or in combination of two or more. As the (meth)acrylic acid ester monomer, a (meth)acrylic acid alkyl ester monomer in which the number of carbon atoms constituting the alkyl group bonded to the non-carbonyl oxygen atom is 4 or more and 9 or less (hereinafter, sometimes abbreviated as "C4-C9 (meth)acrylic acid alkyl ester monomer") is preferred.The use of a C4-C9 (meth)acrylic acid alkyl ester monomer can disperse the solid electrolyte well in the slurry composition, further improving the dispersibility of the slurry composition. It can also impart appropriate flexibility to the solid electrolyte-containing layer, further improving the cell characteristics of the all-solid-state secondary battery. Examples of preferred C4-C9 (meth)acrylic acid alkyl ester monomers include n-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.

[0029] Here, the proportion of (meth)acrylic acid ester monomer units among all structural units contained in the polymer, assuming all structural units to be 100% by mass, must be 15% by mass or more and 40% by mass or less, as described above, preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, preferably 37.5% by mass or less, and more preferably 35% by mass or less. If the proportion of (meth)acrylic acid ester monomer units among all structural units of the polymer is less than 15% by mass, the adhesiveness of the solid electrolyte-containing layer decreases. On the other hand, if the proportion of (meth)acrylic acid ester monomer units among all structural units of the polymer exceeds 40% by mass, the flexibility of the solid electrolyte-containing layer cannot be sufficiently ensured. If the proportion of (meth)acrylic acid ester monomer units among all structural units of the polymer is 15% by mass or more and 40% by mass or less, a solid electrolyte-containing layer with excellent adhesiveness and flexibility can be formed, and the cell characteristics (such as cycle characteristics) of the all-solid-state secondary battery can be improved.

[0030] Other structural units The other structural units are not particularly limited as long as they are structural units derived from a monomer copolymerizable with the above-mentioned nitrile group-containing monomer and (meth)acrylic acid ester monomer. However, from the viewpoints of ensuring the dispersibility of the slurry composition and the flexibility of the solid electrolyte-containing layer and improving the cell characteristics of the all-solid-state secondary battery, diene-based monomer units are preferred.

[0031] Examples of the diene monomer capable of forming the diene monomer unit include aliphatic conjugated diene monomers such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, etc. These may be used alone or in combination of two or more. In the present invention, the term "diene monomer unit" also includes a structural unit (hydride unit) obtained by further hydrogenating a monomer unit contained in a polymer obtained using a diene monomer. Among the diene monomers described above, 1,3-butadiene and isoprene are preferred. In other words, the diene monomer units are preferably 1,3-butadiene units, isoprene units, 1,3-butadiene hydride units, and isoprene hydride units, with 1,3-butadiene hydride units and isoprene hydride units being more preferred.

[0032] When the polymer contains diene monomer units, the proportion of the diene monomer units among all structural units contained in the polymer is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 40% by mass or more, and preferably 75% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, where the total structural units are 100% by mass. When the proportion of the diene monomer units among all structural units is 10% by mass or more, the polymer can be favorably adsorbed to the electrode active material and conductive material, thereby further improving the dispersibility of the slurry composition (particularly the slurry composition for the electrode mixture layer). On the other hand, when the proportion of the diene monomer units among all structural units is 75% by mass or less, the adhesiveness of the solid electrolyte-containing layer can be sufficiently ensured. Therefore, when the proportion of the diene monomer units among all structural units of the polymer is 10% by mass or more and 75% by mass or less, the cell characteristics of the all-solid-state secondary battery can be further improved.

[0033] <<Iodine value>> The polymer preferably has an iodine value of 0.5 mg / 100 mg or more, more preferably 1.0 mg / 100 mg or more, even more preferably 2.0 mg / 100 mg or more, and preferably 20 mg / 100 mg or less, more preferably 15 mg / 100 mg or less, and even more preferably 10 mg / 100 mg or less. If the iodine value of the polymer is 0.5 mg / 100 mg or more, the strength of the polymer can be ensured and the adhesion of the solid electrolyte-containing layer can be improved. If the iodine value is 20 mg / 100 mg or less, oxidative degradation of the electrode active material (especially the positive electrode active material) can be suppressed. Therefore, if the iodine value of the polymer is 0.5 mg / 100 mg or more and 20 mg / 100 mg or less, the cycle characteristics of the all-solid-state secondary battery can be further improved.

[0034] <<Weight average molecular weight (Mw)>> The polymer preferably has a weight-average molecular weight of 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more, and preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. If the weight-average molecular weight of the polymer is 10,000 or more, the adhesion of the solid electrolyte-containing layer can be improved and the cycle characteristics of the all-solid-state secondary battery can be further improved. On the other hand, if the weight-average molecular weight of the polymer is 2,000,000 or less, the dispersibility of the slurry composition can be further improved.

[0035] <<Molecular weight distribution (Mw / Mn)>> The polymer preferably has a molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) of 1.5 or more, more preferably 2.0 or more, and even more preferably 2.5 or more, and preferably 5.5 or less, more preferably 5 or less, and even more preferably 4.5 or less. If the molecular weight distribution of the polymer is 1.5 or more and 5.5 or less, the dispersibility of the slurry composition can be further improved, while the adhesiveness of the solid electrolyte-containing layer can be improved, and the cell characteristics of the all-solid-state secondary battery can be further improved.

[0036] <<Preparation method>> The method for preparing the polymer is not particularly limited. For example, the polymer can be prepared by polymerizing a monomer composition containing the above-mentioned monomers and optionally hydrogenating the polymer. In the present invention, the content of each monomer in the monomer composition can be determined in accordance with the content of each monomer unit in the polymer. The polymerization method is not particularly limited, and any method such as solution polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization can be used. In each polymerization method, a known emulsifier or polymerization initiator can be used as needed. As the emulsifier, a nonionic emulsifier such as polyoxyethylene lauryl ether can be used, but an emulsifier containing a Group 1 or 2 metal such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium dodecyldiphenylethersulfonate, or sodium polyoxyethylene alkyl ether sulfate can also be used.

[0037] The hydrogenation method is not particularly limited, and can be carried out using a known hydrogenation method such as oil phase hydrogenation or aqueous phase hydrogenation. The catalyst used for hydrogenation can be any known selective hydrogenation catalyst, and can include palladium-based catalysts and rhodium-based catalysts. Two or more of these catalysts can be used in combination. The hydrogenation may be carried out, for example, by the method described in Japanese Patent No. 4509792. Specifically, the hydrogenation of the polymer may be carried out after carrying out a metathesis reaction of the polymer in the presence of a catalyst and a co-olefin. Here, known ruthenium catalysts can be used as the catalyst for the metathesis reaction. Among them, Grubbs catalysts such as bis(tricyclohexylphosphine)benzylidene ruthenium dichloride and 1,3-bis(2,4,6-trimethylphenyl)-2-(imidazolidinylidene)(dichlorophenylmethylene)(tricyclohexylphosphine)ruthenium are preferred. Furthermore, olefins having 2 to 16 carbon atoms, such as ethylene, isobutane, and 1-hexane, can be used as the coolefin. Furthermore, known homogeneous hydrogenation catalysts, such as Wilkinson's catalyst ((PPh3)3RhCl), can be used as the hydrogenation catalyst for hydrogenation after the metathesis reaction. When the obtained polymer is recovered by coagulation, a coagulant containing a Group 1 or 2 metal such as calcium chloride may be used.

[0038] <Aromatic halides> The binder composition of the present invention contains an aromatic halide having a structure in which two to four halogen atoms are directly bonded to an aromatic ring. Presumably due to the high polarity of such aromatic halides, preparing a slurry composition using a binder composition containing such an aromatic halide improves the wettability of the solid electrolyte in the slurry composition with respect to the solvent. This improves the dispersibility of the slurry composition. Furthermore, aromatic halides having the above-described specific structure are less likely to cause unexpected side reactions with the solid electrolyte. Therefore, by using a binder composition containing such an aromatic halide, it is possible to prepare a slurry composition with excellent dispersibility and fabricate an all-solid-state secondary battery with excellent cell characteristics, such as cycle performance.

[0039] Here, the aromatic halide is not particularly limited as long as it has a structure in which two or more and four or less halogen atoms are directly bonded to an aromatic ring, and examples thereof include aromatic chlorides, aromatic fluorides, and aromatic bromides. Among these, aromatic chlorides are preferred from the viewpoint of further improving the dispersibility of the slurry composition and achieving even better cell characteristics in the all-solid-state secondary battery. The aromatic chloride is preferably a compound in which two to four hydrogen atoms present on an aromatic hydrocarbon ring, such as a benzene ring, are substituted with chlorine atoms. Examples of such compounds include dichlorobenzenes such as 1,2-dichlorobenzene, 1,3-dichlorobenzene, and 1,4-dichlorobenzene; trichlorobenzenes such as 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, and 1,3,5-trichlorobenzene; and tetrachlorobenzenes such as 1,2,3,4-tetrachlorobenzene and 1,2,4,5-tetrachlorobenzene. Among these, dichlorobenzenes are preferred, and 1,2-dichlorobenzene is more preferred, from the viewpoints of further improving the dispersibility of the slurry composition and the cell characteristics of the all-solid-state secondary battery, as well as enhancing the adhesiveness of the solid electrolyte-containing layer. The aromatic halides may be used alone or in combination of two or more.

[0040] The content of the aromatic halide in the binder composition must be 5 ppm by mass or more and 3,000 ppm by mass or less relative to the content of the above-mentioned polymer, preferably 10 ppm by mass or more, more preferably 15 ppm by mass or more, even more preferably 50 ppm by mass or more, and preferably 1,000 ppm by mass or less, and more preferably 500 ppm by mass or less. If the content of the aromatic halide relative to the polymer is less than 5 ppm by mass, the dispersibility of the slurry composition decreases, and an all-solid-state secondary battery with excellent cell characteristics such as cycle performance cannot be obtained. On the other hand, if the content of the aromatic halide relative to the polymer exceeds 3,000 ppm by mass, it becomes difficult to disperse the electrode active material well, particularly when the slurry composition contains an electrode active material (i.e., when the slurry composition is a slurry composition for an electrode mixture layer), and the dispersibility of the slurry composition decreases. In addition, if the content of the aromatic halide relative to the polymer exceeds 3,000 ppm by mass, halogen gas may be generated inside the all-solid-state secondary battery, which may impair cell characteristics. Therefore, when the content of the aromatic halide in the binder composition is 5 ppm by mass or more and 3,000 ppm by mass or less with respect to the content of the polymer, the dispersibility of the slurry composition can be improved, and the all-solid-state secondary battery can exhibit good cell characteristics such as cycle characteristics.

[0041] The method for incorporating an aromatic halide into the binder composition is not particularly limited. For example, a binder composition containing an aromatic halide can be prepared by carrying out a polymerization reaction and / or a hydrogenation reaction using a reaction solvent containing an aromatic halide when preparing a polymer, or by adding an aromatic halide after preparing a polymer.

[0042] <Metals belonging to the 5th period of the periodic table and to groups 3 to 14 of the periodic table> The binder composition of the present invention preferably contains a period 5 metal. It is presumed that the inclusion of a period 5 metal in the binder composition reduces the electronic resistance of the all-solid-state secondary battery, and the cell characteristics of the all-solid-state secondary battery can be improved.

[0043] Here, from the viewpoint of further improving the cell characteristics of the all-solid-state secondary battery, preferred examples of the fifth period metal include ruthenium (Ru), rhodium (Rh), and palladium (Pd). These may be used alone or in combination of two or more.

[0044] Furthermore, the content of the 5th period metal in the binder composition is preferably 0.5 ppm by mass or more, more preferably 1 ppm by mass or more, even more preferably 2 ppm by mass or more, particularly preferably 8 ppm by mass or more, and preferably 200 ppm by mass or less, more preferably 150 ppm by mass or less, and even more preferably 100 ppm by mass or less, relative to the content of the polymer. If the content of the 5th period metal is 1 ppm by mass or more relative to the polymer, the cell characteristics of the all-solid-state secondary battery can be further improved. On the other hand, if the content of the 5th period metal is 200 ppm by mass or less relative to the polymer, the cycle characteristics of the all-solid-state secondary battery can be sufficiently improved, and short circuits between electrodes due to precipitation of the 5th period metal will not occur.

[0045] The method for incorporating a period 5 metal into the binder composition is not particularly limited. For example, when preparing a polymer, a catalyst containing a period 5 metal, such as the above-mentioned palladium catalyst, rhodium catalyst, ruthenium catalyst, or Wilkinson's catalyst, can be used, or after preparing a polymer, a substance capable of supplying a period 5 metal (for example, a palladium-based compound such as an organic complex or organic salt of palladium, a rhodium-based compound such as an organic complex or organic salt of rhodium, or a ruthenium-based compound such as an organic complex or organic salt of ruthenium) can be added to prepare a binder composition containing a period 5 metal.

[0046] <Metals belonging to Group 1 or 2 of the Periodic Table> The binder composition of the present invention preferably contains a Group 1 or 2 metal. By including a Group 1 or 2 metal in the binder composition, the cell characteristics of an all-solid-state secondary battery can be improved. While the reason for this is unclear, it is presumed that the Group 1 or 2 metal in the slurry composition and in the solid electrolyte-containing layer is adsorbed to the surface of the solid electrolyte by electrostatic interaction or the like, coating the surface, thereby suppressing the reaction between water and the solid electrolyte and inhibiting deterioration of the solid electrolyte due to the reaction.

[0047] Examples of Group 1-2 metals include sodium (Na), potassium (K), lithium (Li), magnesium (Mg), and calcium (Ca). These may be used alone or in combination of two or more. Among these, sodium and calcium are preferred from the viewpoint of further improving the cell characteristics of the all-solid-state secondary battery.

[0048] Furthermore, the content of the Group 1-2 metal in the binder composition is preferably 5 ppm by mass or more, more preferably 10 ppm by mass or more, even more preferably 50 ppm by mass or more, and particularly preferably 110 ppm by mass or more, relative to the content of the polymer described above, and is preferably 3,000 ppm by mass or less, more preferably 2,000 ppm by mass or less, and even more preferably 1,000 ppm by mass or less. If the content of the Group 1-2 metal is 5 ppm by mass or more relative to the polymer, the cell characteristics of the all-solid-state secondary battery can be further improved. On the other hand, if the content of the Group 1-2 metal is 3,000 ppm by mass or less relative to the polymer, there is no risk of the Group 1-2 metal agglomerating the solid electrolyte, the polymer, etc., and the dispersibility of the slurry composition can be sufficiently ensured.

[0049] The method for incorporating a Group 1-2 metal into a binder composition is not particularly limited. For example, a binder composition containing a Group 1-2 metal can be prepared by using an emulsifier and / or coagulant containing the above-mentioned Group 1-2 metal when preparing a polymer, or by adding a substance capable of supplying the Group 1-2 metal (e.g., a hydroxide containing a Group 1-2 metal) after preparing the polymer. Furthermore, the amount of Group 1-2 metal contained in the resulting binder composition can be reduced by, for example, passing the polymer through an ion exchange resin.

[0050] <Solvent> The binder composition of the present invention optionally contains a solvent. It is preferable to use an organic solvent having 6 or more carbon atoms as the solvent. It is presumed that the inclusion of an organic solvent having 6 or more carbon atoms in the binder composition suppresses aggregation of the polymer, solid electrolyte, etc. in a slurry composition prepared using the binder composition, thereby further improving the dispersibility of the slurry composition. Furthermore, organic solvents having 6 or more carbon atoms are less likely to react with the solid electrolyte and, in addition, have a high boiling point, making them easy to handle. Therefore, by using an organic solvent having 6 or more carbon atoms as the solvent, the solid electrolyte, etc., can be uniformly arranged in the solid electrolyte-containing layer, thereby improving the cell characteristics of the all-solid-state secondary battery.

[0051] <<Organic solvents with 6 or more carbon atoms>> Examples of organic solvents having 6 or more carbon atoms include xylene (8 carbon atoms), butyl butyrate (8 carbon atoms), n-butyl ether (8 carbon atoms), diisobutyl ketone (9 carbon atoms), hexyl butyrate (10 carbon atoms), cyclopentyl methyl ether (6 carbon atoms), hexane (6 carbon atoms), cyclohexane (6 carbon atoms), cyclohexanone (6 carbon atoms), butyl acetate (6 carbon atoms), ε-caprolactone (6 carbon atoms), and isobutyl isobutyrate (8 carbon atoms). These may be used alone or in combination of two or more. Among these, xylene, butyl butyrate, diisobutyl ketone, cyclopentyl methyl ether, and isobutyl isobutyrate are more preferred from the viewpoints of further improving the dispersibility of the slurry composition and further enhancing the cell characteristics of the all-solid-state secondary battery.

[0052] <<Other solvents>> The binder composition of the present invention may contain, as a solvent, a solvent (other solvent) other than the above-mentioned organic solvents having 6 or more carbon atoms. As such other solvents, organic solvents having 5 or less carbon atoms, such as cyclopentane and ethyl acetate, can be used. The other solvents may be used alone or in combination of two or more. However, from the viewpoint of sufficiently enhancing the dispersibility of the slurry composition and the cell characteristics of the all-solid-state secondary battery, the proportion of the organic solvent having 6 or more carbon atoms in the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass (i.e., substantially no other solvents are included), with the entire solvent being 100% by mass.

[0053] <Method for preparing binder composition> The method for preparing the binder composition of the present invention is not particularly limited. For example, the binder composition can be prepared by adding, as necessary, an aromatic halide, a substance capable of supplying a period 5 metal, a substance capable of supplying a group 1 or 2 metal, a solvent, and / or other components to the polymer obtained through polymerization and optional metathesis and hydrogenation as described above. Other components that may optionally be contained in the binder composition include the same as the "other components" described below in the section "Slurry composition for all-solid-state secondary batteries."

[0054] (Slurry composition for all-solid-state secondary battery) The slurry composition for an all-solid-state secondary battery of the present invention includes at least a solid electrolyte and a binder composition for an all-solid-state secondary battery of the present invention, which contains a solvent. More specifically, the slurry composition of the present invention includes a solid electrolyte, the polymer, the aromatic halide, and the solvent, and optionally includes an electrode active material and other components. Since the slurry composition of the present invention includes the binder composition of the present invention, the slurry composition has excellent dispersibility, and when used, it is possible to form a solid electrolyte-containing layer that can improve cell characteristics such as cycle characteristics in an all-solid-state secondary battery.

[0055] <Solid electrolyte> The solid electrolyte is not particularly limited as long as it is made of particles made of a solid having ion conductivity, but inorganic solid electrolytes can be preferably used. The inorganic solid electrolyte is not particularly limited, and a crystalline inorganic ion conductor, an amorphous inorganic ion conductor, or a mixture thereof can be used. For example, when the all-solid-state secondary battery is an all-solid-state lithium ion secondary battery, the inorganic solid electrolyte can usually be a crystalline inorganic lithium ion conductor, an amorphous inorganic lithium ion conductor, or a mixture thereof. In particular, from the viewpoint of forming a solid electrolyte-containing layer having even better ion conductivity, it is preferable that the inorganic solid electrolyte contains at least one of a sulfide-based inorganic solid electrolyte and an oxide-based inorganic solid electrolyte. In the following, a case where the slurry composition for an all-solid-state secondary battery is a slurry composition for an all-solid-state lithium-ion secondary battery will be described as an example, but the present invention is not limited to the following example.

[0056] As crystalline inorganic lithium ion conductors, Li3N, LISICON (Li 14 Zn(GeO4)4), perovskite type (e.g., Li 0.5 La 0.5 TiO3), garnet type (e.g. Li7La3Zr2O 12 ), LIPON(Li 3+y PO 4-x N x ), Thio-LISICON(Li3.25 Ge 0.25 P 0.75 S4), argyrodite type (e.g., Li 5.6 PS 4.4 Cl 1.8 ) etc. The above-mentioned crystalline inorganic lithium ion conductors can be used alone or in combination of two or more.

[0057] Furthermore, examples of amorphous inorganic lithium ion conductors include substances that contain sulfur atoms and have ion conductivity, and more specifically, examples include glass Li-Si-SO, Li-PS, and those made using a raw material composition containing LiS and a sulfide of an element of Groups 13 to 15 of the periodic table. Examples of the elements of Groups 13 to 15 include Al, Si, Ge, P, As, and Sb. Specific examples of sulfides of elements of Groups 13 to 15 include Al2S3, SiS2, GeS2, P2S3, P2S5, As2S3, and Sb2S3. Examples of methods for synthesizing amorphous inorganic lithium ion conductors using raw material compositions include amorphization methods such as mechanical milling and melt quenching. Examples of amorphous inorganic lithium ion conductors obtained using raw material compositions containing Li2S and sulfides of elements of Groups 13 to 15 of the periodic table include Li2S-P2S5, Li2S-SiS2, Li2S-GeS2, and Li2S-Al2S3, and more preferably Li2S-P2S5. The amorphous inorganic lithium ion conductors described above can be used alone or in combination of two or more.

[0058] Among the above, as the inorganic solid electrolyte for the all-solid-state lithium ion secondary battery, from the viewpoint of forming a solid electrolyte-containing layer having even more excellent ion conductivity, an amorphous sulfide containing Li and P, Li7La3Zr2O 12 Amorphous sulfides containing Li and P, and Li7La3Zr2O 12Since it has high lithium ion conductivity, its use as an inorganic solid electrolyte can reduce the IV resistance of an all-solid-state secondary battery and improve the output characteristics.

[0059] From the viewpoint of reducing the IV resistance and improving the output characteristics of the battery, the amorphous sulfide containing Li and P is preferably a sulfide glass composed of Li2S and P2S5, and particularly preferably a sulfide glass produced from a mixed raw material of Li2S and P2S5 in a Li2S:P2S5 molar ratio of 65:35 to 85:15. Furthermore, the amorphous sulfide containing Li and P is preferably a sulfide glass ceramic obtained by mechanochemically reacting a mixed raw material of Li2S and P2S5 in a Li2S:P2S5 molar ratio of 65:35 to 85:15. From the viewpoint of maintaining high lithium ion conductivity, the mixed raw material preferably has a Li2S:P2S5 molar ratio of 68:32 to 80:20.

[0060] In addition to the Li2S and P2S5, the inorganic solid electrolyte may contain at least one sulfide selected from the group consisting of Al2S3, B2S3, and SiS2 as a starting material, to the extent that the ionic conductivity is not reduced. Addition of such a sulfide can stabilize the glass component in the inorganic solid electrolyte. Similarly, the inorganic solid electrolyte may contain, in addition to Li2S and P2S5, at least one lithium ortho-oxo-oxide selected from the group consisting of Li3PO4, Li4SiO4, Li4GeO4, Li3BO3, and Li3AlO3. The inclusion of such a lithium ortho-oxo-oxide can stabilize the glass component in the inorganic solid electrolyte.

[0061] The above-mentioned solid electrolytes can be used alone or in combination of two or more. Furthermore, the solid electrolyte preferably has a number average particle size of 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 0.5 μm or more, and preferably 10 μm or less, more preferably 7.5 μm or less, and even more preferably 5.0 μm or less. If the number average particle size of the solid electrolyte is 0.1 μm or more, the dispersibility of the slurry composition can be further improved, and if it is 10 μm or less, the IV resistance of the all-solid-state secondary battery can be reduced, thereby sufficiently improving the cell characteristics. In the present invention, the "number average particle size" of the solid electrolyte can be measured using the method described in the examples.

[0062] <Binder composition> As the binder composition, the binder composition of the present invention containing at least the above polymer, the above aromatic halide, and the above solvent is used.

[0063] The blend ratio of the solid electrolyte and the binder composition is not particularly limited. For example, the amount of the polymer derived from the binder composition contained in the slurry composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and preferably 10 parts by mass or less, per 100 parts by mass of solid electrolyte. If the content of the polymer in the slurry composition is 0.1 parts by mass or more per 100 parts by mass of solid electrolyte, the dispersibility of the slurry composition can be further improved while sufficiently improving the cell characteristics of the all-solid-state secondary battery. If the content of the polymer in the slurry composition is 20 parts by mass or less per 100 parts by mass of solid electrolyte, the ionic conductivity of the solid electrolyte-containing layer can be sufficiently ensured, and the cell characteristics of the all-solid-state secondary battery will not be excessively impaired.

[0064] <Electrode active material> The electrode active material is a material that transfers electrons at the electrode of the all-solid-state secondary battery. For example, when the all-solid-state secondary battery is an all-solid-state lithium ion secondary battery, the electrode active material is usually a material that can absorb and release lithium. In the following, a case where the slurry composition for an all-solid-state secondary battery is a slurry composition for an all-solid-state lithium-ion secondary battery will be described as an example, but the present invention is not limited to the following example.

[0065] The positive electrode active material for the all-solid-state lithium ion secondary battery is not particularly limited, and examples thereof include a positive electrode active material made of an inorganic compound and a positive electrode active material made of an organic compound. The positive electrode active material may be a mixture of an inorganic compound and an organic compound. Examples of inorganic cathode active materials include transition metal oxides, composite oxides of lithium and transition metals (lithium-containing composite metal oxides), and transition metal sulfides. Examples of the transition metals include Fe, Co, Ni, and Mn. Specific examples of inorganic compounds used in cathode active materials include lithium-containing composite metal oxides such as LiCoO2 (lithium cobalt oxide), LiNiO2, LiMnO2, LiMn2O4, LiFePO4, and LiFeVO4; transition metal sulfides such as TiS2, TiS3, and amorphous MoS2; Cu2VO3, amorphous VO-PO5, MoO3, VO5, and VO. 13 These compounds may be partially element-substituted. The positive electrode active materials made of the inorganic compounds described above can be used alone or in combination of two or more. Examples of the positive electrode active material made of an organic compound include polyaniline, polypyrrole, polyacene, disulfide-based compounds, polysulfide-based compounds, and N-fluoropyridinium salts. The positive electrode active materials made of the organic compounds described above can be used alone or in combination of two or more.

[0066] Examples of negative electrode active materials for all-solid-state lithium-ion secondary batteries include carbon allotropes such as graphite and coke. Negative electrode active materials made of carbon allotropes can also be used in the form of mixtures or coatings with metals, metal salts, oxides, etc. Other examples of negative electrode active materials that can be used include oxides or sulfates of silicon, tin, zinc, manganese, iron, nickel, etc.; metallic lithium; lithium alloys such as Li-Al, Li-Bi-Cd, and Li-Sn-Cd; lithium transition metal nitrides; and silicone. The above-mentioned negative electrode active materials can be used alone or in combination of two or more.

[0067] The particle size of the electrode active material (positive electrode active material, negative electrode active material) is not particularly limited and may be the same as that of a conventionally used electrode active material. The amount of the electrode active material in the slurry composition is not particularly limited and may be the same as that of a conventionally used electrode active material.

[0068] <Other ingredients> Other components that may be optionally contained in the slurry composition include, but are not limited to, conductive materials, binders other than the above-mentioned polymers, dispersants, leveling agents, antifoaming agents, and reinforcing materials. These other components are not particularly limited as long as they do not affect the battery reaction. Furthermore, these components may be used alone or in combination of two or more in any ratio.

[0069] Here, the slurry composition for the electrode mixture layer preferably contains a conductive material from the viewpoint of further improving the cell characteristics of the all-solid-state secondary battery. The conductive material is used to ensure electrical contact between electrode active materials. Examples of conductive materials that can be used include conductive carbon materials such as carbon black (e.g., acetylene black, Ketjen Black (registered trademark), furnace black, etc.), graphite, carbon fiber, carbon flakes, and ultrashort carbon fibers (e.g., carbon nanotubes and vapor-grown carbon fibers); and fibers and foils of various metals. These materials can be used alone or in combination of two or more. Among these, carbon nanotubes are preferred from the viewpoint of further improving the cell characteristics of all-solid-state secondary batteries.

[0070] As the carbon nanotubes, single-walled carbon nanotubes, multi-walled carbon nanotubes (including cup-stacked type), and mixtures thereof can be used. Carbon nanotubes have a specific surface area of ​​100m 2 / g or more, and 200m 2 / g or more is more preferable, and 1,000m 2 / g or less, and 2 / g or less is more preferable. If CNTs having a specific surface area within the above range are used, the cell characteristics of the all-solid-state secondary battery can be further improved (in particular, the IV resistance can be reduced). The "specific surface area" of CNTs refers to the nitrogen adsorption specific surface area measured using the BET (Brunauer-Emmett-Teller) method. From the viewpoint of further improving the cell characteristics of the all-solid-state secondary battery, the carbon nanotubes preferably have an average diameter of 0.5 nm or more and 200 nm or less. In addition, from the viewpoint of further improving the cell characteristics of the all-solid-state secondary battery, the carbon nanotubes preferably have an average length of 1 μm or more and 1000 μm or less. The "average diameter" and "average length" of carbon nanotubes can be determined by observing the CNTs with a transmission electron microscope (TEM), measuring the diameter (outer diameter) and length of 50 CNTs from the resulting TEM image, and then calculating the arithmetic mean value of each measurement value.

[0071] The content of the conductive material in the slurry composition for an all-solid-state secondary battery is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass or less, per 100 parts by mass of the electrode active material. If the amount of the conductive material is within the above range, electrical contact between the electrode active materials can be sufficiently ensured, and the cell characteristics of the all-solid-state secondary battery can be further improved.

[0072] <Preparation of Slurry Composition> The above-mentioned slurry composition for an all-solid-state secondary battery is not particularly limited, and can be obtained, for example, by mixing the above-mentioned components using any mixing method. When preparing a slurry composition for an electrode mixture layer containing an electrode active material and a conductive material, the conductive material may be premixed with the above-mentioned polymer to prepare a conductive material dispersion, and then the obtained conductive material dispersion and the electrode active material may be mixed.

[0073] (Solid electrolyte containing layer) The solid electrolyte-containing layer of the present invention is a layer containing a solid electrolyte, and examples of the solid electrolyte-containing layer include an electrode mixture layer (positive electrode mixture layer, negative electrode mixture layer) that transfers electrons via an electrochemical reaction, and a solid electrolyte layer provided between a positive electrode mixture layer and a negative electrode mixture layer that face each other. The solid electrolyte-containing layer of the present invention is formed using the above-mentioned slurry composition for an all-solid-state secondary battery. For example, it can be formed by applying the above-mentioned slurry composition to the surface of a suitable substrate to form a coating film, and then drying the formed coating film. That is, the solid electrolyte-containing layer of the present invention is made of a dried product of the above-mentioned slurry composition, and typically contains a solid electrolyte and a polymer, and may optionally further contain an aromatic halide (partially or entirely remaining after drying) and at least one selected from the group consisting of period 5 metals, group 1-2 metals, electrode active materials, and other components. Note that the components contained in the solid electrolyte-containing layer are those contained in the above-mentioned slurry composition, and the content ratios of these components are typically the same as the content ratios in the above-mentioned slurry composition, except for the aromatic halide and solvent, which may be vaporized by drying. The solid electrolyte-containing layer of the present invention is formed from the slurry composition for an all-solid-state secondary battery of the present invention, and therefore, by using the solid electrolyte-containing layer, an all-solid-state secondary battery having excellent cell characteristics such as cycle characteristics can be produced.

[0074] <Base material> Here, there is no limitation on the substrate to which the slurry composition is applied, and for example, a coating film of the slurry composition may be formed on the surface of a release substrate, the coating film may be dried to form a solid electrolyte-containing layer, and the release substrate may be peeled off from the solid electrolyte-containing layer. In this way, the solid electrolyte-containing layer peeled off from the release substrate may be used as a free-standing film to form battery components (e.g., electrodes, solid electrolyte layers, etc.) of an all-solid-state secondary battery. On the other hand, from the viewpoint of improving the production efficiency of the battery component by omitting the step of peeling off the solid electrolyte-containing layer, a current collector or an electrode may be used as the substrate. For example, when preparing the electrode mixture layer, it is preferable to apply the slurry composition onto a current collector as the substrate.

[0075] <<Release base material>> The release substrate is not particularly limited, and known release substrates such as imide films can be used.

[0076] <<Current collector>> As the current collector, a material that is electrically conductive and electrochemically durable is used. Specifically, as the current collector, for example, a current collector made of iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, etc. can be used. Among them, copper foil is particularly preferred as the current collector used for the negative electrode. Furthermore, aluminum foil is particularly preferred as the current collector used for the positive electrode. Note that the above materials may be used alone or in combination of two or more types in any ratio.

[0077] <<Electrode>> The electrodes (positive and negative electrodes) are not particularly limited, but examples thereof include electrodes in which an electrode mixture layer containing an electrode active material, a solid electrolyte, and a binder is formed on the above-mentioned current collector. The electrode active material, solid electrolyte, and binder contained in the electrode mixture layer in the electrode are not particularly limited, and known materials can be used. The electrode mixture layer in the electrode may correspond to the solid electrolyte-containing layer of the present invention.

[0078] <Method for forming a solid electrolyte-containing layer> Specific examples of the method for forming the solid electrolyte-containing layer include the following methods. 1) A method in which the slurry composition of the present invention is applied to the surface of a current collector or an electrode (in the case of an electrode, the surface on the electrode mixture layer side; the same applies hereinafter) and then dried; 2) a method of immersing a current collector or electrode in the slurry composition of the present invention and then drying it; and 3) A method in which the slurry composition of the present invention is applied to a release substrate, dried to produce a solid electrolyte-containing layer, and the resulting solid electrolyte-containing layer is transferred to the surface of an electrode. Among these, the above methods 1) and 3) which involve coating and drying are particularly preferred because they make it easy to control the thickness of the solid electrolyte-containing layer.

[0079] <<Coating>> The method for applying the slurry composition onto the substrate is not particularly limited, and examples thereof include a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.

[0080] <<Drying>> The method for drying the slurry composition on the substrate is not particularly limited and any known method can be used, including, for example, drying with warm air, hot air, or low-humidity air, vacuum drying, and drying by irradiation with infrared rays or electron beams. When the solid electrolyte-containing layer is an electrode mixture layer, after drying, it may be subjected to a pressing treatment using a roll press or the like. By performing the pressing treatment, the density of the obtained electrode mixture layer can be further increased.

[0081] <<Transcript>> In the above method 3), the method for transferring the solid electrolyte-containing layer onto the surface of the electrode or the like is not particularly limited, and any known transfer method can be used.

[0082] (electrode) An electrode obtained by forming an electrode mixture layer on a current collector using the slurry composition for an all-solid-state secondary battery of the present invention contains at least a solid electrolyte, an electrode active material, and a polymer in the electrode mixture layer, and can exhibit excellent cell characteristics (such as cycle characteristics) in an all-solid-state secondary battery.

[0083] (solid electrolyte layer) In addition, the solid electrolyte layer formed using the slurry composition for an all-solid-state secondary battery of the present invention contains at least a solid electrolyte and a polymer, and can enable the all-solid-state secondary battery to exhibit excellent cell characteristics (such as cycle characteristics).

[0084] (All-solid-state secondary battery) The all-solid-state secondary battery of the present invention includes the above-described solid electrolyte-containing layer of the present invention. Here, the all-solid-state secondary battery of the present invention has, for example, a positive electrode, a solid electrolyte layer, and a negative electrode, and at least one of the positive electrode composite layer of the positive electrode, the negative electrode composite layer of the negative electrode, and the solid electrolyte layer is the solid electrolyte-containing layer of the present invention. That is, the all-solid-state secondary battery of the present invention includes at least one of: a positive electrode including a positive electrode composite layer formed using a slurry composition for a positive electrode composite layer as the slurry composition for an all-solid-state secondary battery of the present invention; a negative electrode including a negative electrode composite layer formed using a slurry composition for a negative electrode composite layer as the slurry composition for an all-solid-state secondary battery of the present invention; and a solid electrolyte layer formed using a slurry composition for a solid electrolyte layer as the slurry composition for an all-solid-state secondary battery of the present invention. Furthermore, the all-solid-state secondary battery of the present invention is provided with the solid electrolyte-containing layer of the present invention, and therefore has excellent cell characteristics such as cycle characteristics. In addition, from the viewpoint of further improving cell characteristics such as cycle characteristics, it is preferable that the positive electrode composite layer of the positive electrode, the negative electrode composite layer of the negative electrode, and the solid electrolyte layer of the all-solid-state secondary battery of the present invention are all solid electrolyte-containing layers of the present invention.

[0085] Here, the all-solid-state secondary battery electrode that can be used in the all-solid-state secondary battery of the present invention and that has an electrode mixture layer that does not correspond to the solid electrolyte-containing layer of the present invention is not particularly limited as long as it has an electrode mixture layer that does not correspond to the solid electrolyte-containing layer of the present invention, and any all-solid-state secondary battery electrode can be used. Furthermore, the solid electrolyte layer that can be used in the all-solid-state secondary battery of the present invention and does not fall under the category of the solid electrolyte-containing layer of the present invention is not particularly limited, and any solid electrolyte layer can be used, for example, the solid electrolyte layers described in JP-A-2012-243476, JP-A-2013-143299, JP-A-2016-143614, and the like. The all-solid-state secondary battery of the present invention can be obtained by stacking a positive electrode and a negative electrode so that the positive electrode composite layer of the positive electrode and the negative electrode composite layer of the negative electrode face each other via a solid electrolyte layer, optionally applying pressure to obtain a laminate, and then placing the laminate in a battery container as is, or after being rolled or folded, depending on the battery shape, and sealing it. If necessary, an expanded metal, an overcurrent prevention element such as a fuse or a PTC element, a lead plate, etc. can be placed in the battery container to prevent pressure buildup inside the battery and overcharging and discharging. The battery shape may be any type, such as a coin type, button type, sheet type, cylindrical type, prismatic type, or flat type. [Example]

[0086] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, the amounts "%", "parts" and "ppm" are based on mass unless otherwise specified. In the examples and comparative examples, the molecular weight (weight average molecular weight, molecular weight distribution) and iodine value of the polymer, the metal content of the binder composition, the number average particle size of the solid electrolyte, the dispersibility of the slurry composition, the adhesiveness of the solid electrolyte-containing layer, and the output characteristics, cycle characteristics and IV resistance of the all-solid-state secondary battery were measured or evaluated by the following methods.

[0087] <Molecular weight of polymer> The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by gel permeation chromatography (GPC) under the following measurement conditions using a 10 mM LiBr-DMF solution, and the molecular weight distribution (Mw / Mn) was also calculated. Separation column: Shodex KD-806M (Showa Denko K.K.) Detector: Differential refractometer detector RID-10A (Shimadzu Corporation) Eluent flow rate: 0.3 mL / min Column temperature: 40℃ Standard polymer: TSK standard polystyrene (manufactured by Tosoh Corporation) <Iodine value of polymer> The obtained polymer was vacuum dried at a temperature of 60°C for 24 hours, and then the iodine value was measured according to JIS K6235 (2006). <Metal Content of Binder Composition> Approximately 1 g of the binder composition was heated in an electric furnace at 550°C for approximately 3 hours and incinerated. Approximately 5 mL of concentrated sulfuric acid was then added to the incinerated binder composition to dissolve it, and approximately 5 mL of concentrated nitric acid was gradually added to carry out wet decomposition. After decomposition, the acid was concentrated and the volume was adjusted to 10 mL with ultrapure water. The content of each metal in the binder composition (relative to the amount of polymer) was measured using an ICP-AES device (manufactured by SII Nanotechnology, model number "SPS-5100"). <Number average particle size of solid electrolyte> The number average particle size of the solid electrolyte was measured using a laser analyzer (Shimadzu Corporation's laser diffraction particle size distribution analyzer "SALD-3100") in accordance with JIS Z8825-1:2001. <Dispersibility of Slurry Composition> The viscosity of the slurry compositions for all-solid-state secondary batteries (slurry composition for electrode composite layer, slurry composition for solid electrolyte layer) was measured using a Brookfield B-type viscometer at 60 rpm (25°C) and evaluated according to the following criteria: A lower viscosity at the same solid content concentration for the same type of slurry composition indicates better dispersion of the solid content, such as the solid electrolyte, contained in the slurry composition. A: Viscosity less than 3000 mPa·s B: Viscosity is 3000 mPa·s or more but less than 5000 mPa·s C: Viscosity is 5000 mPa·s or more but less than 8000 mPa·s D: Viscosity is 8000 mPa·s or more or does not disperse (no fluidity) <Adhesion of solid electrolyte-containing layer> <<Positive electrode composite layer>> The positive electrode was cut into a rectangle measuring 1.0 cm wide x 10 cm long to prepare a test specimen. Cellophane tape (as specified in JIS Z1522) was attached to the surface of the positive electrode composite layer of this test specimen, and the stress was measured when the cellophane tape was peeled off from one end of the specimen in a 180° direction at a rate of 50 mm / min. The measurement was performed three times, and the average value was calculated as the peel strength (N / m) and evaluated according to the following criteria. A higher peel strength indicates better adhesion of the positive electrode composite layer and stronger adhesion to the current collector. A: Peel strength is 3N / m or more B: Peel strength is 2N / m or more and less than 3N / m C: Peel strength is 1N / m or more and less than 2N / m D: Peel strength is less than 1N / m <<Negative electrode composite layer>> The negative electrode was cut into a rectangle measuring 1.0 cm wide x 10 cm long to prepare a test specimen. Cellophane tape (as specified in JIS Z1522) was attached to the surface of the negative electrode composite layer of this test specimen, and the stress was measured when the cellophane tape was peeled off from one end of the specimen in a 180° direction at a rate of 50 mm / min. The measurement was performed three times, and the average value was calculated as the peel strength (N / m) and evaluated according to the following criteria. A higher peel strength indicates better adhesion of the negative electrode composite layer and stronger adhesion to the current collector. A: Peel strength is 4N / m or more B: Peel strength is 3N / m or more and less than 4N / m C: Peel strength is 2N / m or more and less than 3N / m D: Peel strength is less than 2N / m <Output characteristics of all-solid-state secondary batteries> Three all-solid-state secondary batteries were charged to 4.2 V at a constant current of 0.1 C and then discharged to 3.0 V at 0.1 C to determine the 0.1 C discharge capacity. They were then charged to 4.2 V at 0.1 C and then discharged to 3.0 V at 2 C to determine the 2 C discharge capacity. The average of the 0.1 C discharge capacities of the three cells was designated as discharge capacity a, and the average of the 2 C discharge capacities of the three cells was designated as discharge capacity b. The ratio of discharge capacity b to discharge capacity a (capacity ratio) = discharge capacity b / discharge capacity a × 100 (%) was calculated and evaluated according to the following criteria. A higher capacity ratio indicates better output characteristics for the all-solid-state secondary battery. A: Capacity ratio is 80% or more B: Capacity ratio is 70% or more but less than 80% C: Capacity ratio is 50% or more and less than 70% D: Capacity ratio is less than 50% <Cycle characteristics of all-solid-state secondary batteries> The all-solid-state secondary battery was charged from 3 V to 4.2 V at 0.2 C at 25°C, and then discharged from 4.2 V to 3 V at 0.2 C, and this cycle was repeated 50 times. The ratio of the 0.2 C discharge capacity at the 50th cycle to the 0.2 C discharge capacity at the first cycle was calculated as a percentage to obtain the capacity retention rate, which was evaluated according to the following criteria. A higher capacity retention rate indicates less loss in discharge capacity and better cycle characteristics for the all-solid-state secondary battery. A: Capacity retention rate is 90% or more B: Capacity retention rate is 80% or more but less than 90% C: Capacity retention rate is 70% or more but less than 80% D: Capacity retention rate is less than 70% <IV resistance of all-solid-state secondary batteries> The all-solid-state battery was charged to 50% SOC (State of Charge) at 1C (C is a value expressed as rated capacity (mA) / 1h (hours)) in a 25°C atmosphere, and then charged for 30 seconds and discharged for 30 seconds at 0.1C, 0.2C, 0.5C, 1C, and 2C, centered around 50% SOC. The battery voltage after 10 seconds on the discharge side was plotted against the current value, and the slope was calculated as the IV resistance (Ω) (IV resistance during charging and IV resistance during discharging). The obtained IV resistance values ​​(Ω) were evaluated according to the following criteria: A smaller IV resistance value indicates a lower internal resistance. A: IV resistance is less than 80 Ω B: IV resistance is 80Ω or more and less than 90Ω C: IV resistance is 90Ω or more and less than 100Ω D: IV resistance is 100Ω or more

[0088] Example 1 <Preparation of Binder Composition> A reactor was charged with 180 parts of ion-exchanged water, 25 parts of an aqueous solution of sodium dodecylbenzenesulfonate (10% concentration) as an emulsifier, 25 parts of acrylonitrile as a nitrile group-containing monomer, 30 parts of n-butyl acrylate as a (meth)acrylic acid ester monomer, and 0.3 parts of t-dodecyl mercaptan as a molecular weight modifier, in this order. The gas inside the reactor was then purged with nitrogen three times, after which 45 parts of 1,3-butadiene as a diene monomer was charged. The reactor was maintained at 10°C, and 0.1 parts of cumene hydroperoxide and 0.1 parts of ferrous sulfate were charged as polymerization initiators to initiate the polymerization reaction, which was then allowed to proceed with stirring. When the polymerization conversion reached 90%, 0.2 parts of hydroxylamine sulfate per 100 parts of monomer was added to terminate the polymerization. Residual monomer was then removed under reduced pressure at a water temperature of 80°C, yielding an aqueous dispersion of a polymer precursor (nitrile rubber). Then, an aqueous solution of calcium chloride (coagulant) was added in an amount of 12 parts per 100 parts of the polymer precursor solid content in the obtained particulate aqueous dispersion, and the mixture was stirred to coagulate the latex. After that, the latex was filtered while being washed with water, and the obtained coagulated material was vacuum dried at a temperature of 60°C for 12 hours to obtain a polymer precursor (nitrile rubber). Next, the above polymer precursor was hydrogenated using oil phase hydrogenation. The polymer precursor was dissolved in acetone to obtain an acetone solution with a polymer precursor concentration of 12%. This acetone solution was placed in an autoclave, and 200 ppm by mass of palladium-silica catalyst relative to the amount of polymer precursor was added. The hydrogenation reaction was then carried out for 6 hours at a hydrogen pressure of 3.0 MPa. The palladium-silica catalyst was filtered from the resulting reaction product, and the acetone solvent was removed under reduced pressure to obtain the desired polymer, hydrogenated nitrile rubber. The molecular weight and iodine value of this hydrogenated nitrile rubber were measured. The results are shown in Table 1. Next, an appropriate amount of butyl butyrate was added to the obtained hydrogenated nitrile rubber and dissolved, and 1,2-dichlorobenzene as an aromatic halide was added to the obtained polymer solution so that the amount was 50 ppm relative to the amount of hydrogenated nitrile rubber, thereby obtaining a binder composition (solid concentration: 8%). The metal content of the obtained binder composition was measured. The results are shown in Table 1. <Preparation of Slurry Composition for Positive Electrode Composite Layer> Carbon nanotubes as conductive materials (specific surface area: 230 m 2 5.0 parts of hydroxybenzoate (1.0 part per 1000g / g), 1.0 part of the binder composition (as converted to solids), and butyl butyrate were added so that the total was 100 parts, and the mixture was stirred using a disper (3000 rpm, 10 minutes). Thereafter, a bead mill using zirconia beads with a diameter of 1 mm was used to disperse the mixture at a peripheral speed of 8 m / sec for 1 hour, thereby preparing a conductive material dispersion liquid with a solids concentration of 6.0%. 70 parts of lithium cobalt oxide (number average particle diameter: 11.5 μm) as the positive electrode active material, 26.0 parts of sulfide glass composed of Li2S and P2S5 (Li2S / P2S5 = 70 mol% / 30 mol%, number average particle diameter: 0.8 μm) as the solid electrolyte, 2.4 parts (solid content equivalent) of the conductive material dispersion, and 1.6 parts (solid content equivalent) of the binder composition were mixed, and then butyl butyrate was added to adjust the solid content to 80% and mixed in a planetary mixer for 60 minutes. Subsequently, xylene was added to adjust the solid content to 65% and mixed for 10 minutes to prepare a slurry composition for the positive electrode composite layer. The dispersibility of this slurry composition for the positive electrode composite layer was evaluated. The results are shown in Table 1. <Preparation of Slurry Composition for Negative Electrode Mixture Layer> Carbon nanotubes as conductive materials (specific surface area: 230 m 2 5.0 parts of hydroxybenzoate (1.0 part per 1000g / g), 1.0 part of the binder composition (as converted to solids), and butyl butyrate were added so that the total was 100 parts, and the mixture was stirred using a disper (3000 rpm, 10 minutes). Thereafter, a bead mill using zirconia beads with a diameter of 1 mm was used to disperse the mixture at a peripheral speed of 8 m / sec for 1 hour, thereby preparing a conductive material dispersion liquid with a solids concentration of 6.0%. 60 parts of graphite (number average particle diameter: 20 μm) as the negative electrode active material, 36.5 parts of sulfide glass composed of LiS and P2S5 (Li2S / P2S5 = 70 mol% / 30 mol%, number average particle diameter: 0.8 μm) as the solid electrolyte, 1.8 parts (solid content equivalent) of the conductive material dispersion, and 2.2 parts (solid content equivalent) of the binder composition were mixed, and then butyl butyrate was added to adjust the solid content to 65% and mixed in a planetary mixer for 60 minutes. Subsequently, butyl butyrate was added to adjust the solid content to 60% and mixed in a planetary mixer to prepare a slurry composition for the negative electrode composite layer. The dispersibility of this slurry composition for the negative electrode composite layer was evaluated. The results are shown in Table 1. <Preparation of Slurry Composition for Solid Electrolyte Layer> In a glove box under an argon gas atmosphere (water concentration 0.6 ppm, oxygen concentration 1.8 ppm), 100 parts of sulfide glass (LiS / P2S5 = 70 mol% / 30 mol%, number average particle diameter: 0.8 μm) composed of Li2S and P2S5 as a solid electrolyte were mixed with 2 parts (solid content equivalent) of the binder composition. Then, butyl butyrate was added to adjust the solid content to 65% by mass, and the mixture was mixed in a planetary mixer for 60 minutes. Subsequently, butyl butyrate was added to adjust the solid content to 55% by mass, and the mixture was mixed in a planetary mixer to prepare a slurry composition for a solid electrolyte layer. The dispersibility of this slurry composition for a solid electrolyte layer was evaluated. The results are shown in Table 1. <Preparation of positive electrode> The positive electrode composite layer slurry composition was applied to the surface of a current collector (aluminum foil, thickness: 20 μm) and dried (at 120°C for 60 minutes) to form a positive electrode composite layer with a thickness of 50 μm, thereby obtaining a positive electrode. The adhesiveness of the positive electrode composite layer was evaluated using this positive electrode. The results are shown in Table 1. <Preparation of negative electrode> The negative electrode composite layer slurry composition was applied to the surface of a current collector (copper foil, thickness: 15 μm) and dried (at 120°C for 60 minutes) to form a negative electrode composite layer with a thickness of 60 μm, thereby obtaining a negative electrode. Using this negative electrode, the adhesiveness of the negative electrode composite layer was evaluated. The results are shown in Table 1. <Manufacturing of all-solid-state secondary batteries> Next, the solid electrolyte layer slurry composition was applied to an imide film (thickness: 25 μm) and dried (at 120° C. for 60 minutes) to form a solid electrolyte layer (solid electrolyte-containing layer) with a thickness of 150 μm. The solid electrolyte layer on the imide film and the positive electrode were bonded together so that the solid electrolyte layer and the positive electrode composite layer were in contact with each other, and a pressing process was performed to apply a pressure (pressing pressure) of 400 MPa, and the solid electrolyte layer was transferred from the imide film to the positive electrode composite layer, thereby obtaining a positive electrode with a solid electrolyte layer. The positive electrode with the solid electrolyte layer and the negative electrode were bonded together so that the solid electrolyte layer of the positive electrode with the solid electrolyte layer and the negative electrode composite layer of the negative electrode were in contact with each other, and a press treatment was performed by applying a pressure (press pressure) of 400 MPa to the solid electrolyte layer of the positive electrode with the solid electrolyte layer, thereby obtaining an all-solid-state secondary battery. The thickness of the solid electrolyte layer of the all-solid-state secondary battery after pressing was 120 μm. The output characteristics, cycle characteristics, and IV resistance of this all-solid-state secondary battery were evaluated. The results are shown in Table 1.

[0089] (Examples 2 and 3) In preparing the binder compositions, 1,2-dichlorobenzene as an aromatic halide was added in amounts of 2,000 ppm (Example 2) and 7 ppm (Example 3) relative to the amount of hydrogenated nitrile rubber, respectively. The binder compositions, slurry compositions for the positive electrode composite layer, slurry compositions for the negative electrode composite layer, slurry compositions for the solid electrolyte layer, positive electrodes, negative electrodes, and all-solid-state secondary batteries were prepared in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 1.

[0090] (Examples 4 and 5) In preparing the binder compositions, except that 2-ethylhexyl acrylate (Example 4) or cyclohexyl acrylate (Example 5) was used instead of n-butyl acrylate as the (meth)acrylic acid ester monomer, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0091] Examples 6 to 9 In preparing the binder composition, except that the amounts of acrylonitrile (AN), n-butyl acrylate (BA), and 1,3-butadiene (BD) were changed as follows, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1. Example 6: AN 29 parts, BA 25 parts, BD 46 parts Example 7: AN 10 parts, BA 35 parts, BD 55 parts Example 8: AN 25 parts, BA 38 parts, BD 37 parts Example 9: AN 25 parts, BA 18 parts, BD 57 parts

[0092] Example 10 Except for using carbon black (Denka Black (registered trademark)) instead of carbon nanotubes in the preparation of the slurry composition for the positive electrode composite layer and the slurry composition for the negative electrode composite layer, the binder composition, the slurry composition for the positive electrode composite layer, the slurry composition for the negative electrode composite layer, the slurry composition for the solid electrolyte layer, the positive electrode, the negative electrode, and the all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 2.

[0093] Example 11 Except for using the binder compositions prepared as follows, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2. <Preparation of Binder Composition> A polymer precursor (nitrile rubber) was obtained in the same manner as in Example 1. Metathesis of this polymer precursor was carried out as follows. The polymer precursor was dissolved in 141 parts of monochlorobenzene and charged into a reactor. The reactor was then heated to 80°C, and 2 L of a monochlorobenzene solution containing bis(tricyclohexylphosphine)benzylidene ruthenium dichloride as a Grubbs catalyst was added so that the amount of Grubbs catalyst was 0.25 parts per 100 parts of polymer precursor. The reactor was then pressurized to 3.5 MPa with ethylene as a coolefin, and the polymer metathesis reaction was carried out at a stirring speed of 600 rpm. During the reaction, the temperature was maintained constant using a cooling coil connected to a temperature controller and a heat sensor. Hydrogenation was then carried out as follows. After the metathesis reaction, the reactor was degassed three times with 0.7 MPa H2 while continuing to stir. The temperature of the reactor was then raised to 130°C, and 1 L of a monochlorobenzene solution containing Wilkinson's catalyst and triphenylphosphine was added to the reactor. The amount of Wilkinson's catalyst per 100 parts of polymer was 0.075 parts, and the amount of triphenylphosphine was 1 part. The temperature was then raised to 138°C, and the polymer was hydrogenated under a hydrogen pressure (gauge pressure) of 8.4 MPa. The reaction was terminated when the iodine value reached 1.3 mg / 100 mg. After the reaction was completed, 0.2 parts of activated carbon with an average diameter of 15 μm was added to the reactor, and the mixture was stirred for 30 minutes. The mixture was then filtered through a filter with a pore size of 5 μm. Steam was then introduced into the filtrate, and the monochlorobenzene was recovered and removed by steam distillation. The precipitated polymer (hydrogenated nitrile rubber) was separated, dried, and recovered. Subsequently, an appropriate amount of butyl butyrate was added to the obtained hydrogenated nitrile rubber to dissolve it, and 1,2-dichlorobenzene as an aromatic halide was added to the obtained polymer solution so that the amount was 50 ppm relative to the amount of the hydrogenated nitrile rubber, thereby obtaining a binder composition (solid concentration: 8%).

[0094] Example 12 In preparing the binder composition, except that the amount of palladium-silica catalyst was changed to 450 ppm by mass relative to the amount of polymer precursor, the binder composition, slurry composition for the positive electrode composite layer, slurry composition for the negative electrode composite layer, slurry composition for the solid electrolyte layer, positive electrode, negative electrode, and all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0095] Example 13 In preparing the binder composition, except that an aqueous sodium hydroxide solution was added to the aqueous dispersion of the polymer precursor (nitrile rubber) before coagulation and the amount of calcium chloride used as a coagulant was increased, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 2.

[0096] Example 14 In preparing the binder composition, except that the hydrogen pressure and reaction time in the hydrogenation were changed to set the iodine value of the resulting polymer to 1.5 mg / 100 mg, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0097] (Examples 15 and 16) In preparing the binder compositions, except that ethyl acrylate (Example 15) or methyl methacrylate (Example 16) was used instead of n-butyl acrylate as the (meth)acrylic acid ester monomer, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 2.

[0098] (Examples 17 to 19, 23) In preparing the binder composition, the slurry composition for the positive electrode composite layer, the slurry composition for the negative electrode composite layer, and the slurry composition for the solid electrolyte layer, cyclopentyl methyl ether (Example 17), xylene (Example 18), diisobutyl ketone (Example 19), and isobutyl isobutyrate (Example 23) were used instead of butyl butyrate, respectively. The binder composition, the slurry composition for the positive electrode composite layer, the slurry composition for the negative electrode composite layer, the slurry composition for the solid electrolyte layer, the positive electrode, the negative electrode, and the all-solid-state secondary battery were prepared and various evaluations were performed. The results are shown in Tables 2 and 3.

[0099] Example 20 Except for changing the amount of t-dodecyl mercaptan to 6 parts when preparing the binder composition, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 3.

[0100] Example 21 In preparing the slurry composition for the negative electrode composite layer and the slurry composition for the solid electrolyte layer, a binder composition containing polyvinylidene fluoride was used instead of the binder composition containing hydrogenated nitrile rubber. The binder composition, the slurry composition for the positive electrode composite layer, the slurry composition for the negative electrode composite layer, the slurry composition for the solid electrolyte layer, the positive electrode, the negative electrode, and the all-solid-state secondary battery were prepared in the same manner as in Example 1, and various evaluations were performed except for the dispersibility of the slurry composition for the negative electrode composite layer and the slurry composition for the solid electrolyte layer and the adhesiveness of the negative electrode composite layer. The results are shown in Table 3.

[0101] Example 22 Except for using 1,2,4-trichlorobenzene instead of 1,2-dichlorobenzene as the aromatic halide in preparing the binder composition, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0102] Example 24 In preparing the slurry composition for the positive electrode mixture layer and the slurry composition for the negative electrode mixture layer, a conductive material having a specific surface area of ​​230 m 2 / g of carbon nanotubes with a specific surface area of ​​150 m 2 Except for using carbon nanotubes at 1000 kJ / g, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 3.

[0103] (Comparative Examples 1 and 2) In preparing the binder composition, except that the amounts of acrylonitrile (AN), n-butyl acrylate (BA), and 1,3-butadiene (BD) were changed as follows, the binder composition, slurry composition for the positive electrode composite layer, slurry composition for the negative electrode composite layer, slurry composition for the solid electrolyte layer, positive electrode, negative electrode, and all-solid-state secondary battery were prepared and various evaluations were performed in the same manner as in Example 1. The results are shown in Table 4. Comparative example 1: AN25 parts, BA0 parts, BD75 parts Comparative example 2: AN0 parts, BA30 parts, BD70 parts

[0104] (Comparative Example 3) Except for not using the aromatic halide 1,2-dichlorobenzene in preparing the binder composition, a binder composition, a slurry composition for a positive electrode composite layer, a slurry composition for a negative electrode composite layer, a slurry composition for a solid electrolyte layer, a positive electrode, a negative electrode, and an all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 4.

[0105] Comparative Example 4 In preparing the binder composition, 1,2-dichlorobenzene as an aromatic halide was added in an amount of 5,000 ppm relative to the amount of hydrogenated nitrile rubber. The binder composition, slurry composition for the positive electrode composite layer, slurry composition for the negative electrode composite layer, slurry composition for the solid electrolyte layer, positive electrode, negative electrode, and all-solid-state secondary battery were prepared in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 4.

[0106] (Comparative Example 5) In preparing the binder composition, monochlorobenzene was used instead of 1,2-dichlorobenzene as the aromatic halide, and the monochlorobenzene was added in an amount of 200 ppm relative to the amount of hydrogenated nitrile rubber. Except for this, the binder composition, the slurry composition for the positive electrode composite layer, the slurry composition for the negative electrode composite layer, the slurry composition for the solid electrolyte layer, the positive electrode, the negative electrode, and the all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 4.

[0107] In addition, in Tables 1 to 4 shown below, "nitrile group" refers to a nitrile group-containing monomer unit; "(Meth)acrylic acid ester" refers to a (meth)acrylic acid ester monomer unit, "Diene" refers to a diene-based monomer unit; "AN" indicates an acrylonitrile unit; "BA" indicates n-butyl acrylate units; "EHA" indicates 2-ethylhexyl acrylate units; "CHA" represents a cyclohexyl acrylate unit; "EA" indicates an ethyl acrylate unit; "MMA" indicates a methyl methacrylate unit; "H-BD" indicates a 1,3-butadiene hydride unit; "Mw / Mn" indicates the molecular weight distribution, "Mw" indicates the weight average molecular weight, "DCB" stands for 1,2-dichlorobenzene, "TCB" stands for 1,2,4-trichlorobenzene, "CB" indicates monochlorobenzene, "Pd" indicates palladium; "Rh" indicates rhodium, "Ru" indicates ruthenium; "Na" indicates sodium, "Ca" indicates calcium, "DIK" indicates diisobutyl ketone, "XY" indicates xylene, "HB" stands for butyl butyrate; "IBIB" refers to isobutyl isobutyrate; "CPME" refers to cyclopentyl methyl ether; "CNT230" has a specific surface area of ​​230m 2 / g of carbon nanotubes, "CNT150" has a specific surface area of ​​150m 2 / g of carbon nanotubes, "DB" stands for Denka Black, "Positive" indicates the positive electrode, "Negative" indicates the negative electrode, "Solid" refers to a solid electrolyte layer.

[0108] [Table 1]

[0109] [Table 2]

[0110] [Table 3]

[0111] [Table 4]

[0112] From Tables 1 to 3, it can be seen that the binder compositions of Examples 1 to 24 can prepare slurry compositions with excellent dispersibility and can provide all-solid-state secondary batteries with excellent cycle characteristics. It can also be seen that the binder compositions of Examples 1 to 24 can form solid electrolyte-containing layers with excellent adhesiveness and can improve the output characteristics of all-solid-state secondary batteries while reducing the IV resistance. On the other hand, Table 4 shows that in Comparative Example 1, which used a binder composition containing a polymer not containing a (meth)acrylic acid ester monomer unit, and Comparative Example 2, which used a binder composition containing a polymer not containing a nitrile group-containing monomer unit, the dispersibility of the slurry composition, the adhesiveness of the solid electrolyte-containing layer, and the cell characteristics of the all-solid-state secondary battery were reduced. Furthermore, Table 4 shows that in Comparative Example 3, in which a binder composition not containing a predetermined aromatic halide was used, and in Comparative Example 4, in which a binder composition in which the amount of the predetermined aromatic halide exceeded a predetermined upper limit was used, the dispersibility of the slurry composition, the adhesiveness of the solid electrolyte-containing layer, and the cell characteristics of the all-solid-state secondary battery were reduced. Furthermore, Table 4 shows that in Comparative Example 5, in which monochlorobenzene was used instead of the specified aromatic halide, the dispersibility of the slurry composition, the adhesiveness of the solid electrolyte-containing layer, and the cell characteristics of the all-solid-state secondary battery were reduced. [Industrial Applicability]

[0113] According to the present invention, it is possible to provide a binder composition for an all-solid-state secondary battery, which can prepare a slurry composition for an all-solid-state secondary battery having excellent dispersibility and can form a solid electrolyte-containing layer that can cause the all-solid-state secondary battery to exhibit excellent cycle characteristics. Furthermore, according to the present invention, it is possible to provide a slurry composition for an all-solid-state secondary battery that has excellent dispersibility and is capable of forming a solid electrolyte-containing layer that can cause the all-solid-state secondary battery to exhibit excellent cycle characteristics. Furthermore, according to the present invention, it is possible to provide a solid electrolyte-containing layer that can enable an all-solid-state secondary battery to exhibit excellent cycle characteristics, and an all-solid-state secondary battery that has excellent cycle characteristics.

Claims

1. A binder composition for an all-solid-state secondary battery containing a polymer and an aromatic halide, the polymer contains nitrile group-containing monomer units in a proportion of 10% by mass or more and 35% by mass or less, and (meth)acrylic acid ester monomer units in a proportion of 15% by mass or more and 40% by mass or less, The aromatic halide is an aromatic chloride in which two or more and four or less hydrogen atoms present on a benzene ring are substituted with chlorine atoms, and the content of the aromatic halide is 5 ppm by mass or more and 3,000 ppm by mass or less with respect to the content of the polymer.

2. 2. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the binder composition contains a metal belonging to Period 5 of the periodic table and Groups 3 to 14 of the periodic table in an amount of 0.5 ppm by mass or more and 200 ppm by mass or less with respect to the content of the polymer.

3. 3. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the binder composition contains a metal belonging to Group 1 or Group 2 of the periodic table in an amount of 5 ppm by mass or more and 3,000 ppm by mass or less with respect to the content of the polymer.

4. The binder composition for an all-solid-state secondary battery according to any one of claims 1 to 3, wherein the polymer has an iodine value of 0.5 mg / 100 mg or more and 20 mg / 100 mg or less.

5. 5. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the number of carbon atoms constituting the alkyl group bonded to the non-carbonyl oxygen atom possessed by the (meth)acrylic acid ester monomer unit is 4 or more and 9 or less.

6. The binder composition for an all-solid-state secondary battery according to any one of claims 1 to 5, further comprising a solvent.

7. The binder composition for an all-solid-state secondary battery according to claim 1, wherein the aromatic chloride is one or more compounds selected from the group consisting of 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, and 1,2,4,5-tetrachlorobenzene.

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

9. The slurry composition for an all-solid-state secondary battery according to claim 8 , further comprising an electrode active material.

10. The slurry composition for an all-solid-state secondary battery according to claim 9 , further comprising carbon nanotubes.

11. A solid electrolyte-containing layer formed using the slurry composition for an all-solid-state secondary battery according to any one of claims 8 to 10.

12. An all-solid-state secondary battery comprising the solid electrolyte-containing layer according to claim 11.

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