Carbon material dispersion liquid, electrode composition, electrode film, and all-solid-state battery

Abstract

To provide a carbon material dispersion which uses a specific low polar solvent and a dispersant, suppresses deterioration of a sulfide-based solid electrolyte, and is excellent in dispersibility of a carbon material. To provide an electrode composition in which deterioration of a sulfide-based solid electrolyte is suppressed and which is excellent in productivity and battery performance, and to provide an electrode film and an all-solid-state battery.SOLUTION: The above problem is solved by a carbon material dispersion liquid containing a carbon material, a dispersant, and a solvent containing a solvent S, wherein the solvent S is a hydrocarbon having 8 or more carbon atoms and containing a cyclic skeleton, the dispersant contains a structural unit X having an HSP distance of less than 10.0 from the solvent S and a structural unit Y having an HSP distance of 10.0 or more from the solvent S, and the dispersant contains 30% by mass or less of the structural unit Y based on all structural units of the dispersant.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention provides a catalyst comprising a carbon material, a dispersant, and a solvent, which suppresses deterioration of a sulfide-based solid electrolyte, Carbon material dispersion liquid, electrode composition, electrode film, and all-solid-state battery, which also have excellent dispersibility of carbon materials Regarding. [Background technology]

[0002] In recent years, demand for lithium-ion secondary batteries has increased in a wide range of applications, including mobile devices and electric vehicles. All-solid-state batteries that use solid electrolytes and have excellent capacity and safety are being considered. In particular, from the perspective of achieving high capacity, bulk-type all-solid-state batteries in which electrodes are formed from powder materials are attracting attention. The production of electrodes using a wet process using a sulfide-based solid electrolyte is being considered. In order to maximize the performance of all-solid-state batteries, it is necessary to create a sufficient conductive network in the electrodes. It is important to form a solid electrolyte that is responsible for ionic conduction, as well as an electronically conductive solid electrolyte. In other words, a carbon material is required as a conductive additive to provide excellent conductivity in the wet process. To form an electrochemical network, a dispersion in which carbon materials, which are prone to aggregation, are sufficiently dispersed is required. It is necessary to create it.

[0003] Regarding the dispersion liquid used in the wet process using such a sulfide-based solid electrolyte, For example, Patent Document 1 discloses a method for manufacturing a solid electrolyte material containing a sulfide, a carbon material as a conductive additive, and a specific polar The use of a solvent to obtain a workable slurry is described. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-212652 Summary of the Invention [Problem to be solved by the invention]

[0005] However, sulfide-based solid electrolytes are highly reactive, so using a polar solvent can On the other hand, when a low-polarity solvent is used, the sulfide-based solid electrolyte deteriorates. Although this suppresses degradation of the electrolyte, there is a trade-off issue in that the dispersibility of the carbon material decreases. do. The present invention has been made in view of the above background, and is directed to a method for producing a dispersion medium using a specific low-polarity solvent and a dispersant. This suppresses the deterioration of the sulfide-based solid electrolyte and provides excellent dispersibility of the carbon material. The present invention also aims to provide a dispersion liquid in which deterioration of a sulfide-based solid electrolyte is suppressed. and to provide an electrode composition, an electrode film, and an all-solid-state battery that are excellent in productivity and battery performance. The purpose is to: [Means for solving the problem]

[0006] The present inventors have conducted extensive research into the above-mentioned problems and have found that carbon atoms having a cyclic skeleton and 8 or more carbon atoms are A solvent S is a hydrogen chloride, and a structural unit X has an HSP distance of less than 10.0 with respect to the solvent S, and H a dispersant containing 30% by mass or less of structural units Y having an SP distance of 10.0 or more in all structural units; The present invention was accomplished by finding that the dispersibility of carbon materials is excellent by combining I arrived. <1> That is, the present invention relates to a carbon material dispersion containing a carbon material, a dispersant, and a solvent including solvent S, wherein the solvent S is a hydrocarbon having 8 or more carbon atoms and including a cyclic skeleton, the dispersant contains a structural unit X having an HSP distance from the solvent S of less than 10.0, and a structural unit Y having an HSP distance from the solvent S of 10.0 or more, and the dispersant contains 30 mass% or less of the structural unit Y based on all structural units of the dispersant. <2> The present invention relates to a carbon material comprising fibrous carbon. <1> The present invention relates to a carbon material dispersion liquid described above. <3> The present invention relates to a carbon material dispersion liquid containing 1 to 10 mass% of fibrous carbon based on the mass of the carbon material dispersion liquid. <2> The present invention relates to a carbon material dispersion liquid described above. <4> The present invention relates to a method for producing a 1,2,3,4-tetrahydronaphthalene-based ... <1> ~ <3> The present invention relates to the carbon material dispersion liquid according to any one of the above aspects. <5> The present invention relates to a compound in which the structural unit Y comprises a nitrile group. <1> ~ <4> The present invention relates to the carbon material dispersion liquid according to any one of the above aspects. <6> The present invention provides <1> ~ <5> The present invention relates to an electrode composition comprising the carbon material dispersion liquid according to any one of the above aspects, an active material, a solid electrolyte, and a binder. <7> The present invention provides <1> ~ <5> The carbon material dispersion according to any one of claims 1 to 5, or <6> The present invention relates to an electrode film formed from the electrode composition described above. <8> The present invention provides <7> The present invention relates to an all-solid-state battery including an electrode having the electrode film described above. [Effects of the Invention]

[0007] According to the present invention, deterioration of the sulfide-based solid electrolyte is suppressed and the dispersibility of the carbon material is excellent. In addition, the deterioration of the sulfide-based solid electrolyte can be suppressed. and to provide an electrode composition, an electrode film, and an all-solid-state battery that are excellent in productivity and battery performance. can be done. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention relates to a carbon material dispersion liquid containing a carbon material, a dispersant, and a solvent containing solvent S. The solvent S is a hydrocarbon having 8 or more carbon atoms and containing a cyclic skeleton, and the dispersant is a H The structural unit X has an HSP distance of less than 10.0, and the solvent S has an HSP distance of 10.0 or more. and a structural unit Y, and the structural unit Y is contained in an amount of 30 mass % or less based on the total structural units of the dispersant. It is characterized by the The carbon material dispersion of the present invention exhibits excellent dispersibility due to the above-mentioned constitution. Regarding the above, for example, by combining a predetermined solvent and a dispersant, the affinity between the solvent and the dispersant can be improved. It is believed that this effect is achieved by controlling the compatibility and the absorption of solvents by the carbon material. are. The embodiments of the present invention will be described in detail below. The present invention is not limited to the following embodiments. The present invention does not necessarily mean that the present invention is limited to the above embodiments, and the present invention also includes embodiments that are implemented within the scope that does not change the gist of the present invention. do.

[0009] <Carbon materials> Examples of the carbon material in the present invention include fibrous carbon, carbon black, graphite, and the like. These carbon materials may be used alone or in combination of two or more. Among them, the carbon material is preferably fibrous carbon and carbon fiber from the viewpoint of electrical conductivity. It is preferable that the blend contains at least one selected from the group consisting of bon black. The carbon material preferably contains fibrous carbon because it has excellent conductivity even when the amount is small. It's nice.

[0010] [Fiber carbon] Examples of fibrous carbon include carbon nanotubes (hereinafter also referred to as "CNTs"). Vapor grown carbon fiber (hereinafter also referred to as "VGCF") is an example. In the present invention, the carbon nanotube is a cylindrically wound piece of flat graphite. The structure may be a single layer, a double layer, or a multilayer, or may be a mixture of these. Single-walled carbon nanotubes have a structure in which one layer of graphite is rolled up. A multi-walled carbon nanotube has a structure in which two or more layers of graphite are rolled up. The sidewalls of carbon nanotubes do not have to have a graphite structure. The carbon nanotubes having sidewalls with a fast structure are referred to as the carbon nanotubes of the present invention. It can be used as a tube.

[0011] In the present invention, the shape of the fibrous carbon is not limited. Tube-shaped, fishbone-shaped (fishbone or cup stacked type), playing card-shaped (platelet ) and coil shapes. Among others, needle-shaped or cylindrical tube-shaped. The fibrous carbon may be used in one type of shape alone, or in two or more types. The shapes may be combined.

[0012] The form of the fibrous carbon in the present invention may be, for example, graphite whiskers, fillers, etc. Mentas carbon, graphite fiber, ultra-fine carbon tube, carbon tube, carbon carbon fibrils, carbon microtubes, and carbon nanofibers. The fibrous carbon may be used in one form alone or in a combination of two or more forms. They may also be used in combination.

[0013] The average outer diameter of the fibrous carbon is preferably 1 nm or more, and more preferably 5 nm or more. Also, it is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less. The average outer diameter of the fibrous carbon can be determined as follows. First, the fibrous carbon is observed and photographed using a transmission electron microscope. In the center, 300 fibrous carbon fibers are randomly selected and the outer diameter of each is measured. The average outer diameter (nm) of the fibrous carbon is calculated as the number average of the diameters.

[0014] The carbon material may be a combination of two or more types of fibrous carbon having different average outer diameters. The first fibrous carbon may have an average outer diameter of 1 nm or more and less than 5 nm, and the second fibrous carbon may have an average outer diameter of 1 nm or more and less than 5 nm. The average outer diameter of the carbon may be 5 nm or more and 30 nm or less, or may be 20 nm or less. When they are used in combination, the mass ratio of the first fibrous carbon to the second fibrous carbon is 1:10 to 1:10. It may be 1:100, or may be 1:10 to 1:50.

[0015] The average fiber length of the fibrous carbon is preferably 0.5 μm from the viewpoint of forming a conductive network. It is preferably 0.8 μm or more, more preferably 0.8 μm or more, and even more preferably 1.0 μm or more. It is preferably 20 μm or less, and more preferably 10 μm or less. The average fiber length of the fibrous carbon can be determined as follows. The fibrous carbon is observed and photographed using a microscope. 300 pieces of fibrous carbon are selected and the fiber length of each is measured. Next, the number average of the fiber length and The average fiber length (μm) of the fibrous carbon is calculated.

[0016] The value obtained by dividing the average fiber length by the average outer diameter is the aspect ratio. The more fibrous the carbon, the higher the conductivity that can be achieved when forming an electrode. From the viewpoint of electrical conductivity, the aspect ratio is preferably 30 or more, more preferably 50 or more, and further Preferably, it is 80 or more. Also, it is preferably 10,000 or less, more preferably 3,0 00 or less, and more preferably 1,000 or less.

[0017] The specific surface area of ​​the fibrous carbon is preferably 100 m 2 / g or more, more preferably 150m 2 / g or more. 2 / g or less, more preferably 1000m 2 When the fibrous carbon is a multi-walled carbon nanotube, the average particle size is more preferably 800 m / g or less. 2 The specific surface area of ​​the fibrous carbon can be calculated by the BET method using nitrogen adsorption measurement.

[0018] The carbon purity of fibrous carbon is the carbon atom content (mass%) based on the mass of the fibrous carbon. The carbon purity is preferably 80% by mass or more, more preferably 90% by mass or more. The carbon purity is more preferably 95% by mass or more, and particularly preferably 98% by mass or more. By doing so, impurities form dendrites, which can cause problems such as short circuits. It can be suppressed.

[0019] When the carbon material dispersion of the present invention contains fibrous carbon, the content of the fibrous carbon is Based on the mass of the dispersion, preferably 0.1 mass% or more, more preferably 1 mass% or more, More preferably, it is 2% by mass or more. Also, it is preferably 20% by mass or less, and even more preferably 1 0% by mass or less, for example, 1 to 10% by mass, or even 1 to 5% by mass. When the content of the fibrous carbon is within the above range, the fibrous carbon is dispersed well and stably in the dispersion liquid. The presence of the hydroxybenzoates can be suppressed, thereby preventing sedimentation and gelation.

[0020] [Carbon black (CB)] Examples of carbon black in the present invention include acetylene black, furnace black, and the like. Black, hollow carbon black, channel black, thermal black, Ketjen Among them, acetylene black, which generally has a high carbon purity, is preferably used. I can.

[0021] The average primary particle size of the carbon black is preferably 10 nm or more, more preferably 20 nm or more, more preferably 25 nm or more. It is preferably 80 nm or less, and more preferably 60 nm or less. The average primary particle size of carbon black can be determined as follows. Carbon black is observed and photographed using a transmission electron microscope. In this case, 100 spherical carbon black primary particles are arbitrarily selected, and the outer diameter of each is Next, calculate the average primary particle diameter (nm) of the carbon black as the number average of the outer diameter. do.

[0022] When the carbon material dispersion of the present invention contains a carbon material other than fibrous carbon, The content of the carbon material is preferably 1% by mass or more, more preferably 1% by mass or more, based on the mass of the carbon material dispersion liquid. It is more preferably 5% by mass or more, and more preferably 50% by mass or less, for example, 1 to 10% by mass. It may be 50% by mass, or may be 5 to 50% by mass.

[0023] <Solvent> The carbon material dispersion of the present invention contains a solvent S, which is a hydrocarbon having a carbon number of 8 or more and a cyclic skeleton. It contains a solvent containing hydrocarbons with 8 or more carbon atoms that contain a cyclic skeleton, which makes it possible to Deterioration of the electrolyte can be suppressed. In addition, the hydrocarbons have a low water content and a high flash point. Furthermore, when used in combination with a dispersant, which will be described later, By doing so, the dispersibility of the carbon material can be improved. Based on the amount, it is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably It is preferably 90% by mass or more, and may be 100% by mass. In hydrocarbons containing a cyclic skeleton with 8 or more carbon atoms, the cyclic skeleton is part or all of the hydrocarbon. and may contain two or more cyclic skeletons. The element may be saturated or unsaturated. Examples of such hydrocarbons include o-xylene, m-xylene, p-xylene, Ethylbenzene, n-butylbenzene, t-butylbenzene, isobutylbenzene, cyclohexane Octane, 1,1-dimethylcyclohexane, decahydronaphthalene, bicyclohexyl cyclohexylbenzene, 1,2,3,4-tetrahydronaphthalene (hereinafter referred to as "tetrahydronaphthalene" Among them, 1,2,3,4-tetrahydronaphthalene is preferable. These solvents S may be used alone or in combination of two or more.

[0024] Examples of solvents other than solvent S include low-polarity solvents. The low-polarity solvent in the present invention is a solvent with low polarity that is unlikely to react with a sulfur-based solid electrolyte, and is a solvent with a relative dielectric constant of less than 10 and / or a solvent with a solubility of less than 1 g per 100 g of water at 20°C, including non-polar solvents. Preferably, the solvent has a relative dielectric constant of less than 10.0, more preferably 8.0 or less, and even more preferably 6.0 or less. The relative dielectric constant in this specification is a value measured at 20 to 25°C, and can be measured, for example, by performing double-cylinder tube current measurement at 10 kHz using a liquid dielectric constant meter Model 871 (manufactured by Sanyo Trading Co., Ltd.). Examples of such low polarity solvents include highly hydrophobic solvents having an alkyl group with 4 or more carbon atoms (ester or ether solvents), aromatic hydrocarbons, aliphatic hydrocarbons, and the like. Examples of (ester or ether) solvents having an alkyl group having 4 or more carbon atoms include butyl butyrate, pentyl butyrate, hexyl butyrate, butyl acetate, pentyl acetate, hexyl acetate, and butyl propionate. Examples of ether solvents having an alkyl group having 4 or more carbon atoms include dibutyl ether, ethyl butyl ether, tert-butyl methyl ether, and tert-butyl ethyl ether. Examples of aromatic hydrocarbons include toluene. These low polarity solvents may be used alone or in combination of two or more.

[0025] When the carbon material dispersion of the present invention contains fibrous carbon as the carbon material, the content of the solvent is The solvent content is preferably 50 to 99% by mass, more preferably 70 to 99% by mass, and even more preferably 90 to 99% by mass, based on the mass of the carbon material dispersion. When the carbon material dispersion of the present invention contains a carbon material other than fibrous carbon, the solvent content is preferably 40 to 95% by mass, more preferably 60 to 95% by mass, and even more preferably 80 to 95% by mass, based on the mass of the carbon material dispersion. When the solvent content is within the above range, the flowability and dispersion stability of the carbon material dispersion are excellent.

[0026] <Dispersant> The dispersant in the present invention has a structure in which the HSP distance between the dispersant and the solvent S is less than 10.0. A structural unit X and a structural unit Y having an HSP distance of 10.0 or more with respect to a solvent S, The structural unit Y is contained in an amount of 30% by mass or less based on the total structural units of the dispersant. The Hansen solubility parameter (Hansen solubility parameter) distance is the distance between two specific components (solvent S and structural unit X or Y). For this purpose, it is defined by the following mathematical formula (1) and serves as a solubility index for determining whether the two components are compatible with each other. HSP distance ={4(δD1-δD2) 2 +(δP1-δP2) 2 +(δH1-δH2) 2} 0.5 …(1) In equation (1), δD1, δP1, δH1, δD2, δP2, and δH2 are the Hansen solubility parameters for two specific components, and represent the solubility in a three-dimensional space with the dispersion term δD, the polar term δP, and the hydrogen bonding term δH. The dispersion term δD represents the effect of dispersion forces, the polar term δP represents the effect of dipole-dipole forces, and the hydrogen bonding term δH represents the effect of hydrogen bonding forces. The HSP of a particular component can be determined using Hansen Solubility Parameter in Practice (HSHPiP) software.

[0027] For example, if the solvent S is tetralin, the HSP values ​​of tetralin (δD, δP, δH) The formula is (18.7, 1.9, 2.6). And the dispersant is styrene and acrylonitrile. In the case of copolymers of styrene, the structural units derived from styrene have an HSP value of (17.6, 2. 3,3.0), and the HSP distance with tetralin is 2.3 according to the above formula. The structural unit derived from acrylonitrile corresponds to position X. The HSP value is (15.4 ,13.3,6.9), and the HSP distance with tetralin is 14 according to the above formula, It corresponds to structural unit Y. In addition, solvent S is a mixture containing multiple "hydrocarbons with 8 or more carbon atoms containing a cyclic skeleton." In this case, the mixture is determined based on the HSP value and volume fraction of each "hydrocarbon having 8 or more carbon atoms and containing a cyclic skeleton." The HSP value of the substance is calculated and used as the HSP value of solvent S.

[0028] The dispersant in the present invention is, for example, a dispersant having an HSP distance of at least 10.0 with respect to the solvent S. and a structural unit Y having an HSP distance to a solvent S of 10.0 or more. As such a copolymer, for example, polyvinyl bromide can be used. Copolymers containing vinyl alcohol such as butyl alcohol as structural units, hydrogenated nitrile butadiene Examples of the copolymer include copolymers containing acrylonitrile as a structural unit, such as acrylic rubber.

[0029] [Structural Unit X] Examples of the structural unit X include an aromatic ring, a heterocyclic ring, a cyclic olefin, and a chain olefin. These structural units X The solvent S may be used alone or in combination of two or more. In this case, the structural unit X may be, for example, a structural unit (2.3) derived from styrene, (4-methyl-2 ... The structural units (2.1) derived from (2-vinylstyrene) and (2-vinylnaphthalene) Structural units (1.7), (4-vinylpyridine)-derived structural units (4.9), (2-vinylpyridine)-derived structural units (4.9), Structural unit (7.2) derived from cyclohexane (1H-benzimidazole), Structural units derived from (5.9), structural units derived from butadiene (7.0) and their hydrogen The structure (9.3) derived from isoprene, the structural unit (6.7) derived from isoprene, and its hydrogenated structure The structure (9.1) can be used. The numbers in parentheses indicate the ratio of tetralin to each structural unit. This is the HSP distance from the first place.

[0030] When the HSP distance between the solvent S and the structural unit X is 1.0 or more and less than 6.0, the solubility in the solvent Since the decomposition property is improved, the introduction ratio of the structural unit Y can be increased within a range of 30 mass % or less. On the other hand, if the HSP distance is 6.0 or more, or 10.0 or more, the range of dispersant composition can be expanded. When the amount is less than 1000 ppm, the affinity with the carbon material is improved, and the adsorption property may be increased. .

[0031] [Structural Unit Y] Examples of the structural unit Y include a hydroxyl group, a nitrile group, an amide, a carboxylic acid, a dimethylsilyl group, and the like. The structural unit may be a hydroxyl group, and one type may be used alone or two or more types may be used in combination. When the solvent S is tetralin, the structural unit Y may be, for example, vinyl alcohol. Structural units derived from acrylonitrile (18), structural units derived from acrylonitrile (14), Structural units derived from methyl amide (17), structural units derived from acrylic acid (13), The structural unit (15) derived from siloxane can be used. The structural unit improves the intermolecular force of the dispersant with respect to the carbon material, thereby increasing dispersion stability. The values ​​in parentheses are the HSP distances between tetralin and each structural unit.

[0032] The HSP distance between solvent S and structural unit Y reduces the affinity of solvent S to the carbon material. From the viewpoint of generating the desired viscosity, the viscosity is preferably 12.0 or more and 20.0 or less.

[0033] The dispersant in the present invention contains 30 mass % or less of the structural unit Y based on all structural units. It is important that the content is 30 mass % or less, so that hydrocarbons having a carbon number of 8 or more and a cyclic skeleton can be used. From this viewpoint, the amount of the structural unit Y is It is preferably 1% by mass or more and 25% by mass or less.

[0034] In the present invention, the dispersant is a compound having a cyclic skeleton and 8 or more carbon atoms, from the viewpoint of dispersibility of the carbon material. The solubility of the compound in hydrocarbons at room temperature (25°C) is preferably 100 mass % or less, more preferably The solubility is preferably 80% by mass or less. The solubility is preferably 0.01% by mass or more. be.

[0035] When the carbon material contains fibrous carbon, the content of the dispersant in the present invention is Based on the total weight of the conductive material, the content is preferably 10 mass % or more, more preferably 20 mass % or more. From the viewpoint of the efficiency, the content is preferably 200% by mass or less, and more preferably 100% by mass or less.

[0036] The carbon material dispersion of the present invention may contain at least the above-described carbon material, dispersant, and solvent including solvent S. The carbon material dispersion of the present invention may further contain other optional components, such as dispersants, wetting agents, antifoaming agents, surfactants, pH adjusters, wetting and penetrating agents, antioxidants, preservatives, antifungal agents, leveling agents, and thickeners, as long as the effects of the present invention are not impaired. The carbon material dispersion may also contain a polymer component (binder component) as long as the object of the present invention is not impaired. These optional components may be added at any timing during the dispersion production process, such as before, during, or after the dispersion treatment of the carbon material dispersion.

[0037] <Method of manufacturing carbon material dispersion> To obtain the carbon material dispersion of the present invention, a treatment for dispersing a carbon material in a solvent is carried out. The dispersing device used for this treatment is not particularly limited, and examples thereof include Spar (disperser), homogenizer, Silverson mixer, kneader, colloid mill, Two-roll mill, three-roll mill, ball mill, horizontal sand mill, vertical sand mill, ani Bead mill, attritor, planetary mixer, ultrasonic homogenizer, high The dispersion process involves combining two or more different dispersion methods. Good too. For example, when carbon nanotubes are used as the carbon material, the dispersion can be carried out by mixing the carbon nanotubes, dispersant, and solvent together or separately. The carbon nanotubes can be those described above. Furthermore, when performing a dispersion treatment after mixing, the dispersion treatment can be carried out so that the carbon nanotubes in the resulting carbon nanotube dispersion composition have a predetermined average outer diameter and linearity index. The dispersion device used for the dispersion treatment is not particularly limited. As the dispersing device, a dispersing machine that is generally used for dispersing pigments or the like can be used. For example, mixers such as a disperser, a homomixer, and a planetary mixer; homogenizers (BRANSON "Advanced Digital Sonifer (registered trademark)" MODEL 450DA, M-Technique's "Clearmix", PRIMIX's "Filmix", Silverson's "Abramix", etc.); paint conditioner (Red Devil); colloid mills (PUC's "PUC Colloid Mill", IKA's "Colloid Mill MK"); cone mills (IKA's "Cone Mill MKO", etc.); media-type dispersers including ball mills, sand mills (Shinmaru Enterprises' "Dynomill", etc.), attritors, pearl mills (Eirich's "DCP Mill", etc.), and Coball mills; wet jet mills (Genus' "Genus PY", Sugino Machine's "Starburst", Nanomizer's "Nanomizer", etc.), media-less dispersers including M-Technique's "Clear SS-5", Nara Machine's "MICROS", etc.; and other roll mills, etc., but are not limited to these. In some embodiments, the dispersion treatment for preparing the carbon nanotube dispersion composition is preferably carried out using a homogenizer, a media-type disperser, a media-less disperser, or a combination thereof. The dispersion treatment using a homogenizer is preferably carried out under a high pressure of, for example, 10 to 150 MPa. When the dispersion treatment is carried out using a media-type disperser, beads such as zirconia beads are preferably used. The diameter of the beads used is preferably smaller than 2.00 mm, more preferably 1.50 mm or less. In the dispersion treatment, a homogenizer is preferably used, and the homogenizer may be used alone or in combination with at least one of a media-type disperser and a media-less disperser. In the dispersion treatment, the dispersion treatment may be performed without using a media-type disperser so that the carbon nanotubes are not broken by collision between the media and the carbon nanotubes. In this case, the dispersion treatment may be performed using a homogenizer alone or a combination of a homogenizer and a media-less disperser. For example, by performing wet kneading using a media-less disperser before and after the dispersion treatment using the homogenizer, the fiber length of the carbon nanotubes is maintained, and carbon nanotubes having a linearity index within a more appropriate range can be included in the dispersion composition. Examples of commercially available homogenizers include, but are not limited to, "R-MODEL" such as R5 and G-MODEL such as G5" manufactured by MST Corporation, "STARBURST" manufactured by Sugino Machine Ltd., and "OMEGA" manufactured by Ashizawa Finetech Co., Ltd. Examples of commercially available media-less dispersers include, but are not limited to, "3L Kneader" manufactured by Inoue Seisakusho Co., Ltd., "Planetary Mixer" manufactured by Inoue Seisakusho Co., Ltd., "Plastomill" manufactured by Toyo Seiki Seisakusho Co., Ltd., "Twin-screw Kneading Extruder PCM30" manufactured by Ikegai Corporation, and "MIXING ROLL MILL" manufactured by Inoue Seisakusho Co., Ltd.

[0038] <Electrode composition> The electrode composition of the present invention contains a carbon material, a dispersant, a solvent containing solvent S, an active material, a solid electrolyte, and a binder. The electrode composition may contain at least the carbon material dispersion, the active material, the solid electrolyte, and the binder, and may further contain optional components. The electrode composition may be referred to as a composite slurry.

[0039] [Active material] The active material in the present invention is not particularly limited, and may be a positive electrode active material or a negative electrode active material. As the positive electrode active material, for example, metal oxides capable of reversibly doping or intercalating lithium ions, and metal compounds such as metal sulfides can be used. Specific examples of such positive electrode active materials include, for example, lithium manganese composite oxides (e.g., Li x Mn2O4 or Li x MnO2), lithium nickel composite oxides (e.g., LiNiO2), lithium cobalt composite oxides (Li x CoO2), lithium nickel cobalt composite oxides (e.g., Li x Ni 1-y Co y O2), lithium manganese cobalt composite oxides (e.g., Li x Mn y Co 1-y O2), lithium nickel manganese cobalt composite oxides (hereinafter also referred to as NMC) (e.g., Li x Ni y Co z Mn 1-y-z O2), spinel-type lithium manganese nickel composite oxides (e.g., Li x Mn 2-y Ni y O4), etc., composite oxide powders of lithium and transition metals, lithium phosphate powders having an olivine structure (e.g., Li x FePO4, Li x * Fe 1-y Mn y PO4, Li x CoPO4), transition metal oxide powders such as manganese oxide, iron oxide, copper oxide, nickel oxide, vanadium oxides (e.g., V2O5, V6O 13 ), titanium oxide, transition metal sulfide powders such as iron sulfate (Fe2(SO4)3), TiS2, and FeS. However, x, y, and z are numbers, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and 0 < y + z < 1. These positive electrode active materials may be used alone or in combination of two or more.

[0040] As the negative electrode active material, for example, metal Li or its alloy capable of reversibly doping or intercalating lithium ions, tin alloy, silicon alloy negative electrode, Li XTiO2, Li X Fe2O3, Li X Fe3O4, Li X Examples include metal oxide systems such as WO2, conductive polymers such as polyacetylene and poly-p-phenylene, artificial graphite such as highly graphitized carbon materials, or carbonaceous powders such as natural graphite, and resin-fired carbon materials. However, x is a number and 0 < x < 1. These negative electrode active materials may be used alone or in combination of two or more. Particularly when using a silicon alloy negative electrode, although the theoretical capacity is large, the volume expansion is extremely large. Therefore, it is preferably used in combination with artificial graphite such as highly graphitized carbon materials, carbonaceous powders such as natural graphite, resin-fired carbon materials, etc.

[0041] The surface of the active material may be coated with a buffer layer in order to reduce the interfacial resistance with the solid electrolyte. Examples of the buffer layer include oxide solid electrolytes, halide solid electrolytes, sulfide solid electrolytes, and oxide materials. For example, the surface of the active material may be coated with at least one or more buffer layers with a thickness of 1 to 500 nm.

[0042] [Solid electrolyte] As the solid electrolyte in the present invention, a sulfide-based solid electrolyte is used. Also, an oxide solid electrolyte and a halide solid electrolyte may be used in part. The sulfide-based solid electrolyte is not particularly limited. The element contains S and may further contain Li. Also, crystals, non-crystals (glass), glass ceramics obtained by crystallizing glass, or those in which only a part is crystallized may be used. Examples of the sulfide-based solid electrolyte include, for example, Li . Also, those produced by mixing raw materials in an arbitrary molar ratio as exemplified below may also be used. For example, Li Si 9.54 P 1.74 S 1.44 Cl 11.7 Cl 0.3 Li 10 GeP2S 12 Li6PS5Cl, Li7P3S 11 (hereinafter also referred to as LPS). Also, as exemplified below, those produced by mixing raw materials in an arbitrary molar ratio may be used. Example) Li2S-P2S5, Li2S-P2S5-LiCl, Li2S-LiI-P2S 5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S -Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2 O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li 2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-Al2S3, L i2S-SiS2, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-LiI, Li2S-SiS2-P2S5-LiI, Li2S-Si S2-Li4SiO4, Li2S-SiS2-P2O5, Li2S-B2S3, Li2S -B2S3-Li3PO4, Li2S-GeS2, Li2S-Ga2S3, Li2S-G eS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5 , Li2S-GeS2-ZnS, Li2S-GeS2-Al2S3. These may be used alone or in combination of two or more.

[0043] [binder] The binder that may be contained in the electrode composition is not particularly limited, and may be selected appropriately depending on the purpose. The binder used in the secondary battery electrode composition can be selected from, for example, Styrene, propylene, vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic Acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, Styrene, vinyl butyral, vinyl acetal, vinyl pyrrolidone, etc. as structural units Polymers or copolymers containing polyurethane resins, polyester resins, phenolic resins, epoxy resins oxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, acrylic resin, Formaldehyde resin, silicone resin, fluororesin; cellulose resin; styrene-butadiene Elastomers such as diene rubber and fluororubber; polyaniline and polyacetylene Conductive resins; etc. Binders include modified or mixed resins, and copolymers of these resins. It may be the body.

[0044] <Method of manufacturing electrode composition> The electrode composition of the present invention can be prepared by any method using the carbon material dispersion liquid. For example, a method of adding an active material, a solid electrolyte, and a binder to a carbon material dispersion, A method of adding a binder after adding an active material and a solid electrolyte to a dispersion liquid, a carbon material dispersion liquid a method of adding a binder to the dispersion liquid and then adding an active material and a solid electrolyte; A method of adding a solid electrolyte and binder after adding a material, or a method of adding a solid electrolyte to a carbon material dispersion and then adding the active material and binder. A method in which a solid electrolyte is added after the binder is added, and a method in which an active material, a solid electrolyte, and a binder are added after the binder is added. and adding the carbon material dispersion after mixing in a blender. The device to be used is not particularly limited.

[0045] When the carbon material in the electrode composition contains fibrous carbon, the content of the fibrous carbon is determined by the quality of the active material. Based on the amount, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, More preferably, the content is 10 mass % or less. When the carbon material contains other than fibrous carbon, for example, When acetylene black is included, the content of acetylene black is based on the mass of the active material. is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more. It is 0 mass % or less. The carbon material of the electrode composition is either fibrous carbon or a carbon material other than fibrous carbon, and each of these is 2 Two or more different types of compounds may be used, and the total amount of each compound is preferably within the above range. In addition, the carbon material of the electrode composition of the present invention is a combination of fibrous carbon and a carbon material other than fibrous carbon. That's fine.

[0046] The dispersant contained in the electrode composition is preferably 0.01 mass % based on the mass of the active material. The content is 10% by mass or more, and preferably 10% by mass or less.

[0047] The solid content of the electrode composition is preferably 30% by mass based on the mass of the electrode composition. % by mass or more, more preferably 40% by mass or more. Also, it is preferably 90% by mass or less. be.

[0048] <Electrode film> The electrode film includes at least one film formed from a carbon material dispersion or an electrode composition. The electrode film may further include a current collector. The electrode film can be obtained by forming the electrode composition into a film. For example, the electrode film may be a coated film obtained by applying the electrode composition onto a current collector and drying it. The current collector on which the electrode film is provided is not particularly limited. Examples of materials for the current collector include conductive metals and alloys such as Al, Ni, Cu, Ti, Fe, Cr, and stainless steel. The current collector generally has a flat foil shape, but current collectors with a roughened surface, perforated foil shape, and mesh shape can also be used. The current collector may have a coating layer on its surface. Examples of the coating layer include a carbon layer containing conductive carbon or a binder, which improves adhesion to the current collector and electrical conductivity.

[0049] The method for applying the carbon material dispersion onto the current collector is not particularly limited, and examples thereof include die coating. coating method, roll coating method, doctor coating method, knife coating method, Top coating method, gravure coating method, spray coating method, screen printing Examples of the drying method include leaving the coating to dry or using a blow dryer. Examples of drying methods include drying using equipment such as a hot air dryer, an infrared heater, and a far-infrared heater. The electrode film may be subjected to a pressing treatment after coating and drying. Examples of the pressing treatment include: Examples include flat press and roll press, and adjustments such as increasing the temperature during pressing may be made. .

[0050] <All-solid-state battery> The components of the drive unit of an all-solid-state battery are roughly divided into a positive electrode, a negative electrode, and a separator layer. The positive electrode and / or negative electrode are stacked so as to face each other via the electrode film. The separator layer placed between them is made of a solid electrolyte and contains a binder. Good too. The method for laminating the components of the driving part in the all-solid-state battery is not particularly limited. The positive electrode, negative electrode, and separator layers may be formed and laminated separately, and the surface layer of the positive electrode and / or negative electrode may be A separator layer may be formed on the positive electrode or negative electrode to be stacked. Further, adjustments such as increasing the temperature during pressing may be performed. It is possible to press after laminating all of the components, or to press after laminating each component. good. In addition to the components of the drive unit, all-solid-state batteries also have laminated films and metal cases. It may also be provided with an exterior, connection terminals, etc. [Example]

[0051] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples. "Parts by mass" and "%" represent "% by mass." The blending amounts in the table are in parts by mass, and all ingredients except the solvent are The values ​​are calculated as non-volatile content. Note that blanks in the table indicate that no ingredients were blended.

[0052] <Production of dispersants> (Synthesis Example 1) A reaction vessel equipped with a gas inlet tube, a thermometer, a condenser, and a stirrer was charged with methyl ethyl ketone. The reactor was heated to 60°C and 90 parts of styrene were added, and the contents were replaced with nitrogen gas. A mixture of 10 parts of acrylonitrile and 0.6 parts of V-65 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) After the dropwise addition, the reaction was continued for another 6 hours at 60°C. After that, 0.1 parts of V-65 was added, and the reaction was continued for another hour at 60°C to obtain Dispersant 1 solution. The solvent was then distilled off by heating to obtain Dispersant 1.

[0053] (Synthesis Examples 2-4, 6, 7) Dispersants 2 to 4, 6 and 7 were obtained in the same manner as in Synthesis Example 1, except that the blending compositions were changed as shown in Table 1.

[0054] (Synthesis Example 5) A stainless steel polymerization reactor was charged with 20 parts of acrylonitrile, 80 parts of 1,3-butadiene, and Potassium oleate 3 parts, azobisisobutyronitrile 0.3 parts, t-dodecyl mercapto 0.6 parts of ethanol and 200 parts of ion-exchanged water were added. Then, polymerization was carried out at 45°C for 20 hours, and the polymerization was terminated when the conversion rate reached 90%. % acrylonitrile-conjugated diene rubber latex was obtained. The total solids concentration was adjusted to 12% by adding ethanol-exchanged water, and the mixture was placed in a 1 L autoclave equipped with a stirrer. The contents were then poured into a container and nitrogen gas was passed through for 10 minutes to remove dissolved oxygen from the contents. 75 mg of palladium acetate as a conversion catalyst was added to nitric acid in an amount four times the moles of palladium. The catalyst solution was prepared by dissolving the catalyst in 180 mL of ion-exchanged water and added to the autoclave. After replacing the inside of the autoclave with hydrogen gas twice, the autoclave was pressurized with hydrogen gas up to 3 MPa. The contents of the autoclave were heated to 50°C and hydrogenation reaction was carried out for 6 hours. The autoclave was returned to room temperature, and a nitrogen atmosphere was created inside the autoclave. The solid matter was then dried and the 1,3- Dispersant 5 was obtained in which the double bond derived from butadiene was hydrogenated.

[0055] For the resulting dispersants 1 to 7, the formulation composition, HSP values ​​of the structural units, and the HSP distances between each structural unit and various solvents are shown in Table 1. The HSP values ​​of the structural units and the HSP distances between tetralin and o-xylene were measured using Hansen Solubility Parameter software (HSPiP 5th Edition (ver. 5.3.08)). The HSP distances between o-xylene and 1,2,4-trimethylbenzene were measured using Hansen Solubility Parameter software (HSPiP 6th Edition (ver. 6.1.02)).

[0056] [Table 1]

[0057] <Production of carbon material dispersion> [Example 1] Dispersion 1 Add 97 parts of tetralin as a solvent and 1 part of dispersant 1 to a stainless steel container and mix evenly with a disperser. After that, multi-walled carbon nanotubes (LG Ch) were added as the carbon material. Add 2 parts of "LUCAN BT1003M" manufactured by EM Ltd. while stirring with a disperser. A square-hole high-shear screen was added to a high-shear mixer (L5M-A, Silverson). The grind gauge is used to measure the uniformity of the entire material at a speed of 8,600 rpm. Batch dispersion was carried out until the particle size was 250 μm or less. A high-pressure homogenizer (Starburst Lab HJP-17007, Sugino Mashi) was used via piping. The dispersion liquid was supplied to a nozzle (manufactured by Epson) and dispersion treatment was carried out using a single nozzle for 25 passes. The experiment was carried out using a chamber with a nozzle diameter of 0.25 mm and a pressure of 100 MPa. After passing through a nylon mesh with an opening of 48 μm three times, dispersion 1 was obtained.

[0058] [Examples 2 to 13, Comparative Examples 1 and 2] Dispersions 2 to 15 The carbon material, dispersant, and solvent types and contents were changed as shown in Table 2. Carbon material dispersions 2 to 15 were obtained in the same manner as in Example 1.

[0059] <Evaluation of carbon material dispersion> The resulting dispersion was evaluated as follows, and the results are shown in Table 2.

[0060] (Dispersibility evaluation) The temperature of the obtained dispersion was adjusted to 25°C, and after stirring thoroughly with a spatula, the dispersion was immediately measured using an E-type viscometer ( Using a Toki Sangyo Co., Ltd. "TV-100EH", the initial viscosity was measured at a rotor rotation speed of 50 rpm. The measured values ​​were evaluated according to the following criteria. ○: Viscosity is 100 mPa·s or less △: Viscosity is greater than 100 mPa·s

[0061] (Storage stability evaluation) The obtained dispersion was stored at 25°C for 7 days, and then the dispersion was evaluated in the same manner as described above (Evaluation of Dispersibility). The viscosity was measured and the rate of change in viscosity was calculated. The appearance was also visually observed. The appearance was evaluated according to the following criteria. ○: The rate of change is within 20% and no sedimentation or separation is observed △: The rate of change is more than 20%, or sedimentation or separation is observed.

[0062] <Production of electrode composition> Electrode compositions for positive and negative electrodes were produced using the obtained carbon material dispersions 1 to 15. The work of producing the electrode compositions was carried out in a glove box kept in an argon atmosphere with a dew point of −60° C. or lower.

[0063] [Example 2-1] Positive electrode composition P1 4.7 parts of a tetralin solution containing 15 mass% of a styrene-based elastomer resin (styrene-ethylene-butylene-styrene block copolymer (SEBS)) as a binder, 57.7 parts of the active material NMC, 10.6 parts of the solid electrolyte LPS, 9.5 parts of the obtained carbon material dispersion 1, and 17.5 parts of tetralin were weighed into a container, and the mixture was stirred at 2,000 rpm for 60 seconds using a planetary centrifugal mixer (Thinky Awatori Rentaro, ARE-310) to obtain a positive electrode composition P1.

[0064] [Examples 2-2 to 2-13, Comparative Examples 2-1 and 2-2] Positive electrode compositions P2 to P15 Positive electrode compositions P2 to P15 were obtained in the same manner as in Example 2-1, except that the carbon material dispersion liquid 1 was changed to dispersion liquids 2 to 11.

[0065] [Example 3-1] Negative electrode composition N1 4.7 parts of a tetralin solution containing 15% by mass of SEBS as a styrene-based elastomer resin as a binder, 51.93 parts of artificial graphite, 5.77 parts of silicon monoxide (SiO), 10.6 parts of the solid electrolyte LPS as active materials, 10.1 parts of the obtained carbon material dispersion 1, and 16.9 parts of tetralin were weighed into a container, and the mixture was stirred at 2,000 rpm for 3 minutes using a planetary centrifugal mixer (Thinky Awatori Rentaro, ARE-310) to obtain a negative electrode composition N1.

[0066] [Examples 3-1 to 3-13, Comparative Examples 3-1 and 3-2] Negative electrode compositions N2 to N15 Negative electrode compositions N2 to N15 were obtained in the same manner as in Example 3-1, except that dispersion liquid 1 of a carbon material was changed to dispersion liquids 2 to 15.

[0067] <Production of reference electrode composition (Px, Nx)> 98 parts of tetralin and 2 parts of multi-walled carbon nanotubes (JEIO Corporation's "JENOTUBE 10B") were weighed and mixed in a container. Next, 150 parts of zirconia beads were added, and the mixture was shaken for 2 hours using a paint shaker. The zirconia beads were then removed by filtration. Molecular sieves were then added, and the mixture was stirred overnight using a mix rotor to dehydrate, yielding a reference carbon material dispersion. A reference electrode composition for a positive electrode (Px) and a reference electrode composition for a negative electrode (Nx) were obtained in the same manner as in Example 2-1 and Example 3-1, except that the carbon material dispersion liquid 1 was changed to the above-mentioned reference carbon material dispersion liquid.

[0068] <Evaluation of electrode composition> Using the obtained electrode compositions (P1 to P15, Px, N1 to N15, Nx), electrodes were fabricated and evaluated according to the following procedure. The results are shown in Table 2. The work of fabricating the electrodes and the work of assembling the evaluation cells were carried out in a glove box maintained in an argon atmosphere with a dew point of -60°C or below.

[0069] (Evaluation of positive electrode cycle characteristics) The obtained electrode compositions for positive electrodes (P1 to P15) and the reference electrode composition (Px) were applied to aluminum foil with a thickness of 20 μm using an applicator with a gap of 200 μm, and then dried on a hot plate at 150°C for 30 minutes to obtain electrodes for positive electrodes 1 to 15 and a reference positive electrode. The fabricated positive electrodes 1-15 and the reference positive electrode were each punched to a diameter of 10 mm and used as working electrodes. The working electrode and 50 mg of LPS powder were placed in the cylindrical container of the all-solid-state battery evaluation cell, and a pressure of 300 MPa was applied to create an LPS layer on the working electrode. On the opposite side of the LPS layer, metal indium foil and metal lithium foil were placed in that order as counter electrodes and pressurized to 100 MPa. The cell was then assembled and secured with bolts, which were then tightened using a torque wrench to the specified pressure, yielding a positive electrode evaluation cell. The resulting evaluation cell was placed in a thermostatic chamber at 25°C and subjected to charge / discharge measurements using a charge / discharge device (SM-8, manufactured by Hokuto Denko Corporation). Constant-current, constant-voltage charging (cutoff current: 0.01C) was performed at a charge rate of 0.1C with a charge cutoff voltage of 4.2V, followed by constant-current discharging at a discharge rate of 0.1C with a discharge cutoff voltage of 2.5V. This procedure was repeated 200 times. 1C was defined as the current value required to charge or discharge the theoretical capacity of the positive electrode in 1 hour. First, the cycle characteristics were calculated as the ratio of the third 0.1 C discharge capacity to the 200th 0.1 C discharge capacity using the following formula 1. (Formula 1) Cycle characteristic = 200th 0.1 C discharge capacity / 3rd 0.1 C discharge capacity × 100 (%) Next, a relative value (%) based on the cycle characteristics when the reference positive electrode was used as the working electrode was calculated using the following formula 2, and evaluated according to the following criteria. (Formula 2) Relative value = cycle characteristic when positive electrodes 1 to 11 are used as working electrodes / cycle characteristic when reference positive electrode is used as working electrode × 100 (%) [Evaluation criteria] ○: Relative value is 200% or more △: Relative value is 120% or more and less than 200% ×: Relative value is less than 120%

[0070] (Evaluation of negative electrode cycle characteristics) The obtained negative electrode compositions (N1 to N15) and reference electrode composition (Nx) were applied to a 20 μm thick copper foil as a current collector using an applicator with a 200 μm gap, and then dried on a hot plate at 150°C for 30 minutes to obtain negative electrodes 1 to 15 and a reference negative electrode. The fabricated negative electrodes 1-15 and the reference negative electrode were each punched to a diameter of 10 mm and used as working electrodes. The working electrode and 50 mg of LPS powder were placed in the cylindrical container of the all-solid-state battery evaluation cell, and a pressure of 300 MPa was applied to create an LPS layer on the working electrode. On the opposite side of the LPS layer, metal indium foil and metal lithium foil were placed in that order as counter electrodes and pressurized to 100 MPa. The cell was then assembled and secured with bolts, which were then tightened using a torque wrench to the specified pressure, yielding a negative electrode evaluation cell. The resulting evaluation cell was placed in a thermostatic chamber at 25°C and subjected to charge / discharge measurements using a charge / discharge device (SM-8, manufactured by Hokuto Denko Corporation). Constant-current, constant-voltage charging (cutoff current: 0.01C) was performed at a charge rate of 0.1C with a charge cutoff voltage of 0.05V, followed by constant-current discharging at a discharge rate of 0.1C with a discharge cutoff voltage of 1.5V. This procedure was repeated 200 times. 1C was defined as the current value required to charge or discharge the theoretical capacity of the negative electrode in 1 hour. First, the cycle characteristics were calculated as the ratio of the third 0.1 C discharge capacity to the 200th 0.1 C discharge capacity using the following formula 3. (Formula 3) Cycle characteristic = 200th 0.1 C discharge capacity / 3rd 0.1 C discharge capacity × 100 (%) Next, a relative value (%) based on the cycle characteristics when the reference negative electrode was used as the working electrode was calculated using the following formula 4, and evaluated according to the following criteria. (Formula 4) Relative value = cycle characteristic when negative electrodes 1 to 11 are used as working electrodes / cycle characteristic when reference negative electrode is used as working electrode × 100 (%) [Evaluation criteria] ○: Relative value is 200% or more △: Relative value is 120% or more and less than 200% ×: Relative value is less than 120%

[0071] [Table 2]

[0072] The abbreviations in Table 2 are as follows: BT1003M:LUCAN BT1003M (manufactured by LG Chem Ltd, multilayer CNT, average outer diameter 10~15nm, specific surface area 186m) 2 / g) 10B: JENOTUBE 10B (manufactured by JEIO, multi-walled CNT, average outer diameter 10 nm, average fiber length 100-200 μm, bundle shape, BET specific surface area 230 m 2 / g) Li-400: Denka Black Li-400 (manufactured by Denka Co., Ltd., acetylene black, average particle size 48 nm, specific surface area 39 m 2 / g) TUBALL: OCSiAl, single-walled CNT, average outer diameter 1.6 nm, carbon purity 93%, specific surface area 975 m 2 / g SBR: Styrene butadiene rubber Tetralin: 1,2,3,4-tetrahydronaphthalene

[0073] Solvent S is a hydrocarbon containing a cyclic skeleton with 8 or more carbon atoms, and the HSP distance between solvent S and solvent S is 10 The structural unit X whose HSP distance is less than 0.0 and the structural unit Y whose HSP distance is 10.0 or more are all constituent units. The carbon material dispersion of the present invention, which is combined with a dispersant contained in the carbon material dispersion at a concentration of 30 mass % or less in the carbon material dispersion, is The initial viscosity was low, the storage stability was good, and the dispersion was excellent. By using a carbon material dispersion liquid with such excellent dispersibility as an electrode composition, when it is made into an electrode film, An excellent conductive network is formed, resulting in an all-solid-state battery with excellent output and suppression of cycle deterioration. It is possible. On the other hand, in Comparative Example 1, the dispersant did not contain the structural unit Y, and the initial viscosity was high and the storage stability was poor. The evaluation showed that sedimentation occurred and the dispersibility was poor. The content is 30% by mass or more, and the initial viscosity is high. Separation occurs in the storage stability evaluation, and dispersibility is poor. The results were as follows: It was thought that the affinity for the solvent was insufficient and it did not function adequately as a dispersant. can be done.

Claims

1. A carbon material dispersion containing a carbon material, a dispersant, and a solvent containing solvent S, the solvent S is a hydrocarbon having a carbon number of 8 or more and containing a cyclic skeleton, The dispersant comprises a structural unit X having an HSP distance of less than 10.0 with respect to the solvent S, and and a structural unit Y having an HSP distance of 10.0 or more with respect to the solvent S, % by mass or less of the structural unit Y.

2. The carbon material dispersion according to claim 1 , wherein the carbon material comprises fibrous carbon.

3. 3. The carbon material dispersion according to claim 2, wherein the carbon fiber content is 1 to 10% by mass based on the mass of the carbon material dispersion. Carbon material dispersion liquid.

4. 4. The method according to claim 1, wherein the solvent S is 1,2,3,4-tetrahydronaphthalene.

3. The carbon material dispersion liquid according to claim 1.

5. The carbon material dispersion according to any one of claims 1 to 3, wherein the structural unit Y contains a nitrile group.

6. The carbon material dispersion liquid according to any one of claims 1 to 3, an active material, a solid electrolyte, and a binder. An electrode composition comprising:

7. An electrode film formed from the electrode composition according to claim 6.

8. An all-solid-state battery comprising an electrode having the electrode film according to claim 7.

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