Mixture sheet for electrochemical devices, electrochemical device, and method for producing mixture sheet for electrochemical devices

Abstract

The purpose of the present disclosure is to provide: a mixture sheet for electrochemical devices, the mixture sheet being capable of having improved sheet strength, while maintaining good electrochemical characteristics; an electrochemical device; and a method for producing a mixture sheet for electrochemical devices. The present disclosure provides a mixture sheet for electrochemical devices, the mixture sheet containing a silicone compound which is in a liquid state at 25°C, a binder, and an electrochemical device material, wherein the content of the silicone compound is 0.5-20% by mass with respect to the solid content of the mixture sheet for electrochemical devices, and the kinematic viscosity of the silicone compound at 25°C is 5 cSt to 60,000 cSt.

Description

Mixture sheet for electrochemical device, electrochemical device, and method for manufacturing mixture sheet for electrochemical device

[0001] The present disclosure relates to a mixture sheet for an electrochemical device, an electrochemical device, and a method for manufacturing a mixture sheet for an electrochemical device.

[0002] BACKGROUND ART With the recent trend toward lighter and smaller electrical appliances, the development of electrochemical devices such as lithium ion secondary batteries with high energy density has been progressing.

[0003] As technologies relating to electrochemical devices, Patent Document 1 discloses an electrode for a secondary battery using a powdered active material, a conductive material, and a fluorine-containing polymer resin, and Patent Document 2 discloses a free-standing solid composite electrolyte membrane using solid ion-conductive inorganic particles and a tetrafluoroethylene (co)polymer. Furthermore, Patent Document 3 discloses a solid electrolyte slurry and an electrode slurry containing an inorganic solid electrolyte material and a liquid inert to the inorganic solid electrolyte material.

[0004] Japanese Patent Application Laid-Open No. 2007-026984 Japanese Patent Application Laid-Open No. 2022-546129 Japanese Patent Application Laid-Open No. 2016-062709

[0005] When a mixture sheet for an electrochemical device is produced using a slurry such as that described in Patent Document 3, there is an advantage in that a large-area sheet can be obtained, but it tends to be difficult to obtain the sheet strength required for handling (transporting, etc.) the sheet during the manufacturing process. Furthermore, by increasing the amount of binder, it is possible to obtain the sheet strength required during the manufacturing process, but electrochemical properties such as discharge capacity tend to deteriorate. As such, it has been difficult to obtain a mixture sheet for an electrochemical device that combines electrochemical properties and sheet strength using conventional methods.

[0006] An object of the present disclosure is to provide a mixture sheet for electrochemical devices that can improve sheet strength while maintaining good electrochemical properties, an electrochemical device, and a method for manufacturing a mixture sheet for electrochemical devices.

[0007] The present disclosure (1) is a mixture sheet for electrochemical devices, comprising a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, wherein the content of the silicone compound is 0.5 to 20 mass% relative to the solid content of the mixture sheet for electrochemical devices, and the kinetic viscosity of the silicone compound at 25°C is 5 cSt to 60,000 cSt.

[0008] The present disclosure (2) is the mixture sheet for an electrochemical device according to the present disclosure (1), wherein the silicone compound has a polyoxyalkylene chain.

[0009] The present disclosure (3) is the electrochemical device mixture sheet according to the present disclosure (1) or (2), wherein the content of the silicone compound is 0.5 to 15 mass% with respect to the solid content of the electrochemical device mixture sheet.

[0010] The present disclosure (4) is a mixture sheet for an electrochemical device, comprising a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, wherein the silicone compound has a polyoxyalkylene chain.

[0011] The present disclosure (5) is a mixture sheet for an electrochemical device according to any one of the present disclosures (1) to (4), wherein the silicone compound has a saturated water content at 25° C. of more than 30 ppm.

[0012] The present disclosure (6) is the composite sheet for electrochemical devices according to any one of the present disclosures (1) to (5), wherein the silicone compound has a mass loss rate of 20% by mass or less when heated at 150°C for 24 hours.

[0013] The present disclosure (7) is the mixture sheet for electrochemical devices according to any one of the present disclosures (1) to (6), characterized in that the content of the binder is 0.5 to 10 mass% with respect to the solid content of the mixture sheet for electrochemical devices.

[0014] The present disclosure (8) is a mixture sheet for an electrochemical device according to any one of the present disclosures (1) to (7), which contains a metal salt.

[0015] The present disclosure (9) is the composite sheet for an electrochemical device according to the present disclosure (8), wherein the content of the metal salt relative to the silicone compound is 0.1 to 30 mass %.

[0016] The present disclosure (10) is a mixture sheet for an electrochemical device according to any one of the present disclosures (1) to (9), wherein the mixture sheet for an electrochemical device is an electrode mixture sheet or an electrolyte mixture sheet.

[0017] The present disclosure (11) is the composite sheet for an electrochemical device according to any one of the present disclosures (1) to (10), in which the binder is a fluorine-based polymer material.

[0018] The present disclosure (12) is the composite sheet for electrochemical devices according to the present disclosure (11), wherein the binder is at least one selected from the group consisting of polytetrafluoroethylene, poly(vinylidene fluoride-co-hexafluoropropylene), and poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene).

[0019] The present disclosure (13) is the mixture sheet for an electrochemical device according to the present disclosure (12), in which the binder is polytetrafluoroethylene.

[0020] The present disclosure (14) is a mixture sheet for an electrochemical device according to any one of the present disclosures (1) to (13), which contains a conductive assistant.

[0021] The present disclosure (15) is an electrochemical device using the mixture sheet for an electrochemical device according to any one of the present disclosures (1) to (14).

[0022] The present disclosure (16) provides a method for producing a mixture sheet for electrochemical devices, the method including: a step (1) of mixing a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material; and a step (2) of rolling the mixture for electrochemical devices obtained in the step (1) into a sheet.

[0023] The present disclosure (17) is the manufacturing method according to the present disclosure (16), wherein the kinematic viscosity of the silicone compound at 25°C is 5 cSt to 60,000 cSt, the silicone compound has a polyoxyalkylene chain, and the binder is polytetrafluoroethylene.

[0024] According to the present disclosure, it is possible to provide a mixture sheet for electrochemical devices, an electrochemical device, and a method for manufacturing a mixture sheet for electrochemical devices, which can improve sheet strength while maintaining good electrochemical properties.

[0025] The present disclosure will be specifically described below.

[0026] <Electrochemical device mixture sheet> The first present disclosure relates to a mixture sheet for electrochemical devices, including a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, wherein the content of the silicone compound is 0.5 to 20 mass% relative to the solid content of the electrochemical device mixture sheet, and the silicone compound has a kinematic viscosity at 25°C of 5 cSt to 60,000 cSt.

[0027] The electrochemical device mixture sheet of the first present disclosure has the above-described configuration, and therefore can improve the strength of electrode sheets and solid electrolyte sheets while maintaining good electrochemical properties. This is thought to be because the silicone compound imparts fluidity to the electrochemical device material during sheet formation, thereby enabling the formation of a uniform sheet. In particular, when the binder contains a fibrillar resin, it is thought that strength is improved because the flow deformation during formation promotes the generation of fibrils. Furthermore, the silicone compound imparts fluidity to the electrochemical device material during sheet formation, thereby improving sheet strength, which makes it possible to reduce the amount of binder used and improve the energy density of the electrochemical device.

[0028] The silicone compound is liquid at 25°C and has a kinematic viscosity at 25°C of 5 cSt to 60,000 cSt. If the kinematic viscosity is too low, the silicone compound may flow out during pressure molding, while if the kinematic viscosity is too high, the electrochemical device material may not be given sufficient fluidity, and the sheet strength may not be improved. From the viewpoint of imparting fluidity to the electrochemical device material, the kinematic viscosity is preferably 10 cSt or more, more preferably 100 cSt or more, and is preferably 20,000 cSt or less, more preferably 10,000 cSt or less. In this specification, the kinematic viscosity is a value determined at 25°C using an Ubbelohde viscometer in accordance with ASTM D445-46T.

[0029] The silicone compound is not particularly limited as long as it has a siloxane bond, but it is preferable that it has a polyoxyalkylene chain together with the siloxane bond. Examples of the constituent units of the polyoxyalkylene chain include oxyethylene, oxypropylene, oxybutylene, etc. The proportions thereof are not particularly limited.

[0030] The higher the affinity of the silicone compound with water molecules, i.e., the greater the saturated water content, the higher its polarity tends to be. Furthermore, when the polarity of the silicone compound is high, electrochemical properties such as discharge capacity tend not to deteriorate. This is thought to be due to the ability of ions to move within the silicone compound. From this perspective, the silicone compound preferably has a saturated water content of more than 30 ppm at 25°C, more preferably 50 ppm or more, and even more preferably 100 ppm or more. There is no particular upper limit, but when the silicone compound does not have a polyoxyalkylene chain, it is usually 1000 ppm or less. In this specification, the saturated water content is measured by the following method. A mixture is obtained by adding water in an amount five times the volume of the silicone compound, stirring the mixture, and allowing it to stand at 25°C for 24 hours. The mixture is then centrifuged to separate it into an aqueous phase and a silicone compound-rich phase, and the concentrated phase is measured using Karl Fischer titration. The moisture content was measured using a Karl Fischer moisture meter (MKC-610, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) and Aquamicron AX (manufactured by Mitsubishi Chemical Corporation) as the Karl Fischer reagent, and the sample amount was 1 g. When the silicone compound has a polyalkylene chain, it is miscible with water, and therefore the saturated moisture content is considered to be infinite.

[0031] If the silicone compound has a high water content, the electrochemical device material may be deteriorated by the water, resulting in a loss of electrochemical properties. Therefore, it is preferable to dehydrate the silicone compound before use. The dehydration treatment is not particularly limited, but for example, the silicone compound is placed in an evaporator and 1.0 × 10 ２ An example of a method is to dry the silicone compound for 3 to 6 hours while heating in an oil bath or the like at 80 to 150°C at 100 Pa. The moisture content of the silicone compound after drying is preferably 150 ppm or less, and more preferably 100 ppm or less. There is no particular lower limit, and the lower limit may be 0 ppm, but it is usually 10 ppm or more. In this specification, the moisture content is measured using Karl Fischer titration.

[0032] The electrochemical device mixture sheet of the first present disclosure may be manufactured through a process involving heating, such as thermoforming. However, if the silicone compound volatilizes due to heating, sufficient improvement effects may not be achieved. Furthermore, if the silicone compound volatilizes, air bubbles may form in the sheet, resulting in a defective product. Therefore, it is preferable that the silicone compound is less likely to volatilize. From this perspective, the silicone compound preferably has a mass loss rate of 20% by mass or less when heated at 150°C for 24 hours, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The lower limit is not particularly limited and may be 0% by mass, but is typically 0.5% by mass or more. In this specification, the mass loss rate is measured by the following method. 5 g of the silicone compound is weighed into an aluminum cup (diameter 50 mm, height 12 mm), and the mass is measured before and after heating in a hot air circulation oven at 150°C for 24 hours. The mass loss rate is calculated according to the following formula. Three samples are taken, and the results are averaged. The average value is used. Mass reduction rate (mass%) = [(mass (g) of silicone compound before heating) - (mass (g) of silicone compound after heating)] / (mass (g) of silicone compound before heating) x 100

[0033] The silicone compound preferably has an ionic conductivity of 1.0×10 when 1% by mass of LiTFSI is dissolved therein. －９ S / cm or more, more preferably 1.0×10 －８ S / cm or more, more preferably 1.0×10 －７ The upper limit is not particularly limited, but is preferably 1.0 × 10 －３ The ionic conductivity is a value obtained by measuring at 25°C using a Mettler Toledo SevenCompact S230. The measuring instrument is calibrated in advance using a standard solution of 12.88 mS / cm before use.

[0034] From the viewpoint of imparting fluidity to the electrochemical device material, the content of the silicone compound is 0.5 to 20 mass % relative to the solid content of the electrochemical device mixture sheet. The content is preferably 1 mass % or more, more preferably 5 mass % or more, and is preferably 15 mass % or less, more preferably 10 mass % or less. Note that the content does not refer to the amount of the silicone compound added, but rather to the amount extracted from the electrochemical device mixture sheet.

[0035] In this specification, the solid content of the electrochemical device mixture sheet refers to components that are given fluidity by the silicone compound and remain solid after mixing with the silicone compound. The solid content does not include substances that dissolve in the silicone compound after mixing (such as metal salts). In the examples described below, the active material, conductive additive, and binder correspond to the solid content.

[0036] As the binder, a fluorine-based polymer material, a non-fluorine-based polymer material, or the like can be used.

[0037] Examples of the non-fluorinated polymer material include polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, chitosan, alginic acid, polyacrylic acid, polyimide, cellulose, nitrocellulose, SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, NBR (acrylonitrile-butadiene rubber), ethylene-propylene rubber, styrene-butadiene-styrene block copolymers or hydrogenated products thereof, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-styrene copolymer, styrene-isoprene-styrene block copolymers or hydrogenated products thereof, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, propylene-α-olefin copolymer, and polymer compositions having ionic conductivity for alkali metal ions (particularly lithium ions).

[0038] Examples of the fluorine-based polymer material include those in which the fluorine-containing monomer constituting the polymer is tetrafluoroethylene (TFE), hexafluoropropylene (HFP), vinylidene fluoride (VdF), perfluoroalkyl vinyl ether (PAVE), chlorotrifluoroethylene (CTFE), trifluoroethylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, vinyl fluoride, iodine-containing fluorinated vinyl ether, ２ = CFRf １ (In the formula, Rf １ is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms), and a fluorine-containing monomer represented by the general formula (2-1): CHF=CHRf ２ (Rf ２ is a straight-chain or branched fluoroalkyl group having 1 to 12 carbon atoms). The polymer may be copolymerized with at least one monomer selected from the group consisting of a fluorine-containing monomer represented by the formula (III), where ethylene (Et), propylene (Pr), alkyl vinyl ether, or another fluorine-free monomer, a monomer that provides a crosslinkable group (cure site), and a reactive emulsifier monomer, as needed.

[0039] The monomer that provides the crosslinkable group is not particularly limited as long as it provides a polymer with a crosslinking site for forming a crosslink with a crosslinking agent. For example, CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ C.N., C.F. ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ COOH, C.F. ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ CH ２ I, CF ２ = CFOCF ２ CF２ CH ２ I, CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) CN, CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COOH, CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) CH ２ OH, CH ２ = CHCF ２ CF ２ I, CH ２ =CH(CF ２ ) ２ CH=CH ２ , C.H. ２ =CH(CF ２ ) ６ CH=CH ２ , C.F. ２ = CFO (CF ２ ) ５ CN is an example.

[0040] The reactive emulsifier monomer is not particularly limited as long as it is a compound having at least one unsaturated bond and at least one hydrophilic group. For example, ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ , C.H. ２ =CFCF ２ CF (CF ３ ) OCF ２ CF ２ COONH ４ , C.F. ２ = CFOCF ２ CF (CF ３ ) OCF (CF ３ ) COONH ４ Examples include:

[0041] The binder may be used alone or in any combination of two or more kinds in any ratio.

[0042] The binder is preferably the above-mentioned fluorine-based polymer material, and in particular, at least one selected from the group consisting of polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene), and poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene), is preferred, and PTFE is more preferred.

[0043] The binder may be a combination of two or more of the above fluorine-based polymer materials, and a combination of PTFE and a fluorine-based polymer material other than PTFE is preferred. Among these, a combination of at least one selected from the group consisting of PTFE and poly(vinylidene fluoride-co-hexafluoropropylene) and PTFE and poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene) is preferred.

[0044] When the binder contains PTFE, the PTFE content in the binder is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, and particularly preferably 85% by mass or more. The upper limit of the PTFE content in the binder is not particularly limited and may be 100%.

[0045] Furthermore, a fibrillar resin can also be used as the binder. The fibrillar resin is a resin that easily fibrillates when shear stress is applied, and examples thereof include liquid crystal polymer (LCP), cellulose, acrylic resin, ultra-high molecular weight polyethylene, and PTFE. Among these, PTFE is preferred from the viewpoints of chemical stability, thermal stability, and processability.

[0046] The PTFE may be a homopolymer of tetrafluoroethylene (TFE), or may be a modified PTFE containing a polymerized unit based on TFE (TFE unit) and a polymerized unit based on a modified monomer (hereinafter also referred to as "modified monomer unit"). The modified PTFE may contain 99.0 mass% or more of TFE unit and 1.0 mass% or less of modified monomer unit. The modified PTFE may also be composed of only TFE unit and modified monomer unit. The modified PTFE is preferred as the PTFE because it improves binding force, sheet strength and flexibility.

[0047] In order to improve the binding force, sheet strength, and flexibility of the modified PTFE, the content of the modified monomer unit is preferably in the range of 0.00001 to 1.0 mass% relative to the total polymerized units. The lower limit of the content of the modified monomer unit is more preferably 0.0001 mass%, even more preferably 0.001 mass%, even more preferably 0.005 mass%, and particularly preferably 0.010 mass%. The upper limit of the content of the modified monomer unit is preferably 0.90 mass%, more preferably 0.80 mass%, more preferably 0.50 mass%, even more preferably 0.40 mass%, and even more preferably 0.30 mass%. In this specification, the modified monomer unit refers to a part of the molecular structure of PTFE that is derived from the modified monomer.

[0048] The content of each of the above-mentioned polymerized units can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0049] The above-mentioned modified monomer is not particularly limited as long as it can be copolymerized with TFE, and for example, can be listed perfluoroolefin such as hexafluoropropylene (HFP); hydrogen-containing fluoroolefin such as trifluoroethylene, vinylidene fluoride (VDF); perhaloolefin such as chlorotrifluoroethylene (CTFE); perfluorovinyl ether; perfluoroallyl ether; (perfluoroalkyl) ethylene, ethylene etc. In addition, the modified monomer used can be one kind or multiple kinds.

[0050] The perfluorovinyl ether is not particularly limited, and examples thereof include perfluorovinyl ethers represented by the following general formula (A): CF ２ =CF-ORff (A) (wherein Rff represents a perfluoroorganic group). In this specification, the term "perfluoroorganic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoroorganic group may have an ether oxygen.

[0051] Examples of the perfluorovinyl ether include perfluoro(alkyl vinyl ether) [PAVE], in which Rff in the general formula (A) is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0052] Examples of the perfluoroalkyl group in the PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group.

[0053] The perfluorovinyl ether further includes those in which Rff is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms in the general formula (A), and those in which Rff is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms in the general formula (A)

[0054]

[0055] (wherein m represents 0 or an integer of 1 to 4), and Rff is a group represented by the following formula:

[0056]

[0057] (wherein n represents an integer of 1 to 4).

[0058] The (perfluoroalkyl)ethylene [PFAE] is not particularly limited, and examples thereof include (perfluorobutyl)ethylene [PFBE] and (perfluorohexyl)ethylene.

[0059] Examples of perfluoroallyl ethers include those represented by the general formula (B): CF ２=CF-CF ２ -ORff １ (B) (wherein, Rff １ represents a perfluoroorganic group.

[0060] The above Rff １ is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. ２ =CF-CF ２ -O-CF ３ , C.F. ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ At least one selected from the group consisting of CF ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ More preferably, at least one selected from the group consisting of CF ２ =CF-CF ２ -O-CF ２ CF ２ CF ３ is more preferred.

[0061] The modified monomer is preferably at least one selected from the group consisting of PAVE, HFP, VDF, and CTFE, and more preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether) [PMVE], HFP, VDF, and CTFE, in terms of improving the stretchability, binding strength, and flexibility of the composite sheet.

[0062] The PTFE may have a core-shell structure. Examples of PTFE having a core-shell structure include modified PTFE particles containing a core of high molecular weight PTFE and a shell of lower molecular weight PTFE or modified PTFE. Examples of such modified PTFE include the PTFE described in JP-A-2005-527652.

[0063] Examples of commonly available PTFE include F-104, F-106, F-107, F-104C, F-121, F-201, F-205, F-208, and F-302 manufactured by Daikin Industries, Ltd.; 60X, 601X, 602X, 605XTX, 613AX, 62X, 62NX, 62XTX, 640XTX, 641XTX, 650XTX, 669X, 669NX, 6CX, 6CNX, CFP6000X, 6J, 6CJ, 62J, 640J, and 641J manufactured by Chemours; and T F2029, TF2025Z, TF2053Z, TF2073Z, TF2001Z, TF2071USZ, TF2072Z, etc.; CD145, CD123, CD126E, CD097, CD084E, CD086EL, CD086EH, CD090E, CD122E, CD141E, CD127E, etc. manufactured by AGC; and DF681F, DF680F, DF330F, DF291F, DF230F, DF210F, DF132F, DF130F, DF120F manufactured by Solvay.

[0064] The PTFE preferably has an endothermic peak temperature of 320°C or higher, more preferably 325°C or higher, even more preferably 330°C or higher, even more preferably 335°C or higher, even more preferably 340°C or higher, even more preferably 342°C or higher, and particularly preferably 344°C or higher, in order to form a composite sheet with even greater strength. The endothermic peak temperature is also preferably 350°C or lower. The endothermic peak temperature is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry (DSC) at a heating rate of 10°C / min on PTFE that has no history of being heated to a temperature of 300°C or higher. When there are two or more minimum points in one melting peak, each of them is taken as the endothermic peak temperature.

[0065] The PTFE preferably exhibits one or more endothermic peaks in the range of 333 to 347°C in the heat of fusion curve when heated at a rate of 10°C / min using a differential scanning calorimeter (DSC), and the heat of fusion at 290 to 350°C calculated from the heat of fusion curve is 62mJ / mg or more.

[0066] In order to obtain good sheet strength, the content of the binder is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, relative to the solid content of the composite sheet for electrochemical devices, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0067] The content of the binder is the amount added when the amount added during the production of the electrochemical device mixture sheet is known, but when the amount added is unknown, it can be calculated, for example, by the following method. When a good solvent is present in the binder, a good solvent in an amount approximately 10 times the volume of the powder obtained by pulverizing the electrochemical device mixture sheet is added and stirred for 24 hours to obtain an extract, and the extract is then filtered, and the amount of binder present in the obtained filtrate is taken as the content of the binder. When a good solvent is not present in the binder, for example, as in

[0051] of WO 2023 / 119814, the amount of residue obtained when a process is performed to dissolve and remove components other than the binder is taken as the content of the binder.

[0068] The electrochemical device material may be, for example, an electrode active material. That is, the mixture sheet for electrochemical device according to the first aspect of the present disclosure may be an electrode mixture sheet containing an electrode active material.

[0069] The electrode material may be a positive electrode active material or a negative electrode active material.

[0070] The positive electrode active material is not particularly limited as long as it can electrochemically absorb and release alkali metal ions, but for example, a material containing an alkali metal and at least one transition metal is preferred. Specific examples include alkali metal-containing transition metal composite oxides and alkali metal-containing transition metal phosphate compounds. Of these, alkali metal-containing transition metal composite oxides that generate high voltage are particularly preferred as the positive electrode active material. Examples of the alkali metal ions include lithium ions, sodium ions, and potassium ions, with lithium ions being preferred.

[0071] Examples of the alkali metal-containing transition metal composite oxide include those represented by the formula: M ａ Mn ２－ｂ M １ ｂ O ４ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0.9≦a; 0≦b≦1.5; M １ and Mn is at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), a lithium-manganese spinel composite oxide represented by the formula: MNi １－ｃ M ２ ｃ O ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦c≦0.5; M ２ is at least one metal selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), or a lithium-nickel composite oxide represented by the formula: MCo １－ｄ M ３ ｄO ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦d≦0.5; M ３ and M is at least one metal selected from the group consisting of Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li.

[0072] Among these, MCoO is preferred because it can provide electrochemical devices with high energy density and high output. ２ , M MnO ２ , MNiO ２ , M.M. ２ O ４ , MNi ０．８ Mn ０．１ Co ０．１ O ２ , MNi ０．８ Co ０．１５ Al ０．０５ O ２ , or MNi １／３ Co １／３ Mn １／３ O ２ etc. are preferred, and compounds represented by the following general formula are preferred. ０．８ Mn ０．１ Co ０．１ O ２ is particularly preferred. ｈ Co ｉ Mn ｊ M ５ ｋ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ５ represents at least one selected from the group consisting of Fe, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge, and (h+i+j+k)=1.0, 0≦h≦1.0, 0≦i≦1.0, 0≦j≦1.5, 0≦k≦0.2.

[0073] Examples of the alkali metal-containing transition metal phosphate compound include those represented by the following general formula: ｅ M ４ ｆ (P.O. ４ ) ｇ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ４ represents at least one selected from the group consisting of V, Ti, Cr, Mn, Fe, Co, Ni, and Cu, and 0.5≦e≦3, 1≦f≦2, and 1≦g≦3. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li.

[0074] The transition metal in the alkali metal-containing transition metal phosphate compound is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, or the like, and specific examples thereof include LiFePO ４ , Li ３ Fe ２ (P.O. ４ ) ３ , LiFeP ２ O ７ Iron phosphates such as LiCoPO ４ and lithium transition metal phosphate compounds in which a part of the transition metal atoms constituting the main component of these compounds is substituted with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc. The lithium-containing transition metal phosphate compounds preferably have an olivine structure.

[0075] Other examples of the positive electrode active material include lithium-nickel-based composite oxides. The lithium-nickel-based composite oxides are represented by the following general formula: Li ｙ Ni １－ｘ M ｘ O ２ (wherein x is 0.01≦x≦0.7, y is 0.9≦y≦2.0, and M is a metal atom (excluding Li and Ni)) is preferred.

[0076] Other positive electrode active materials include MFePO４ , MNi ０．８ Co ０．２ O ２ , M １．２ Fe ０．４ Mn ０．４ O ２ , MNi ０．５ Mn １．５ O ２ , M.V. ３ O ６ , M ２ MnO ３ In particular, M ２ MnO ３ , MNi ０．５ Mn １．５ O ２ These positive electrode active materials are preferred in that their crystalline structure does not collapse even when the secondary battery is operated at a voltage exceeding 4.4 V or a voltage of 4.6 V or higher. Therefore, electrochemical devices such as secondary batteries using positive electrode materials containing the above-mentioned positive electrode active materials are preferred because they are less likely to reduce their remaining capacity and change their resistance increase rate even when stored at high temperatures, and their battery performance does not deteriorate even when operated at high voltages.

[0077] Other positive electrode active materials include M ２ MnO ３ and M.M. ６ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ６ Examples of the material include solid solution materials with transition metals such as Co, Ni, Mn, and Fe.

[0078] The solid solution material may be, for example, a material represented by the general formula M ｘ [Mn （１－ｙ） M ７ ｙ ]O ｚ In the formula, M is at least one metal selected from the group consisting of Li, Na, and K, and M ７is composed of at least one metal element other than M and Mn, and contains, for example, one or more elements selected from the group consisting of Co, Ni, Fe, Ti, Mo, W, Cr, Zr and Sn. The values ​​of x, y and z in the formula are in the ranges of 1<x<2, 0≦y<1 and 1.5<z<3. Among them, Li １．２ Mn ０．５ Co ０．１４ Ni ０．１４ O ２ Li like ２ MnO ３ Based on LiNiO ２ and LiCoO ２ A manganese-containing solid solution material containing manganese is preferred in that it can provide an alkali metal ion secondary battery having a high energy density.

[0079] Furthermore, it is preferable to include lithium phosphate in the positive electrode active material, since this improves continuous charging characteristics. Although there is no limitation on the use of lithium phosphate, it is preferable to use a mixture of the positive electrode active material and lithium phosphate. The amount of lithium phosphate used, based on the total amount of the positive electrode active material and lithium phosphate, is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0080] Alternatively, a substance having a different composition may be attached to the surface of the positive electrode active material, such as an oxide, such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, or bismuth oxide; a sulfate, such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, or aluminum sulfate; a carbonate, such as lithium carbonate, calcium carbonate, or magnesium carbonate; or carbon.

[0081] The positive electrode active material may be used alone or in any combination or ratio of two or more different types of materials. ２ and LiNi ０．３３ Co ０．３３ Mn ０．３３O ２ combination with ternary systems such as LiCoO ２ and LiMn ２ O ４ Or a combination of this with a material in which a part of Mn is replaced with another transition metal, or LiFePO ４ and LiCoO ２ Alternatively, a combination of Co with other transition metals or the like may be used.

[0082] The content of the positive electrode active material is preferably 50 to 90 mass% of the positive electrode mixture in terms of high electrochemical capacity. The content in the positive electrode active material layer is preferably 60 mass% or more, more preferably 70 mass% or more, and particularly preferably 75 mass% or more. The upper limit is preferably 88 mass% or less, more preferably 86 mass% or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electrochemical capacity may be insufficient. Conversely, if the content is too high, the ionic conductivity, electronic conductivity, and electrode strength may be insufficient.

[0083] The negative electrode active material is not particularly limited, and examples thereof include carbonaceous materials such as lithium metal, artificial graphite, graphite carbon fiber, resin-baked carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-baked carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon; silicon-containing compounds such as silicon and silicon alloys; Li ４ Ti ５ O １２ Among these, those containing at least a carbonaceous material and silicon-containing compounds are particularly suitable.

[0084] The negative electrode active material used in the present disclosure preferably contains silicon as a constituent element, which allows the production of a high-capacity battery.

[0085] The silicon-containing material includes silicon particles, particles having a structure in which silicon particles are dispersed in a silicon-based compound, and silicon-based particles having the general formula SiO ｘ(0.5≦x≦1.6), or a mixture thereof. By using these, a negative electrode mixture for a lithium ion secondary battery having higher initial charge / discharge efficiency, high capacity, and excellent cycle characteristics can be obtained.

[0086] Silicon oxide in the present disclosure is a general term for amorphous silicon oxide, and silicon oxide before disproportionation has the general formula SiO ｘ (0.5≦x≦1.6). Preferably, x satisfies 0.8≦x<1.6, and more preferably 0.8≦x<1.3. This silicon oxide can be obtained, for example, by heating a mixture of silicon dioxide and metallic silicon to produce silicon monoxide gas, which is then cooled and precipitated.

[0087] The content of the negative electrode active material is preferably 50 to 90% by mass of the negative electrode mixture in terms of high electrochemical capacity. The content in the negative electrode active material layer is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 75% by mass or more. The upper limit is preferably 88% by mass or less, more preferably 86% by mass or less. If the content of the negative electrode active material in the negative electrode active material layer is low, the electrical capacity may be insufficient. Conversely, if the content is too high, the ionic conductivity, electronic conductivity, and electrode strength may be insufficient.

[0088] The electrochemical device material may be an electrolyte such as a solid electrolyte. That is, the mixture for electrochemical devices according to the first present disclosure may be an electrolyte mixture sheet containing an electrolyte, and is preferably a solid electrolyte mixture sheet containing a solid electrolyte.

[0089] The solid electrolyte may be a sulfide-based solid electrolyte or an oxide-based solid electrolyte. In particular, when a sulfide-based solid electrolyte is used, it has the advantage of being flexible.

[0090] The sulfide-based solid electrolyte is not particularly limited, and may be Li ２ S-P ２ S ５ , Li ２ S-P ２ S ３ , Li ２ S-P ２ S ３ -P ２ S５ , Li ２ S-SiS ２ , LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ S ５ , LiI-Li ２ S-P ２ O ５ , LiI-Li ３ P.O. ４ -P ２ S ５ , LiI-Li ２ S-SiS ２ -P ２ S ５ , Li ２ S-SiS ２ -Li ４ SiO ４ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ３ P.S. ４ -Li ４ GeS ４ , Li ３．４ P ０．６ Si ０．４ S ４ , Li ３．２５ P ０．２５ Ge ０．７６ S ４ , Li ４－ｘ Ge １－ｘ P ｘ S ４ (x=0.6~0.8), Li ４＋ｙ Ge １－ｙ Ga ｙ S ４ (y=0.2-0.3), LiPSCl, LiCl, Li ７－ｘ－２ｙ P.S. ６－ｘ－ｙ Cl ｘ (0.8≦x≦1.7, 0<y≦-0.25x+0.5), Li １０ SnP ２ S １２ Any one selected from the above, or a mixture of two or more thereof, can be used. ７－ｘ－２ｙ P.S. ６－ｘ－ｙ Cl ｘ(0.8≦x≦1.7, 0<y≦−0.25x+0.5) is preferred, and Li ６ P.S. ５ Cl is particularly preferred.

[0091] The sulfide-based solid electrolyte preferably contains lithium. Sulfide-based solid electrolytes containing lithium are used in solid-state batteries that use lithium ions as a carrier, and are particularly preferred in terms of electrochemical devices having high energy density.

[0092] In the composite sheet for electrochemical devices according to the first present disclosure, the content of the solid electrolyte is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, and is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0093] The mixture sheet for an electrochemical device according to the first present disclosure may be an electrode mixture sheet for a solid battery containing an electrode active material and a solid electrolyte.

[0094] In the electrochemical device composite sheet according to the first aspect of the present disclosure, the content of the electrochemical device material is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and is preferably 99.5% by mass or less, more preferably 98.5% by mass or less, and even more preferably 97.5% by mass or less.

[0095] The electrochemical device mixture sheet according to the first present disclosure may contain a metal salt. The inclusion of a metal salt improves ionic conductivity. In the electrochemical device mixture sheet according to the first present disclosure, the metal salt is preferably dissolved in the silicone compound.

[0096] Any metal salt can be used, for example, an alkali metal salt or an alkaline earth metal salt. These can be used alone or in any combination and ratio of two or more. Among these, alkali metal salts are preferred, and lithium salts are more preferred.

[0097] Specific examples of the lithium salt include the following: LiPF ６ , LiBF ４ , LiClO ４ , LiAlF ４ , LiSbF ６ , LiTaF ６ , LiWF ７ , LiAsF ６ , LiAlCl ４ , LiI, LiBr, LiCl, LiB １０ Cl １０ , Li ２ SiF ６ , Li ２ PFO ３ , LiPO ２ F ２ Inorganic lithium salts such as LiWOF ５ Lithium tungstates such as HCO ２ Li, C.H. ３ CO ２ Li, C.H. ２ FCO ２ Li, CHF ２ CO ２ Li, CF ３ CO ２ Li, CF ３ CH ２ CO ２ Li, CF ３ CF ２ CO ２ Li, CF ３ CF ２ CF ２ CO ２ Li, CF ３ CF ２ CF ２ CF ２ CO ２ Lithium carboxylate salts such as Li; FSO ３ Li, C.H. ３ SO ３ Li, C.H. ２ FSO ３ Li, CHF ２ SO ３ Li, CF ３ SO ３ Li, CF ３ CF ２ SO ３ Li, CF３ CF ２ CF ２ SO ３ Li, CF ３ CF ２ CF ２ CF ２ SO ３ Li, lithium methyl sulfate, lithium ethyl sulfate (C ２ H ５ OSO ３ Lithium salts having an S═O group, such as lithium bis(trifluoromethanesulfonimide) (LiTFSI), lithium bis(monofluorosulfonimide) (LiFSI), and LiN(FCO). ２ , LiN(FCO)(FSO ２ ), LiN(FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , lithium bisperfluoroethanesulfonylimide, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, lithium cyclic 1,2-ethanedisulfonylimide, lithium cyclic 1,3-propanedisulfonylimide, lithium cyclic 1,4-perfluorobutanedisulfonylimide, LiN(CF ３ SO ２ ) (FSO ２ ), LiN(CF ３ SO ２ ) (C ３ F ７ SO ２ ), LiN(CF ３ SO ２ ) (C ４ F ９ SO ２ ), LiN (POF ２ ) ２ Lithium imide salts such as LiC(FSO２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ Lithium methide salts such as: ａ (C ｎ F ２ｎ＋１ ) ６－ａ (wherein a is an integer of 0 to 5, and n is an integer of 1 to 6) ３ (C ２ F ５ ) ３ , LiPF ３ (CF ３ ) ３ , LiPF ３ (iso-C ３ F ７ ) ３ , LiPF ５ (iso-C ３ F ７ ), LiPF ４ (CF ３ ) ２ , LiPF ４ (C ２ F ５ ) ２ ), LiPF ４ (CF ３ SO ２ ) ２ , LiPF ４ (C ２ F ５ SO ２ ) ２ , LiBF ３ CF ３ , LiBF ３ C ２ F ５ , LiBF ３ C ３ F ７ , LiBF ２ (CF ３ ) ２ , LiBF ２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ Fluorine-containing organic lithium salts such as LiSCN and LiB(CN) ４ , LiB(C ６ H ５ ) ４ , Li ２ (C ２ O ４ ), LiP(C ２ O ４ ) ３ , Li ２ B １２ F ｂ H １２－ｂ (b is an integer of 0 to 3), etc.

[0098] Among them, LiTFSI, LiFSI, LiPF ６ , LiBF ４ , LiSbF ６ , LiTaF ６ , LiPO ２ F ２ , FSO ３ Li, CF ３ SO ３ Li, LiN (FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , lithium cyclic 1,2-perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC(FSO ２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ , LiBF ３ CF ３, LiBF ３ C ２ F ５ , LiPF ３ (CF ３ ) ３ , LiPF ３ (C ２ F ５ ) ３ and the like are preferred, and LiTFSI, LiFSI, LiPF ６ is particularly preferred.

[0099] These lithium salts may be used alone or in combination of two or more. A preferred example of a combination of two or more is LiPF ６ and LiBF ４ In combination with LiPF ６ and LiPO ２ F ２ , C ２ H ５ OSO ３ Li or FSO ３ When used in combination with Li, it has the effect of improving high-temperature storage characteristics, load characteristics, and cycle characteristics.

[0100] Another example is the combined use of an inorganic lithium salt and an organic lithium salt, which has the effect of suppressing deterioration due to high-temperature storage. ３ SO ３ Li, LiN (FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , lithium cyclic 1,2-perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC(FSO ２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ )３ , LiBF ３ CF ３ , LiBF ３ C ２ F ５ , LiPF ３ (CF ３ ) ３ , LiPF ３ (C ２ F ５ ) ３ etc. are preferred.

[0101] In the composite sheet for electrochemical devices according to the first aspect of the present disclosure, the content of the metal salt is preferably 0.1% by mass or more, more preferably 1% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, relative to the silicone compound.

[0102] The electrochemical device mixture sheet of the first present disclosure may contain a conductive aid. Examples of the conductive aid include, but are not limited to, metal materials such as copper, nickel, and gold; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; and carbon materials such as needle coke, carbon nanotubes, fullerenes, and amorphous carbon such as VGCF. These may be used alone or in any combination and ratio of two or more.

[0103] In the composite sheet for electrochemical devices according to the first present disclosure, the content of the conductive auxiliary agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1% by mass or more, and is preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 5% by mass or less.

[0104] The thickness of the composite sheet for electrochemical devices according to the first present disclosure is preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 180 μm or less, and particularly preferably 150 μm or less, and is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more.

[0105] The mixture sheet for electrochemical device according to the first aspect of the present disclosure can be used as an electrolyte mixture sheet or an electrode mixture sheet.

[0106] The second present disclosure relates to a mixture sheet for electrochemical devices, comprising a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, wherein the silicone compound has a polyoxyalkylene chain.

[0107] The mixture sheet for electrochemical devices according to the second present disclosure can achieve the same effects as the mixture sheet for electrochemical devices according to the first present disclosure, and the preferred embodiments described for the mixture sheet for electrochemical devices according to the first present disclosure can also be applied to the mixture sheet for electrochemical devices according to the second present disclosure.

[0108] Hereinafter, the mixture sheets for electrochemical devices according to the first and second aspects of the present disclosure will also be collectively referred to as mixture sheets for electrochemical devices according to the present disclosure.

[0109] <Method for manufacturing a mixture sheet for electrochemical devices> The mixture sheet for electrochemical devices of the present disclosure can be obtained by a manufacturing method including, for example, step (1) of mixing a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, and step (2) of rolling the mixture for electrochemical devices obtained in step (1) into a sheet. The present disclosure also relates to this manufacturing method.

[0110] The manufacturing method of the present disclosure provides a mixture sheet for electrochemical devices in which the silicone compound is well dispersed within the sheet. This enhances the effect of the silicone compound in imparting fluidity to electrochemical device materials, thereby further improving sheet strength. Note that the mixture sheet for electrochemical devices obtained by the manufacturing method of the present disclosure is usually not coated with the silicone compound.

[0111] The silicone compound, binder, and electrochemical device material in the above step (1) are the same as those described in the electrochemical device mixture sheet of the present disclosure.

[0112] In the above step (1), the mixing conditions are preferably 3000 rpm or less. It is preferably 10 rpm or more, more preferably 15 rpm or more, and even more preferably 20 rpm or more, and is preferably 2000 rpm or less, more preferably 1500 rpm or less, and even more preferably 1000 rpm or less. If the mixing speed is below the above range, it takes a long time to mix, which affects productivity. Furthermore, if the mixing speed is above the above range, excessive shear stress may be applied, resulting in a mixture sheet with poor strength and flexibility.

[0113] In the above step (1), the materials may be mixed and then shaped into a bulk form. Specific methods for shaping into a bulk form include extrusion molding, press molding, etc. The term "bulk form" does not particularly specify a shape, and may refer to a state in which the material is in the form of a single mass, including rods, sheets, spheres, cubes, etc.

[0114] Specific examples of the rolling method in the step (2) include rolling using a roll press, a plate press, a calender roll, etc. The temperature during rolling is preferably 100 to 250°C.

[0115] Furthermore, after the above step (2), a step (3) may be carried out in which a larger load is applied to the obtained rolled sheet to roll it into an even thinner sheet, or step (3) may be carried out repeatedly. In this way, by rolling the rolled sheet little by little in stages rather than thinning it all at once, flexibility is improved. The number of times step (3) is carried out is preferably from 2 to 10 times, and more preferably from 3 to 9 times. Specific rolling methods include, for example, a method in which two or more rolls are rotated and the rolled sheet is passed between them to process it into a thinner sheet.

[0116] It is also preferable to include a step (4) after the step (2) or the step (3) in which the rolled sheet is crushed, re-formed into a bulk form, and rolled into a sheet. It is also preferable to repeat the step (4). The number of times of the step (4) is preferably from 1 to 12 times, more preferably from 2 to 11 times.

[0117] In the above step (4), specific methods for roughly crushing the rolled sheet and forming it into a bulk shape include folding the sheet, forming it into a rod or thin film sheet, chipping, etc. In the present disclosure, "rough crushing" means changing the shape of the rolled sheet obtained in step (2) or (3) into a different shape so that it can be rolled into a sheet in the next step, and also includes cases where the rolled sheet is simply folded.

[0118] Furthermore, step (4) may be followed by step (3) or may be repeated. Furthermore, uniaxial or biaxial stretching may be performed in steps (2), (3), and (4).

[0119] In the above steps (2), (3), and (4), the rolling ratio is preferably 10% or more, more preferably 20% or more, and preferably 80% or less, more preferably 65% ​​or less, and even more preferably 50% or less. If the rolling ratio is below the above range, the number of rolling operations increases, which takes more time and affects productivity. Furthermore, if the rolling ratio is above the above range, if the binder contains a fibrillating resin, fibrillation may proceed excessively, resulting in a mixture sheet with poor strength and flexibility. The rolling ratio here refers to the reduction in thickness of the sample after rolling relative to the thickness before rolling. The sample before rolling may be a bulk raw material composition or a sheet-like raw material composition. The thickness of the sample refers to the thickness in the direction in which a load is applied during rolling.

[0120] <Electrochemical Device> The present disclosure also relates to an electrochemical device using the mixture sheet for an electrochemical device of the present disclosure.

[0121] The electrochemical device of the present disclosure may use the mixture sheet for electrochemical devices of the present disclosure as an electrode mixture sheet, may use the mixture sheet for electrochemical devices of the present disclosure as an electrolyte mixture sheet, or may use the mixture sheet as an electrode mixture sheet and an electrolyte mixture sheet.

[0122] The electrochemical device of the present disclosure preferably comprises a positive electrode, a negative electrode, etc., and more specifically, is preferably a secondary battery comprising these, and particularly preferably a lithium ion secondary battery.

[0123] The positive electrode is preferably composed of a current collector and an electrode mixture sheet containing the positive electrode active material. Examples of materials for the positive electrode current collector include metals such as aluminum, titanium, tantalum, stainless steel, and nickel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly aluminum or its alloys, are preferred.

[0124] Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, expanded metal, punched metal, and foam metal in the case of a metal material, and carbon plate, carbon thin film, and carbon cylinder in the case of a carbon material. Of these, metal foil is preferred. The metal foil may be appropriately formed into a mesh shape. The thickness of the metal foil is optional, but is usually 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, and is usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, handling may be impaired.

[0125] In addition, it is also preferable that the surface of the current collector is coated with a conductive additive, from the viewpoint of reducing the electrical contact resistance between the current collector and the positive electrode active material layer. Examples of the conductive additive include carbon and precious metals such as gold, platinum, and silver.

[0126] The positive electrode may be manufactured by a conventional method, for example, by laminating an electrode mixture sheet and a current collector with an adhesive therebetween, followed by vacuum drying.

[0127] The density of the positive electrode mixture sheet is preferably 2.80 g / cm ３ More preferably, 3.00 g / cm ３ More preferably, 3.20 g / cm ３ or more, and preferably 3.80 g / cm ３ or less, more preferably 3.75 g / cm ３ More preferably, 3.70 g / cm or less ３ The range is as follows. If the temperature exceeds this range, the permeability of the electrolyte to the vicinity of the current collector / active material interface will decrease, and the charge / discharge characteristics, especially at high current densities, will decrease, and high output may not be obtained. If the temperature falls below this range, the conductivity between the active materials will decrease, and the battery resistance will increase, and high output may not be obtained.

[0128] The negative electrode is preferably composed of a current collector and an electrode mixture sheet containing the negative electrode active material. Examples of materials for the negative electrode current collector include metals such as copper, nickel, titanium, tantalum, and stainless steel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly copper, nickel, and alloys thereof, are preferred.

[0129] Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, expanded metal, punched metal, and foam metal in the case of a metal material, and carbon plate, carbon thin film, and carbon cylinder in the case of a carbon material. Of these, metal foil is preferred. The metal foil may be appropriately formed into a mesh shape. The thickness of the metal foil is optional, but is usually 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, and is usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, handling may be impaired.

[0130] The negative electrode may be produced by a conventional method, for example, by laminating the electrode mixture sheet and a current collector with an adhesive therebetween, followed by vacuum drying.

[0131] The density of the negative electrode mixture is preferably 1.3 g / cm ３ More preferably, 1.4 g / cm ３ More preferably, 1.5 g / cm ３ or more, and preferably 2.0 g / cm ３ or less, more preferably 1.9 g / cm ３ More preferably, 1.8 g / cm or less ３ The range is as follows. If the temperature exceeds this range, the permeability of the electrolyte to the vicinity of the current collector / active material interface will decrease, and the charge / discharge characteristics, especially at high current densities, will decrease, and high output may not be obtained. If the temperature falls below this range, the conductivity between the active materials will decrease, and the battery resistance will increase, and high output may not be obtained.

[0132] The secondary battery may be a secondary battery using an electrolytic solution or a solid-state secondary battery. In this specification, the solid-state secondary battery may be a secondary battery containing a solid electrolyte, and may be a semi-solid-state secondary battery containing a solid electrolyte and a liquid component as the electrolyte, or an all-solid-state secondary battery containing only a solid electrolyte as the electrolyte.

[0133] The secondary battery using the above-mentioned electrolyte solution can use the electrolyte solution, separator, etc. used in known secondary batteries, which will be described in detail below.

[0134] The electrolyte is preferably a non-aqueous electrolyte, which may be prepared by dissolving a known electrolyte salt in a known organic solvent for dissolving electrolyte salts.

[0135] The organic solvent for dissolving the electrolyte salt is not particularly limited, and one or more of known hydrocarbon solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; and fluorine-based solvents such as fluoroethylene carbonate, fluoroethers, and fluorinated carbonates can be used.

[0136] As the electrolyte salt, the above-mentioned lithium salt can be used.

[0137] The concentration of the electrolyte salt is preferably 0.8 mol / L or more, more preferably 1.0 mol / L or more, and the upper limit is usually 1.5 mol / L or less, although it depends on the organic solvent used to dissolve the electrolyte salt.

[0138] A secondary battery using the above-mentioned electrolyte solution preferably further includes a separator. The material and shape of the separator are not particularly limited as long as it is stable to the electrolyte solution and has excellent liquid retention properties, and any known separator can be used. Among them, it is preferable to use a material that is stable to the electrolyte solution, such as resin, glass fiber, or inorganic material, and that is in the form of a porous sheet or nonwoven fabric with excellent liquid retention properties.

[0139] Examples of materials that can be used for the resin or glass fiber separator include polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, and glass filters. These materials may be used alone or in any combination and ratio, such as polypropylene / polyethylene two-layer films and polypropylene / polyethylene / polypropylene three-layer films. Among these, porous sheets or nonwoven fabrics made from polyolefins such as polyethylene and polypropylene are preferred for the separator, due to their excellent electrolyte permeability and shutdown effect.

[0140] The thickness of the separator is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is thinner than the above range, the insulating properties and mechanical strength may be reduced. If the separator is thicker than the above range, not only may the battery performance such as rate characteristics be reduced, but also the energy density of the entire electrolyte battery may be reduced.

[0141] On the other hand, inorganic materials include, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate, and these are used in particulate or fibrous form.

[0142] As for the form, thin film shapes such as nonwoven fabric, woven fabric, and microporous film are used. Thin film shapes with a pore size of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-mentioned independent thin film shapes, separators can be used in which a composite porous layer containing the above-mentioned inorganic particles is formed on the surface layer of the positive electrode and / or negative electrode using a resin binder. For example, a porous layer can be formed on both sides of the positive electrode using alumina particles with a 90% particle size of less than 1 μm and a fibrillar resin as a binder.

[0143] The material of the outer case is not particularly limited as long as it is a substance that is stable against the electrolyte used. Specifically, metals such as nickel-plated steel sheet, stainless steel, aluminum or aluminum alloy, magnesium alloy, or a laminate film of resin and aluminum foil (laminate film) can be used. From the viewpoint of weight reduction, metals such as aluminum or aluminum alloy and laminate film are preferably used.

[0144] Examples of exterior cases using metals include those in which metals are welded together to form a sealed, airtight structure by laser welding, resistance welding, or ultrasonic welding, or those in which the metals are used via a resin gasket to form a crimped structure. Examples of exterior cases using the above-mentioned laminate film include those in which resin layers are heat-sealed to form a sealed, airtight structure. In order to improve sealing properties, a resin different from the resin used in the laminate film may be interposed between the resin layers. In particular, when a sealed structure is formed by heat-sealing the resin layers via a current collecting terminal, a resin having a polar group or a modified resin into which a polar group has been introduced is preferably used as the interposed resin, since the metal and the resin are bonded together.

[0145] The shape of the secondary battery using the above-mentioned electrolyte solution is arbitrary, and examples thereof include cylindrical, prismatic, laminated, coin, large, etc. The shapes and configurations of the positive electrode, negative electrode, and separator can be changed according to the shape of each battery.

[0146] The solid secondary battery preferably includes a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode.

[0147] The solid secondary battery may include a separator between the positive electrode and the negative electrode, such as a porous membrane made of polyethylene, polypropylene, or the like; a nonwoven fabric made of a resin such as polypropylene; or a nonwoven fabric made of glass fiber, or the like.

[0148] The solid secondary battery may further include a battery case. The shape of the battery case is not particularly limited as long as it can accommodate the above-mentioned positive electrode, negative electrode, solid electrolyte layer, etc., but specific examples include a cylindrical shape, a square shape, a coin shape, and a laminate shape.

[0149] The solid secondary battery can be produced, for example, by stacking a positive electrode, a solid electrolyte layer sheet, and a negative electrode in this order and pressing them together.

[0150] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0151] Next, the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0152] The following materials were used. All of the silicone compounds were liquid at 25°C. The silicone compounds were also subjected to a dehydration treatment (a silicone compound was placed in an evaporator and 1.0 x 10 ２ The silicone compound A1 was prepared by subjecting the silicone compound A1 to drying for 6 hours while heating in an oil bath at 130°C and a kinematic viscosity of 100 cSt at 25°C. The silicone compound A1 was then used. <Silicone Compound> Silicone compound A1: KF-96-100CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 100 cSt, mass loss rate when heated at 150°C for 24 hours: 6.0% by mass, polyoxyalkylene chain: no, ionic conductivity when 1% by mass of LiTFSI is dissolved: 5.5 × 10 －７ S / cm, saturated water content: 84 ppm, water content after drying: 43 ppm) Silicone compound A2: KF-96L-2CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 2 cSt, mass loss rate when heated at 150°C for 24 hours: 99.9 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 1.2 × 10 －８S / cm, saturated water content: 21 ppm, water content after drying: 11 ppm) Silicone compound A3: KF-96L-5CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 5 cSt, mass loss rate when heated at 150°C for 24 hours: 99.9 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 1.4 × 10 －８ S / cm, saturated water content: 20 ppm, water content after drying: 11 ppm) Silicone compound A4: KF-96H-60,000 CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 60,000 cSt, mass loss rate when heated at 150°C for 24 hours: 0.5 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 7.4 × 10 －９ S / cm, saturated water content: 101 ppm, water content after drying: 49 ppm) Silicone compound A5: KF-96H-1,000,000 CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 1,000,000 cSt, mass loss rate when heated at 150°C for 24 hours: 0.4 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 4.8 × 10 －９ S / cm, saturated water content: 147 ppm, water content after drying: 53 ppm) Silicone compound A6: KF-96-20CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 20 cSt, mass loss rate when heated at 150°C for 24 hours: 12 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 5.8 × 10 －８ S / cm, saturated water content: 25 ppm, water content after drying: 14 ppm) Silicone compound A7: KF-96-10CS manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 10 cSt, mass loss rate when heated at 150°C for 24 hours: 31 mass%, polyoxyalkylene chain: none, ionic conductivity when 1 mass% of LiTFSI is dissolved: 5.1 × 10 －８S / cm, saturated water content: 20 ppm, water content after drying: 10 ppm) Silicone compound B1: KF-643 manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity at 25°C: 19 cSt, mass loss rate when heated at 150°C for 24 hours: 3.2 mass%, polyoxyalkylene chain: present, ionic conductivity when 1 mass% of LiTFSI is dissolved: 2.3 × 10 －５ S / cm, saturated moisture content: infinite, moisture content after drying: 81 ppm) <Binder> PTFE (prepared in Preparation Example 1 below) Poly(vinylidene fluoride-co-hexafluoropropylene) (prepared in Preparation Example 2 below) Poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene) (prepared in Preparation Example 3 below) <Metal salt> Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) manufactured by Tokyo Chemical Industry Co., Ltd.

[0153] PTFE was prepared and analyzed in the following manner.

[0154] <Average primary particle diameter> The PTFE aqueous dispersion was diluted with water until the solid content became 0.15% by mass, and the transmittance of the 550 nm projected light per unit length of the diluted latex obtained and the number-based average primary particle diameter determined by measuring the unidirectional diameter by a transmission electron microscope photograph were measured, and a calibration curve was prepared. Using this calibration curve, the average primary particle diameter was determined from the measured transmittance of the 550 nm projected light of each sample.

[0155] <Polymer Solids Concentration> 1 g of the aqueous PTFE dispersion is dried in a blower dryer at 150°C for 60 minutes, and the ratio of the mass of the heating residue to the mass (1 g) of the aqueous dispersion is expressed as a percentage.

[0156] <Standard Specific Gravity (SSG)> Using a sample molded in accordance with ASTM D4895 89, the standard specific gravity was measured by the water displacement method in accordance with ASTM D 792.

[0157] A white solid A was obtained by the method described in Synthesis Example 1 of WO 2021 / 045228.

[0158] (Preparation Example 1) 3,480 g of deionized water, 100 g of paraffin wax, and 5.3 g of white solid A were charged into a 6-liter stainless steel autoclave equipped with a stirring blade and a temperature-controlling jacket, and the autoclave was heated to 70 ° C. while purging with nitrogen gas to remove oxygen. TFE was injected to adjust the system pressure to 0.78 MPaG, and the system temperature was maintained at 70 ° C. while stirring. Next, an aqueous solution prepared by dissolving 15.0 mg of ammonium persulfate in 20 g of water was injected with TFE to initiate the polymerization reaction. As the polymerization reaction progressed, the system pressure decreased, but TFE was added to maintain the system temperature at 70 ° C. and the system pressure at 0.78 MPaG. When 400 g of TFE had been consumed from the start of polymerization, an aqueous solution prepared by dissolving 18.0 mg of hydroquinone as a radical scavenger in 20 g of water was injected with TFE. The polymerization continued thereafter, and when the polymerization amount of TFE reached approximately 1,200 g from the start of polymerization, stirring and the supply of TFE were stopped, and the gas in the system was immediately released to normal pressure, thereby terminating the polymerization reaction. The aqueous dispersion was removed and cooled, and the paraffin wax was separated to obtain a PTFE aqueous dispersion. The resulting PTFE aqueous dispersion had an average primary particle size of 310 nm and a solids concentration of 25.3% by mass. The resulting PTFE aqueous dispersion was diluted to a solids concentration of 13% by mass, and the PTFE was coagulated while stirring in a container, followed by filtration to obtain a wet PTFE powder. The resulting wet PTFE powder was dried at 180 ° C for 18 hours to obtain PTFE. The SSG of the resulting PTFE was 2.156.

[0159] (Preparation Example 2) 1650 ml of pure water was placed in a 3 L stainless steel autoclave and purged with nitrogen, then slightly pressurized with hexafluoropropylene (HFP), and the temperature was adjusted to 80 ° C. while stirring at 380 rpm. HFP was injected up to 0.23 MPa, and a mixed monomer solution of vinylidene fluoride (VdF) and HFP in a molar ratio of 78.2 / 21.8 was further injected up to 1.472 MPa. 0.097 cc of 2-methylbutane was injected with nitrogen, and a solution of 36.4 g of ammonium persulfate dissolved in 80 ml of pure water was injected with nitrogen to start polymerization. When the pressure dropped to 1.44 MPa, the pressure was increased to 1.50 MPa with continuous monomer. This was repeated for about 9.3 hours, and after 607 g of continuous monomer was charged, the gas in the autoclave was released, and the autoclave was cooled and 2299 g of dispersion was recovered. The solids content of the dispersion was 26.9 wt %. Magnesium chloride was added to the dispersion to cause coagulation, and the resulting mixture was dried to obtain 610 g of a polymer. The resulting polymer contained HFP and VdF in a molar ratio of 22.1 / 77.9. The Mooney viscosity (ML1+10 (121°C)) of the resulting polymer was 140, and the Tg was determined to be -18°C by DSC. No heat of fusion was observed in the second run.

[0160] (Preparation Example 3) 1500 ml of pure water and CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ 0.3001 g of 50% aqueous solution, C ５ F １１ COONH ４6.001 g of a 50% aqueous solution was added and purged with nitrogen, and then slightly pressurized with vinylidene fluoride (VdF). The temperature was adjusted to 80 ° C. while stirring at 600 rpm, and VdF was injected up to 1.22 MPa. Further, a mixed monomer solution of VdF and 2,3,3,3-tetrafluoropropene in a molar ratio of 77.2 / 22.8 was injected up to 1.501 MPa. 0.1 g of ammonium persulfate dissolved in 4 ml of pure water was injected with nitrogen to start polymerization. When the continuous monomer reached 11 g, 1.6738 g of 1,1,1,2,3,3,3-heptafluoro-2-iodo-propane was added. When the pressure dropped to 1.44 MPa, the pressure was increased to 1.50 MPa with the continuous monomer. This process was repeated for approximately 6.2 hours, and after 521 g of continuous monomer had been charged, the gas in the autoclave was released and cooled, and 2087 g of dispersion was recovered. The solids content of the dispersion was 26.08%. Calcium chloride was added to this dispersion to cause coagulation, and the resulting mixture was dried to obtain 524.3 g of polymer. The resulting polymer contained 2,3,3,3-tetrafluoropropene and VdF in a molar ratio of 23.1 / 76.9. The Mooney viscosity (ML1+10 (121°C)) of the resulting polymer was 25, and the Tg was determined to be -14°C by DSC.

[0161] The preparation of the mixture sheet of the experimental example, the evaluation of the mixture sheet, and the evaluation of the battery were carried out according to the following procedures.

[0162] (Preparation of Positive Electrode Mixture Sheet) Active Material (Experimental Examples 1 to 23: LiNi ０．８ Mn ０．１ Co ０．１ O ２ , Experimental Example 24: LiFePO ４ , Experimental Example 25: LiCoO ２) and a conductive additive (SuperP Li: carbon black manufactured by Imerys) were weighed, placed in a V-type mixer, and mixed at 37 rpm for 10 minutes to obtain a mixture consisting of an active material and a conductive additive. Next, the mixture and a silicone compound were added, placed in a high-speed fluid mixer, and processed at 200 rpm for 1 minute to disperse the mixture. In Experimental Examples 18 to 25, a metal salt was dissolved in the silicone compound before use. Then, a weighed binder (Experimental Examples 1 to 21, 24, and 25: PTFE; Experimental Example 22: PTFE and poly(vinylidene fluoride-co-hexafluoropropylene); Experimental Example 23: PTFE and poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene)) was added to the mixture and allowed to cool sufficiently in a constant temperature bath at 5°C. A mixture consisting of an active material, a conductive additive, a binder, and a silicone compound, or a mixture consisting of an active material, a conductive additive, a binder, a silicone compound, and a metal salt, was placed in a high-speed fluid mixer and homogenized by processing at 1500 rpm for 3 minutes. The composition ratio (mass ratio) of the active material and the conductive additive was fixed at 98.0:2.0 (active material:conductive additive), and the amount of binder relative to the total amount of the active material, conductive additive, and binder was as shown in Tables 1 and 2. The mixture was then sufficiently heated in a thermostatic bath at 80 ° C. and then processed in a high-speed fluid mixer at 2500 rpm for 8 minutes to promote fibrillation and obtain an electrode mixture. The electrode mixture was placed in a rolling mill arranged in parallel and capable of rotating metal rolls at different peripheral speeds, and an electrode mixture sheet was obtained (temperature: 60 ° C., left roll rotation speed: 1 m / min, right roll rotation speed: 0.8 m / min). The obtained electrode mixture sheet was again placed in a rolling mill and rolled to obtain an electrode mixture sheet with stronger sheet strength. All of the obtained electrode mixture sheets were free-standing films. The electrode mixture sheet was then placed in a roll press and the gap was adjusted. The final thickness of the positive electrode mixture layer was adjusted to 80 μm. Tables 1 and 2 show the contents of the silicone compound, binder, and metal salt.The content of the silicone compound is the amount relative to the solid content (active material, conductive additive, and binder) of the electrode mixture sheet. 500 mg of pulverized electrode mixture sheet was placed in a vial, 10 mL of a hexane:acetone = 1:1 volume ratio solution was added, and the mixture was stirred for 24 hours to obtain an extract. The extract was then filtered using a membrane filter (pore size 0.1 μm) and the amount present in the obtained filtrate was measured. The binder content is the amount relative to the solid content of the electrode mixture sheet, and the metal salt content is the amount relative to the silicone compound, and both are added amounts.

[0163] (Measurement of Strength of Positive Electrode Mixture Sheet) The positive electrode mixture sheet was cut out to prepare a 4 mm wide strip-shaped test piece. Measurement was performed using a tensile tester (AGS-100NX manufactured by Shimadzu Corporation) at a speed of 100 mm / min. The distance between chucks was 40 mm. Displacement was applied until fracture, and the maximum stress measured was taken as the strength of each sample. Experimental Example 1 was set to 100, and the evaluation was based on the following criteria: 10: 150 or more 9: 140 or more but less than 150 8: 130 or more but less than 140 7: 120 or more but less than 130 6: 115 or more but less than 120 5: 110 or more but less than 115 4: 105 or more but less than 110 3: 100 or more but less than 105 2: 95 or more but less than 100 1: Less than 95

[0164] (Preparation of Positive Electrode) The above positive electrode mixture sheet was bonded to 20 μm aluminum foil as follows. For the adhesive, a slurry prepared by dissolving polyvinylidene fluoride (PVDF) in N-methylpyrrolidone (NMP) and dispersing carbon black at an 80:20 ratio was used. The above adhesive was applied to the aluminum foil and dried on a hot plate at 120 ° C. for 15 minutes to form a current collector with an adhesive layer. Thereafter, the positive electrode mixture sheet was placed on the current collector with the adhesive layer, and the positive electrode mixture sheet and current collector were bonded together using a roll press heated to 100 ° C. The sheet was then cut to the desired size and tabbed to form a positive electrode.

[0165] (Preparation of Negative Electrode) To 98 parts by mass of a carbonaceous material (graphite), 1 part by mass of an aqueous dispersion of sodium carboxymethyl cellulose (concentration of sodium carboxymethyl cellulose: 1% by mass) and 1 part by mass of an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber: 50% by mass) were added as thickeners and binders, and the mixture was mixed in a disperser to form a slurry. The resulting slurry was applied to a copper foil with a thickness of 10 μm, dried, rolled in a press, cut to the desired size, and tabbed to form a negative electrode.

[0166] (Preparation of Electrolyte Solution) As an organic solvent, a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC:EMC = 30:70 (volume ratio)) was weighed into a sample bottle, and 1 mass % each of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) was dissolved therein to prepare a mixed solution. LiPF was added to this mixed solution so that the concentration in the electrolyte solution was 1.1 mol / L. ６ The salts were mixed at 23° C. to obtain a non-aqueous electrolyte solution.

[0167] (Preparation of Aluminum Laminated Cell) The above positive electrode was placed opposite to the negative electrode via a 20 μm-thick microporous polyethylene film (separator), and the nonaqueous electrolyte solution obtained above was poured into the cell. After the nonaqueous electrolyte solution had sufficiently permeated the separator and the like, the cell was sealed, pre-charged, and aged to prepare a lithium ion secondary battery.

[0168] <Battery Evaluation> The lithium ion secondary battery manufactured as described above was subjected to constant current-constant voltage charging (hereinafter referred to as CC / CV charging) (0.1 C cut) at 45°C at a current equivalent to 0.33 C up to 4.25 V, and then discharged to 3 V at a constant current of 0.33 C. This constituted one cycle, and the initial discharge capacity was calculated from the discharge capacity at the third cycle. The discharge capacity characteristics per unit mass of the active material (mass discharge capacity characteristics) were then calculated using the following formula: Calculation formula: Mass discharge capacity characteristics (mAh / g) = Initial discharge capacity (mAh) / Mass (g) of active material in positive electrode mixture The calculated mass discharge capacity characteristics were ranked by relative evaluation. Experimental Example 1 was set to 100, and the batteries were evaluated according to the following criteria. 7: 120 or more 6: 115 or more but less than 120 5: 110 or more but less than 115 4: 105 or more but less than 110 3: 100 or more but less than 105 2: 95 or more but less than 100 1: Less than 95

[0169]

[0170] (Preparation of a positive electrode mixture sheet for a solid-state battery) ０．８ Mn ０．１ Co ０．１ O ２ ), conductive additive (SuperP Li: carbon black manufactured by Imerys), solid electrolyte (Li ６ P.S. ５Cl (Sigma-Aldrich), and silicone compound A1 were weighed and placed in a high-speed fluid mixer. The mixture was mixed at 200 rpm for 1 minute to obtain a mixture of active material, conductive additive, solid electrolyte, and silicone compound. A weighed binder (fibrillar resin: PTFE powder) was then added to the mixture and thoroughly cooled in a thermostatic bath at 5°C. The mixture of active material, conductive additive, solid electrolyte, binder, and silicone compound was mixed in a high-speed fluid mixer and mixed at 1500 rpm for 3 minutes to homogenize the mixture. The composition ratio (mass ratio) of the active material, conductive additive, binder, and solid electrolyte was active material:conductive additive:binder:solid electrolyte:silicone compound A1 = 66.5:2:1.5:30:3. Thereafter, the mixture was sufficiently heated in a constant temperature bath at 80 ° C., and then treated with a high-speed fluid mixer at 2500 rpm for 8 minutes to promote fibrillation, thereby obtaining an electrode mixture. The electrode mixture was placed in a rolling mill arranged in parallel and capable of rotating metal rolls at different peripheral speeds, to obtain a positive electrode mixture sheet (temperature: 60 ° C., left roll rotation speed: 1 m / min, right roll rotation speed: 0.8 m / min). The obtained positive electrode mixture sheet was again placed in the rolling mill and rolled to obtain a positive electrode mixture sheet with stronger sheet strength. Then, the positive electrode mixture sheet was placed in a roll press, and the gap was adjusted. The final thickness of the positive electrode mixture layer was adjusted to 85 μm. The obtained positive electrode mixture sheet was a free-standing film.

[0171] (Preparation of a solid electrolyte mixture sheet for a solid battery: Experimental Example 26) Solid electrolyte (Li ６ P.S. ５Cl: manufactured by Sigma-Aldrich), and silicone compound A1 were weighed, placed in a high-speed fluid mixer, and processed at 200 rpm for 1 minute to obtain a mixture consisting of a solid electrolyte and a silicone compound. A weighed binder (fibrillar resin: PTFE powder) was then added to the mixture, and the mixture was thoroughly cooled in a 5°C thermostatic bath. The mixture consisting of the binder, solid electrolyte, and silicone compound was placed in a high-speed fluid mixer and processed at 1500 rpm for 3 minutes to homogenize the mixture. The composition ratio (mass ratio) of the binder, solid electrolyte, and silicone compound was binder:solid electrolyte:silicone compound = 1.5:98.5:3. The mixture was then sufficiently heated in a thermostatic bath at 80°C, and then processed in a high-speed fluid mixer at 2500 rpm for 8 minutes to promote fibrillation, thereby obtaining a solid electrolyte mixture. The solid electrolyte mix was fed into a rolling mill in which metal rolls were arranged in parallel and could rotate at different peripheral speeds, to obtain a solid electrolyte mix sheet (temperature: 60°C, left roll rotation speed: 1 m / min, right roll rotation speed: 0.8 m / min). The obtained solid electrolyte mix sheet was fed into the rolling mill again and rolled to obtain a solid electrolyte mix sheet with stronger sheet strength. The solid electrolyte mix sheet was then fed into a roll press, and the gap was adjusted. The final thickness of the solid electrolyte layer was adjusted to 45 μm. The solid electrolyte mix sheet was a free-standing membrane.

[0172] (Fabrication of Solid-State Battery) After the fabricated positive electrode and solid electrolyte layer were punched, the positive electrode and a lithium foil serving as the negative electrode were placed opposite each other, stacked with the solid electrolyte layer sandwiched between them, and pressed together to fabricate a solid-state battery.

[0173] (Preparation of a solid electrolyte mixture sheet for a solid battery by a coating method: Experimental Example 27) Solid electrolyte (Li ６ P.S. ５Cl: manufactured by Sigma-Aldrich), and silicone compound A1 were weighed, placed in a high-speed fluid mixer, and processed at 200 rpm for 1 minute to obtain a mixture consisting of a solid electrolyte and a silicone compound. Separately, the binder obtained in Preparation Example 3 was dissolved in butyl butyrate to prepare a 5 wt. % binder solution. This was added to the mixture and mixed for 2 minutes at 2000 rpm using a planetary mixer to obtain a solid electrolyte slurry composition. The composition ratio (mass ratio) of binder, solid electrolyte, and silicone compound was adjusted to binder:solid electrolyte:silicone compound = 30:70:3. The obtained solid electrolyte slurry composition was applied to a PET film using a doctor blade (gap 80 μm), dried in a drying oven at 100 °C for 12 hours, and then placed in a roll press. The gap was adjusted to a final thickness of 50 μm. The solid electrolyte layer was then peeled off from the PET film to obtain a free-standing solid electrolyte mixture sheet.

[0174] (Fabrication of Solid-State Battery) After the fabricated positive electrode and solid electrolyte layer were punched, the positive electrode and a lithium foil serving as the negative electrode were placed opposite each other, stacked with the solid electrolyte layer sandwiched between them, and pressed together to fabricate a solid-state battery.

[0175] (Measurement of Strength of Solid Electrolyte Mixture Sheet) The solid electrolyte mixture sheet was cut out to prepare a 4 mm wide strip-shaped test piece. Measurement was performed using a tensile tester (AGS-100NX manufactured by Shimadzu Corporation) at a speed of 100 mm / min. The distance between chucks was 40 mm. Displacement was applied until fracture, and the maximum stress measured was taken as the strength of each sample. Experimental Example 1 was set to 100, and the samples were evaluated according to the following criteria. The results are shown in Table 3. 10: 150 or more 9: 140 or more but less than 150 8: 130 or more but less than 140 7: 120 or more but less than 130 6: 115 or more but less than 120 5: 110 or more but less than 115 4: 105 or more but less than 110 3: 100 or more but less than 105 2: 95 or more but less than 100 1: Less than 95

[0176] <Battery Evaluation> The solid-state battery manufactured as described above was subjected to constant current-constant voltage charging (hereinafter referred to as CC / CV charging) (0.1 C cut) at 45°C at a current equivalent to 0.33 C up to 4.25 V, and then discharged to 3 V at a constant current of 0.33 C. This constituted one cycle, and the initial discharge capacity was calculated from the discharge capacity at the third cycle. The discharge capacity characteristics per unit mass of the active material (mass discharge capacity characteristics) were then calculated using the following formula: Calculation formula: Mass discharge capacity characteristics (mAh / g) = Initial discharge capacity (mAh) / Mass (g) of active material in positive electrode mixture The calculated mass discharge capacity characteristics were ranked by relative evaluation. Experimental Example 1 was set to 100, and evaluation was performed according to the following criteria. The results are shown in Table 3. 7: 120 or more 6: 115 or more but less than 120 5: 110 or more but less than 115 4: 105 or more but less than 110 3: 100 or more but less than 105 2: 95 or more but less than 100 1: Less than 95

[0177]

Claims

1. A mixture sheet for electrochemical devices comprising a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material, wherein the content of the silicone compound is 0.5 to 20 mass% relative to the solid content of the mixture sheet for electrochemical devices, and the kinetic viscosity of the silicone compound at 25°C is 5 cSt to 60,000 cSt.

2. The composite sheet for electrochemical devices according to claim 1, wherein said silicone compound has a polyoxyalkylene chain.

3. The mixture sheet for electrochemical devices according to claim 1 or 2, wherein the content of the silicone compound is 0.5 to 15 mass % based on the solid content of the mixture sheet for electrochemical devices.

4. A composite sheet for electrochemical devices comprising a silicone compound that is liquid at 25° C., a binder, and an electrochemical device material, wherein the silicone compound has a polyoxyalkylene chain.

5. The composite sheet for electrochemical devices according to any one of claims 1 to 4, wherein the silicone compound has a saturated moisture content at 25°C of more than 30 ppm.

6. A composite sheet for electrochemical devices according to any one of claims 1 to 5, wherein the silicone compound has a mass loss rate of 20 mass % or less when heated at 150°C for 24 hours.

7. The mixture sheet for electrochemical devices according to any one of claims 1 to 6, characterized in that the content of the binder is 0.5 to 10 mass % based on the solid content of the mixture sheet for electrochemical devices.

8. The mixture sheet for electrochemical devices according to any one of claims 1 to 7, which contains a metal salt.

9. The composite sheet for electrochemical devices according to claim 8, wherein the content of said metal salt relative to said silicone compound is 0.1 to 30% by mass.

10. The mixture sheet for electrochemical devices according to any one of claims 1 to 9, wherein the mixture sheet for electrochemical devices is an electrode mixture sheet or an electrolyte mixture sheet.

11. The composite sheet for electrochemical devices according to any one of claims 1 to 10, wherein the binder is a fluorine-containing polymer material.

12. The composite sheet for electrochemical devices according to claim 11, wherein the binder is at least one selected from the group consisting of polytetrafluoroethylene, poly(vinylidene fluoride-co-hexafluoropropylene), and poly(vinylidene fluoride-co-2,3,3,3-tetrafluoropropylene).

13. The composite sheet for electrochemical devices according to claim 12, wherein the binder is polytetrafluoroethylene.

14. The composite sheet for electrochemical devices according to any one of claims 1 to 13, further comprising a conductive assistant.

15. An electrochemical device using the mixture sheet for electrochemical devices according to any one of claims 1 to 14.

16. A method for producing a mixture sheet for electrochemical devices, comprising: a step (1) of mixing a silicone compound that is liquid at 25°C, a binder, and an electrochemical device material; and a step (2) of rolling the mixture for electrochemical devices obtained in the step (1) into a sheet.

17. The method according to claim 16, wherein the kinetic viscosity of said silicone compound at 25° C. is 5 cSt to 60,000 cSt, said silicone compound has a polyoxyalkylene chain, and said binder is polytetrafluoroethylene.

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