Battery mixture, method for adjusting viscosity of battery mixture, method for manufacturing battery mixture, method for manufacturing battery member, battery member, secondary battery, and kit

Abstract

The present invention relates to a battery mixture containing an oxime, a vinylidene fluoride polymer, and a solid electrolyte. The present invention also relates to a method for adjusting the viscosity of a battery mixture, the method comprising: a step for preparing a composition containing a vinylidene fluoride polymer, a solid electrolyte, and a nonaqueous solvent; and a step for adding an oxime to the composition. The present invention also relates to a method for manufacturing a battery mixture, the method comprising: a step for preparing an oxime, a vinylidene fluoride polymer, a solid electrolyte, and a nonaqueous solvent; and a step for mixing the oxime, the vinylidene fluoride polymer, the solid electrolyte, and the nonaqueous solvent.

Description

Battery mixture, method for adjusting viscosity of battery mixture, method for manufacturing battery mixture, method for manufacturing battery component, battery component, secondary battery, and kit

[0001] The present invention relates to a battery mixture, a method for adjusting the viscosity of a battery mixture, a method for producing a battery mixture, a method for producing a battery component, a battery component, a secondary battery, and a kit.

[0002] Solid-state batteries, which use a solid electrolyte instead of a liquid electrolyte, are expected to be candidates for the next generation of secondary batteries because they can achieve higher capacities than secondary batteries that use liquid electrolytes and are also highly safe.

[0003] A solid-state battery has a structure in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated. Each layer contains a solid electrolyte and a binder. When fabricating a positive electrode layer or a negative electrode layer, a slurry mixture containing a positive electrode active material or a negative electrode active material is applied, dried, and pressed.

[0004] Vinylidene fluoride polymers are also useful as binders for various layers of solid-state batteries. However, there is a problem in that slurries for producing the positive electrode layer, solid electrolyte layer, and negative electrode layer of solid-state batteries containing vinylidene fluoride polymers may gel. In response to this problem, Patent Documents 1 and 2 disclose that slurries using vinylidene fluoride polymers copolymerized with specific fluorinated monomers retain fluidity for several tens of hours after production.

[0005] International Publication No. WO 2021 / 125150 International Publication No. WO 2022 / 054540

[0006] Patent Documents 1 and 2 state that vinylidene fluoride polymers copolymerized with specific fluorinated monomers (e.g., trifluoroethylene) retain fluidity even after production. However, according to the findings of the present inventors, even slurries using these copolymers may retain fluidity, but may have a very high viscosity, making them difficult to apply, or may even gel, if shear heating occurs in the slurry due to stirring during slurry production.

[0007] It is known that gelation can occur in conventional batteries that use an electrolyte solution when the slurry used to manufacture electrodes contains a vinylidene fluoride polymer. However, as described in Patent Document 1, gelation of the slurry used to manufacture each layer of a solid-state battery is believed to be caused by the solid electrolyte used in the solid-state battery. Therefore, gelation of the slurry used to manufacture electrodes of conventional batteries cannot be considered to be the same as gelation of the slurry used to manufacture each layer of a solid-state battery. Methods for suppressing gelation of the slurry used to manufacture electrodes of conventional batteries are not necessarily effective for the slurry used to manufacture each layer of a solid-state battery.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery mixture that can suppress gelation of a mixture containing a vinylidene fluoride polymer, a method for adjusting the viscosity of the battery mixture, a method for producing the battery mixture, a method for producing a battery component using the battery mixture, a battery component and a secondary battery produced from the battery mixture, and a kit for producing the battery mixture.

[0009] One aspect of the present invention for solving the above problems relates to a battery mixture according to the following [1] to [5]. [1] A battery mixture containing an oxime, a vinylidene fluoride polymer, and a solid electrolyte. [2] A slurry viscosity (η １ ) after 3 hours from the preparation, the slurry viscosity (η ２ ) value ratio (η ２ / η １) is 1.00 or less. [3] The battery mixture according to [1] or [2], wherein the content of the oxime is such that the amount of hydroxyimino groups contained in the oxime per 1 g of the vinylidene fluoride polymer is 6.0 mmol / g or more and 80.0 mmol / g or less. [4] The battery mixture according to any of [1] to [3], wherein the content of the oxime is such that the amount of hydroxyimino groups contained in the oxime per 1 g of the vinylidene fluoride polymer is 2.0 mmol / g or more and 70.0 mmol / g or less. [5] The battery mixture according to any of [1] to [4], wherein the vinylidene fluoride polymer contains 80 mol % or more of structural units derived from vinylidene fluoride relative to all structural units.

[0010] Another aspect of the present invention for solving the above problems relates to the following methods for adjusting the viscosity of a battery mixture [6] to [7]: [6] A method for adjusting the viscosity of a battery mixture, comprising: preparing a composition containing a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent; and adding an oxime to the composition. [7] The method for adjusting the viscosity of a battery mixture according to [6], in which the oxime is added to the composition in a gel state.

[0011] Another aspect of the present invention for solving the above problems is a method for adjusting the viscosity of a battery mixture according to the following [8] to [9]: [8] A method for producing a battery mixture, comprising the steps of: preparing an oxime, a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent; and mixing the oxime, the vinylidene fluoride polymer, the solid electrolyte, and the non-aqueous solvent. [9] The method for producing a battery mixture according to [8], wherein the vinylidene fluoride contains 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride.

[0012] Another aspect of the present invention for solving the above problems relates to the following methods for producing battery components

[10] to

[12] .

[10] A method for producing a battery component, comprising a step of applying and drying the battery mixture according to any one of claims 1 to 5, which contains a non-aqueous solvent.

[11] The method for producing a battery component according to

[10] , wherein the battery mixture contains an electrode active material.

[12] The method for producing a battery component according to

[10] or

[12] , wherein the battery mixture does not contain an electrode active material.

[0013] Another aspect of the present invention for solving the above problems relates to battery members according to the following

[13] and

[15] to

[17] .

[13] A battery member produced by the method according to any one of

[10] to

[12] .

[15] A battery member containing an oxime, a vinylidene fluoride polymer, and a solid electrolyte.

[16] The battery member according to

[13] , which contains an electrode active material.

[17] The battery member according to

[15] or

[16] , which does not contain an electrode active material.

[0014] Another aspect of the present invention for solving the above problems relates to secondary batteries according to the following items

[14] and

[18] .

[14] A secondary battery comprising the battery component according to item

[13] .

[18] A secondary battery comprising the battery component according to any one of items

[15] to

[17] .

[0015] Another aspect of the present invention for solving the above-mentioned problems relates to the kit described below in

[19] :

[19] A kit for producing the battery mixture according to any one of [1] to [5], wherein the oxime and other materials are stored in separate containers.

[0016] According to the present invention, there are provided a battery mixture capable of suppressing gelation of a mixture containing a vinylidene fluoride polymer, a method for adjusting the viscosity of the battery mixture, a method for producing the battery mixture, a method for producing a battery component using the battery mixture, a battery component and a secondary battery produced from the battery mixture, a battery component and a secondary battery produced from the battery mixture, and a kit for producing the battery mixture.

[0017] [Material Mixture] One embodiment of the present invention relates to a material mix for a battery, which comprises an oxime, a vinylidene fluoride polymer, and a solid electrolyte.

[0018] The thickening and gelling of a mixture containing a solid active material also occurs in a mixture for forming a solid electrolyte layer that does not contain a positive electrode active material or a negative electrode active material. Therefore, it is believed that the thickening and gelling of the mixture are caused by the solid active material. In contrast, according to the findings of the present inventors, adding an oxime to a thickened or gelled mixture can reduce the viscosity of the mixture, and adding an oxime during the preparation of the mixture can suppress the thickening and gelling of the mixture.

[0019] (Oxime) An oxime is a compound in which the oxygen atom of the carbonyl group of an aldehyde or ketone is replaced with a hydroxyimino group (=NOH). The oxime may be an oxime derived from an aldehyde (RCH=NOH) or an oxime derived from a ketone (R'RC=NOH).

[0020] The type of oxime is not particularly limited. Examples of oximes include acetone oxime (acetoxime), 2-butanone oxime (methyl ethyl ketone oxime), methyl isopropyl ketone oxime, methyl tertiary butyl ketone oxime, ditertiary butyl ketone oxime, 2-pentanone oxime, 3-pentanone oxime, 1-cyclohexyl-1-propanone oxime, formaldehyde oxime, acetaldoxime (acetaldehyde oxime), butyraldoxime (benzaldehyde oxime), benzaloxime (benzaldehyde oxime), acetophenone oxime, benzophenone oxime, 4-hydroxyacetophenone oxime, cyclopropanone oxime, cyclobutanone oxime, cyclopentanone oxime, cyclohexanone oxime, Examples include cycloheptanone oxime, cyclooctanone oxime, cyclononanone oxime, cyclodecanone oxime, cyclododecanone oxime, benzoquinone dioxime, benzoquinone monooxime, 2,3-butanedione monooxime, acetamide oxime, 3-hydroxy-3-methyl-2-butanone oxime, α-benzoin oxime, 1,3-dihydroxyacetone oxime, 2-isonitrosopropiophenone, dimethylglyoxime, methylethylglyoxime, diethylglyoxime, diphenylglyoxime, benzophenone dioxime, piperidone oxime, 2,4-pentanedione dioxime, 2-diethyl ether oxime, ethyl acetohydroxime, and ethyl cyanoglyoxylate oxime.

[0021] The oxime may be a polymer containing a hydroxyimino group (hereinafter also simply referred to as an "oxime polymer") or an oligomer containing a hydroxyimino group (hereinafter also simply referred to as an "oxime oligomer").

[0022] Oxime polymers and oxime oligomers can be synthesized by polymerizing a monomer or oligomer containing a hydroxyimino group, or by reacting a polymer or oligomer having a ketone group in the backbone with hydroxyamine. Examples of polymers having a ketone group in the backbone include poly(methyl vinyl ketone), polyketone (PK), polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), and polyether ketone ether ketone ketone (PEKEKK). Specific examples of oxime polymers and oxime oligomers include poly(methyl vinyl oxime).

[0023] These oximes may be used alone or in combination of two or more.

[0024] These oximes can be oximes represented by the following formula (1) or oximes represented by the following formula (2).

[0025]

[0026] In formula (1), R １ and R ２ R independently represent a functional group that is a hydrogen atom, an aldehyde group, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, or a heterocyclic group having 3 to 13 carbon atoms. Each of the alkyl groups may be linear, branched, or have an ester bond. １ and R ２ may be bonded to each other to form a ring.

[0027] The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 2 carbon atoms. The alkenyl group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. The alkynyl group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. The cycloalkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 7 carbon atoms, and even more preferably 5 to 7 carbon atoms. The aryl group preferably has 6 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms. The aralkyl group preferably has 7 to 14 carbon atoms, more preferably 7 to 11 carbon atoms, and even more preferably 7 to 9 carbon atoms. The heterocyclic group preferably has 3 to 13 carbon atoms, more preferably 3 to 10 carbon atoms, and even more preferably 3 to 8 carbon atoms.

[0028]

[0029] In formula (2), R ３ and R ４ R independently represent a functional group that is a hydrogen atom, an aldehyde group, a nitrile group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, or a heterocyclic group having 3 to 13 carbon atoms. Each of the alkyl groups may be linear, branched, or have an ester bond. ３ and R ４ may be bonded to each other to form a ring.

[0030] The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 2 carbon atoms. The alkenyl group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. The alkynyl group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. The cycloalkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 7 carbon atoms, and even more preferably 5 to 7 carbon atoms. The aryl group preferably has 6 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms. The aralkyl group preferably has 7 to 14 carbon atoms, more preferably 7 to 11 carbon atoms, and even more preferably 7 to 9 carbon atoms. The heterocyclic group preferably has 3 to 13 carbon atoms, more preferably 3 to 10 carbon atoms, and even more preferably 3 to 8 carbon atoms.

[0031] X represents a single bond or an alkylene group having from 1 to 5 carbon atoms. The alkylene group may be linear or branched.

[0032] From the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture and effectively suppressing the thickening and gelling of the mixture, the oxime represented by formula (1) is preferably R １ and R ２ are preferably independently a hydrogen atom or an oxime group representing an alkyl group having 1 to 5 carbon atoms. The alkyl group may be linear or branched. １ and R ２ may be bonded to each other to form a ring. １ or R ２ When the alkyl groups constituting the formula (I) are linear or branched, one or both of the alkyl groups preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or more and 2 or less carbon atoms, and even more preferably 1 carbon atom.

[0033] In addition, from the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture and effectively suppressing the thickening and gelling of the mixture, R １ and R ２ The total number of carbon atoms in each of these is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less, and even more preferably 1.

[0034] In addition, from the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture and effectively suppressing the gelling of the mixture, R １ and R ２ are preferably bonded to each other to form a ring. The number of carbon atoms constituting the ring is preferably 3 or more and 12 or less, and more preferably 4 or more and 8 or less.

[0035] Represented by formula (1), R １ or R ２ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, examples of the oxime include acetoxime, 2-butanone oxime, methyl isopropyl ketone oxime, methyl tertiary butyl ketone oxime, ditertiary butyl ketone oxime, 2-pentanone oxime, formaldehyde oxime, acetaldoxime, butylaldoxime, cyclopropanone oxime, cyclobutanone oxime, cyclopentanone oxime, cyclohexanone oxime, cycloheptanone oxime, cyclooctanone oxime, cyclononanone oxime, and cyclodecanone oxime.

[0036] In addition, from the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture and effectively suppressing the thickening and gelling of the mixture, the oxime represented by formula (2) is preferably R ３ and R ４ are preferably independently a hydrogen atom or an oxime group representing an alkyl group having 1 to 5 carbon atoms. The alkyl group may be linear or branched. ３ and R ４ may be bonded to each other to form a ring. ３ or R ４When the alkyl groups constituting the formula (I) are linear or branched, one or both of the alkyl groups preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or more and 2 or less carbon atoms, and even more preferably 1 carbon atom.

[0037] Furthermore, from the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture and effectively suppressing the thickening and gelling of the mixture, X is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably an alkylene group having 1 carbon atom.

[0038] Represented by formula (2), R ３ and R ４ Examples of oximes in which represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms include dimethylglyoxime, methylethylglyoxime, diethylglyoxime, 2,4-pentanedionedioxime, and the like.

[0039] From the viewpoint of effectively reducing the viscosity of the thickened or gelled mixture or effectively suppressing the thickening and gelling of the mixture, the oxime is represented by the formula (1), １ and R ２ are independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or an oxime represented by formula (2), ３ and R ４ are preferably oximes in which R are independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. １ and R ２ are preferably oximes in which each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0040] In the oxime represented by formula (1) and the oxime represented by formula (2), some or all of the hydrogen atoms of the alkyl group may be substituted with an alkyl group having 1 to 10 carbon atoms, an aryl group, a hydroxyl group, or an amino group.

[0041] The content of oxime in the mixture is preferably such that the amount of hydroxyimino groups contained in the oxime is 6.0 mmol to 80.0 mmol per 1 g of vinylidene fluoride polymer, more preferably 25.0 mmol to 80.0 mmol, even more preferably 50.0 mmol to 80.0 mmol, and particularly preferably 50.0 mmol to 75.0 mmol. The greater the amount of hydroxyimino groups, the more effectively the viscosity of the thickened or gelled mixture can be reduced, and the more effectively the thickening and gelling of the mixture can be suppressed. On the other hand, by setting the amount of hydroxyimino groups to 80.0 mmol or less per 1 g of vinylidene fluoride polymer, it is possible to prevent an extreme decrease in the viscosity of the mixture, resulting in a decrease in coatability and an inability to control the thickness of the coating layer.

[0042] Furthermore, the content of oxime in the mixture is preferably such that the amount of hydroxyimino groups contained in the oxime is 2.0 mmol to 70.0 mmol per 1 g of solid electrolyte, more preferably 10.0 mmol to 70.0 mmol, and particularly preferably 20.0 mmol to 60.0 mmol. The greater the amount of hydroxyimino groups, the more effectively the viscosity of the thickened or gelled mixture can be reduced, and the thickening and gelling of the mixture can be effectively suppressed. On the other hand, by setting the amount of hydroxyimino groups to 70.0 mmol or less per 1 g of solid electrolyte, it is possible to prevent an extreme decrease in the viscosity of the mixture, which reduces coatability and makes it impossible to control the thickness of the coating layer.

[0043] (Vinylidene fluoride polymer) The vinylidene fluoride polymer acts as a binder for binding the solid electrolytes together or the solid electrolyte to the positive electrode active material or the negative electrode active material, and also acts as a binder for binding them to the current collector.

[0044] The vinylidene fluoride polymer may be a homopolymer of vinylidene fluoride, or a copolymer of vinylidene fluoride and a monomer copolymerizable with vinylidene fluoride.

[0045] When the vinylidene fluoride polymer is a copolymer, it may be a copolymer of vinylidene fluoride with any known monomer copolymerizable with vinylidene fluoride.

[0046] When the vinylidene fluoride polymer is a copolymer, it can be a copolymer with a compound represented by the following formula (3), a perfluoroalkyl vinyl ether, an unsaturated dibasic acid, an ester of an unsaturated dibasic acid, etc. The vinylidene fluoride polymer as a copolymer may be a copolymer with one or more of these compounds.

[0047]

[0048] In formula (3), R ５ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a carboxyl group substituted with an alkyl group having 1 to 5 carbon atoms. ６ and R ７ are independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The alkyl group may be linear or branched. From the viewpoint of facilitating the polymerization reaction, R ５ and R ６ is preferably a substituent with little steric hindrance. ５ and R ６ are each independently preferably hydrogen or an alkyl group having 1 to 3 carbon atoms, more preferably hydrogen or a methyl group.

[0049] Y in formula (3) is a single bond or an atomic group having a molecular weight of 500 or less and a main chain composed of 1 to 20 atoms. The molecular weight of the atomic group is more preferably 200 or less. The lower limit of the molecular weight of the atomic group is not particularly limited, but is usually 15. The smaller the molecular weight of the atomic group, the more resistant the mixture to thickening and gelation. In this specification, the "number of atoms in the main chain" refers to the ratio of the carboxyl group written to the right of Y in formula (3) to the group (R ５ R ６ C=CR ７-) with the fewest number of atoms. Y may be linear or branched containing a functional group as a side chain. When Y has a side chain, it may have only one side chain or may have multiple side chains. When Y is a single bond, the compound represented by formula (3) is a compound in which the carboxyl group is not bonded to R ７ It has a structure in which it is directly bonded to the carbon atom bonded to

[0050] Examples of the compound represented by formula (3) include acrylic acid (AA), methacrylic acid, 2-carboxyethyl acrylate (CEA), 2-carboxyethyl methacrylate, maleic acid monomethyl ester, acryloyloxyethyl succinate (AES), acryloyloxypropyl succinate (APS), methacryloyloxyethyl succinate, and methacryloyloxypropyl succinate, etc. These compounds may be used alone or in combination.

[0051] Examples of perfluoroalkyl vinyl ethers include vinyl fluoride, trifluoroethylene (TFE), tetrafluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether.

[0052] Examples of unsaturated dibasic acids include maleic acid, fumaric acid, and citraconic acid.

[0053] Examples of the esters of unsaturated dibasic acids include maleic acid monomethyl ester (MMM), maleic acid monoethyl ester, citraconic acid monomethyl ester, and citraconic acid monoethyl ester.

[0054] The vinylidene fluoride polymer contains 50 mol% or more, preferably 80 mol% or more, and more preferably 90 mol% or more of structural units derived from vinylidene fluoride relative to all structural units. The upper limit of the amount of structural units derived from vinylidene fluoride is not particularly limited, but can be 100 mol%.

[0055] Furthermore, in the vinylidene fluoride polymer, the amount of structural units derived from compounds other than vinylidene fluoride is 50 mol % or less, preferably 20 mol % or less, and more preferably 10 mol % or less, relative to all structural units. The structural units derived from compounds other than vinylidene fluoride are not particularly limited, but in the case of a copolymer, it is sufficient that the amount is greater than 0 mol %.

[0056] The amount of structural units derived from vinylidene fluoride and the amount of structural units derived from compounds other than vinylidene fluoride are １ H NMR spectrum or １９ It can be determined by F NMR spectrum or neutralization titration.

[0057] The vinylidene fluoride polymer may be one in which the amount of fluorine-containing compounds other than vinylidene fluoride is less than 0.5 wt %. According to the findings of the present inventors, the viscosity of a mixture containing a vinylidene fluoride polymer in which the amount of fluorine-containing compounds other than vinylidene fluoride is less than 0.5 wt % can be effectively reduced by adding an oxime after the mixture has thickened or gelled.

[0058] Furthermore, the vinylidene fluoride polymer may contain 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride. According to the findings of the present inventors, the viscosity of a mixture containing a vinylidene fluoride polymer containing 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride can be effectively reduced by adding an oxime after the mixture has thickened or gelled. Furthermore, the viscosity and gelation of a mixture containing a vinylidene fluoride polymer containing 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride can be effectively suppressed by adding an oxime when the mixture is mixed with a non-aqueous solvent to form a slurry.

[0059] Examples of fluorine-containing compounds that can be contained in these vinylidene fluoride polymers include the above-mentioned perfluoroalkyl vinyl ethers, etc. Among these, hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), and trifluoroethylene (TFE) are preferred, and hexafluoropropylene (HFP) and chlorotrifluoroethylene (CTFE) are more preferred, since they are particularly effective in suppressing thickening and gelation when added as an oxime during slurrying.

[0060] Inherent viscosity (η) of vinylidene fluoride polymer ｉ The inherent viscosity is not particularly limited, but is preferably 0.5 dl / g or more and 5.0 dl / g or less, more preferably 1.0 dl / g or more and 4.5 dl / g or less, and even more preferably 1.5 dl / g or more and 4.0 dl / g or less. When the inherent viscosity is within the above range, thickness unevenness during coating is less likely to occur, making it easier to form the positive electrode layer, the negative electrode layer, and the solid electrolyte layer.

[0061] Inherent viscosity (η ｉ The inherent viscosity (η) is calculated by the following method. 80 mg of vinylidene fluoride polymer is dissolved in 20 mL of N,N-dimethylformamide to prepare a polymer solution. The viscosity η of the prepared polymer solution is measured using an Ubbelohde viscometer in a thermostatic bath at 30°C. Then, the inherent viscosity (η) is calculated from the following formula: ｉ ) is calculated. ｉ =(1 / C)・ln(η / η ０ ) In the above formula, η ０ is the viscosity of the solvent N,N-dimethylformamide, and C is the concentration of vinylidene fluoride polymer in the prepared polymer solution (0.4 g / dL).

[0062] The polymerization method for vinylidene fluoride polymers is not particularly limited, and conventionally known polymerization methods can be used. Examples of polymerization methods include suspension polymerization, emulsion polymerization, solution polymerization, etc. Among these, aqueous suspension polymerization or emulsion polymerization is preferred because of ease of post-treatment, and aqueous suspension polymerization is more preferred.

[0063] In the mixture for forming the electrode layers (positive electrode layer and negative electrode layer), the content of the vinylidene fluoride polymer in the mixture can be 0.2 mass % or more and 20 mass % or less, preferably 0.2 mass % or more and 10 mass % or less, and more preferably 0.2 mass % or more and 4 mass % or less, relative to the total amount of solids.

[0064] In the mixture for forming the solid electrolyte layer, the content of the vinylidene fluoride polymer in the mixture can be 0.5 mass % or more and 80 mass % or less, preferably 0.5 mass % or more and 50 mass % or less, and more preferably 0.5 mass % or more and 20 mass % or less, relative to the total amount of solids.

[0065] (Solid Electrolyte) Examples of the solid electrolyte include known sulfide-based solid electrolytes and oxide-based solid electrolytes.

[0066] Examples of sulfide-based solid electrolytes include Li ２ S-SiS ２ , LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ S ５ , LiI-Li ２ O-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 , Li ２ S-P ２ S ５ , Li ３ P.S. ４ These include:

[0067] Examples of oxide-based solid electrolytes include LLTO-based compounds ((La, Li)TiO ３ ), Li ６ La ２ CaTa ２ O １２ , Li ６ La ２ ANb ２ O１２ (A: alkaline earth metal), Li ２ Nd ３ TeSbO １２ , Li ３ BO ２．５ N ０．５ , Li ９ SiAlO ８ , LAGP compound (Li １＋ｘ Al ｘ Ge ２－ｘ (PO4) ３ (0≦x≦1)), Li ２ O-Al ２ O ３ -TiO ２ -P ２ O ５ LATP-based compounds such as Li １＋ｘ Al ｘ Ti ２－ｘ (P.O. ４ ) ３ (0≦x≦1)), Li １＋ｘ Ti ２－ｘ Al ｘ Si ｙ (P.O. ４ ) ３－ｙ (0≦x≦1, 0≦y≦1), Li １＋ｙ Al ｘ M ２－ｘ (P.O. ４ ) ３ (M is Ti, Ge, Sr, Sn, Zr or Ca, and 0≦x≦1, 0≦y≦1), LiTi ｘ Zr ２－ｘ (P.O. ４ ) ３ (0≦x≦1), LISICON (Li ４－２ｘ Zn ｘ GeO ４ (0≦x≦1)), LIPON-based compounds (Li ３＋ｙ P.O. ４－ｘ N ｘ (0≦x≦1, 0≦y≦1)), NASICON-based compounds (LiTi ２ (P.O. ４ ) ３ etc.), garnet compounds (Li ７ La ３ Zr ２ O １２ , Li ７－ｘ La３ Zr １－ｘ Nb ｘ O １２ (0≦x≦1, etc.)

[0068] The oxide-based solid electrolyte is preferably a garnet-based compound because it has high lithium ion conductivity. The garnet-based compound is represented by the following formula (4): Li ７－ｘ La ３ (Zr ２－ｘ M ｘ ) O １２ ...(4) (wherein M=Nb or Ta, and x satisfies 0≦x≦2) is preferred. Examples of materials represented by formula (4) include Li ７ La ３ Zr ２ O １２ (LLZO) and the like.

[0069] The solid electrolyte is preferably a compound that, when extracted with water at room temperature (25°C) according to the extraction method specified in JIS K 5101-16-2 (2004), results in an extraction water with a pH of 10.5 or higher. Such a solid electrolyte is likely to dehydrofluorinate the vinylidene fluoride polymer, which tends to increase the viscosity of the mixture. However, the mixture according to this embodiment can suppress the increase in viscosity by using an oxime.

[0070] Specifically, the pH of the extracted water is a value obtained by adding the electrode active material to ultrapure water in an amount 50 times the weight of the electrode active material, stirring the mixture with a magnetic stirrer at a rotation speed of 600 rpm for 10 minutes, and measuring the pH of the extracted water using a pH meter, Model: F-21, manufactured by Horiba, Ltd.

[0071] A mixture containing a positive electrode active material having a pH of 10.5 or higher contains a large amount of base, which easily deteriorates vinylidene fluoride and causes viscosity increase. Therefore, in order to prevent the thickening of the slurry-like mixture and the resulting gelation, it is usually necessary to remove the base by washing the positive electrode active material with water. In contrast, the mixture according to this embodiment is less likely to thicken or gel even when using a positive electrode active material containing a large amount of base. Therefore, the mixture according to this embodiment does not require washing the positive electrode active material with water during production.

[0072] The volume average particle size of the oxide-based solid electrolyte is not particularly limited, but is preferably 0.01 μm or more and 100 μm or less, more preferably 0.05 μm or more and 50 μm or less, and even more preferably 0.1 μm or more and 10 μm or less.

[0073] (Electrode Active Material) The above-mentioned mixture may be a mixture containing an electrode active material for forming a positive electrode layer or a negative electrode layer, or may be a mixture not containing an electrode active material for forming a solid electrolyte layer.

[0074] The electrode active material absorbs or releases ions, such as lithium ions, thereby enabling the secondary battery to be charged and discharged.

[0075] The electrode active material may be a positive electrode active material or a negative electrode active material.

[0076] The positive electrode active material is not particularly limited, but is preferably a lithium metal oxide.

[0077] Examples of lithium metal oxides include LiMnO ２ , LiMn ２ O ４ , LiCoO ２ , LiNiO ２ , LiNi ｘ Co １－ｘ O ２ (0<x<1), LiNi ｘ Co ｙ Mn １－ｘ－ｙ O ２ (0<x<1, 0<y<1), LiNi ｘ Co ｙ Al１－ｘ－ｙ O ２ (0<x<1, 0<y<1), LiFePO ４ etc. are included.

[0078] From the viewpoint of increasing the capacity density and thereby increasing the capacity of the secondary battery, the positive electrode active material is preferably a lithium metal compound containing Ni, and from the viewpoint of suppressing crystal structure changes during charge / discharge processes and stabilizing cycle characteristics, the positive electrode active material is more preferably a lithium metal compound containing Ni and Co.

[0079] From the viewpoint of increasing the charging potential of the secondary battery and also improving the cycle characteristics, the positive electrode compound is preferably a lithium metal oxide (ternary lithium metal oxide) represented by the following formula (5).

[0080] LiNi ｘ Co ｙ M ｚ O ２ ...(5)

[0081] In formula (5), M is Mn or Al, 0<x<1, 0<y<1, 0<z<1, and x+y+z=1.

[0082] Examples of ternary lithium metal oxides include Li １．００ Ni ０．５ Co ０．２ Mn ０．３ O ２ (NCM523), Li １．００ Ni ０．６ Co ０．２ Mn ０．２ O ２ (NCM622), Li １．００ Ni ０．８３ Co ０．１２ Mn ０．０５ O ２ (NCM811), and Li １．００ Ni ０．８５ Co ０．１５ Al ０．０５ O ２ (NCA811) and the like.

[0083] The negative electrode active material is not particularly limited, and known materials such as carbon materials, metal / alloy materials, and metal oxides can be used. Among these, carbon materials are preferred from the viewpoint of further increasing the energy density of the secondary battery. Examples of the carbon materials include artificial graphite, natural graphite, non-graphitizable carbon, and easily graphitizable carbon.

[0084] These electrode active materials may be used alone or in combination of two or more.

[0085] The content of the electrode active material in the mixture is preferably 40% by mass or more and 99.9% by mass or less based on the total amount of solids. When the amount of the active material is within this range, for example, sufficient charge / discharge capacity is obtained, and battery performance is likely to be good.

[0086] (Non-aqueous solvent) The mixture may be in the form of a slurry containing a non-aqueous solvent, or may be a mixture of powders or particles containing no non-aqueous solvent.

[0087] Examples of non-aqueous solvents include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoamide, dioxane, tetrahydrofuran, tetramethylurea, triethyl phosphate, trimethyl phosphate, acetone, ethyl acetate, n-butyl acetate, n-butanol, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, toluene, diisobutyl ketone, butyl butyrate, and methyl ethyl ketone. Of these, diisobutyl ketone is preferred when a sulfide-based solid electrolyte is used, and N-methyl-2-pyrrolidone is preferred when an oxide-based solid electrolyte is used. These non-aqueous solvents may be used alone or in combination.

[0088] The amount of solids in the mixture is not particularly limited, but is preferably, for example, 10 parts by mass or more and 85 parts by mass or less relative to the total amount of the constituent components of the slurry.

[0089] (Other Substances) The mixture may contain a polymer other than vinylidene fluoride polymer, a conductive aid, a pigment dispersant, an insulating filler, a lithium salt, a dispersion stabilizer, an adhesion aid, a thickener, a dispersant, a flame retardant, an antifoaming agent, and various coupling agents.

[0090] Examples of the conductive additive include carbonaceous materials such as carbon black, carbon nanotubes, graphite fine powder and graphite fiber, and metal fine powder and metal fiber such as nickel and aluminum.

[0091] Examples of pigment dispersants include polyvinylpyrrolidone and the like.

[0092] Examples of insulating fillers include insulating inorganic fillers such as alumina, magnesia, and silica, and insulating organic fillers such as polytetrafluoroethylene, polyimide, and polyacrylonitrile.

[0093] Examples of plasticizers include ethylene carbonate, propylene carbonate, and ethyl methyl carbonate.

[0094] Examples of lithium salts include LiPF ６ , LiFSI, and LiTFSI, etc.

[0095] The content of these other substances in the mixture is preferably 15% by mass or less based on the total amount of solids.

[0096] [Method for Producing the Combination] The combination can be produced by mixing the above-mentioned components.

[0097] The mixing method is not particularly limited, and the oxime, vinylidene fluoride polymer, and solid electrolyte may be dry-mixed, or the oxime, vinylidene fluoride polymer, and solid electrolyte may be wet-mixed together with a non-aqueous solvent. The mixture obtained by dry mixing may be mixed with a non-aqueous solvent to form a slurry when the battery is fabricated.

[0098] Furthermore, the non-aqueous solvent-containing mixture may be mixed with the oxime during preparation, or the oxime may be added after the slurry (composition) obtained by wet-mixing the vinylidene fluoride polymer and the solid electrolyte with the non-aqueous solvent has thickened or gelled. Alternatively, the vinylidene fluoride copolymer and the oxime may be dissolved in the non-aqueous solvent in advance and added during preparation. Similarly, the oxime may be dissolved in the non-aqueous solvent in which the solid electrolyte has been dispersed in advance and added during preparation, or the oxime may be dissolved in the non-aqueous solvent in which the electrode active material has been dispersed in advance and added during preparation.

[0099] According to the findings of the present inventors, adding an oxime to a slurry composition containing a solid electrolyte, a vinylidene fluoride polymer, and a non-aqueous solvent after thickening or gelling can reduce the viscosity of the composition, making it easier to apply (first production method: method for adjusting the viscosity of a mixture). Furthermore, depending on the type of vinylidene fluoride polymer, mixing an oxime together with the solid electrolyte, the vinylidene fluoride polymer, and a non-aqueous solvent to prepare a slurry can prevent thickening and gelling of the slurry mixture (second production method).

[0100] (First Manufacturing Method) In the first manufacturing method, a composition containing a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent is prepared, and an oxime is added to this composition.

[0101] The composition may be prepared by a known method, for example, by stirring and mixing a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent. The method for adding each component during mixing is not particularly limited. The vinylidene fluoride polymer, the solid electrolyte, and the non-aqueous solvent may be added to a mixing container and mixed simultaneously, or multiple components may be mixed in advance, and the resulting premix may be mixed with the remaining components. Furthermore, each component may be added at once or in stages. Mixing these components produces a slurry-like composition.

[0102] When preparing a positive electrode layer or a negative electrode layer, a positive electrode active material or a negative electrode active material is mixed when preparing the composition. When preparing a solid electrolyte layer, a positive electrode active material or a negative electrode active material is not mixed when preparing the composition. Furthermore, when the mixture contains other additives, the additives are mixed when preparing the composition.

[0103] The oxime is added after the composition is prepared. The composition tends to thicken and gel after preparation. Adding the oxime to the thickened or gelled composition reduces the viscosity of the composition or restores its fluidity, thereby adjusting the viscosity of the mixture to a range that allows application. When adding the oxime to the gelled composition, the composition may be crushed in advance to facilitate penetration of the oxime. In this case, the viscosity of the composition may be reduced by adding the oxime, leaving it for a certain period of time to allow the oxime to penetrate, and then stirring, or by adding the oxime, stirring, and then leaving it for a certain period of time to allow the oxime to penetrate.

[0104] According to the findings of the present inventors, in the first production method, the viscosity of the composition can be reduced or the fluidity can be restored by adding an oxime, regardless of the type of vinylidene fluoride polymer.

[0105] (Second Manufacturing Method) In the second manufacturing method, an oxime, a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent are prepared and mixed to produce a slurry mixture.

[0106] The mixing may be carried out by a known method. The method for adding each component during mixing is not particularly limited. The oxime, vinylidene fluoride polymer, solid electrolyte, and non-aqueous solvent may be added to a mixing container and mixed simultaneously, or a plurality of components may be mixed in advance, and the resulting premix may be mixed with the remaining components. Furthermore, each component may be added at once or in stages. By mixing these components, a slurry mixture can be obtained.

[0107] When preparing a positive electrode layer or a negative electrode layer, the positive electrode active material or the negative electrode active material is mixed when preparing the mixture. When preparing a solid electrolyte layer, the positive electrode active material or the negative electrode active material is not mixed when preparing the mixture. Furthermore, if the mixture contains other additives, the additives are also mixed.

[0108] The mixture thus obtained is prevented from thickening and gelling, and may also lose viscosity over time after preparation.

[0109] For example, the slurry mixture produced by the second production method has a slurry viscosity (η １ ) after 3 hours from the preparation, the slurry viscosity (η ２ ) value ratio (η ２ / η １ ) is 1.00 or less, preferably 0.95 or less, and more preferably 0.90 or less.

[0110] According to the findings of the present inventors, the second production method can significantly suppress thickening and gelation of a mixture when preparing the mixture containing a vinylidene fluoride polymer in which the amount of a fluorine-containing compound other than vinylidene fluoride is 0.5 wt % or more, and can also reduce the viscosity after preparation.

[0111] In addition, a kit in which the materials for the mixture are stored in multiple containers may be used to produce the mixture by the first production method and the second production method. The kit may be a kit including a container in which a vinylidene fluoride polymer is stored and a container in which an oxime is stored, a kit including a container in which a solid electrolyte is stored and a container in which an oxime is stored, or a kit including a container in which an electrode active material is stored and a container in which an oxime is stored. The materials included in these kits may be used in combination with other materials to produce the mixture by the first production method or the second production method described above.

[0112] In this case, the oxime included in the kit can be selected to be used in either the first production method or the second production method depending on the type of vinylidene fluoride polymer. In other words, the oxime can be used after the prepared composition has thickened or gelled, regardless of the type of vinylidene fluoride polymer (first production method). Alternatively, when preparing a mixture containing a vinylidene fluoride polymer suitable for the second production method (e.g., a vinylidene fluoride polymer containing 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride), the oxime may be added when preparing the mixture (second production method).

[0113] [Battery Components and Manufacturing Method Thereof] The above-described mixture can be used to manufacture battery components, specifically, a positive electrode layer, a negative electrode layer, and a solid electrolyte layer.

[0114] Specifically, these layers can be prepared by applying the above-mentioned mixture onto a substrate and drying it.

[0115] The substrate may be a transfer sheet or transfer substrate, another already formed layer, or a current collector when preparing a positive electrode layer or a negative electrode layer. When the mixture is applied to the transfer sheet or transfer substrate and dried, the layer formed on the other already formed layer can be transferred from the substrate to the other layer. The layers of the secondary battery are stacked in the order of positive electrode layer, solid electrolyte layer, negative electrode layer, solid electrolyte layer, positive electrode layer, etc., and current collectors are connected to the positive electrode layer and negative electrode layer as necessary to obtain a secondary battery.

[0116] Coating and drying can be performed by known methods. For example, coating can be performed by a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, a die coating method, a dip coating method, or the like. The drying temperature can be 20°C or higher and 250°C or lower, preferably 40°C or higher and 200°C or lower, and more preferably 60°C or higher and 180°C or lower. The drying time can be 10 seconds or higher and 300 minutes or lower, preferably 1 minute or higher and 200 minutes or lower. Drying may be performed multiple times at different temperatures. Pressure may be applied during drying.

[0117] The obtained member (positive electrode layer, negative electrode layer, or solid electrolyte layer) has a mixture layer containing a vinylidene fluoride polymer and a solid electrolyte, and optionally containing an electrode active material and other additives. The oxime may be completely volatilized during drying, or the oxime may remain in the mixture layer. The amount of the remaining oxime is not particularly limited, but is preferably 0 μg / m ２ More than (or above the detection limit) 500 μg / m ２ It can be as follows:

[0118] These components can be used in solid-state and semi-solid-state batteries.

[0119] [Other Embodiments] It goes without saying that the above-described embodiments are exemplary embodiments of the present invention, and the present invention may include embodiments other than the above-described embodiments within the scope of its core technical concept.

[0120] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0121] 1. Preparation of vinylidene fluoride polymer 1-1. Preparation of VDF homopolymer (Preparation Example 1) A 2-liter autoclave was charged with 1,026 g of ion-exchanged water, 0.2 g of methyl cellulose, 400 g of vinylidene fluoride monomer, 2.4 g of di-n-propyl peroxydicarbonate, 2.4 g of methanol, and 3.0 g of ethyl acetate, and the polymerization temperature was set to 26° C., and then the temperature was raised to 40° C. for 12 hours to carry out suspension polymerization. After completion of the polymerization, the obtained polymer slurry was heat-treated at 95° C. for 30 minutes, dehydrated, washed with water, and further dried at 80° C. for 20 hours to obtain a VDF homopolymer.

[0122] 1-2. Preparation of VDF / HFP Copolymer (Preparation Example 2) 1,160 g of ion-exchanged water, 0.6 g of methyl cellulose, 360 g of vinylidene fluoride (VDF), 40 g of hexafluoropropylene (HFP), and 3.6 g of diisopropyl peroxydicarbonate were placed in a 2-liter autoclave and polymerized at 45° C. The resulting copolymer was heat-treated at 95° C. for 60 minutes, dehydrated, washed with water, and further dried at 80° C. for 20 hours to obtain a VDF / HFP copolymer.

[0123] 1-3. Preparation of VDF / HFP / MMM Copolymer (Preparation Example 3) 1,160 g of ion-exchanged water, 0.6 g of methylcellulose, 344 g of vinylidene fluoride (VDF), 56 g of hexafluoropropylene (HFP), 2.2 g of maleic acid monomethyl ethyl ester (MMM), and 3.6 g of diisopropyl peroxydicarbonate were placed in a 2-liter autoclave and polymerized at 45° C. The resulting copolymer was heat-treated at 95° C. for 60 minutes, dehydrated, washed with water, and further dried at 80° C. for 20 hours to obtain a VDF / HFP / MMM copolymer.

[0124] 1-4. Preparation of VDF / APS Copolymer (Preparation Example 4) A 2-liter autoclave was charged with 1,096 g of ion-exchanged water, 0.2 g of Metrose 90SH-100 (Shin-Etsu Chemical Co., Ltd.), 2.2 g of a 50 wt % diisopropyl peroxydicarbonate-Flon 225cb solution, 426 g of vinylidene fluoride, and an initial amount of 0.2 g of acryloyloxypropyl succinic acid (APS). After heating to 26°C over 1 hour, the temperature was maintained at 26°C, and a 6 wt % aqueous APS solution was gradually added at a rate of 0.5 g / min. The resulting polymer slurry was dehydrated and dried to obtain a VDF / APS copolymer. A total of 4.0 g of APS was added, including the amount initially added.

[0125] 1-5. Preparation of VDF / TFE Copolymer (Preparation Example 5) 1,300 g of ion-exchanged water was charged into a 4 L autoclave and thoroughly purged with nitrogen. Then, 1,300 g of octafluorocyclobutane was charged, and the system was maintained at 37°C and a stirring speed of 580 rpm. Then, 200 g of a mixed gas containing trifluoroethylene (TFE) and vinylidene fluoride (VDF) in a TFE / VDF ratio of 9 / 91% by mass and 0.4 g of ethyl acetate were charged, followed by the addition of 1 g of a 50% by mass solution of di-n-propyl peroxydicarbonate in methanol to initiate polymerization. Since the pressure in the system decreased as the polymerization progressed, a mixed gas of TFE / VDF = 28 / 72% by mass was continuously supplied, and the system pressure was maintained at 1.3 MPaG. Stirring was continued for 17 hours to obtain a VDF / TFE copolymer.

[0126] 1-6. Preparation of VDF / AA Copolymer (Preparation Example 6) A 2-liter autoclave was charged with 524 g of ion-exchanged water, 0.4 g of Metrose 90SH-100 (Shin-Etsu Chemical Co., Ltd.), 4 g of a 50 wt % perbutyl perpivalate-Flon 225cb solution, 396 g of vinylidene fluoride, and an initial amount of 0.2 g of acrylic acid (AA), and heated to 50°C. A 1 wt % aqueous AA solution was continuously fed into the reaction vessel while maintaining a constant pressure during polymerization. The resulting polymer slurry was dehydrated and dried to obtain a VDF / AA copolymer. A total of 3.96 g of AA was added, including the amount initially added.

[0127] 1-7. Preparation of VDF / CTFE Copolymer (Preparation Example 7) 1,040 g of ion-exchanged water, 0.2 g of methyl cellulose, 384 g of vinylidene fluoride (VDF), 16 g of chlorotrifluoroethylene (CTFE), and 2.0 g of diisopropyl peroxydicarbonate were placed in a 2-liter autoclave and polymerized at 45° C. The resulting copolymer was heat-treated at 95° C. for 60 minutes, dehydrated, washed with water, and further dried at 80° C. for 20 hours to obtain a VDF / CTFE copolymer.

[0128] 1-8. Preparation of VDF / HFP / AA Copolymer (Preparation Example 8) A 2-liter autoclave was charged with 1,316 g of ion-exchanged water, 0.4 g of Metrose SM-100 (Shin-Etsu Chemical Co., Ltd.), 2.4 g of diisopropyl peroxydicarbonate, 400 g of vinylidene fluoride (VDF), 4 g of hexafluoropropylene (HFP), and an initial amount of 0.2 g of acrylic acid (AA), and heated to 50°C. A 1 wt% aqueous AA solution was continuously fed into the reaction vessel under conditions of maintaining a constant pressure during polymerization. The resulting polymer slurry was dehydrated and dried to obtain a VDF / HFP / AA copolymer. A total of 4 g of AA was added, including the amount initially added.

[0129] 1-9. Measurement of polymerization ratio of each polymer powder １The H NMR spectrum was measured under the following conditions: The apparatus used was an AVANCE AC 400FT NMR spectrometer (manufactured by Bruker). <Measurement conditions> Frequency: 400 MHz Measurement solvent: DMSO-d6 Measurement temperature: 25°C

[0130] The amount of structural units derived from vinylidene fluoride in the polymer and the amount of structural units derived from the comonomer, １ It was calculated from the H NMR spectrum, specifically, based on the integrated intensity of signals mainly derived from the comonomer and signals mainly derived from vinylidene fluoride observed at 2.24 ppm and 2.87 ppm.

[0131] When a comonomer having a structure derived from acrylic acid or monomethyl maleate was used as the comonomer, the amount of structural units containing the structure derived from acrylic acid or monomethyl maleate in the polymer was determined by neutralization titration using a 0.03 mol / L aqueous sodium hydroxide solution. More specifically, 0.3 g of the polymer was dissolved in 9.7 g of acetone at approximately 80°C, and then 3 g of pure water was added to prepare a titration solution. Using phenolphthalein as an indicator, neutralization titration was performed at room temperature using a 0.03 mol / L aqueous sodium hydroxide solution.

[0132] 2. Preparation of Mixture (First Manufacturing Method) The VDF homopolymer obtained in Preparation Example 1 was dissolved in N-methyl-2-pyrrolidone (NMP) to prepare a 10 wt % binder solution. LLZO (solid electrolyte) and the binder solution were weighed and kneaded.

[0133] In Combination 1, the mass ratio of the solid electrolyte to the VDF homopolymer (solid electrolyte:VDF homopolymer) was 10:90.

[0134] After preparation, the viscosity of the mixture was measured after standing for two days. Then, 2-butanone oxime was added to the mixture, and the mixture was stirred at 2000 rpm for three minutes using a mixer (manufactured by Shinky Corporation). The amount added was adjusted so that 57.4 mmol of 2-butanone oxime (amount of hydroxyimino groups: 0.06 mol) was contained per gram of vinylidene fluoride polymer. The viscosity of the mixture was measured three hours after the addition of the oxime and stirring.

[0135] Combinations 2 to 8 were prepared by changing the type of VDF polymer, the type of oxime, and the mass ratio of each. Similarly, the mixture was allowed to stand, the viscosity was measured before the addition of the oxime, the oxime was added and stirred, and the viscosity was measured after the addition of the oxime.

[0136] The viscosity was measured using an E-type viscometer at 25°C and a shear rate of 2 s －１ Specifically, the slurry (mixture) was charged into the measuring device, and then the device was left to stand for 60 seconds, after which the rotor was rotated to measure the viscosity. The value measured 300 seconds after the rotor started to rotate was taken as the slurry viscosity.

[0137] Table 1 shows the type of VDF polymer, the type and amount of oxime used in preparing Combinations 1 to 8, the slurry composition (mass ratio of solid electrolyte to vinylidene fluoride polymer to added oxime), and the viscosities of the mixtures before and after the addition of oxime. The amount of oxime added indicates the amount of hydroxyimino groups per 1 g of VDF polymer ("Amount added A" in the table) or the amount of hydroxyimino groups per 1 g of solid electrolyte ("Amount added B" in the table). When the viscosity could not be measured due to gelation, this is indicated as "gelation."

[0138]

[0139] 3. Preparation of Mixture (Second Manufacturing Method) The VDF / HFP copolymer obtained in Preparation Example 2 was dissolved in N-methyl-2-pyrrolidone (NMP) to prepare a 10 wt % binder solution.

[0140] LLZO (solid electrolyte), a binder solution, and 2-butanone oxime were kneaded to prepare Mixture 9. The mass ratio of the solid electrolyte to the VDF / HFP copolymer (solid electrolyte:VDF / HFP copolymer) in Mixture 9 was 20:80. In addition, the amount of hydroxyimino groups in 2-butanone oxime relative to 1 g of vinylidene fluoride polymer was 57.4 mmol.

[0141] The type of VDF polymer, the type of oxime, and the mass ratio thereof were changed to prepare Combinations 10 to 22. Note that no oxime was added to Combinations 19 to 22.

[0142] The viscosity was measured using an E-type viscometer at 25°C and a shear rate of 2 s －１ The viscosity was measured at 100°C. Specifically, the slurry (mixture) was charged into the measuring device, waited for 60 seconds, and then the rotor was rotated to measure the viscosity. At this time, the value 300 seconds after the start of rotor rotation was taken as the slurry viscosity. For each prepared mixture, the viscosity immediately after preparation and the viscosity after storage at 25°C under a nitrogen atmosphere for 3 hours were measured.

[0143] The type of VDF polymer, type of oxime, and slurry composition (mass ratio of solid electrolyte, vinylidene fluoride polymer, and added oxime) used in preparing Combinations 1 to 8, as well as the viscosities of the mixtures immediately after preparation and after 3 hours of storage, are shown in Tables 2 and 3. The amount of oxime added indicates the amount of hydroxyimino groups per 1 g of VDF polymer ("Amount added A" in the table) or the amount of hydroxyimino groups per 1 g of solid electrolyte ("Amount added B" in the table). When viscosity could not be measured due to gelation, this is indicated as "gelation."

[0144]

[0145]

[0146] As is clear from Tables 1 to 3, the battery mixture containing an oxime, a vinylidene fluoride polymer, and a solid electrolyte was able to reduce viscosity and recover fluidity even when gelling and thickening occurred, and was also resistant to gelling and thickening.

[0147] 4. Method for Preparing Mixture (Third Production Method) The VDF / HFP copolymer obtained in Preparation Example 2 was dissolved in N-methyl-2-pyrrolidone (NMP) to prepare a 10 wt % binder solution.

[0148] LiFePO ４ (active material), LLZO (solid electrolyte), Super-P (conductive additive), binder solution, and 2-butanone oxime were kneaded to prepare mixture 23. The mass ratio of the active material, solid electrolyte, conductive additive, and VDF / HFP copolymer in mixture 23 (active material:solid electrolyte:conductive additive:VDF / HFP copolymer) was 80:10:2:10. At this time, the amount of hydroxyimino groups in 2-butanone oxime per 1 g of vinylidene fluoride polymer was 57.4 mmol.

[0149] Mixtures 24 and 25 were prepared by changing the mass ratio of the active material, solid electrolyte, and oxime.

[0150] The viscosity was measured using an E-type viscometer at 25°C and a shear rate of 2 s －１ The viscosity was measured at 100°C. Specifically, the electrode slurry (mixture) was charged into the measuring device, and then the rotor was rotated to measure the viscosity. The value measured 300 seconds after the start of rotor rotation was taken as the slurry viscosity. The viscosity of each prepared mixture was measured immediately after preparation and after storage at 25°C under a nitrogen atmosphere for 3 hours.

[0151] Table 4 shows the type of VDF polymer, type of oxime, and slurry composition (mass ratio of solid electrolyte, vinylidene fluoride polymer, and added oxime) used in preparing Combinations 23 to 25, as well as the viscosities of the mixtures immediately after preparation and after 3 hours of storage. The amount of oxime added indicates the amount of hydroxyimino groups per 1 g of VDF polymer ("Amount added A" in the table) or the amount of hydroxyimino groups per 1 g of solid electrolyte ("Amount added B" in the table). When the viscosity could not be measured due to gelation, this is indicated as "gelation."

[0152]

[0153] As is clear from Table 4, the effect of oxime in inhibiting gelation was also confirmed in the battery mixture for an electrode containing an active material.

[0154] This application claims priority from Japanese Patent Application No. 2024-053653, filed March 28, 2024. The subject matter described in the specification and claims of that application as originally filed is incorporated herein by reference.

[0155] The present invention can suppress gelation of a mixture for producing a solid-state battery and reduce the viscosity thereof, thereby facilitating the production of the solid-state battery.

Claims

1. A battery mixture comprising an oxime, a vinylidene fluoride polymer, and a solid electrolyte.

2. The viscosity of the slurry immediately after adding the non-aqueous solvent (η １ ) relative to the slurry viscosity (η ２ ) value ratio (η ２ / η １ 2. The battery mixture according to claim 1, wherein the value of (a) is 1.00 or less.

3. The battery mixture according to claim 1, wherein the content of the oxime is such that the amount of hydroxyimino groups contained in the oxime per 1 g of the vinylidene fluoride polymer is 6.0 mmol / g or more and 80.0 mmol / g or less.

4. The battery mixture according to claim 1, wherein the content of the oxime is such that the amount of hydroxyimino groups contained in the oxime relative to the solid electrolyte is 2.0 mmol / g or more and 70.0 mmol / g or less.

5. The battery mixture according to claim 1, wherein the vinylidene fluoride polymer contains 80 mol % or more of constituent units derived from vinylidene fluoride relative to all constituent units.

6. A method for adjusting the viscosity of a battery mixture, comprising: preparing a composition containing a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent; and adding an oxime to the composition.

7. The method for adjusting the viscosity of a battery mixture according to claim 6, wherein the oxime is added to the composition in a gel state.

8. A method for producing a battery mixture, comprising: preparing an oxime, a vinylidene fluoride polymer, a solid electrolyte, and a non-aqueous solvent; and mixing the oxime, the vinylidene fluoride polymer, the solid electrolyte, and the non-aqueous solvent.

9. The method for producing a battery mixture according to claim 8, wherein the vinylidene fluoride polymer contains 0.5 wt % or more of a fluorine-containing compound other than vinylidene fluoride.

10. A method for producing a battery component, comprising the steps of applying and drying the battery mixture according to any one of claims 1 to 5, which contains a non-aqueous solvent.

11. The method for producing a battery component according to claim 10, wherein the battery mixture contains an electrode active material.

12. The method for producing a battery component according to claim 10, wherein the battery mixture does not contain an electrode active material.

13. A battery component manufactured by the method of claim 10.

14. A secondary battery comprising the battery component according to claim 13.

15. A battery component comprising an oxime, a vinylidene fluoride polymer, and a solid electrolyte.

16. The battery component according to claim 15, comprising an electrode active material.

17. The battery component according to claim 15, which does not contain an electrode active material.

18. A secondary battery comprising the battery component according to any one of claims 15 to 17.

19. A kit for producing the battery mixture according to any one of claims 1 to 5, in which the oxime and other materials are stored in separate containers.

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