Elastomer particles for electrochemical device binders, binders for electrochemical devices, binder solutions, electrodes and electrochemical devices

Abstract

To provide elastomer particles for electrochemical device binders that can suppress aggregation and have excellent solubility and moisture removal properties during drying. [Solution] The present invention provides elastomer particles for use as a binder for electrochemical devices, wherein the average particle size is in the range of 1.00 mm to 106.0 mm.

Description

[Technical Field]

[0001] This disclosure relates to elastomer particles for electrochemical device binders, binders for electrochemical devices, binder solutions, electrodes, and electrochemical devices. [Background technology]

[0002] Patent Document 1 describes a binder used in a solid-state battery slurry containing sulfide-based solid electrolyte particles, characterized in that it comprises a polymer having vinylidene fluoride units and at least one copolymer unit (A) selected from the group consisting of monomer units having a structure represented by the following general formula (1) and monomer units having a structure represented by the following general formula (2). General formula (b1):-(CH2-CFRf1)- General formula (b2):-(CHF-CHRf2)- In the formula, Rf1 and Rf2 are linear or branched fluorinated alkyl or fluorinated alkoxy groups having 1 to 12 carbon atoms, and if they have 2 or more carbon atoms, they may contain an oxygen atom between carbon atoms. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2021 / 015229 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present disclosure aims to provide elastomer particles for electrochemical device binders that can suppress aggregation and have excellent solubility and moisture removal properties during drying. [Means for solving the problem]

[0005] According to this disclosure, elastomer particles for use as a binder for electrochemical devices are provided, wherein the average particle size is in the range of 1.00 mm or more and 106.0 mm or less. [Effects of the Invention]

[0006] According to this disclosure, it is possible to provide elastomer particles for electrochemical device binders that can suppress aggregation and have excellent solubility and moisture removal properties during drying. [Modes for carrying out the invention]

[0007] The following describes specific embodiments of this disclosure in detail, but this disclosure is not limited to the embodiments described below.

[0008] (Elastomer particles for use as binders in electrochemical devices) This disclosure relates to elastomer particles (sometimes referred to as "elastomer particles for electrochemical device binders" in this disclosure) used as binders for electrochemical devices. The elastomer particles for electrochemical device binders of this disclosure have an average particle size in the range of 1.00 mm to 106.0 mm. Because the average particle size of the elastomer particles for electrochemical device binders of this disclosure is within the above range, they are less likely to aggregate even when stored at high temperatures for a long time. Therefore, the elastomer particles for electrochemical device binders of this disclosure do not easily increase in average particle size even when stored at high temperatures for a long time, and are easy to handle. Furthermore, because the average particle size of the elastomer particles for electrochemical device binders of this disclosure is within the above range, they can be easily dissolved in solvents such as butyl butyrate used to prepare solutions of electrochemical device binders. Therefore, by using the elastomer particles for electrochemical device binders of this disclosure, for example, a binder solution used to form electrodes of an electrochemical device can be easily prepared. Furthermore, since the average particle size of the elastomer particles for electrochemical device binders of this disclosure is within the above range, they can be easily dried, and the moisture content in the elastomer particles can be easily reduced to a degree that does not easily degrade the solid electrolyte and can produce a battery with excellent battery characteristics.

[0009] The average particle size of the elastomer particles must be within the range of 1.00 mm to 106.0 mm, with a preferred upper limit of 53.00 mm or less, and more preferably 13.20 mm or less. Setting the lower limit of the average particle size of the elastomer particles to 1.00 mm or more can suppress the aggregation of the elastomer particles. In addition, setting the upper limit of the average particle size of the elastomer particles to 106.0 mm or less can improve the solubility of the elastomer particles and their ability to remove moisture during drying.

[0010] In this disclosure, the average particle size of elastomer particles is expressed as a combination of a lower limit and an upper limit. Here, the average particle size of the elastomer particles being within the range of 1.00 mm to 2.00 mm means that, when sieved using metal mesh sieves in accordance with JIS Z 8801-1:2006, the majority of the elastomer particles pass through a sieve with a mesh opening of 2.0 mm, but at least some do not pass through a sieve with a mesh opening of 1.00 mm. In other words, the upper limit of the average particle size is the same as the mesh opening of the smallest sieve among the one or more sieves through which 50% or more of the elastomer particles have been sieved, as described above. The lower limit of the average particle size is the same as the mesh opening of the largest sieve among the one or more sieves through which 50% or more of the elastomer particles have not been sieved, as described above. For example, in this specification, the average particle size of elastomer particles that pass through a sieve with a mesh size of 2.00 mm but do not pass through a sieve with a mesh size of 1.00 mm is expressed as 1.00 mm or more and 2.00 mm or less, and is within the range of 1.00 mm or more and 2.00 mm or less. The average particle size of the elastomer particles is within the range of 1.00 mm to 2.00 mm, that is, the lower limit is 1.00 mm or more and the upper limit is 2.00 mm or less, but there are no particular limitations on the combination of the lower and upper limits. For example, the average particle size of the elastomer particles may be 1.00 mm to 1.18 mm, 1.40 mm to 1.70 mm, 1.40 mm to 2.00 mm, or 1.00 mm to 1.70 mm.

[0011] The shape of the elastomer particles is not particularly limited and may be polyhedral, spherical, ellipsoidal, plate-like, needle-like, columnar, or any other shape as long as it is granular.

[0012] The elastomer particles for electrochemical device binders of this disclosure are less prone to aggregation even when stored at high temperatures for extended periods. In one embodiment, the average particle size of the elastomer particles measured after storing the elastomer particles for electrochemical device binders of this disclosure at 50°C for 24 hours is 1.00 to 106.0 mm, more preferably 5.00 mm or more, even more preferably 10.00 mm or more, even more preferably 80.00 mm or less, and even more preferably 50.00 mm or less.

[0013] The moisture content of the elastomer particles for electrochemical device binders according to this disclosure is preferably 500 ppm by mass or less, more preferably 200 ppm by mass or less, and even more preferably 100 ppm by mass or less. The lower limit is not particularly limited, but may be 1 ppm by mass or more. By having the moisture content of the elastomer particles within the above range, even when the elastomer particles are used in the manufacture of a solid electrolyte battery, the solid electrolyte is less likely to degrade, and a battery with excellent battery characteristics can be obtained.

[0014] The moisture content of elastomer particles can be measured using a Karl Fischer moisture meter in an environment with a dew point of -50°C.

[0015] The elastomer particles for electrochemical device binders of this disclosure readily dissolve in solvents such as butyl butyrate used to prepare solutions of electrochemical device binders. In one embodiment, when elastomer particles equivalent to 20% by mass of the total mass of butyl butyrate and elastomer particles are added to butyl butyrate and stirred at 50°C for 8 hours, all of the elastomer particles dissolve.

[0016] As the elastomer forming the elastomer particles, at least one selected from the group consisting of fluorine-containing elastomers and fluorine-free elastomers can be used.

[0017] As the fluorine-containing elastomer, a fluorine-containing copolymer containing vinylidene fluoride units and fluorinated monomer units (excluding vinylidene fluoride units) is preferred.

[0018] As the fluorinated monomer unit, at least one selected from the group consisting of hexafluoropropylene units, tetrafluoroethylene units, trifluoroethylene units, chlorotrifluoroethylene units, monofluoroethylene units, monomer units represented by general formula (b1), and monomer units represented by general formula (b2) is preferred. General formula (b1):-CH2-CFRf1 -[[-END]] (wherein, Rf 1 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and when having 2 or more carbon atoms, may contain an oxygen atom between carbon-carbon atoms.) General formula (b2): -CHF-CHRf 2 -[[-END]] (wherein, Rf 2 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and when having 2 or more carbon atoms, may contain an oxygen atom between carbon-carbon atoms.)

[0019] General formula (b1): -CH2-CFRf<关于 1 - in, Rf 1 is a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or a linear or branched fluorinated alkoxy group having 1 to 12 carbon atoms. Both the fluorinated alkyl group and the fluorinated alkoxy group may contain an oxygen atom (-O-) between carbon-carbon atoms when having 2 or more carbon atoms.)

[0020] Rf 1 's fluorinated alkyl group may be a partially fluorinated alkyl group in which a part of the hydrogen atoms bonded to the carbon atoms are substituted by fluorine atoms, or a perfluorinated alkyl group in which all of the hydrogen atoms bonded to the carbon atoms are substituted by fluorine atoms. Also, Rf 1 's fluorinated alkyl group may have a hydrogen atom substituted by a substituent other than a fluorine atom, but preferably does not contain a substituent other than a fluorine atom.)

[0021] Rf 1 's fluorinated alkoxy group may be a partially fluorinated alkoxy group in which a part of the hydrogen atoms bonded to the carbon atoms are substituted by fluorine atoms, or a perfluorinated alkoxy group in which all of the hydrogen atoms bonded to the carbon atoms are substituted by fluorine atoms. Also, Rf 1The fluorinated alkoxy group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms.

[0022] Rf 1 The number of carbon atoms is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and particularly preferably 1.

[0023] Rf 1 For example, the general formula is: -(Rf 11 ) m -(O) p -(Rf 12 -O) n -Rf 13 (In the formula, Rf 11 and Rf 12 These are, independently, linear or branched fluorinated alkylene groups having 1 to 4 carbon atoms, Rf 13 The group is preferably a linear or branched fluorinated alkyl group having 1 to 4 carbon atoms, where p is 0 or 1, m is an integer from 0 to 4, and n is an integer from 0 to 4.

[0024] Rf 11 and Rf 12 The fluorinated alkylene group may be a partially fluorinated alkylene group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or it may be a perfluorinated alkylene group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 11 and Rf 12 The fluorinated alkylene group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms. Rf 11 and Rf 12 In each occurrence, they may be the same or different.

[0025] Rf 11Examples of fluorinated alkylene groups include -CHF-, -CF2-, -CH2-CF2-, -CHF-CF2-, -CF2-CF2-, -CF(CF3)-, -CH2-CF2-CF2-, -CHF-CF2-CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2-, -CF2-CF(CF3)-, -C(CF3)2-, -CH2-CF2-CF2-CF2-, -CHF-CF2-CF2-CF2-, -CF2-CF2-CF2-CF2-, -CH(CF3)-CF2-CF2-, -CF(CF3)-CF2-CF2-, and -C(CF3)2-CF2-, among which perfluorinated alkylene groups having 1 or 2 carbon atoms are preferred, and -CF2- is more preferred.

[0026] Rf 12 Examples of fluorinated alkylene groups include -CHF-, -CF2-, -CH2-CF2-, -CHF-CF2-, -CF2-CF2-, -CF(CF3)-, -CH2-CF2-CF2-, -CHF-CF2-CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2-, -CF2-CF(CF3)-, -C(CF3)2-, -CH2-CF2-CF2-CF2-, -CHF-CF2-CF Examples include 2-CF2-, -CF2-CF2-CF2-CF2-, -CH(CF3)-CF2-CF2-, -CF(CF3)-CF2-CF2-, and -C(CF3)2-CF2-, among which perfluorinated alkylene groups having 1 to 3 carbon atoms are preferred, and -CF2-, -CF2CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2- or -CF2-CF(CF3)- are more preferred.

[0027] Rf 13 The fluorinated alkyl group may be a partially fluorinated alkyl group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or a perfluorinated alkyl group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 13 The fluorinated alkyl group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms (for example, reactive functional groups such as -CN, -I, and -Br).

[0028] Rf 13 Examples of fluorinated alkyl groups include -CH2F, -CHF2, -CF3, -CH2-CH2F, -CH2-CHF2, -CH2-CF3, -CHF-CH2F, -CHF-CHF2, -CHF-CF3, -CF2-CH2F, -CF2-CHF2, -CF2-CF3, -CH2-CF2-CH2F, -CHF-CF2-CH2F, -CF2-CF2-CH2F, -CF(CF3)-CH2F, -CH2-CF2-CHF2, -CHF-CF2-CHF2, -CF2-CF2-CHF2, -CF(CF3)-CHF2, -CH2-CF2-CF3, -CHF-CF2-CF 3. Examples include -CF2-CF2-CF3, -CF(CF3)-CF3, -CH2-CF2-CF2-CF3, -CHF-CF2-CF2-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3, -CF(CF3)-CF2-CF3, -C(CF3)2-CF3, and among these, -CF3, -CHF-CF3, -CF2-CHF2, -CF2-CF3, -CF2-CF2-CF3, -CF(CF3)-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3 or -CF(CF3)-CF2-CF3 are preferred.

[0029] For p, 0 is preferable.

[0030] m is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0. Furthermore, when p is 0, it is preferable that m is also 0.

[0031] n is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0.

[0032] The repeating unit represented by the general formula (b1) is: -CH2-CF[-CF3]-, -CH2-CF[-CF2CF3]-, -CH2-CF[-CF2CF2CF3]-, -CH2-CF[-CF2CF2CF2CF3]-, -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CHF-CF3]-, -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CF2-CF3]-, -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CF(CF3)-CF3]-, -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CH(CF3)-CF2-CF3]-, -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CF(CF3)-CF2-CF3]-, -CH2-CF[-OCF2OCF3]-, -CH2-CF[-OCF2CF2CF2OCF3]-, -CH2-CF[-CF2OCF2OCF3]-, -CH2-CF[-CF2OCF2CF2CF2OCF3]-, or -CH2-CF[-O-CF2-CF3]- This is preferable, -CH2-CF[-CF3]-, or -CH2-CF[-CF2-O-CF(CF3)-CF2-O-CHF-CF3]-, This is preferable.

[0033] General formula (b2):-CHF-CHRf 2 -In Rf 2 This refers to a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or a linear or branched fluorinated alkoxy group having 1 to 12 carbon atoms. Both fluorinated alkyl groups and fluorinated alkoxy groups can contain oxygen atoms (-O-) between carbon atoms if they have 2 or more carbon atoms.

[0034] Rf 2 The fluorinated alkyl group may be a partially fluorinated alkyl group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or it may be a perfluorinated alkyl group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 2The fluorinated alkyl group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms.

[0035] Rf 2 The fluorinated alkoxy group may be a partially fluorinated alkoxy group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or it may be a perfluorinated alkoxy group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 2 The fluorinated alkoxy group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms.

[0036] Rf 2 The number of carbon atoms is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and particularly preferably 1.

[0037] Rf 2 For example, the general formula is: -(Rf 21 ) m -(O) p -(Rf 22 -O) n -Rf 23 (In the formula, Rf 21 and Rf 22 These are, independently, linear or branched fluorinated alkylene groups having 1 to 4 carbon atoms, Rf 23 A preferred group is one that is linear or branched, has 1 to 4 carbon atoms, is a fluorinated alkyl group, where p is 0 or 1, m is an integer from 0 to 4, and n is an integer from 0 to 4.

[0038] Rf 21 and Rf 22 The fluorinated alkylene group may be a partially fluorinated alkylene group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or it may be a perfluorinated alkylene group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 21 and Rf22 The fluorinated alkylene group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms. Rf 21 and Rf 22 In each occurrence, they may be the same or different.

[0039] Rf 21 Examples of fluorinated alkylene groups include -CHF-, -CF2-, -CH2-CF2-, -CHF-CF2-, -CF2-CF2-, -CF(CF3)-, -CH2-CF2-CF2-, -CHF-CF2-CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2-, -CF2-CF(CF3)-, -C(CF3)2-, -CH2-CF2-CF2-CF2-, -CHF-CF2-CF2-CF2-, -CF2-CF2-CF2-CF2-, -CH(CF3)-CF2-CF2-, -CF(CF3)-CF2-CF2-, and -C(CF3)2-CF2-, among which perfluorinated alkylene groups having 1 or 2 carbon atoms are preferred, and -CF2- is more preferred.

[0040] Rf 22 Examples of fluorinated alkylene groups include -CHF-, -CF2-, -CH2-CF2-, -CHF-CF2-, -CF2-CF2-, -CF(CF3)-, -CH2-CF2-CF2-, -CHF-CF2-CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2-, -CF2-CF(CF3)-, -C(CF3)2-, -CH2-CF2-CF2-CF2-, -CHF-CF2-CF Examples include 2-CF2-, -CF2-CF2-CF2-CF2-, -CH(CF3)-CF2-CF2-, -CF(CF3)-CF2-CF2-, and -C(CF3)2-CF2-, among which perfluorinated alkylene groups having 1 to 3 carbon atoms are preferred, and -CF2-, -CF2CF2-, -CF2-CF2-CF2-, -CF(CF3)-CF2- or -CF2-CF(CF3)- are more preferred.

[0041] Rf 23The fluorinated alkyl group may be a partially fluorinated alkyl group in which some of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or a perfluorinated alkyl group in which all of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Also, Rf 23 The fluorinated alkyl group may have hydrogen atoms substituted with substituents other than fluorine atoms, but it is preferable that it does not contain substituents other than fluorine atoms (for example, reactive functional groups such as -CN, -I, and -Br).

[0042] Rf 23 Examples of fluorinated alkyl groups include -CH2F, -CHF2, -CF3, -CH2-CH2F, -CH2-CHF2, -CH2-CF3, -CHF-CH2F, -CHF-CHF2, -CHF-CF3, -CF2-CH2F, -CF2-CHF2, -CF2-CF3, -CH2-CF2-CH2F, -CHF-CF2-CH2F, -CF2-CF2-CH2F, -CF(CF3)-CH2F, -CH2-CF2-CHF2, -CHF-CF2-CHF2, -CF2-CF2-CHF2, -CF(CF3)-CHF2, -CH2-CF2-CF3, -CHF-CF2-CF 3. Examples include -CF2-CF2-CF3, -CF(CF3)-CF3, -CH2-CF2-CF2-CF3, -CHF-CF2-CF2-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3, -CF(CF3)-CF2-CF3, -C(CF3)2-CF3, and among these, -CF3, -CHF-CF3, -CF2-CHF2, -CF2-CF3, -CF2-CF2-CF3, -CF(CF3)-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3 or -CF(CF3)-CF2-CF3 are preferred.

[0043] For p, 0 is preferable.

[0044] m is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0. Furthermore, when p is 0, it is preferable that m is also 0.

[0045] n is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0.

[0046] The repeating unit represented by the general formula (b2) is: -CHF-CH[-CF3]-, -CHF-CH[-CF2CF3]-, -CHF-CH[-CF2CF2CF3]-, or -CHF-CH[-CF2CF2CF2CF3]-, This is preferable, -CHF-CH[-CF3]- This is preferable.

[0047] If the fluorinated monomer units do not have reactive functional groups, the fluorinated copolymer may further contain monomer units having reactive functional groups in addition to vinylidene fluoride units and fluorinated monomer units (excluding vinylidene fluoride units). Examples of reactive functional groups include cyano groups, carboxyl groups, alkoxycarbonyl groups, I, Br, -CH2OH, and carbon-carbon double bonds.

[0048] As monomers having reactive functional groups, at least one selected from the group consisting of CF2=CFOCF2CF(CF3)OCF2CF2CN, CF2=CFOCF2CF(CF3)OCF2CF2COOH, CF2=CFOCF2CF2CH2I, CF2=CFOCF2CF(CF3)OCF2CF2CH2I, CH2=CFCF2OCF(CF3)CF2OCF(CF3)CN, CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOH, and CH2=CFCF2OCF(CF3)CF2OCF(CF3)CH2OH is preferred.

[0049] The molar ratio (a / b) of vinylidene fluoride units (a) to fluorinated monomer units (b) in the elastomer is preferably 87 / 13 to 20 / 80, more preferably 84 / 16 or less, even more preferably 82 / 18 or less, even more preferably 50 / 50 or more, and even more preferably 70 / 30 or more. This range is preferred in order to suppress aggregation between elastomers.

[0050] The total content of vinylidene fluoride units and fluorinated monomer units in the elastomer is preferably 99.0 to 100 mol%, more preferably 99.5 mol% or more, even more preferably 99.9 mol% or more, and still more preferably 99.99 mol% or more, relative to the total monomer units. The content of monomer units having reactive functional groups is preferably 0 to 1.0 mol%, more preferably 0.01 mol% or more, more preferably 0.5 mol% or less, even more preferably 0.1 mol% or less, and still still more preferably 0.01 mol% or less, relative to the total monomer units. In one embodiment, the elastomer is a fluorine-containing copolymer consisting only of vinylidene fluoride units and fluorinated monomer units.

[0051] In this disclosure, the monomer content can be measured by NMR spectroscopy. Measurement device: Varian VNMRS400 Resonance frequency: 376.04 (Sfrq) Pulse width: 30° (pw=6.8)

[0052] The glass transition temperature of the fluorine-containing copolymer is preferably 25°C or lower, more preferably 0°C or lower, even more preferably -5°C or lower, and particularly preferably -10°C or lower.

[0053] The glass transition temperature is determined by using a differential scanning calorimeter (Mettler-Toledo DSC822e or Hitachi High-Tech Science X-DSC7000) to obtain a DSC curve by cooling 10 mg of the sample to -75°C and then raising the temperature at 20°C / min. The temperature at which the extension of the baseline before and after the second-order transition of the DSC curve intersects with the tangent line at the inflection point of the DSC curve is defined as the glass transition temperature.

[0054] The Mooney viscosity (ML1+10(121°C)) of the fluorine-containing copolymer at 121°C is preferably 2 or higher, more preferably 5 or higher, even more preferably 10 or higher, and still more preferably 30 or higher.

[0055] Mooney viscosity is a value measured in accordance with ASTM-D1646-15 and JIS K6300-1:2013.

[0056] To ensure good solubility in solvents, the elastomer preferably has a number-average molecular weight (Mn) of 7,000 to 5,000,000, a mass-average molecular weight (Mw) of 10,000 to 1,000,000, and an Mw / Mn ratio of 1.0 to 30.0, and more preferably 1.5 to 25.0. The above number-average molecular weight (Mn), mass-average molecular weight (Mw), and Mw / Mn are values ​​measured by gel permeation chromatography (GPC).

[0057] As a fluorine-free elastomer, a fluorine-free copolymer containing at least two monomer units selected from the group consisting of aromatic vinyl units, conjugated diene units, (meth)acrylic acid ester units, α,β-unsaturated nitrile units, and alkylene units is preferred.

[0058] Examples of aromatic vinyl units include units derived from aromatic vinyl such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, vinyltoluene, and chlorostyrene, with styrene units being preferred.

[0059] Examples of conjugated diene units include units derived from conjugated dienes such as butadiene, isoprene, chloroprene, and 2-chloro-1,3-butadiene, with butadiene units being preferred.

[0060] Examples of (meth)acrylic acid ester units include units derived from (meth)acrylic acid esters such as alkyl (meth)acrylates like methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate, with methyl (meth)acrylate units being preferred.

[0061] Examples of α,β-unsaturated nitrile units include units derived from α,β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, with acrylonitrile being preferred.

[0062] Alkylene units are units obtained by hydrogenating units derived from conjugated dienes such as butadiene, isoprene, chloroprene, and 2-chloro-1,3-butadiene; and units derived from 1-olefin monomers such as ethylene, propylene, 1-butene, and 1-hexene, with units obtained by hydrogenating 1,3-butadiene units being preferred.

[0063] Examples of fluorine-free copolymers include copolymers containing aromatic vinyl units, conjugated diene units, (meth)acrylic acid ester units, and α,β-unsaturated nitrile units; copolymers containing alkylene units and α,β-unsaturated nitrile units; and so on. Examples of fluorine-free copolymers may be styrene-butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NBR).

[0064] (Binding agent for electrochemical devices) The elastomer particles for electrochemical device binders of this disclosure can be suitably used as binders for electrochemical devices. That is, this disclosure includes the use of the above-mentioned elastomer particles as binders for electrochemical devices.

[0065] Electrochemical device binders are used to bond electrode materials together in the electrolyte layer, electrode material layer, etc., of electrochemical devices, or to create a tight bond between the electrode material layer and the current collector. Binding agents are typically used in mixture with a solvent.

[0066] The binder for electrochemical devices of this disclosure may contain a resin material in addition to the elastomer particles for electrochemical device binders described above.

[0067] The solubility parameter (SP value) of the resin material is preferably 5 MPa. 1 / 2 Above 20 MPa 1 / 2 The following, and more preferably 7.5 MPa 1 / 2 The above is true, and more preferably 10 MPa 1 / 2 The above is preferable, and more preferably 19.5 MPa 1 / 2 The following, and more preferably 19 MPa 1 / 2 The following applies: When the solubility parameter (SP value) of the resin material is within the above range, the compatibility with elastomer particles is improved, and an electrolyte layer or electrode material layer in which elastomer particles and resin material are highly dispersed can be obtained.

[0068] As for the resin material, polymethyl methacrylate (SP value = 19.0 MPa) 1 / 2 ), polystyrene (SP value = 19.1 MPa) 1 / 2 ), and polyvinyl butyral (SP value = 18.0 MPa) 1 / 2 At least one selected from the group consisting of ) is preferred.

[0069] When a binder for electrochemical devices contains elastomer particles and resin material, the ratio of elastomer particles to resin material in the binder is preferably 10 / 90 to 99.5 / 0.5 by mass, more preferably 20 / 80 or more, even more preferably 40 / 60 or more, particularly preferably 50 / 50 or more, more preferably 99 / 1 or less, and even more preferably 90 / 10 or less.

[0070] The average particle size of the binder for electrochemical devices is preferably in the range of 1.00 mm to 106.0 mm. The upper limit is more preferably 53.00 mm or less, and even more preferably 13.20 mm or less. By adjusting the average particle size of the binder for electrochemical devices to the above range, aggregation of the binder can be suppressed, even when the binder contains a resin material in addition to elastomer particles, and the solubility of the binder and the moisture removal properties during drying can be improved. The average particle size of the binder can be measured in the same way as the average particle size of the elastomer particles.

[0071] The moisture content of the binder for electrochemical devices is preferably 500 ppm by mass or less, more preferably 200 ppm by mass or less, and even more preferably 100 ppm by mass or less. The lower limit is not particularly limited, but may be 1 ppm by mass or more. By adjusting the moisture content of the binder for electrochemical devices to within the above range, even when the binder for electrochemical devices is used in the manufacture of a solid electrolyte battery, it is possible to obtain a battery with excellent battery characteristics that is less likely to degrade the solid electrolyte.

[0072] (Binding agent solution) The binder solution of this disclosure contains the elastomer particles for electrochemical device binders described above, or the binder for electrochemical devices described above, and a solvent.

[0073] Examples of solvents include water; nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and dimethylformamide; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate, and butyl butyrate; ether solvents such as tetrahydrofuran, dioxane, ethyl cellosolve, methyl cellosolve, diglyme, triglime, dibutyl ether, and anisole; aromatic hydrocarbon solvents such as xylene, toluene, solvent naphtha, and mesitylene; aliphatic hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, and mineral spirits; and mixed solvents thereof.

[0074] When the binder solution of this disclosure is used to form the solid electrolyte layer or electrode material layer of a solid electrolyte battery, it is preferable to use a low-polarity solvent as the solvent. By using a low-polarity solvent, reactions between the solvent and the sulfide-based solid electrolyte are less likely to occur, even in solid electrolyte batteries using sulfide-based solid electrolytes. In this disclosure, a low-polarity solvent is defined as one with a relative permittivity of less than 20 at a frequency of 100 kHz. More preferably, it is less than 10.

[0075] Since the elastomer particles for electrochemical device binders of this disclosure have the average particle size described above, they can be easily dissolved in these low-polarity solvents that can be used when manufacturing solid electrolyte batteries. Therefore, by using the elastomer particles for electrochemical device binders of this disclosure, for example, a binder solution used to form electrodes of an electrochemical device can be easily prepared.

[0076] The solvent preferably contains at least one compound selected from the group consisting of aromatic compounds, ester compounds, aliphatic hydrocarbon compounds, ether compounds, and carbonate compounds. Preferably, it is an aromatic compound or an ester compound, and most preferably an ester compound.

[0077] The low-polarity solvent is not particularly limited and can include n-heptane, n-octane, n-nonane, n-decane, n-butyl ether, dibutyl ether, anisole, diisopentyl ether, ethylbenzene, ethyl acetate, ethyl butyrate, butyl butyrate, propyl propionate, butyl methacrylate, dimethyl carbonate, diethyl carbonate, methylphenyl ether, cyclopentyl methyl ether, ethylene carbonate, diphenyl ether, fluorobenzene, trifluoromethylbenzene, bistrifluoromethylbenzene, benzene, mesitylene, thiol, and the like.

[0078] As a solvent, at least one selected from the group consisting of propyl propionate, butyl methacrylate, ethyl acetate, ethyl butyrate, butyl butyrate, mesitylene, dibutyl ether, n-heptane, and anisole is preferred, with butyl butyrate being more preferred. A mixed solvent using two or more of these is also acceptable.

[0079] The content of the binder for electrochemical devices in the binder solution is preferably 0.1 to 40% by mass, more preferably 1% by mass or more, even more preferably 5% by mass or more, even more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0080] (Electrochemical devices) The elastomer particles for electrochemical device binders, the binder for electrochemical devices, or the binder solution disclosed herein can be used to form the electrolyte layer of an electrochemical device, the electrode material layer of an electrode in an electrochemical device, and so on. The electrode material layer can be prepared, for example, by mixing a binder solution containing elastomer particles for electrochemical device binders or the binder for electrochemical devices with electrode materials such as a conductive additive, a solid electrolyte, and an electrode active material to prepare a slurry, coating the resulting slurry onto a current collector, and drying the resulting coating film. An electrode having the electrode material layer thus obtained can be suitably used as an electrode in an electrochemical device.

[0081] In one embodiment, the slurry contains a conductive additive. Examples of conductive additives include carbon black such as acetylene black and Ketjenblack; carbon fibers such as multi-walled carbon nanotubes, single-walled carbon nanotubes, carbon nanofibers, and vapor-grown carbon fibers (VGCF); and metal powders such as SUS powder and aluminum powder.

[0082] The content of the conductive additive in the slurry is preferably 0.1 to 5% by mass, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0083] Examples of electrochemical devices include batteries such as secondary batteries and capacitors. Batteries may be primary batteries, storage batteries (secondary batteries), or energy storage elements. Batteries may be non-aqueous electrolyte batteries or solid electrolyte batteries. Non-aqueous electrolyte batteries include all batteries that have an electrolyte and a power generation element. Examples of non-aqueous electrolyte batteries include lithium-ion primary batteries, lithium-ion secondary batteries, nickel-metal hydride batteries, lithium-ion capacitors, and electric double-layer capacitors. Solid electrolyte batteries include all batteries that have a solid electrolyte layer.

[0084] (solid electrolyte battery) The elastomer particles for electrochemical device binders, binders for electrochemical devices, and binder solutions of this disclosure can be particularly suitably used to form a solid electrolyte layer or electrode material layer of a solid electrolyte battery.

[0085] The solid electrolyte battery may be a primary battery, a rechargeable battery (secondary battery), or an energy storage element. As the solid electrolyte battery, an all-solid-state lithium-ion secondary battery using an inorganic solid electrolyte is preferred. Examples of solid electrolyte batteries include oxide-based solid batteries and sulfide-based solid batteries. The elastomer particles for electrochemical device binders, the binder for electrochemical devices, and the binder solution of this disclosure are particularly suitable as binders for solid batteries using inorganic solid electrolytes, such as sulfide-based solid batteries. As the sulfide-based solid battery, an all-solid-state lithium-ion secondary battery using a sulfide-based solid electrolyte is preferred.

[0086] A slurry for a solid electrolyte battery can be prepared using the elastomer particles for electrochemical device binders, the binder for electrochemical devices, and the binder solution of this disclosure. The slurry for the solid electrolyte battery contains elastomer particles for electrochemical device binders, the binder for electrochemical devices, or the binder solution, and a solid electrolyte.

[0087] A slurry for solid electrolyte batteries is used to form a layer containing a solid electrolyte. The slurry for solid electrolyte batteries of this disclosure can be used to form a positive electrode material layer containing a solid electrolyte, a solid electrolyte layer containing a solid electrolyte, or a negative electrode material layer containing a solid electrolyte.

[0088] The slurry for solid electrolyte batteries contains a solid electrolyte, preferably an inorganic solid electrolyte. As the solid electrolyte, a solid electrolyte capable of intercalating and releasing metal ions such as lithium ions can be used. Examples of solid electrolytes include sulfide-based solid electrolytes, oxide-based solid electrolytes, and crystalline oxides / oxynitrides. Among these, the slurry for solid electrolyte batteries preferably contains a sulfide-based solid electrolyte.

[0089] The sulfide-based solid electrolyte is not particularly limited as long as it is a solid electrolyte containing sulfur atoms, such as Li2S-P2S5, Li2S-P2S3, Li2S-P2S3-P2S5, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, LiI-Li2S-SiS2-P2S5, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li3PS4-Li4GeS4, Li 3.4 P 0.6 Si 0.4 S4, Li 3.25 P 0.25 Ge 0.76 S4, Li 4-x Ge 1-x P x S4, Li6PS5Cl, etc. can be mentioned.

[0090] As the oxide-based solid electrolyte, LiPON (lithium phosphate oxynitride), Li2O-B2O3-P2O5, Li2O-SiO2, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, La 0.51 Li 0.34 TiO 0.74 , Li3PO4, Li2SiO2, LiSiO4, Li 0.5 La 0.5 TiO3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, etc. can be mentioned.

[0091] As the crystalline oxide·oxynitride, LiI, Li3N, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li3PO (4-3 / 2w) N w (w<1), Li 3.6 Si 0.6 P 0.4 O4, etc. can be mentioned.

[0092] The slurry for solid electrolyte batteries of this disclosure contains a solvent. As the solvent, any of the solvents described above that may be contained in the binder solution of this disclosure can be used, and among these, low-polarity solvents are preferred.

[0093] The slurry for solid electrolyte batteries preferably further contains a conductive additive. Examples of conductive additives include carbon black such as acetylene black and Ketjen black; carbon fibers such as multi-walled carbon nanotubes, single-walled carbon nanotubes, carbon nanofibers, and vapor-grown carbon fibers (VGCF); and metal powders such as SUS powder and aluminum powder.

[0094] The solid electrolyte battery slurry of this disclosure may further contain an electrode active material. The electrode active material may be either a positive electrode active material or a negative electrode active material.

[0095] Examples of positive electrode active materials include LiCoO2, Li(Ni,Co,Al)O2, and Li 1+x Ni 1 / 3 Mn 1 / 3 Co 1 / 3 O2 (where x is a non-negative real number), LiNiO2, LiMn2O4, LiCoMnO4, Li2NiMn3O8, Li3Fe2(PO4)3, Li3V2(PO4)3, Li 1+x Mn 2-x-y M y Heteroatomic-substituted Li-Mn spinel having a composition represented by O4 (where M is at least one metal selected from the group consisting of Al, Mg, Co, Fe, Ni, and Zn, and y is a real number of 0 or more), lithium titanate (Li x TiO y Examples include lithium metal phosphate having a composition represented by LiMPO4 (where M is Fe, Mn, Co, or Ni).

[0096] Among the positive electrode active materials, LiCoO2, Li(Ni,Co,Al)O2, and LiNi are particularly noteworthy. 1 / 3 Mn 1 / 3 Co 1 / 3O2 is preferred. Furthermore, in this disclosure, positive electrode active materials coated on the surface of each of these materials may be used. The coating material usable in this disclosure should contain a substance that has lithium ion conductivity and can maintain the form of a coating layer on the surface of the active material. Examples of coating materials include LiNbO3 and Li4Ti5O. 12 Examples include Li3PO4. The shape of the positive electrode active material is not particularly limited, but a powder form is preferred.

[0097] The average particle size of the positive electrode active material is preferably, for example, 1 to 50 μm, more preferably 1 to 20 μm, and especially 3 to 7 μm. If the average particle size of the positive electrode active material is too small, it may become difficult to handle, and if the average particle size is too large, it may be difficult to obtain a flat positive electrode material layer. The average particle size of the positive electrode active material can be determined, for example, by measuring the particle size of the active material carrier observed with a scanning electron microscope (SEM) and averaging the results.

[0098] Examples of negative electrode active materials include carbonaceous materials such as artificial graphite, graphite carbon fiber, resin-calcined carbon, pyrolysis vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-calcined carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon, as well as silicon-containing compounds such as silicon and silicon alloys, and Li4Ti5O 12 Examples include any one of the following, or a mixture of two or more. Among these, materials containing at least a portion of carbonaceous material, or silicon-containing compounds, can be used particularly suitably.

[0099] The binder content in the slurry for solid electrolyte batteries is preferably 0.1 to 15 parts by mass per 100 parts by mass of solid content of the slurry for solid electrolyte batteries.

[0100] The solid content concentration of the slurry for solid electrolyte batteries is preferably 20 to 75% by mass, and more preferably 30 to 70% by mass.

[0101] Methods for preparing a slurry for a solid electrolyte battery include dispersing and mixing a solid electrolyte and optionally an electrode active material in a solution or dispersion obtained by dissolving or dispersing elastomer particles or a binder in a solvent. Alternatively, the elastomer particles or binder and the solid electrolyte may be mixed first, and then the solvent may be added to prepare the slurry for the solid electrolyte battery.

[0102] Solid electrolyte battery slurry can be used to form the solid electrolyte layer of a solid electrolyte battery. The solid electrolyte layer can be produced, for example, by coating a transfer sheet with solid electrolyte battery slurry, drying the resulting coating, placing the transfer sheet on the electrode material layer so that the coating surface is in contact with it, pressing it, and then peeling off the transfer sheet.

[0103] Methods for coating solid electrolyte battery slurries onto transfer sheets include spraying, screen printing, doctor blade application, bar coating, roll coating, gravure printing, and die coating. Drying methods include, for example, vacuum drying, heat drying, and vacuum heat drying. There are no specific restrictions on the conditions for vacuum drying and heat drying; they can be set as appropriate.

[0104] Solid electrolyte battery slurry can be used to form electrode material layers such as a positive electrode material layer and a negative electrode material layer. The electrode for the solid electrolyte battery comprises an electrode material layer formed from the solid electrolyte battery slurry described above. The electrode for the solid electrolyte battery can be used as either a positive or negative electrode.

[0105] The electrode may consist only of an electrode material layer formed by the slurry for solid electrolyte batteries described above, or it may consist of a current collector and an electrode material layer formed by the slurry for solid electrolyte batteries described above. The electrode material layer is formed using the slurry for solid electrolyte batteries and may be provided on one side of the current collector or on both sides.

[0106] The thickness of the electrode material layer varies depending on the intended use of the solid electrolyte battery, but is preferably 10 to 250 μm, more preferably 20 to 200 μm, and even more preferably 30 to 150 μm.

[0107] Examples of materials for the current collector include aluminum, stainless steel (SUS), nickel, iron, titanium, chromium, gold, platinum, and zinc, with aluminum and stainless steel (SUS) being preferred. Examples of shapes for the current collector include foil, plate, and mesh, with foil being preferred.

[0108] Electrodes can be manufactured, for example, by coating a current collector with the above-mentioned solid electrolyte battery slurry and drying the resulting coating. Coating methods include spraying, screen printing, doctor blade application, bar coating, roll coating, gravure printing, and die coating. Drying methods include vacuum drying, heat drying, and vacuum heat drying. There are no specific restrictions on the conditions for vacuum drying and heat drying; they can be set as appropriate.

[0109] The coating amount of slurry for solid electrolyte batteries varies depending on the composition of the slurry and the intended use of the electrode, but is generally 5-30 mg / cm³ in dry state. 2 It is approximately as follows. Furthermore, the electrode thickness is not particularly limited, but is generally between 10 and 250 μm.

[0110] In one embodiment of a solid electrolyte battery, the battery comprises a positive electrode material layer, a negative electrode material layer, and a solid electrolyte layer formed between the positive electrode material layer and the negative electrode material layer. In another embodiment of a solid electrolyte battery, the battery comprises a positive electrode comprising a positive electrode material layer and a current collector, a negative electrode comprising a negative electrode material layer and a current collector, and a solid electrolyte layer formed between the positive electrode and the negative electrode. In a solid electrolyte battery, at least one of the positive electrode material layer, the negative electrode material layer, and the solid electrolyte layer is formed from the solid electrolyte battery slurry described above.

[0111] A solid electrolyte battery may be a primary battery, a rechargeable battery (secondary battery), or an energy storage element. As a solid electrolyte battery, an all-solid-state lithium-ion secondary battery using an inorganic solid electrolyte is preferred. Examples of solid electrolyte batteries include oxide-based solid batteries and sulfide-based solid batteries. As a sulfide-based solid battery, an all-solid-state lithium-ion secondary battery using a sulfide-based solid electrolyte is preferred.

[0112] A solid electrolyte battery may include a separator between the positive and negative electrodes. Examples of the separator include porous membranes such as polyethylene and polypropylene, and nonwoven fabrics such as resin nonwoven fabrics such as polypropylene and glass fiber nonwoven fabrics.

[0113] Solid electrolyte batteries may further include a battery case. The shape of the battery case is not particularly limited as long as it can accommodate the positive electrode, negative electrode, solid electrolyte layer, etc., as described above, but examples include cylindrical, prismatic, coin-type, laminated type, etc.

[0114] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0115] <1> According to the first aspect of this disclosure, Elastomer particles for use as a binder for electrochemical devices are provided, wherein the average particle size is in the range of 1.00 mm to 106.0 mm. <2> According to the second aspect of this disclosure, Elastomer particles according to a first aspect are provided, having a water content of 500 ppm by mass or less. <3> According to the third aspect of this disclosure, The elastomer forming the elastomer particles is A fluorine-containing copolymer containing vinylidene fluoride units and fluorinated monomer units (excluding vinylidene fluoride units), The provided elastomer particles are such that the fluorinated monomer unit is at least one selected from the group consisting of hexafluoropropylene units, tetrafluoroethylene units, trifluoroethylene units, chlorotrifluoroethylene units, monofluoroethylene units, monomer units represented by general formula (b1), and monomer units represented by general formula (b2). General formula (b1):-CH2-CFRf 1 - (In the formula, Rf 1 This refers to a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and if it has 2 or more carbon atoms, it may contain an oxygen atom between carbon atoms. General formula (b2):-CHF-CHRf 2 - (In the formula, Rf 2 This refers to a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and if it has 2 or more carbon atoms, it may contain an oxygen atom between carbon atoms. <4> According to the fourth aspect of this disclosure, A third-viewpoint elastomer particle is provided, wherein the molar ratio (a / b) of vinylidene fluoride units (a) to fluorinated monomer units (b) in the elastomer is 87 / 13 to 20 / 80. <5> According to the fifth aspect of this disclosure, The elastomer particles described above are provided, wherein the elastomer forming the elastomer particles is a fluorine-free copolymer containing at least two monomer units selected from the group consisting of aromatic vinyl units, conjugated diene units, (meth)acrylic acid ester units, α,β-unsaturated nitrile units, and alkylene units. <6> According to the sixth aspect of this disclosure, A binder for electrochemical devices containing elastomer particles according to any of the first to fifth aspects is provided. <7> According to the seventh aspect of this disclosure, Furthermore, a binder for electrochemical devices containing a resin material is provided from a sixth perspective. <8> According to the eighth aspect of this disclosure, The solubility parameter (SP value) of the aforementioned resin material is 5-20 MPa 1 / 2 A binder for electrochemical devices is provided from a seventh perspective. <9> According to the ninth aspect of this disclosure, A binder for electrochemical devices is provided in a seventh or eighth aspect, wherein the resin material is at least one selected from the group consisting of polymethyl methacrylate, polystyrene, and polyvinyl butyral. <10> According to the tenth aspect of this disclosure, A binder for electrochemical devices according to any of the sixth to ninth aspects is provided, as well as a binder solution containing a solvent. <11> According to the eleventh aspect of this disclosure, A binder solution according to a tenth aspect is provided, wherein the content of the binder for the electrochemical device is 0.1 to 15% by mass. <12> According to the 12th aspect of this disclosure, A slurry containing a binder solution and a conductive additive according to the 10th or 11th aspect is provided. <13> According to the 13th aspect of this disclosure, A slurry for a solid electrolyte battery is provided, containing a binder solution and a solid electrolyte according to the tenth or eleventh aspect. <14> According to the fourteenth aspect of this disclosure, An electrode is provided comprising an electrode material layer formed from a slurry according to a twelfth or thirteenth aspect. <15> According to the 15th aspect of this disclosure, An electrochemical device is provided that includes electrodes from a 14th perspective. <16> According to the sixteenth aspect of this disclosure, An electrochemical device from a 15th perspective, which is a solid electrolyte battery, is provided. [Examples]

[0116] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to such embodiments.

[0117] (Example 1) In a 3L stainless steel autoclave, add 1500ml of pure water, 0.3001g of CH2=CFCF2OCF(CF3)CF2OCF(CF3)COONH 450% aqueous solution, and C5F 11 6.001 g of COONH 450% aqueous solution was added, the mixture was purged with nitrogen, and slight pressure was applied with vinylidene fluoride (VdF). The mixture was stirred at 600 rpm and the temperature was controlled to 80°C. VdF was then injected to 1.22 MPa, and a mixed monomer solution of VdF and 2,3,3,3-tetrafluoropropene in a molar ratio of 77.2 / 22.8 was injected to 1.501 MPa. Polymerization was started by injecting 0.1 g of ammonium persulfate dissolved in 4 ml of pure water under nitrogen pressure. When 11 g of continuous monomer was reached, 1.6738 g of 1,1,1,2,3,3,3-heptafluoro-2-iodopropane 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, after which 521 g of continuous monomer was added. The gas in the autoclave was then released, and the mixture was cooled to collect 2087 g of dispersion. The solid content of the dispersion was 26.08 mass%. Calcium chloride was added to this dispersion to cause coagulation, and drying yielded 524.3 g of elastomer. The obtained elastomer 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 obtained elastomer was 25, and the glass transition temperature (Tg) was determined to be -14°C by DSC.

[0118] Comparative Example 1 The elastomer (FKM) obtained in Preparation Example 1 was crushed using a rubber chopper and a rotary cutter to obtain elastomer particles. The average particle size of the obtained elastomer particles was measured using the method described later. The average particle size and evaluation results are shown in Table 1.

[0119] Comparative Example 2, Examples 1-4 The elastomer (FKM) obtained in Preparation Example 1 was pulverized in the same manner as in Comparative Example 1 to obtain elastomer particles having the average particle size shown in Table 1. The average particle size and evaluation results are shown in Table 1.

[0120] Example 5 SBR (butadiene-styrene-alkyl methacrylate copolymer, TRD2001, manufactured by JSR) was dried to obtain an elastomer. The obtained elastomer (SBR) was pulverized in the same manner as in Comparative Example 1 to obtain elastomer particles. The average particle size of the elastomer particles was measured by the method described later. The average particle size and evaluation results are shown in Table 1.

[0121] Example 6 NBR (acrylonitrile-butadiene copolymer, Nipol DN101, manufactured by Nippon Zeon Co., Ltd.) was pulverized in the same manner as in Comparative Example 1 to obtain elastomer particles. The average particle size of the elastomer particles was measured by the method described later. The average particle size and evaluation results are shown in Table 1.

[0122] Examples 7-8 The elastomer particles prepared in Example 3 and PMMA:methyl methacrylate polymer (manufactured by Tokyo Chemical Industry Co., Ltd.) as the resin material were weighed in the mass ratio shown in Table 1. These were placed in a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture consisting of elastomer particles and resin material. The average particle size of the obtained mixture was measured by the method described later. The average particle size and evaluation results are shown in Table 1.

[0123] Example 9 NBR (acrylonitrile-butadiene copolymer, Nipol DN101, manufactured by Nippon Zeon Co., Ltd.) and PMMA (methyl methacrylate polymer, manufactured by Tokyo Chemical Industry Co., Ltd.) were weighed in the mass ratios shown in Table 1. These were placed in a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture consisting of elastomer particles and resin material. The average particle size of the obtained mixture was measured by the method described later. The average particle size and evaluation results are shown in Table 1.

[0124] <Average particle size of elastomer particles and mixtures> The average particle size of elastomer particles and mixtures was determined by dry sieving using a metal mesh sieve conforming to JIS Z 8801-1:2019. 200g of the sample (elastomer) was placed in a 20cm diameter mesh sieve and vibrated in one direction within the horizontal plane at an amplitude of approximately 100mm and a rate of approximately 120 reciprocations per minute for 5 minutes.

[0125] Standard sieves with mesh openings of 125.0 mm, 106.0 mm, 90.00 mm, 75.00 mm, 63.00 mm, and 53.00 mm are stacked from top to bottom. The percentage of elastomer particles or mixtures remaining on each sieve is determined in mass%, and the particle size at which this percentage is 50% or more is determined. This value is then taken as the average particle size.

[0126] The material that fell through the 53.00mm sieve was similarly sieved using standard sieves of 45.00mm, 31.50mm, 22.40mm, 16.00mm, 11.20mm, and 8.00mm. The material that fell through the 8.00mm sieve was similarly sieved using standard sieves of 5.60mm, 4.00mm, 2.80mm, 2.00mm, 1.40mm, and 1.00mm.

[0127] <Cohesiveness> 500g of elastomer particles or mixture were placed in a tray (30cm long x 24cm wide x 5cm high), leveled, and stored in a constant temperature bath at 50°C for 24 hours. The average particle size of the elastomer particles or mixture after storage was measured using the method described above. The results are shown in Table 1.

[0128] <Moisture content> 250g of elastomer particles or mixture were placed in a tray (30cm long x 24cm wide x 5cm high), leveled, and vacuum-dried in a vacuum dryer (ADP300, manufactured by Yamato Scientific Co., Ltd.) at 50°C for 48 hours.

[0129] The moisture content of elastomer particles or mixtures after vacuum drying was measured by the following method. A Karl Fischer moisture meter (ADP-511 / MKC-510N, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) with a boat-type moisture vaporizer was used. The moisture was heated to 210°C in the vaporizer and the vaporized moisture was measured. Nitrogen gas was flowed as the carrier gas at a flow rate of 200 mL / min, and the measurement time was 30 minutes. ChemAqua was used as the Karl Fischer reagent. The sample volume was 1.5 g.

[0130] <Solubility Test> Elastomer particles or mixtures were dissolved in butyl butyrate using a planetary mixer at 50°C for 8 hours until the solid content concentration reached 20% by mass, and the solution state was visually inspected. The evaluation criteria were as follows. ◎: Completely dissolved in 4 hours ○: Completely dissolved in 8 hours △: Partially dissolved in 8 hours ×: Insoluble

[0131] (Preparation of slurry for positive electrode) LiNi coated with LiNbO3 as the positive electrode active material 1 / 3 Mn 1 / 3 Co 1 / 3 A slurry was prepared by mixing 70% by mass of O2(NMC), 25% by mass of Li6PS5Cl as a solid electrolyte, 3% by mass of VGCF as a conductive material, and 2% by mass of the elastomer or mixture prepared in the example or comparative example as a binder in butyl butyrate solvent. In Comparative Example 1, the elastomer particles aggregated, making it impossible to weigh and prepare a slurry in that state.

[0132] (Preparation of electrolyte slurry) A slurry was prepared by mixing 90% by mass of Li6PS5Cl as a solid electrolyte with 10% by mass of the elastomer or mixture prepared in the example or comparative example as a binder in butyl butyrate solvent. In Comparative Example 1, the elastomer particles aggregated, making it impossible to weigh and prepare a slurry in that state.

[0133] (Fabrication of the positive electrode) The slurry prepared above for the positive electrode was coated onto the aluminum foil, which served as the positive electrode current collector, using a doctor blade. The mixture was then dried in a vacuum dryer at 120°C for 12 hours, resulting in a positive electrode with a 110 μm thick positive electrode layer formed on the surface of the positive electrode current collector. This active material layer showed no visible problems, demonstrating successful film formation.

[0134] (Preparation of a solid electrolyte layer) The electrolyte slurry prepared above was coated onto a peelable substrate (PET foil) using a doctor blade, and dried in a vacuum dryer at 120°C for 12 hours to form a 40 μm thick solid electrolyte layer on the substrate. This solid electrolyte layer showed no problems upon visual inspection, demonstrating successful film formation.

[0135] (Fabrication of solid-state batteries) After punching out the positive electrode and solid electrolyte layer prepared as described above, the positive electrode and the lithium foil that will become the negative electrode were placed opposite each other, the solid electrolyte layer was sandwiched between them, and the layers were pressed together to create a solid-state secondary battery.

[0136] <Battery evaluation> The solid-state secondary battery manufactured as described above was charged to 4.25V at 45°C using a constant current-constant voltage charge (hereinafter referred to as CC / CV charge) with a current equivalent to 0.33C (0.1C cut-off). Then, it was discharged to 3V with a constant current of 0.33C, and this was considered one cycle. The initial discharge capacity was determined from the discharge capacity of the third cycle. The discharge capacity characteristics per unit mass of the active material (mass discharge capacity characteristics) were then determined using the following formula. • Calculation formula Mass discharge capacity characteristic (mAh / g) = Initial discharge capacity (mAh) / Mass of active material in the positive electrode layer (g) The obtained mass discharge capacity characteristics were ranked using a relative evaluation. Comparative Example 2 was set as 100, and the evaluation was performed according to the following criteria. The results are shown in Table 1. 7:120 or more 6:115 or more and less than 120 5: 110 or more, less than 115 4:105 or more and less than 110 3: 100 or more, less than 105 2:95 or more and less than 100 Less than 1:95

[0137] [Table 1]

Claims

1. Elastomer particles used as binders for electrochemical devices, The elastomer forming the elastomer particles is A fluorine-containing copolymer containing vinylidene fluoride units and fluorinated monomer units (excluding vinylidene fluoride units), The fluorinated monomer unit is at least one selected from the group consisting of hexafluoropropylene units, tetrafluoroethylene units, trifluoroethylene units, chlorotrifluoroethylene units, monofluoroethylene units, monomer units represented by general formula (b1), and monomer units represented by general formula (b2). The water content of the elastomer particles is 1 ppm by mass or more and 500 ppm by mass or less. Elastomer particles having an average particle size in the range of 1.00 mm to 106.0 mm. General formula (b1): -CH 2 -CFRf 1 - (In the formula, Rf 1 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and if it has 2 or more carbon atoms, it may contain an oxygen atom between carbon atoms.) General formula (b2): -CHF-CHRf 2 - (In the formula, Rf 2 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and if it has 2 or more carbon atoms, it may contain an oxygen atom between carbon atoms.)

2. The elastomer particle according to claim 1, wherein the molar ratio (a / b) of vinylidene fluoride units (a) to fluorinated monomer units (b) in the elastomer is 87 / 13 to 20 / 80.

3. The elastomer particles according to claim 1, wherein the elastomer forming the elastomer particles is a fluorine-free copolymer containing at least two monomer units selected from the group consisting of aromatic vinyl units, conjugated diene units, (meth)acrylic acid ester units, α,β-unsaturated nitrile units, and alkylene units.

4. A binder for electrochemical devices containing the elastomer particles described in claim 1.

5. Furthermore, the binder for electrochemical devices according to claim 4, further comprising a resin material.

6. The solubility parameter (SP value) of the aforementioned resin material is 5 to 20 MPa １／２ The binder for electrochemical devices according to claim 5.

7. The binder for electrochemical devices according to claim 5, wherein the resin material is at least one selected from the group consisting of polymethyl methacrylate, polystyrene, and polyvinyl butyral.

8. A binder for an electrochemical device according to claim 4 or 5, and a binder solution containing a solvent.

9. The binder solution according to claim 8, wherein the content of the binder for electrochemical devices is 0.1 to 15% by mass.

10. A slurry containing the binder solution, conductive additive, and electrode active material described in claim 8.

11. A slurry for a solid electrolyte battery containing the binder solution and solid electrolyte described in claim 8.

12. An electrode comprising an electrode material layer formed from the slurry described in claim 10.

13. An electrochemical device comprising the electrode described in claim 12.

14. The electrochemical device according to claim 13, which is a solid electrolyte battery.

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