Compositions in powder form based on fluorinated polymers or hydrophilic polymers

Abstract

The present invention relates to a composition, preferably in powder form, comprising monomer units derived from monomer M0, which is vinylidene fluoride, or formula R 1 R 2 C=C(R 3 ) A monomer unit derived from monomer M2 of C(O)R [wherein substituent R 1 , R 2 and R 3 R is independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is H and a C1-C5 alkyl group optionally substituted with one or more -OH groups or a 5-membered or 6-membered heterocycle containing at least one nitrogen atom in its ring chain. 18 The present invention relates to a composition comprising: selected from the group consisting of alkyl groups; or a polymer P1 comprising a mixture of the monomer units M0 or M2; and characterized in that the polymer P1 has a particle size distribution Dv99 of 89 μm or less and a particle size distribution Dv10 of 2.0 μm or more.

Description

[Technical Field]

[0001] This invention generally relates to the field of electrical energy storage in lithium-ion rechargeable secondary batteries. More specifically, the invention relates to compositions that can be used as a coating for separators. [Background technology]

[0002] The market for separators for electrochemical devices is dominated by the use of polyolefins (e.g., Celgard(R) or Hipore(R)) manufactured by extrusion and / or stretching using dry or wet processes. Separators must simultaneously possess thin thickness, optimal affinity for electrolytes, and sufficient mechanical strength and heat resistance. Among the most advantageous alternatives to polyolefins, polymers with better affinity for standard electrolytes have been proposed to reduce the internal resistance of the system, such as poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF), and poly(vinylidene fluoride-hexafluoropropene) (P(VDF-co-HFP)). Another option is to deposit a coating on one or two surfaces of the polyolefin separator. The main evaluation criteria for separator coatings are dry adhesion, wet adhesion, ionic conductivity, and thermal stability.

[0003] Dry adhesion is measured after assembly by pressing or laminating the coated separators with electrodes. This adhesion increases with the temperature and pressure applied after coating. However, it is preferable to use mild pressurization / lamination conditions, i.e., a pressure reduction that avoids / limits pore closure and thus minimizes the impact on ionic conductivity, and a moderate temperature that limits energy consumption to maintain high line speed / productivity.

[0004] The wet adhesion of the coating to the separator is measured after impregnation with the electrolyte. This adhesion decreases as the coating softens with the electrolyte solvent, leading to swelling of the polymers present in the coating, and in some cases even dissolution of the coating. The rate of swelling, dissolution, or loss of integrity is used as the primary indicator of wet adhesion performance.

[0005] Ionic conductivity is a result of porosity and represents the movement of Li ions through the separator and its coating. In aqueous pathway coatings, this porosity corresponds to the gaps between the solid particles constituting the coating, i.e., polymer particles (from latex or powder redispersed in water) and / or ceramic particles. In solvent pathway coatings, this porosity is formed by the phase inversion required before or during drying (e.g., exposure of acetone-based coatings to moisture). Without phase inversion, simple evaporation of the solvent forms a continuous non-porous coating. Guarley permeability is used as the primary indicator of ionic conductivity. In addition to the permeability of the initially coated separator, other aspects may affect ionic conductivity, i.e., interaction with the electrolyte (a slight swelling of the polymer is preferable if it allows for improved wettability / affinity to the electrolyte, and excessive swelling of the polymer is undesirable if it leads to a reduction in pore size / clogging), and the effects of pressing or lamination (reducing pore size / clogging).

[0006] The thermal stability of polyolefin separators alone (PE, PP, or PP / PE / PP multilayer) is low, and they exhibit significant temperature shrinkage. Coatings containing inorganic particles can significantly improve thermal stability.

[0007] Poly(vinylidene fluoride) (PVDF) and its derivatives are advantageous as a major constituent material of separators and as coatings for polyolefin separators because of their electrochemical stability and high dielectric constant which promotes ion dissociation and thus conductivity. The crystallinity of P(VDF-co-HFP) copolymers (copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP)) is lower than that of PVDF. Therefore, an advantage of these P(VDF-co-HFP) copolymers is that they promote conductivity.

[0008] There is still a need to develop a novel coating for separators that is easy to use and has a good compromise between dry adhesiveness, wet adhesiveness, and ionic conductivity.

[0009] Therefore, an object of the present invention is to overcome at least one of the drawbacks of the prior art, that is, to propose a polymer coating for a separator that can prevent swelling or dissolution in one or more electrolyte solvents while maintaining good adhesion properties and good ionic conductivity. SUMMARY OF THE INVENTION

[0010] According to a first aspect, the present invention is a composition, preferably in powder form, comprising monomer units derived from monomer M0 which is vinylidene fluoride, or monomer units derived from monomer M2 of the formula R 1 R 2 C=C(R 3 )C(O)R, [wherein the substituents R 1 , R 2 and R 3 are independently selected from the group consisting of H and C1-C5 alkyl; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR’, and R’ is H and optionally substituted with one or more -OH groups or a 5- or 6-membered heterocyclic ring containing at least one nitrogen atom in its ring chain, C1-C 18The present invention relates to a composition comprising: selected from the group consisting of alkyl groups; or a polymer P1 comprising a mixture of the monomer units M0 or M2; and characterized in that the polymer P1 has a particle size distribution Dv99 of 89 μm or less and a particle size distribution Dv10 of 2.0 μm or more.

[0011] Dv99 is the particle size at the 99th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by laser particle size analysis. Dv10 is the particle size at the 10th percentile (by volume) of the cumulative particle size distribution. This parameter can also be determined by laser particle size analysis. The particle size distribution is measured using a Microtrac S3500 particle size analyzer, with water as the dispersion medium, or in a dry state.

[0012] Particle size has been observed to play a crucial role in obtaining good adhesion, air permeability, or conductivity properties. The polymer P1 according to the present invention has a particle size distribution specifically selected to improve at least one of the above properties. Specifically, if the polymer particles are too large at a low basis weight, the coverage of the separator is excessively low, failing to achieve the desired properties. If the particles are too small, ion movement within the separator becomes insufficient. Also, if the particle size distribution is excessively non-uniform, the adhesion properties are reduced. By specifically selecting the particles of the polymer P1 having the size distribution referred to in this patent application, a separator coating comprising the composition according to the present invention has demonstrated a good compromise between different targeted compositions.

[0013] In a preferred embodiment, the polymer P1 is a copolymer comprising a homopolymer of vinylidene fluoride, or monomer units derived from vinylidene fluoride, and monomer units derived from monomer M1 selected from the group consisting of vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, perfluoroalkyl vinyl ether, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene, and chlorotrifluoropropene, or mixtures thereof; or a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from monomer M2 as defined in this patent application.

[0014] According to a preferred embodiment, the polymer P1 has a particle size distribution Dv90 of 50 μm or less, preferably 46 μm or less.

[0015] According to a preferred embodiment, the monomer M1 is hexafluoropropylene.

[0016] According to a preferred embodiment, the mass content of monomer M1 in polymer P1 is 0.5% to 20% based on the total weight of polymer P1, or the mass content of monomer M2 in polymer P1 is 0.01% to 10% based on the total weight of polymer P1.

[0017] According to a preferred embodiment, the melt viscosity of the polymer P1 is measured at 230°C and 100s according to the standard ASTM D3835. -1 The shear rate is 10kP or higher.

[0018] In a preferred embodiment, the polymer P1 also comprises carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, epoxy, amides, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, and phosphonic acid; preferably, carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, hydroxyl, phosphoric acid, and phosphonic acid.

[0019] According to a preferred embodiment, the polymer P1 has a particle size distribution Dv99 of 89 μm or less and a particle size distribution Dv10 of 2.9 μm or more.

[0020] According to a preferred embodiment, the polymer P1 contains monomer units derived from monomer M2 selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-dodecyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide, lauryl acrylate, n-octyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, ureidomethacrylate, and mixtures thereof.

[0021] According to a preferred embodiment, the polymer P1 does not contain a fluoro-based surfactant.

[0022] In another aspect, the present invention provides a separator comprising the composition according to the present invention.

[0023] According to a preferred embodiment, the separator includes a porous support and the composition according to the present invention, and the composition is deposited on one of the surfaces of the porous support.

[0024] According to another aspect, the present invention provides a lithium-ion secondary battery including an anode, a cathode, and a separator, wherein the separator is according to the present invention.

[0025] According to another aspect, the present invention provides a binder for a lithium-ion battery including the composition according to the present invention.

[0026] According to another aspect, an electrode for a lithium-ion battery including a metal current collector, wherein at least one surface thereof is covered with a layer of a substrate containing an active material and a binder, and the binder is according to the present invention.

[0027] According to another aspect, the present invention provides a lithium-ion secondary battery including an anode, a cathode, and a separator, wherein the anode or the cathode is an electrode according to the present invention.

Mode for Carrying Out the Invention

[0028] According to a first aspect, the present invention provides a composition in powder form including polymer P1.

[0029] Polymer P1 The polymer P1 may include monomer units derived from a monomer M0 which is vinylidene fluoride.

[0030] The polymer P1 has substituents R 1 , R 2 and R 3 which are each independently selected from the group consisting of H and C1-C5 alkyl, of the formula R 1 R 2 C=C(R 3)May contain monomer units derived from monomer M2 of C(O)R [wherein R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is a C1-C that is optionally substituted with H and one or more -OH groups or a 5 or 6-membered heterocycle containing at least one nitrogen atom in its ring chain]. 18 [Selected from the group consisting of alkyl groups]. The polymer P1 may contain a mixture of the monomer units M0 and M2.

[0031] The heterocycle may be saturated, unsaturated, or aromatic. The heterocycle may be monocyclic or bicyclic. The heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxyindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone ring. The heterocycle may be substituted with one or more C1-C5 alkyl groups. As described above, C1-C 18 The alkyl group is optionally substituted on the heterocycle. The latter can be bonded to the alkyl chain via a nitrogen atom or any other atom forming the heterocycle. Preferably, the heterocycle is 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone.

[0032] The monomer M2 is of formula R 1 R 2 C=C(R 3 )C(O)R, and substituent R 1 , R 2 and R 3 R is independently selected from the group consisting of H and C1-C5 alkyl groups, R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is H and C1-C5 alkyl groups optionally substituted with one or more -OH groups. 18The monomer M2 is selected from the group consisting of alkyl groups or 5- or 10-membered heterocycles containing at least one nitrogen atom in its ring chain. Preferably, the heterocycle is as defined above. In particular, the heterocycle is 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone. Preferably, the substituent R' is selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, n-dodecyl, amyl, isoamyl, hexyl, 2-ethylhexyl, lauryl, n-octyl, hydroxyethyl, hydroxybutyl, hydroxypropyl, and ethyl, substituted with a ureido group. In particular, the monomer M2 is of formula R 1 R 2 C=C(R 3 )C(O)R, with substituent R 1 and R 2 H is R 3 is H or CH3; R is -OR', where R' is selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, hydroxypropyl, hydroxybutyl, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, and 4-imidazolidinone.

[0033] More specifically, the monomer M2 may be acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-dodecyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide, lauryl acrylate, n-octyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, ureidomethacrylate, or mixtures thereof. Among these, monomer M2 having an alkyl group containing 1 to 8 carbon atoms is preferred, and alkyl group containing 1 to 5 carbon atoms is more preferred. The polymer P1 may contain one or more monomer units derived from monomer M2 as defined herein.

[0034] The polymer P1 may contain monomer units derived from monomer M1 that can copolymerize with vinylidene fluoride.

[0035] The comonomers compatible with vinylidene fluoride may be halogenated (fluorinated, chlorinated, or brominated) or non-halogenated. The monomer M1 is vinyl fluoride; trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkyl vinyl) ethers such as perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); monomer of formula CF2=CFOCF2CF(CF3)OCF2CF2X [wherein X is SO2F, CO2H, CH2OH, CH2OCN, or CH2OPO3H]; monomer of formula CF2=CFOCF2CF2SO2F; monomer of formula F(CF2)nCH2OCF=CF2 [wherein n is 1, 2, 3, 4, or 5]; and R 1 CH2OCF=CF2 monomer [wherein R 1 [where m is hydrogen or F(CF2)m, and m is 1, 2, 3, or 4];R 2 OCF=CH2 monomer [wherein R 2[where p is F(CF2)p and p is 1, 2, 3 or 4]; perfluorobutylethylene (PFBE); can be selected from the group consisting of trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3trifluoro-1-propene, or mixtures thereof. Among trifluoropropenes, 3,3,3-trifluoropropene can be mentioned. Among tetrafluoropropenes, 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene can be mentioned. Among pentafluoropropenes, 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene can be mentioned. Chlorofluoroethylene can represent either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene. 1-chloro-1-fluoroethylene isomers are preferred. The chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.

[0036] Advantageously, the monomer M1 may be selected from the group consisting of vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD), perfluorobutylethylene (PFBE), trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, and 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or mixtures thereof.

[0037] Preferably, the monomer M1 can be selected from the group consisting of perfluoro(alkyl vinyl) ethers such as vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), and perfluoro(propyl vinyl) ether (PPVE); perfluorobutylethylene (PFBE), trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, and chlorotrifluoropropene, or mixtures thereof.

[0038] More preferably, the monomer M1 may be selected from the group consisting of vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether, perfluorobutylethylene, trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, and chlorotrifluoropropene, or mixtures thereof.

[0039] In particular, the monomer M1 may be selected from the group consisting of vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, and hexafluoropropylene, or mixtures thereof.

[0040] According to one embodiment, in the polymer P1, the mass content of vinylidene fluoride units is preferably at least 50%, preferably at least 60%, more preferably more than 70%, and particularly more than 80%, based on the total weight of the polymer P1. Therefore, the mass content of the monomer M1 in the polymer P1 is less than 50%, advantageously less than 40%, preferably less than 30%, and more preferably less than 20%, based on the total weight of the polymer P1. According to a preferred embodiment, the mass content of the monomer M1 in the polymer P1 is 0.5% to 20%, advantageously 0.5% to 19%, preferably 0.5% to 18%, more preferably 0.5% to 17%, particularly 0.5% to 16%, and more specifically 0.5% to 15%, based on the total weight of the polymer P1. The mass content of the monomer M1 in the polymer P1 may also be 1% to 20%, advantageously 1% to 19%, preferably 1% to 18%, more preferably 1% to 17%, particularly 1% to 16%, and more specifically 1% to 15%, based on the total weight of the polymer P1. The mass content of the monomer M1 in the polymer P1 may also be 2% to 20%, advantageously 2% to 19%, preferably 2% to 18%, more preferably 2% to 17%, particularly 2% to 16%, and more specifically 2% to 15%, based on the total weight of the polymer P1.

[0041] According to a preferred embodiment, the polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, preferably the mass content of monomer units derived from vinylidene fluoride is at least 50%, preferably at least 60%, more preferably at least 70%, and advantageously at least 80%, based on the total weight of the polymer P1. More specifically, the polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, wherein the mass content of vinylidene fluoride units is greater than 65% and the mass content of hexafluoropropylene units is less than 35%, preferably the polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, wherein the mass content of vinylidene fluoride units is greater than 85% and the mass content of hexafluoropropylene units is less than 15%.

[0042] According to a particular embodiment, polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, wherein the mass content of hexafluoropropylene is 0.5% to 20%, advantageously 0.5% to 19%, preferably 0.5% to 18%, more preferably 0.5% to 17%, particularly 0.5% to 16%, and more specifically 0.5% to 15%, based on the total weight of polymer P1. Advantageously, polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, wherein the mass content of hexafluoropropylene is 1% to 20%, advantageously 1% to 19%, preferably 1% to 18%, more preferably 1% to 17%, particularly 1% to 16%, and more specifically 1% to 15%, based on the total weight of polymer P1. Preferably, polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropylene, wherein the mass content of hexafluoropropylene is 2% to 20%, advantageously 2% to 19%, preferably 2% to 18%, more preferably 2% to 17%, particularly 2% to 16%, and more specifically 2% to 15%, based on the total weight of polymer P1. In particular, in this embodiment, the mass content of vinylidene fluoride units is preferably at least 50%, preferably at least 60%, more preferably more than 70%, and particularly more than 80%, based on the total weight of polymer P1.

[0043] If the polymer P1 has a mass content of at least 50%, preferably at least 60%, more preferably more than 70%, and particularly more than 80% of vinylidene fluoride units, the polymer P1 may also contain the monomer M2 in a mass content of 0.05% to 10% based on the total weight of the polymer P1, and optionally, the monomer M1 may be one of the embodiments detailed above. Preferably, in this embodiment, the monomer M2 is present in a mass content of 0.05% to 5% based on the total weight of the polymer P1, particularly 0.05% to 2%.

[0044] If the polymer P1 contains at least 50% by weight of the monomer M2, it may also contain monomer units derived from the monomer M3. The monomer M3 is (A) Alkenyl compounds containing functional groups, or (B) It may be an alkenyl compound that does not have a functional group.

[0045] Alkenyl compounds (A) containing functional groups include, for example, α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, crotonic acid, and itaconic acid; vinyl ester compounds such as vinyl acetate and vinyl neodecanoate; and amidated compounds such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, and diacetoneacrylamide. The compound includes acrylic acid esters such as 2-hydroxyethyl acrylate, N-dialkylaminoethyl acrylate, glycidyl acrylate, n-dodecyl acrylate, and fluoroalkyl acrylate; and methacrylic acid esters such as dialkylaminoethyl methacrylate, fluoroalkyl methacrylate, 2-hydroxyethyl methacrylate, n-octyl methacrylate, t-butyl methacrylate, glycidyl methacrylate, and ethylene glycol dimethacrylate; maleic anhydride; and alkenyl glycidyl ether compounds such as allyl glycidyl ether. Among these, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, N-methylolacrylamide, N-methylolmethacrylamide, diacetone acrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and allyl glycidyl ether are preferred. These compounds may be used individually or as a mixture of two or more. Alkenyl compounds without functional groups (B) include, for example, conjugated dienes such as 1,3-butadiene and isoprene; divinyl hydrocarbon compounds such as divinylbenzene; and alkenyl cyanides such as acrylonitrile and methacrylonitrile. Among these, preferred compounds are 1,3-butadiene and acrylonitrile. These compounds may be used individually or as a mixture of two or more. It is preferable that functional alkenyl compounds (A) are used in a proportion of less than 50% by weight relative to the weight of polymer P1, and alkenyl compounds without functional groups (B) are used in a proportion of less than 30% by weight relative to the weight of polymer P1.

[0046] As described above, the polymer P1 has a specific particle size distribution. This makes it possible to achieve desired properties and have a good compromise between adhesion and ionic conductivity.

[0047] Therefore, the polymer P1 has a Dv99 particle size distribution of less than 89 μm. Dv99 is the particle size at the 99th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by laser particle size analysis. This applies to all Dv99 values ​​described herein. This particle size distribution is measured using a particle size analyzer and is measured by a dry method of laser diffraction on powder. Advantageously, the polymer P1 has a particle size distribution Dv99 of 85 μm or less, preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, advantageously preferably 55 μm or less, preferentially preferably 50 μm or less, and particularly preferably 45 μm or less.

[0048] The polymer P1 may have a particle size distribution Dv99 of 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, advantageously preferably 17 μm or more, preferably preferably 19 μm or more, particularly preferably 20 μm or more, and more specifically preferably 24 μm or more.

[0049] Therefore, according to a particular embodiment, the polymer P1 has a particle size distribution Dv99 of 89 μm or less, preferably 85 μm or less, more preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, preferably 55 μm or less, preferredly 50 μm or less, particularly preferably 45 μm or less. Also, the polymer P1 has a particle size distribution Dv99 of 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, preferably preferably 17 μm or more, preferredly preferably 19 μm or more, particularly preferably 20 μm or more, more specifically preferably 24 μm or more.

[0050] The polymer P1 may also have a particle size distribution Dv10 of 2.0 μm or larger. Dv10 is the particle size at the 10th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by the laser particle size measurement method as described above. This particle size distribution is also measured using a particle size analyzer and is measured by a dry method of laser diffraction on the powder. This applies to all Dv10 values ​​described herein. The polymer P1 may have a particle size distribution Dv10 of 2.1 μm or larger, advantageously 2.2 μm or larger, preferably 2.3 μm or larger, more preferably 2.4 μm or larger, particularly 2.5 μm or larger, more specifically 2.6 μm or larger, preferably 2.7 μm or larger, advantageously preferably 2.8 μm or larger, preferentially 2.9 μm or larger, and more preferably 3.0 μm or larger. However, it should be noted that if the polymer P1 has a particle size distribution Dv10 of less than 2.9, this will result in a disadvantage in ionic conductivity. Specifically, the pores of the separator support and the pores between the polymer P1 particles tend to become clogged. Therefore, it is preferable to encourage a particle size distribution Dv10 of 3.0 μm or larger.

[0051] The polymer P1 may have a particle size distribution Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, more preferably 3.9 μm or more, and more preferably 4.0 μm or more. The polymer P1 may have a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, more preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0052] Therefore, according to a particular embodiment, the polymer P1 has a particle size distribution Dv10 of 2.0 μm or more, preferably 2.1 μm or more, preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, preferably 2.6 μm or more, preferably 2.7 μm or more, preferably 2.8 μm or more, more preferably 2.9 μm or more, and particularly preferably 3.0 μm or more. The polymer P1 has a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0053] Therefore, according to a particular embodiment, the polymer P1 has a particle size distribution Dv10 of 3.1 μm or more, preferably 3.2 μm or more, preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, preferably 3.9 μm or more, and more preferably 4.0 μm or more. The polymer P1 has a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0054] The polymer P1 may also have a particle size distribution Dv90 of less than 50 μm. Dv90 is the particle size at the 90th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by the laser particle size measurement method as described above. This particle size distribution is also measured using a particle size analyzer and is measured by a dry method of laser diffraction on powder. This applies to all Dv90 values ​​described herein. Advantageously, the polymer P1 has a particle size distribution Dv90 of 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, advantageously preferably 36 μm or less, preferentially preferably 34 μm or less, particularly preferably 32 μm or less, and more specifically preferably 30 μm or less. The polymer P1 may have a particle size distribution Dv90 of 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably 8 μm or more, more preferably 9 μm or more, and preferably 10 μm or more.

[0055] Therefore, according to a particular embodiment, the polymer P1 has a particle size distribution Dv90 of 50 μm or less, preferably 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, preferably preferably 36 μm or less, preferably preferably 34 μm or less, particularly preferably 32 μm or less, and most particularly preferably 30 μm or less. The polymer P1 has a particle size distribution Dv90 of 1 μm or more, preferably 2 μm or more, preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably preferably 8 μm or more, preferably preferably 9 μm or more, and particularly preferably 10 μm or more.

[0056] According to a preferred embodiment, the polymer P1 is Dv99; 89 μm or less, advantageously 85 μm or less, preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, advantageously preferably 55 μm or less, preferably preferably 50 μm or less, particularly preferably 45 μm or less; Dv10 of 2.0 μm or more, preferably 2.1 μm or more, more preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, more preferably 2.6 μm or more, preferably 2.7 μm or more, more preferably 2.8 μm or more, more preferably 2.9 μm or more, particularly preferably 3.0 μm or more; or Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably preferably 3.8 μm or more, more preferably 3.9 μm or more, more preferably 4.0 μm or more; and The particle size distribution Dv90 is 50 μm or less, advantageously 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, advantageously preferably 36 μm or less, preferentially preferably 34 μm or less, particularly preferably 32 μm or less, and more specifically preferably 30 μm or less.

[0057] According to another preferred embodiment, the polymer P1 is Dv99: 89 μm or less, preferably 85 μm or less, more preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, preferably 55 μm or less, preferredly 50 μm or less, particularly preferably 45 μm or less; 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, preferably 17 μm or more, preferredly 19 μm or more, particularly preferably 20 μm or more, more particularly preferably 24 μm or more; Dv10 of 2.0 μm or more, preferably 2.1 μm or more, more preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, preferably 2.6 μm or more, preferably preferably 2.7 μm or more, preferably preferably 2.8 μm or more, more preferably preferably 2.9 μm or more, particularly preferably 3.0 μm or more; or Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, preferably 3.9 μm or more, more preferably 4.0 μm or more; and Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, more specifically 7 μm or less; The particle size distribution Dv90 is 50 μm or less, preferably 48 μm or less, more preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, preferably 36 μm or less, more preferably 34 μm or less, particularly preferably 32 μm or less, and most particularly preferably 30 μm or less; 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably 8 μm or more, more preferably 9 μm or more, and particularly preferably 10 μm or more.

[0058] The polymer P1, when measured according to standard ASTM D3835, was found to be at 230°C and 100s. -1 At a shear rate of 10 kP or more, preferably 12 kP or more, more preferably 14 kP or more, and especially when measured according to standard ASTM D3835, at 230°C and 100 s -1 It may have a melt viscosity of 15 kP or more at a shear rate. Preferably, when polymer P1 contains monomer units M0, at least 50% by weight based on its total weight, and optionally M1, the melt viscosity of polymer P1, when measured according to standard ASTM D3835, is 230°C and 100 s. -1The shear rate is 10 kP or higher. Advantageously, the melt viscosity of polymer P1, when measured according to standard ASTM D3835, is 230°C and 100 s. -1 The shear rate is 12 kP or higher, preferably 14 kP or higher, and more preferably 15 kP or higher. Preferably, when polymer P1 contains monomer units derived from vinylidene fluoride and monomer units derived from hexafluoropropene M1, the melt viscosity of polymer P1 is measured according to standard ASTM D3835 at 230°C and 100 s. -1 The shear rate is 10 kP or higher. Advantageously, the melt viscosity of polymer P1, when measured according to standard ASTM D3835, is 230°C and 100 s. -1 The shear rate is 12kP or higher, preferably 14kP or higher, and more preferably 15kP or higher.

[0059] According to a preferred embodiment, if the polymer P1 contains monomer units M0, at least 50% by weight based on their total weight, and optionally M1, the melt viscosity of the polymer P1 is measured according to standard ASTM D3835 at 230°C and 100s. -1 The shear rate is 40 kP or higher. Advantageously, the melt viscosity of the polymer P1 is 45 kP or higher, preferably 50 kP or higher, more preferably 55 kP or higher, particularly when measured according to standard ASTM D3835 at 230°C for 100 seconds. -1 The shear rate is 60kP or higher.

[0060] According to a particular embodiment, if polymer P1 contains monomer units M0, at least 50% by weight based on their total weight, and optionally M1, polymer P1 contains functional groups that improve adhesion to metals. Thus, polymer P1 may contain carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, epoxy, e.g., glycidyl, amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, and phosphonic acid; preferably, carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, hydroxyl, phosphoric acid, and phosphonic acid; in particular, it may contain monomer units having at least one functional group selected from the group consisting of at least one carboxylic acid, carboxylic acid anhydride, and carboxylic acid ester functional group. The functional groups may be introduced by chemical reaction according to techniques well known to those skilled in the art, and the reaction may be grafting or copolymerization of a monomer having at least one of the functional groups and vinylidene fluoride or a vinyl functional group that can copolymerize with monomer M1. The functional groups may be introduced via transfer agents used in methods for synthesizing polymer P1. The transfer agent may be a polymer having a molar mass of 20,000 g / mol or less and having a functional group selected from the following group: carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, epoxy (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, or phosphonic acid. Acrylic acid oligomers are an example of this type of transfer agent. According to a preferred embodiment, the transfer agent is an acrylic acid oligomer having a molar mass of 20,000 g / mol or less. Alternatively, the functional group may be introduced by an oligomer or polymer compound containing the functional group and mixed with polymer P1. The oligomer or polymer compound may be impregnated with or mixed with polymer P1, or may be closely mixed with it. In this case, the functional group may be derived from a (meth)acrylic acid compound selected from acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, and acryloyloxypropyl succinate.For example, the functional group may be an oligomer or polymer containing monomer units derived from monomers selected from the group consisting of acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, and acryloyloxypropyl succinate. According to one embodiment, the oligomer or polymer has a weight-average molecular weight of 100,000 g / mol or less, preferably less than 80,000 g / mol, preferably less than 60,000 g / mol, more preferably less than 40,000 g / mol, and particularly less than 20,000 g / mol. The weight-average molecular weight is determined by GPC using a Waters 2695e instrument connected to a Wyatt NEON refractometer (7.8 mm inner diameter × 30 cm, 5 μm) with two PL gel mixed C columns and a guard column (7.8 mm inner diameter × 30 cm, 5 μm) under the following conditions: temperature: 35°C; flow rate: 1.0 mL / min; injection volume: 100 μL. The sample is prepared to a concentration of 1 mg / mL in THF. Twelve poly(methyl methacrylate) samples with molecular weights ranging from 535 to 2,210,000 g / mol are used as calibration standards. If the functional group described above is present, its content in polymer P1 is at least 0.01 mol%, preferably at least 0.1 mol%, and 15 mol% or less, preferably 10 mol% or less.

[0061] According to a particular embodiment, if the polymer P1 contains monomer units derived from monomer M2 at a rate of at least 50% by weight based on its total weight, then the polymer P1 has a pH of 1.5–4.0, advantageously 1.6–3.9, preferably 1.7–3.8, more preferably 1.8–3.7, particularly 1.9–3.6, and more specifically 2.0–3.5, measured in water at room temperature. Measure the pH using a Mettler Toledo SevenEasy brand or equivalent pH meter and an InLab Routine Pro electrode. Before calibration, check the cleanliness of the electrode. Wash the electrode with warm soapy water if necessary. Ensure that the pH electrode is always filled with KCl packing solution. Calibrate the device with buffers of pH 10, 7, and 4. For calibration, immerse the electrode in the pH 10 buffer and press it to Cal; once the pH stabilizes, repeat the operation with the pH 7 buffer, then the pH 4 buffer. Rinse the electrode with distilled water and dry it between each buffer. The electrodes are pre-prepared by immersing them in a 0.1 M HCl solution for 1-2 hours before measurement, followed by rinsing with deionized water. To measure the pH, the electrodes are immersed directly in the product for testing and stirred for a few seconds. The measurement is allowed to stand for 15 minutes to stabilize, and the value displayed by the pH meter is read. The measurement is performed at room temperature.

[0062] Preferably, if the polymer P1 contains at least 50% by weight of monomer units derived from monomer M2 based on its total weight, the polymer P1 has a glass transition temperature of 230°C or less. Advantageously, the polymer P1 has a glass transition temperature of 220°C or less, preferably less than 200°C, more preferably less than 180°C, particularly less than 160°C, and more specifically 150°C or less. The glass transition temperatures shown herein are calculated using Fox's formula, which is used to predict the glass transition temperature of random copolymers.

[0063] 1 / Tg,copo≒Σiωi / Tg,i [In the formula, Tg and copo are the glass transition temperatures of the copolymer.] Tg,i are the homopolymer i corresponding to each comonomer. ωi is the mass fraction of monomer i that constitutes this copolymer.

[0064] The mass fraction is expressed without units. The glass transition temperature is expressed in Kelvin. The temperature is then converted to Celsius.

[0065] As described above, polymer P1 does not contain fluoro-based surfactants. Polymer P1 may contain 10 ppm to 2% by weight of a surfactant containing polyethylene glycol or polypropylene glycol units. Preferably, the surfactant has an HLB value of 1 to 20, particularly 1 to 5 or 10 to 15. In particular, the surfactant contains polyethylene glycol segments and polypropylene glycol segments, with an HLB value of 1 to 5 and 5,000 to 10,000 g.mol -1 It has a weight-average molecular weight of . Alternatively, the surfactant comprises polyethylene glycol segment and polypropylene glycol segment, with an HLB value of 10 to 15 and a content of 500 to 2500 g.mol. -1 It has a weight-average molecular weight.

[0066] <Composition> Preferably, the composition according to the present invention comprises, based on the total weight of the composition, at least 50%, advantageously at least 60%, preferably at least 70%, more preferably at least 80%, particularly at least 90%, and more specifically at least 95% of the polymer P1 according to the present invention.

[0067] According to a particular embodiment, if polymer P1 contains monomer units M0, at least 50% by weight based on their total weight, and optionally M1, then the composition is acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-dodecyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide, lauryl acrylate, n-octyl acrylate, hydroxypropyl meth Polymer P2 may optionally contain monomer units derived from monomers selected from the group consisting of droxybutyl acrylate, methyl acrylic acid, methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, and ureidomethacrylate.

[0068] According to a particular embodiment, if polymer P1 contains at least 50% by weight of monomer units M2 based on its total weight, the composition may optionally include polymer P3 comprising monomer units comprising monomer units derived from monomers selected from the group consisting of vinylidene fluoride or monomer M1 as defined in this patent application, or mixtures thereof.

[0069] The polymer P1 can be obtained by emulsion or suspension polymerization according to common techniques known to those skilled in the art. The polymer P1 is generally obtained in the form of a latex, dispersion, or aqueous solution. The compositions according to the present invention can be obtained from a latex containing the polymer P1 through a drying step, followed by a step to achieve a desired size distribution. The drying step can be carried out by atomization or co-atomization, preferably at a temperature of 100°C to 220°C, or by freeze-drying. The powder can also be obtained by grinding techniques, for example, cryogenic grinding, where the mixture is brought to a temperature below room temperature before grinding, for example, by liquid nitrogen. At the end of the powder production process, i.e., after the drying step, the particle size can be adjusted and optimized by selection or screening methods and / or by grinding, granulation, screening, compression, or shearing. One or more of these techniques can be used to achieve a desired size distribution.

[0070] If the composition includes polymer P2 or polymer P3 in addition to polymer P1, the polymers may be mixed in powder form or in aqueous dispersion form and subsequently dried. Polymer P1 may also form interpermeable polymer networks (IPN or semi-IPN) with polymer P2 or polymer P3.

[0071] Preferably, polymers P2 and P3 have the same size distribution as polymer P1. Therefore, polymer P2 or polymer P3 has a particle size distribution Dv99 of less than 89 μm. Dv99 is the particle size at the 99th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by laser particle size analysis. This applies to all Dv99 values ​​described herein. This particle size distribution is measured using a particle size analyzer and is measured by a dry method of laser diffraction on powder. Advantageously, polymer P2 or polymer P3 has a particle size distribution Dv99 of 85 μm or less, preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, advantageously preferably 55 μm or less, preferentially preferably 50 μm or less, particularly preferably 45 μm or less.

[0072] The polymer P2 or polymer P3 may have a particle size distribution Dv99 of 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, advantageously preferably 17 μm or more, preferably preferably 19 μm or more, particularly preferably 20 μm or more, and more specifically preferably 24 μm or more.

[0073] Therefore, according to a particular embodiment, the polymer P2 or polymer P3 has a particle size distribution Dv99 of 89 μm or less, preferably 85 μm or less, more preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, preferably 55 μm or less, preferredly 50 μm or less, particularly preferably 45 μm or less. Also, the polymer P2 or polymer P3 has a particle size distribution Dv99 of 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, preferably preferably 17 μm or more, preferredly preferably 19 μm or more, particularly preferably 20 μm or more, more specifically preferably 24 μm or more.

[0074] The polymer P2 or polymer P3 may also have a particle size distribution Dv10 of 2.0 μm or larger. Dv10 is the particle size at the 10th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by the laser particle size measurement method as described above. This particle size distribution is also measured using a particle size analyzer and is measured by a dry method of laser diffraction on the powder. This applies to all Dv10 values ​​described herein. The polymer P2 or polymer P3 may have a particle size distribution Dv10 of 2.1 μm or larger, advantageously 2.2 μm or larger, preferably 2.3 μm or larger, more preferably 2.4 μm or larger, particularly 2.5 μm or larger, more specifically 2.6 μm or larger, preferably 2.7 μm or larger, advantageously preferably 2.8 μm or larger, preferentially 2.9 μm or larger, and more preferably 3.0 μm or larger.

[0075] The polymer P2 or polymer P3 may have a particle size distribution Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, more preferably 3.9 μm or more, and more preferably 4.0 μm or more. The polymer P2 or polymer P3 may have a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, more preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0076] Therefore, according to a particular embodiment, the polymer P2 or polymer P3 has a particle size distribution Dv10 of 2.0 μm or more, preferably 2.1 μm or more, preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, preferably 2.6 μm or more, preferably 2.7 μm or more, preferably 2.8 μm or more, more preferably 2.9 μm or more, and particularly preferably 3.0 μm or more. The polymer P2 or polymer P3 has a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0077] Therefore, according to a particular embodiment, the polymer P2 or polymer P3 has a particle size distribution Dv10 of 3.1 μm or more, preferably 3.2 μm or more, preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, preferably 3.9 μm or more, and more preferably 4.0 μm or more. The polymer P2 or polymer P3 has a particle size distribution Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, and more specifically 7 μm or less.

[0078] The polymer P2 or polymer P3 may also have a particle size distribution Dv90 of 50 μm or less. Dv90 is the particle size at the 90th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by the laser particle size measurement method as described above. This particle size distribution is also measured using a particle size analyzer and is measured by a dry method of laser diffraction on powder. This applies to all Dv90 values ​​described herein. Advantageously, the polymer P2 or polymer P3 has a particle size distribution Dv90 of 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, advantageously preferably 36 μm or less, preferentially preferably 34 μm or less, particularly preferably 32 μm or less, and more specifically preferably 30 μm or less. The polymer P2 or polymer P3 may have a particle size distribution Dv90 of 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably 8 μm or more, preferably 9 μm or more, and preferably 10 μm or more.

[0079] Therefore, according to a particular embodiment, the polymer P2 or polymer P3 has a particle size distribution Dv90 of 50 μm or less, preferably 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, preferably preferably 36 μm or less, preferably preferably 34 μm or less, particularly preferably 32 μm or less, and most particularly preferably 30 μm or less. The polymer P2 or polymer P3 has a particle size distribution Dv90 of 1 μm or more, preferably 2 μm or more, preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably preferably 8 μm or more, preferably preferably 9 μm or more, and particularly preferably 10 μm or more.

[0080] According to a preferred embodiment, the polymer P2 or the polymer P3 is Dv99; 89 μm or less, advantageously 85 μm or less, preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, advantageously preferably 55 μm or less, preferably preferably 50 μm or less, particularly preferably 45 μm or less; Dv10 of 2.0 μm or more, preferably 2.1 μm or more, more preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, more preferably 2.6 μm or more, preferably 2.7 μm or more, more preferably 2.8 μm or more, more preferably 2.9 μm or more, particularly preferably 3.0 μm or more; or Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably preferably 3.8 μm or more, more preferably 3.9 μm or more, more preferably 4.0 μm or more; and The particle size distribution Dv90 is 50 μm or less, advantageously 48 μm or less, preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, advantageously preferably 36 μm or less, preferentially preferably 34 μm or less, particularly preferably 32 μm or less, and more specifically preferably 30 μm or less.

[0081] According to another preferred embodiment, the polymer P2 or the polymer P3 is Dv99: 89 μm or less, preferably 85 μm or less, more preferably 80 μm or less, more preferably 75 μm or less, particularly 70 μm or less, more specifically 65 μm or less, preferably 60 μm or less, preferably 55 μm or less, preferredly 50 μm or less, particularly preferably 45 μm or less; 5 μm or more, preferably 7 μm or more, more preferably 9 μm or more, particularly 11 μm or more, more specifically 13 μm or more, preferably 15 μm or more, preferably 17 μm or more, preferredly 19 μm or more, particularly preferably 20 μm or more, more particularly preferably 24 μm or more; Dv10 of 2.0 μm or more, preferably 2.1 μm or more, more preferably 2.2 μm or more, more preferably 2.3 μm or more, particularly 2.4 μm or more, more specifically 2.5 μm or more, preferably 2.6 μm or more, preferably preferably 2.7 μm or more, preferably preferably 2.8 μm or more, more preferably preferably 2.9 μm or more, particularly preferably 3.0 μm or more; or Dv10 of 3.1 μm or more, preferably 3.2 μm or more, more preferably 3.3 μm or more, more preferably 3.4 μm or more, particularly 3.5 μm or more, more specifically 3.6 μm or more, preferably 3.7 μm or more, preferably 3.8 μm or more, preferably 3.9 μm or more, more preferably 4.0 μm or more; and Dv10 of 12 μm or less, preferably 11 μm or less, preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm or less, more specifically 7 μm or less; The particle size distribution Dv90 is 50 μm or less, preferably 48 μm or less, more preferably 46 μm or less, more preferably 44 μm or less, particularly 42 μm or less, more specifically 40 μm or less, preferably 38 μm or less, preferably 36 μm or less, more preferably 34 μm or less, particularly preferably 32 μm or less, and most particularly preferably 30 μm or less; 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, more preferably 4 μm or more, particularly 5 μm or more, more specifically 6 μm or more, preferably 7 μm or more, preferably 8 μm or more, more preferably 9 μm or more, and particularly preferably 10 μm or more.

[0082] <Separator> The composition according to the present invention may be used as one of the materials for preparing separators in electrochemical devices. The composition is preferably used in a separator coating. In addition to the composition, the separator coating may contain inorganic particles that help form micropores (gaps between inorganic particles) in the coating. The addition of inorganic particles may also contribute to heat resistance or improve wettability. In one embodiment, the coating contains 50% to 99% by weight of inorganic particles relative to the weight of the coating. These inorganic particles must be electrochemically stable (not oxidized and / or reduced within the range of voltage used). Also, the powdered inorganic material preferably has high ionic conductivity. Low-density materials are preferred over high-density materials because they can reduce the weight of the battery produced. The dielectric constant is preferably 5 or higher. According to one embodiment, the inorganic particles are BaTiO3, Pb(Zr,Ti)O3, Pb 1-x La x Zr y O3(0 <x<1、0<y<1)、PbMg3Nb 2 / 3The material is selected from the group consisting of )3, PbTiO3, hafnia (HfO(HfO2)), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2O3, boehmite (γ-AlO(OH)), Al2O3, TiO2, SiC, ZrO2, boron silicate, BaSO4, nanoclay, or mixtures thereof. In this case, the ratio of polymer P1, and optionally P2 and P3 solids to inorganic particles is 0.5 to 40 parts by weight of solids of the total composition per 60 to 99.5 parts by weight of inorganic particles. Advantageously, the ratio of polymer P1, and optionally P2 and P3 solids to inorganic particles is 0.5 to 35 parts by weight per 65 to 99.5 parts by weight of inorganic particles. Preferably, the ratio of polymer P1, and optionally P2 and P3 solids, to inorganic particles is 0.5 to 30 parts by weight per 70 to 99.5 parts by weight of inorganic particles. The separator coating may optionally contain additives selected from thickeners, pH adjusters, anti-settling agents, surfactants, wetting agents, fillers, defoamers, and transient or non-transient adhesion promoters in an amount of 0% to 15% by weight, preferably 0.1% to 10% by weight, relative to the polymer. The fillers listed as additives here are different from the inorganic particles described above.

[0083] The separator according to the present invention includes the above-described coating, which is optionally disposed on one or both sides of a porous support. In this case, the coating is used to coat the separator support on at least one surface in a single-layer or multi-layer form. There are no particular limitations on the selection of the support coated with the coating of the present invention, as long as it is a porous substrate having pores. The support may consist of a single layer or several distinct layers. If it consists of several layers, the coating according to the present invention is disposed on the outer surface of the support, i.e., the surface that first comes into contact with the electrolyte composition used in the battery. Advantageously, the application of the coating to the support is carried out by an aqueous or solvent route. The porous substrate may be in the form of a membrane or a fibrous fabric. If the porous substrate is fibrous, it may be a nonwoven web that forms a porous web, for example, a web obtained by direct spinning or melt-blown (spunbond or melt-blown type) or electrospinning. Examples of porous substrates useful as supports in the present invention include, but are not limited to, polyolefins, polyethylene terephthalate, polybutylene terephthalate, polyesters, polyacetals, polyamides, polycarbonates, polyimides, polyetheretherketones, polyethersulfones, poly(phenylene oxide), poly(phenylene sulfide), polyethylene naphthalate, or mixtures thereof. However, other heat-resistant engineering plastics may also be used and are not particularly limited. Nonwoven materials made from natural and synthetic materials can also be used as substrates for separators. Porous substrates generally have a thickness of 1 to 50 μm and are typically films obtained by extrusion and stretching (wet or dry method) or cast nonwoven fabric. Porous substrates preferably have a porosity of 5% to 95%. The average size (diameter) of the pores is preferably 0.001 to 50 μm, more preferably 0.01 to 10 μm.

[0084] According to another embodiment, the separator includes a porous support as described above, on which a first layer of inorganic particles as defined in this patent application is deposited. A second layer containing the composition according to the present invention is deposited on the first layer.

[0085] According to an alternative embodiment, the separator does not include a porous support. In this case, the separator consists of the above-described coating and comprises the composition. It is deposited directly onto the cathode or anode of an electrochemical device. The absence of a porous support makes it possible to limit the manufacturing cost and dimensions of the electrochemical device. In this case, the coating replaces the porous support. In this embodiment, the composition preferably has a porosity of 5% to 95%. The separator coating of the present invention has a good compromise of properties for applications of separator coatings, namely good dry and wet adhesion, good preserved integrity, and good resistance to electrolyte solvents with moderate swelling.

[0086] <electrode> The composition may also preferably be used as an electrode binder for a cathode. The electrode comprises the composition of the present invention, a conductive agent, and an active material.

[0087] In a preferred embodiment, the electrode has the following mass composition.

[0088] a. 50% to 99.9%, preferably 50% to 99% active material, b. Conductive agent in an amount of 25% to 0%, preferably 25% to 0.5%. c. 25% to 0.05%, preferably 25% to 0.5%, of the composition according to the present invention. d. At least one additive selected from the group consisting of plasticizers, ionic liquids, dispersants for conductive agents, and flow aids, in an amount of 0% to 5%; the sum of all these percentages is 100%.

[0089] The conductive agent of the electrode consists of one or more materials that can improve conductivity. Some examples include carbon black such as acetylene black or Ketjen black; carbon fibers such as carbon nanotubes, carbon nanofibers, or vapor-grown carbon fibers; and metal powders such as SUS powder or aluminum powder.

[0090] The active material is a material capable of intercepting and deintercepting lithium ions.

[0091] In a preferred embodiment, the electrode is a negative electrode. In particular, in the case of a negative electrode, the active material is a carbon material such as lithium alloy, metal oxide, graphite or hard carbon, silicon, silicon alloy and Li4Ti5O 12 It is selected from the group consisting of the following. The form of the negative electrode active material is not particularly limited, but is preferably particulate.

[0092] In another preferred embodiment, the electrode is the positive electrode. Preferably, in the case of the cathode, the active material is LiCoO2, Li(Ni,Co,Al)O2, Li (1+x) Ni a Mn b Co c (x is a real number greater than or equal to 0, a = 0.8, 0.6, 0.5 or 1 / 3, b = 0.1, 0.2, 0.3 or 1 / 3, c = 0.1, 0.2 or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, Li3NiMn3O3, Li3Fe2(PO4)3, Li3V2(PO4)3, Li 1+x Mn 2-x-y M y LiMn spinel substituted with different elements having a composition represented by O4, where M represents at least one metal selected from Al, Mg, Co, Fe, Ni, and Zn, and x and y independently represent real numbers from 0 to 2, and lithium titanate Li x TiO y x and y independently represent real numbers between 0 and 2, and are selected from the group consisting of metallic lithium phosphate having a composition represented by LiMPO4, and M represents Fe, Mn, Co, or Ni. Furthermore, the surface of each of the above materials can be coated. The coating material is not particularly limited as long as it contains a material that is conductive to lithium ions and can be maintained on the surface of the active material in the form of a coating layer. Examples of coating materials are LiNbO3, Li4Ti5O 12 It also contains Li3PO4. The form of the cathode active material is not particularly limited, but is preferably particulate.

[0093] The electrode may be prepared by a method using or not using a solvent, the method comprising the following steps: A step of mixing an active filler, the composition according to the present invention, a conductive filler, and an optional additive by a method for producing an electrode formulation that can be applied to a metal substrate by a solvent-free method or by a method in the presence of a solvent; A method for obtaining a Li-ion battery electrode that does not use a solvent, or the deposition of the electrode compound onto a metal substrate in the presence of a solvent. Optionally, a solvent evaporation step; and A process of compacting the electrodes by heat treatment (a process of applying a temperature in the range up to 50°C higher than the melting temperature of the polymer without mechanical pressure) and / or thermomechanical treatment such as calendering or thermal compression.

[0094] The term "solvent-free" processing refers to a process that does not require a step to evaporate residual solvent downstream of the deposition process.

[0095] If a solvent is used, it may be water or an organic solvent, particularly a polar organic solvent having a dipole moment greater than 1.5 Debye. Examples of organic solvents include, but are not limited to, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, tetrahydrofuran, dimethyl sulfoxide, acetone, methyl ethyl ketone, cyclohexanone, gamma-butyrolactone, and gamma-valerolactone.

[0096] While not exhaustive, some methods for solvent-free mixing of various components of electrode formulations include stirring, air jet mixing, high shear mixing, V-mixer mixing, screw mixer mixing, double cone mixing, drum mixing, conical mixing, double Z-arm mixing, fluidized bed mixing, planetary mixer mixing, mechanofusion mixing, extrusion mixing, calendering mixing, and grinding mixing.

[0097] Other mixing processes that may be mentioned include mixing options using a liquid such as water, e.g., spray drying (co-spraying or co-spraying) or spraying a liquid containing a binder and / or conductive filler onto a fluidized powder bed of active filler.

[0098] The metal support for the electrode is generally made of aluminum for the cathode and copper for the anode. The metal support may be surface-treated and have a conductive primer with a thickness of 5 μm or more. The support may be a woven or nonwoven fabric made of carbon fiber. The electrode is compacted by heat treatment, by going through an oven, under an infrared lamp, by going through a calender with heated rollers, or by going through a press with a heated plate. Another alternative consists of a two-step process. First, the electrode is heat-treated in an oven, under an infrared lamp, or in contact with a heated plate without pressure. Then, a compression step at ambient temperature or a high temperature is performed by a calender or plate press. This step can adjust the porosity of the electrode and improve its adhesion to the metal substrate. [Examples]

[0099] Three polymer samples, A1, A2, and A3, were tested. The three polymers, A1, A2, and A3, are copolymers of vinylidene fluoride and hexafluoropropylene, containing carboxylic acid functional groups, and were measured according to standard ASTM D3835 at 230°C and standard 100s. -1 It has a melt viscosity of 74.25 kP, measured at a shear rate of . In all three cases, the hexafluoropropylene content is 4.5% by weight. Two other samples, A4 and A5, according to the present invention were prepared. Sample A4 is a copolymer of vinylidene fluoride and 10% hexafluoropropylene, measured at 230°C and 100 s in accordance with standard ASTM D3835. -1It has a melt viscosity of 16.0 kP, measured at a shear rate of 230°C and 100 s. Sample A5 is a copolymer of vinylidene fluoride and 6.1 wt% hexafluoropropylene, and was measured according to standard ASTM D3835 at 230°C and 100 s. -1 It has a melt viscosity of 49.1 kP, measured at a shear rate of .

[0100] The size distribution of the three samples is shown in Table 1 below.

[0101] [Table 1]

[0102] From these three powder samples, separator coatings were prepared according to the following protocol. For each coating, adhesion and Gurley values ​​were measured and reported as a function of the amount of copolymer applied to prepare the separator. In the test performed on sample A1, the application amount was 1.2 g / m². 2 The result was as follows: In the test conducted with sample A2, the application amount was 1.6 g / m². 2 The result was as follows: In the test conducted with sample A3, the application amount was 2.8 g / m². 2 That was the case.

[0103] <Preparation of redispersed powder composition> A powdered sample (100g) and a dispersant (BYK-21486, 2g) are added to a CMC solution (Nippon Paper F04HC, 4.5g in 900g of deionized water). The powder is then dispersed, and optionally, the mixture is deaggregated using a Filmix mixer at 10m / sec and 20°C for 1 hour. A binder (BYK-LPC-22346, 6g) and a wetting agent (BYK-LPX-20990, 1.8g) are then added to the dispersion, and the mixture is homogenized using a magnetic stirrer at 1000rpm for 20 minutes.

[0104] <Measurement of particle size distribution> The specific particle sizes D10, D90, and D99 represent the volume-average values ​​of the 10%, 90%, and 99% of the cumulative volume in the particle size distribution, measured using a Microtrac S3500 Bluewave with water as the dispersion medium. Analysis can be performed directly on the redispersed powder composition. To analyze the powder, follow this protocol: Place 0.5 g of powder into a 100 mL jar containing 2 mL of surfactant (10% Triton X-100) and 60 mL of demineralized water. Stir the mixture with a magnetic stirring bar at 200 rpm for 10 minutes, then stir in an ultrasonic tank for 5 minutes. Analyze the mixture in wet mode using a Microtrac S3500 Bluewave particle size analyzer.

[0105] <Separator coating> Next, this mixture is applied to the Celgard(R)C210 SP separator at a speed of 30 mm / second using a coating bar equipped with a 50 μm opening doctor blade. The coated separator is dried at 60°C for 5 minutes.

[0106] <Inspector> The basis weight of the deposited coating is measured using a precision balance by weighing 24 mm diameter discs cut out by a punch, based on the difference between the coated separator and the bare separator.

[0107] <Dry adhesion> Using a roller press operating at 90°C, 1.5 MPa, and 2.4 m / min, two separator samples are assembled by bringing the coated surfaces into contact. A 22.5 cm strip is cut from this assembly, and one side of it is then attached to an aluminum plate (3 × 10 cm) with double-sided tape. At one end of the sample, the double layer of the separator is peeled off by hand over a distance of approximately 5 mm. The sample is then placed in a 180° tensile test with this portion of the separator peeled off at one jaw and the aluminum plate at the other jaw. The peel strength is measured at 50 mm / min and reported against the width of the sample, normalized by the basis weight of the coating.

[0108] <Gurley measurement> The Gurley permeability of each coated separator is measured (using a Gurley 4110N concentration meter with a 4320EN automatic timer), and then the permeability of the support (measured at 415 seconds / 100cc) is subtracted to obtain the Gurley permeability value of the coating, which is then normalized by the coating basis weight.

[0109] The results are shown in Table 2 below.

[0110] [Table 2]

[0111] As demonstrated by the above examples, the use of the compositions according to the present invention results in improved adhesion while maintaining acceptable ionic conductivity for the intended application. The selection of polymers having a specific size distribution as described in claim 1 offers significant advantages over polymers with excessively high or non-uniform size distributions.

Claims

1. A composition, preferably in powder form, comprising monomer units derived from monomer M0 which is vinylidene fluoride, or a monomer of the formula R １ R ２ C═C(R ３ )C(O)R monomer units derived from monomer M2 [wherein the substituents R １ , R ２ and R ３ are, independently of each other, selected from the group consisting of H and C １ -C ５ alkyl; R is selected from the group consisting of -NHC(CH ３ ) ２ CH ２ C(O)CH ３ or -OR'; R' is H, and C １ -C １８ alkyl optionally substituted with one or more -OH groups or a 5- or 6-membered heterocyclic ring containing at least one nitrogen atom in its ring chain]; or a polymer P1 comprising a mixture of said monomer units M0 or M2; characterized in that the polymer P1 has a particle size distribution Dv99 of 89 μm or less and a particle size distribution Dv10 of 2.0 μm or more.

2. The composition according to claim 1, characterized in that the polymer P1 is a copolymer comprising a homopolymer of vinylidene fluoride, or monomer units derived from vinylidene fluoride, and monomer units derived from monomer M1 selected from the group consisting of vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, perfluoroalkyl vinyl ether, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene, and chlorotrifluoropropene, or mixtures thereof; or a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from monomer M2 as described in claim 1.

3. The composition according to claim 2, characterized in that the monomer M1 is hexafluoropropylene.

4. The composition according to claim 2 or 3, characterized in that the mass content of monomer M1 in polymer P1 is 0.5% to 20% based on the total weight of polymer P1, or the mass content of monomer M2 in polymer P1 is 0.01% to 10% based on the total weight of polymer P1.

5. The melt viscosity of the polymer P1, when measured according to standard ASTM D3835, was 230°C and 100 s. －１ The composition according to any one of claims 2 to 4, characterized in that the shear rate is 10 kP or more.

6. The composition according to any one of claims 2 to 5, wherein the polymer P1 also contains a functional group selected from the group consisting of carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, epoxy, amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, and phosphonic acid; preferably, the composition according to any one of claims 2 to 5.

7. The composition according to any one of claims 2 to 6, characterized in that the polymer P1 has a particle size distribution Dv99 of 89 μm or less and a particle size distribution Dv10 of 2.9 μm or more.

8. The composition according to claim 1, characterized in that the polymer P1 contains monomer units derived from monomer M2 selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-dodecyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide, lauryl acrylate, n-octyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, ureidomethacrylate, and mixtures thereof.

9. The composition according to any one of claims 1 to 8, characterized in that the polymer P1 has a particle size distribution Dv90 of 50 μm or less, preferably 46 μm or less.

10. The composition according to any one of claims 1 to 9, characterized in that the polymer P1 does not contain a fluoro surfactant.

11. A separator comprising the composition according to any one of claims 1 to 9.

12. The separator according to claim 11, comprising a porous support and a composition according to any one of claims 1 to 9, wherein the composition is deposited on one of the surfaces of the porous support.

13. A lithium-ion secondary battery comprising an anode, a cathode, and a separator, wherein the separator is as described in claim 12.

14. A binder for a Li-ion battery comprising the composition according to any one of claims 1 to 9.

15. An electrode for a lithium-ion battery including a metal current collector, wherein at least one surface thereof is covered with a layer of a substrate containing an active substance and a binder, and the binder is as described in claim 14.

16. A lithium-ion secondary battery comprising an anode, a cathode, and a separator, wherein the anode or cathode is the electrode described in claim 15.

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