Anode coating composition

Abstract

The present invention relates to an anode coating composition comprising a polymer and an alkali metal salt having a mass ratio greater than or equal to 0.6.

Description

Title of the invention: Anode coating composition technical field

[0001] The present invention relates to an electrode coating composition. In particular, the present invention relates to a coating composition for protecting an anode, preferably a metallic anode of secondary batteries, as well as its production method. Technological background of the invention

[0002] With the development of mobile electronic devices such as mobile phones and laptops, the demand for rechargeable secondary batteries as a power source for these devices is increasing considerably. The use of secondary batteries as a power source for hybrid electric vehicles (HEVs) and electric vehicles (EVs) is becoming more common. Demand for lithium secondary batteries with high energy density, high discharge voltage, and high efficiency is growing. Current lithium-ion secondary batteries contain a liquid electrolyte based on generally flammable products. Future generations of batteries under development aim to preferentially use electrolytes in solid or near-solid form, which notably allows the use of lithium metal at the negative electrode. The use of lithium metal results in increased energy density.

[0003] In general, secondary lithium-ion batteries include carbon-based materials such as graphite, lithium metal, metals such as tin or silicon or their oxide, alloys including them as the active negative electrode material.

[0004] Until recently, the development of high energy density batteries using lithium as the negative electrode has attracted considerable interest.

[0005] For example, compared to other electrochemical systems with a lithium-inserted carbon negative electrode and a nickel or cadmium electrode, which increase the weight and volume of the negative electrode, lithium metal has the characteristics of low weight and high capacity. It is attracting considerable attention as the active material for the negative electrode of electrochemical batteries. A lithium metal negative electrode, or a negative electrode consisting primarily of lithium metal, offers the possibility of constructing a battery that is lighter and has a higher energy density than conventional batteries. The use of lithium electrodes has therefore increased. However, the use of batteries combining solid electrolytes and a lithium metal electrode has some drawbacks. Lithium metal is a metal that exhibits high reactivity and is difficult to handle. The interface that forms between the anode and the solid electrolyte can be resistive depending on the electrolytes used, which limits battery performance. Lithium dendrites can also form during charge / discharge cycles, leading to a short circuit in the battery when the dendrite passes through the separator and reaches the cathode.

[0006] To limit these problems, the transfer of lithium ions between the solid electrolyte and the lithium metal anode must be easier (implying a low interface resistance) or the flow of lithium ions in the vicinity of the anode must be as homogeneous as possible. Summary of the invention

[0007] According to a first aspect, the present invention relates to a coating composition for a negative electrode comprising at least one PI polymer and at least one SI alkali metal salt characterized in that the mass ratio Sl / Pl is greater than or equal to 0.6; said mass ratio Sl / Pl corresponding to the ratio between the mass of said at least one SI alkali metal salt and the mass of said at least one PI polymer in said composition.

[0008] The applicant has, surprisingly, found that the coating composition as described in the present invention makes it possible to limit the formation of dendrites while maintaining a low interface resistance.

[0009] According to a preferred embodiment, said polymer PI is selected from the group consisting of fluorinated polymer P1A, acrylic polymer PIB, polyethers PIC, vinyl polymers P1D, cellulose-based polymers PIE, polymers comprising a silane functional group PIF; or a mixture of these.

[0010] According to a preferred embodiment, said polymer PI is a P1A polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride.

[0011] According to a preferred embodiment, said polymer PI is a P1A polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a monomer Mla' selected from the group consisting of vinyl fluoride, 1,2-difluoroethylene, hexafluoropropylene, or a mixture thereof.

[0012] According to a preferred embodiment, said alkali metal salt SI is selected from the group consisting of LiCF3SO3, LiPF6, LiClO4, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2CF2CF3)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2CF2CF3), LiN(SO2CF3)(SO2CF2CF3), LiAsF6, LiBF2C2O4, LiNO3, LiPF3(CF2CF3)3, LiTDI, NaCF3SO3, NaPF6, NaC1O4, NaBF4, NaB(C2O4)2, NaN(SO2F)2, NaN(SO2CF3)2, NaN(SO2C2F3)2, NaN(SO2CF2CF3)2, NaN(SO2F)(SO2CF3), NaN(SO2F)(SO2CF2CF3 ), NaN(SO2CF3)(SO2CF2CF3), NaAsF6, NaBF2C2O4, NaNO3, NaPF3(CF2CF3)3, NaTDI, KCF3SO3, KPF6, KC104, KBF4, KB(C2O4)2, KN(SO2F)2, KN(SO2CF3)2, KN(SO2C2F3)2, KN(SO2CF2CF3)2, KN(SO2F)(SO2CF3), KN(SO2F)(SO2CF2CF3), KN(SO2CF3)(SO2CF2 CF3), KAsF6, KBF2C2O4, KNO3, KPF3(CF2CF3)3 and KTDI or a mixture thereof.

[0013] According to a preferred embodiment, said composition comprises at least one plasticizer selected from the group consisting of vinylidene carbonate, fluoroethylene carbonate, 4-fluoro-l,3-dioxolan-2-one, trans-4,5-difluoro-l,3-dioxolan-2-one, ethylene carbonate, propylene carbonate, (2-cyanoethyl)triethoxysilane, 3-methoxypropionitrile, sulfolane, triethylphosphate, γ-butyrolactone, ethers such as polyethylene glycol dimethyl ethers, in particular diethylene glycol dimethyl ether (EG2DME), triethylene glycol dimethyl ether (EG3DME), and tetraethylene glycol dimethyl ether (EG4DME) or ionic liquids.

[0014] According to a preferred embodiment, the mass ratio Sl / Pl is greater than or equal to 0.8, preferably greater than or equal to 1.

[0015] According to another aspect, the present invention relates to a negative electrode comprising an electrochemically active material, optionally deposited on a current collector, said electrochemically active material being coated with said coating composition according to the present invention.

[0016] According to a preferred embodiment, said electrochemically active material is selected from the group consisting of lithium alloy, lithium metal, sodium alloy, potassium alloy, sodium metal and potassium metal.

[0017] According to another aspect, the present invention relates to a negative electrode comprising a current collector coated with said coating composition according to the present invention.

[0018] According to a preferred embodiment, said coating composition has a thickness of less than 10 pm.

[0019] According to another aspect, the present invention relates to a method for preparing an electrode according to the present invention comprising the steps of: a. Preparation of a composition comprising said at least one polymer PI, said at least one alkali metal salt SI and a solvent; b. Deposition of the composition prepared in step a) onto a current collector or onto an electrochemically active material to form an electrode; c. Consolidation of said electrode formed in step b) by heat treatment.

[0020] According to another aspect, the present invention relates to a battery comprising a negative electrode according to the present invention.

[0021] According to a preferred embodiment, said battery is a secondary lithium-ion, sodium-ion or potassium-ion battery.

[0022] According to a preferred embodiment, said battery is an all-solid-state battery. Brief description of the figures

[0023] Fig. 1 represents the total strength of systems obtained with coating compositions according to the invention or comparative compositions. Detailed description of the invention

[0024] As mentioned above, the applicant has found a new electrode coating composition, in particular anode coating, which allows, in addition to limiting the formation of dendrites, maintaining a low resistance at the interface between the anode and the electrolyte, the latter preferably being solid. Composition

[0025] According to a first aspect of the present invention, a coating composition for a negative electrode is provided. This coating composition comprises a PI polymer and an alkali metal salt (SI). Preferably, the mass ratio Sl / Pl is greater than or equal to 0.6. In this application, the mass ratio Sl / Pl is defined as the ratio of the mass of at least one alkali metal salt (SI) to the mass of at least one PI polymer in this composition.

[0026] According to a preferred embodiment, said mass ratio Sl / Pl is greater than or equal to 0.64, advantageously greater than or equal to 0.68, preferably greater than or equal to 0.70, more preferably greater than or equal to 0.74, in particular greater than or equal to 0.78, more particularly greater than or equal to 0.80, preferably greater than or equal to 0.84, advantageously preferred greater than or equal to 0.88, preferably preferred greater than or equal to 0.90, more preferably preferred greater than or equal to 0.94, particularly preferred greater than or equal to 0.98, more particularly preferred greater than or equal to 1.0.

[0027] According to a more preferred embodiment, said mass ratio Sl / Pl is greater than or equal to 1.02, advantageously greater than or equal to 1.04, preferably greater than or equal to 1.06, more preferably greater than or equal to 1.08, in particular greater than or equal to 1.10, more particularly greater than or equal to 1.12, preferably greater than or equal to 1.14, advantageously greater than or equal to 1.16, preferably greater than or equal to 1.18, more preferably greater than or equal to 1.20, particularly greater than or equal to 1.24, more particularly greater than or equal to 1.26. When the mass ratio Sl / Pl is greater or equal to 1.0, it was observed that the interface resistance decreased to a more acceptable level.

[0028] According to a more preferred embodiment, said mass ratio Sl / Pl is greater than or equal to 1.28, advantageously greater than or equal to 1.30, preferably greater than or equal to 1.32, more preferably greater than or equal to 1.34, in particular greater than or equal to 1.36, more particularly greater than or equal to 1.38, preferably greater than or equal to 1.40, advantageously greater than or equal to 1.42, preferably greater than or equal to 1.44, more preferably greater than or equal to 1.45. It has been observed that the interface resistance decreases sharply with increasing mass ratio Sl / Pl. Compared to an uncoated anode, an anode containing the coating composition according to the present invention exhibits low interface resistance as the mass ratio Sl / Pl increases, as demonstrated in the examples.

[0029] PI Polymer

[0030] As mentioned above, the PI polymer is selected from the group consisting of fluorinated polymer P1A, acrylic polymer PIB, polyethers PIC, vinyl polymers P1D, cellulose-based polymers PIE, polymers comprising a silane functional group PIF; or a mixture thereof. In this application, the term alkyl refers to linear or branched alkyl radicals.

[0031] PI A Polymer

[0032] According to a preferred embodiment, said fluorinated polymer P1A comprises in its chain at least monomeric units derived from a fluorinated monomer Mla selected from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.

[0033] Preferably, said fluorinated polymer P1A comprises monomeric units derived from a monomer Mla selected from the group consisting of vinyl fluoride; vinylidene fluoride (VDF); 1,2-difluoroethylene; 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); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2=CFOCF2CF2SO2F; the product of formula F(CF2)nCH2OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R1CH2OCF=CF2 in which R1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the product of formula R2OCF=CH2 in which R2 is F(CF2)p and p is 1, 2, 3 or 4; perfluorobutylethylene (PFBE); trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, and 2-trifluoromethyl-3,3,3-trifluoro-1-propene or a mixture thereof. Among the trifluoropropenes is 3,3,3-trifluoropropne. Examples of tetrafluoropropenes include 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene. Examples of pentafluoropropenes include 1,1,3,3,3-pentafluoropropene and 1,2,3,3,3-pentafluoropropene. Chlorofluoroethylene can refer to either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene. The 1-chloro-1-fluoroethylene isomer is preferred. Chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.

[0034] In particular, said fluorinated polymer P1A comprises at least monomeric units derived from a monomer Mla, namely vinylidene fluoride. The fluorinated polymer P1A may be a homopolymer or a copolymer of vinylidene fluoride.

[0035] According to a particular embodiment, the fluorinated polymer P1A is a vinylidene fluoride homopolymer.

[0036] According to another particular embodiment, the fluorinated polymer P1A is a polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mla' copolymerizable with vinylidene fluoride, or monomeric units derived from a non-fluorinated monomer Mla” or a mixture of the two.

[0037] According to one embodiment, said fluorinated polymer P1A comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mla' selected from the group consisting of vinyl fluoride; 1,2-difluoroethylene; 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); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2 =CFOCF2CF2SO2F; the product of formula F(CF2)nCH2OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R1CH2OCF=CF2 in which R1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the product of formula R2 OCF=CH2 in which R2 is F(CF2)p and p is 1, 2, 3 or 4;perfluorobutyl ethylene (PFBE); trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-; trifluoro-l-propene or a mixture thereof. Preferably, the fluorinated polymer P1A comprises monomeric units derived from a vinylidene fluoride monomer Mla and monomeric units derived from a fluorinated monomer Mla' selected from the group consisting of vinyl fluoride; 1,2-difluoroethylene, hexafluoropropylene; perfluoro(alkyl vinyl)ethers such as perfluoro(methyl vinyl)ether, perfluoro(ethyl vinyl)ether or perfluoro(propyl vinyl)ether; perfluoro(l,3-dioxole); perfluoro(2,2-dimethyl-l,3-dioxole); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2=CFOCF2CF2SO2F; the product of formula F(CF2)nCH2OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R'CH2OCF=CF2 in which R' is hydrogen or F(CF2)z and z is 1, 2, 3 or 4; the product of formula R”OCF=CH2 in which R” is F(CF2)z and z is 1, 2, 3 or 4;trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, or 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or a mixture thereof. In particular, the fluorinated polymer P1A comprises monomeric units derived from a monomer Mla, being vinylidene fluoride, and monomeric units derived from a fluorinated monomer Mla' selected from the group consisting of 1,2-difluoroethylene and hexafluoropropylene, or a mixture thereof. Said polymer P1A may, in particular, be a copolymer of vinylidene fluoride and hexafluoropropene. Preferably, said monomeric units derived from a fluorinated monomer Mla' may be present in a mass content of 1 to 40% based on the total weight of the polymer P1A, advantageously from 3 to 35%, preferably from 3 to 30%, more preferably from 3 to 25%.

[0038] According to another embodiment, said fluorinated polymer P1A comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a non-fluorinated monomer Mla” of formula RaRb C=C(Rc)C(O)Rd in which the substituents Ra, Rb and Rc are independently selected from the group consisting of H and Ci-C5 alkyl; Rd is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -ORd' with Rd' selected from the group consisting of H and Ci-Ci8 alkyl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H, -OC(O)Rd”, -C(O)O-Rd' ' or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its cyclic chain; Rd” being selected from the group consisting of Ci-C6 alkyl or C6-Ci2 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H group(s). Said heterocycle may be saturated or unsaturated or aromatic.The said heterocycle can be monocyclic or bicyclic. The said... The heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, delta-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone ring. This heterocycle may be substituted by one or more C1-C5 alkyl groups. As mentioned above, the alkyl CrCi8 group is optionally substituted by the heterocycle. The heterocycle may be linked to the alkyl chain by the nitrogen atom or any other atom forming the heterocycle. Preferably the heterocycle is 2-pyrrolidone, delta-lactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.The monomer Mla” may be of the formula RaRbC=C(Rc)C(O)R d in which the substituents Ra, Rb and Rc are independently selected from the group consisting of H and Ci-C5 alkyl; Rd is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -ORd' with Rd' selected from the group consisting of H and CrCi8 alkyl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H, -OC(O)Rd”, -C(O)O-Rd” or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its cyclic chain; Rd” being selected from the group consisting of Ci-C6 alkyl or C6-Ci2 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H. Preferably, the heterocycle is as defined above, in particular the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.Preferably, the substituent Rd' 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, ethyl substituted with a ureido group. In particular, said monomer Mla” is of formula RaRbC=C(Rc)C(O)Rd in which the substituents Ra and Rb are H; Rc is H or CH3; Rd is -ORd' with Rd' selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, hydroxypropyl, hydroxybutyl, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.More specifically, said monomer Mla” 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 methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylate of n-butyl, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, . Amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, ureido methacrylate, monomers of formula CH2=CH(CO2CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-CH2CH2CO2H), CH2=CH(CO2CH(CH3)CH2-OC(O)-CH2CH2CO2H), CH2=CH(CO 2CH2CH2-OC(O)-C6H4CO2H), CH2=CH(CO2CH2CH2CH2CH(CO2H)CH2CH2CO2H); and mixtures thereof. Among these, said monomer Mla” with an alkyl group having from 1 to 8 carbon atoms is preferred, and an alkyl group having from 1 to 5 carbon atoms is more preferable. Said fluorinated polymer P1A may comprise one or more monomeric units derived from said monomer Mla” as defined herein. In polymer P1A, said monomeric units derived from said monomer Mla” as defined herein may be present in a molar content of 0.05 to 10%, preferably from 0.1 to 5% by mol.

[0039] According to another embodiment, said fluorinated polymer P1A comprises monomeric units derived from a monomer Mla being vinylidene fluoride, monomeric units derived from a fluorinated monomer Mla', monomeric units derived from a non-fluorinated monomer Mla” of formula RaRbC=C(Rb)C(O)Rd; said monomers Mla' and Mla” being as defined above.For example, said fluorinated polymer P1A comprises monomeric units derived from a monomer Mla being vinylidene fluoride, monomeric units derived from a fluorinated monomer Mla' being hexafluoropropene, and monomeric units derived from a non-fluorinated monomer Mla” selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, the monomers of formula CH2=CH(CO2CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-CH2CH2CO2H), CH2=CH(CO2CH2CH2CH 2-OC(O)-CH2CH2CO2H),CH2=CH(CO2CH(CH3)CH2-OC(O)-CH2CH2CO2H),CH2 =CH(CO2CH2CH2-OC(O)-C6H4CO2H),CH2=CH(CO2CH2CH2CH2CH(CO2H)CH2CH2 CO2H); and mixtures of these.

[0040] In said fluorinated polymer P1A, the mass percentage of monomeric units Mla is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%. Preferably, when the fluorinated monomer Mla is vinylidene fluoride, the mass percentage of vinylidene fluoride monomeric units in said fluorinated polymer P1A is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.

[0041] According to a particular embodiment, the fluorinated polymer P1A can be functionalized in whole or in part, which allows it to improve adhesion to metal. Thus, said fluorinated polymer P1A can comprise monomeric units bearing at least one of the functions selected from the group consisting of carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups such as glycidyl, amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolic, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, phosphonic; preferably at least one carboxylic acid or hydroxyl function.

[0042] The function is introduced by a chemical reaction which may be grafting, or a copolymerization of the fluorinated monomer with a monomer bearing at least one of said functional groups and a vinyl function capable of copolymerizing with the fluorinated monomer, according to techniques well known to those skilled in the art.

[0043] According to one embodiment, the functional group carries a carboxylic acid function which is a (meth)acrylic acid type group selected from acrylic acid, methacrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, hydroxyethylhexyl(meth)acrylate and acryloyloxy propylsuccinate.

[0044] According to one embodiment, the units bearing the carboxylic acid function further comprise a heteroatom selected from oxygen, sulfur, nitrogen and phosphorus.

[0045] According to one embodiment, the functionality is introduced via the transfer agent used during the synthesis process. The transfer agent is a polymer with a molecular mass less than or equal to 20,000 g / mol and bearing functional groups selected from the following: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolic, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, and phosphonic groups. An example of such a transfer agent is acrylic acid oligomers. According to a preferred embodiment, the transfer agent is an acrylic acid oligomer with a molecular mass less than or equal to 20,000 g / mol. Alternatively, the functional group may be introduced by an oligomeric or polymeric compound comprising said functional group and mixed with the fluorinated polymer P1A.The oligomeric or polymeric compound can be impregnated in or mixed with the fluorinated polymer P1A or intimately mixed with it. In this case, the functional group can be derived from a (meth)acrylic acid compound selected from acrylic acid, methacrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, . hydroxybutyl(meth)acrylate, hydroxyethylhexyl(meth)acrylate, and acryloyloxy propylsuccinate. For example, the functional group may be an oligomer or a polymer comprising monomeric units derived from a monomer selected from the group consisting of acrylic acid, methacrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, hydroxyethylhexyl(meth)acrylate, and acryloyloxy propylsuccinate. In one embodiment, said oligomer or polymer has a weight-average molecular mass less than or equal to 100,000 g / mol, advantageously less than 80,000 g / mol, preferably less than 60,000 g / mol, more preferably less than 40,000 g / mol, and in particular less than 20,000 g / mol.The average molecular mass by weight is determined by GPC using a Waters 2695e apparatus coupled with a Wyatt NEON refractometer equipped with two PL Gel mixed C columns and a guard column (7.8 mm ID). x 30 cm, 5 µm) under the following conditions: Temperature: 35°C; flow rate: 1.0 mL / min; injection volume: 100 pL. Samples are prepared at a concentration of 1 mg / ml in THF. Twelve poly(methyl methacrylate) samples with a molecular mass of 535 to 2,210,000 g / mol are used as calibration standards. Said oligomer or polymer is preferably added during the production process of the P1A fluorinated polymer. The functional group content of the PVDF is at least 0.01 mol%, preferably at least 0.1 mol%, and at most 15 mol%, preferably at most 10 mol%.

[0046] Said fluorinated polymer P1A preferably has a high molecular weight. By high molecular weight, as used here, is meant a fluorinated polymer P1A having a molten viscosity greater than 100 Pa.s, preferably greater than 500 Pa.s, more preferably greater than 1000 Pa.s, according to the ASTM D-3835 method measured at 232°C and 100 sec-1.

[0047] The fluorinated polymer P1A used in the invention can be obtained by known polymerization methods such as emulsion or suspension polymerization. According to a preferred embodiment, the fluorinated polymer P1A is prepared by an emulsion polymerization process in the presence of a non-fluorinated surfactant. Thus, the fluorinated polymer P1A may comprise between 10 ppm and 2 wt% of a non-fluorinated surfactant comprising polyethylene glycol or polypropylene glycol units. Preferably, the non-fluorinated surfactant has an HLB value of 1 to 20, in particular an HLB value of 1 to 5 or 10 to 15. In particular, the non-fluorinated surfactant comprises at least one polyethylene glycol segment and at least one polypropylene glycol segment, and has an HLB value of 1 to 5 and a weight-average molecular weight of 5000 to 10000 g.mol-1. Alternatively, said surfactant comprises at least one segment of polyethylene glycol and at least one segment of polypropylene glycol, and has an HLB value of 10 to 15 and a weight-average molecular weight of 500 to 2500 g·mol⁻¹. Said P1A fluorinated polymer may be in the form of a latex, generally having a solids content of 10 to 60% by weight, preferably 10 to 50%, and a weight-average particle size of less than 1 micrometer, preferably less than 1000 nm, preferably less than 800 nm, and more preferably less than 600 nm. The weight-average particle size is generally at least 20 nm, preferably at least 50 nm, and advantageously the average size is in the range of 100 to 400 nm. The polymer particles may form agglomerates with a weight-average size of 1 to 30 micrometers, and preferably 2 to 10 micrometers. Agglomerates can break down into discrete particles during formulation and application to a substrate.

[0048] According to a preferred embodiment, the fluorinated polymer P1A is prepared by a suspension polymerization process. In this type of suspension process, a dispersant is used. The dispersant may be polyvinyl alcohol (PVA) or a compound comprising a cellulose motif such as methylcellulose, hydroxypropylmethylcellulose, or carboxymethylcellulose. The average particle size is between 1 µm and 500 µm, preferably between 10 µm and 500 µm. The average particle size is determined by laser diffraction. A Malvern INSITEC System particle size analyzer is used for the measurement. This measurement is performed in a dry process by laser diffraction on a powder with a focal length of 100 mm.

[0049] Said fluorinated polymer PI A can be in powder form. This is obtained from latex which is subjected, for example, to a drying step and optionally to granulation.

[0050] According to certain embodiments, the vinylidene fluoride contained in said P1A fluorinated polymer is bio-based. The term "bio-based" means "derived from biomass." This improves the polymer's environmental footprint. Bio-based VDF can be characterized by a renewable carbon content, i.e., carbon of natural origin from a biomaterial or biomass, of at least 1 atomic percent as determined by the 14C content according to standard NF EN 16640. The term "renewable carbon" indicates that the carbon is of natural origin and comes from a biomaterial (or biomass), as described below.According to certain embodiments, the bio-carbon content of VDF may be greater than 5%, preferably greater than 10%, preferably greater than 25%, preferably greater than or equal to 33%, preferably greater than 50%, preferably greater than or equal to 66%, preferably greater than 75%, preferably greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, advantageously equal to 100%.

[0051] PIB acrylic polymer

[0052] Said PIB polymer comprises monomeric units derived from a monomer Mlb of formula (I), (II), (III), (IV), (V) or a mixture thereof

[0053] R'R2C=C(R3)((X2)p -CO2R4) (I)

[0054] R5R6C=C(R7)(OC(O)R8) (II)

[0055] R9R10C=CRnC(O)OC(O)CR12=CR13R14 (III)

[0056] in which

[0057] R1, R2 and R3 are independently selected from each other from the group consisting of H, CO2H and alkyl Ci-C5;

[0058] R4 is, independently for each unit n, selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 and -OR25 with R25 selected from the group consisting of H and CrCi8 alkyl optionally substituted by one or more group(s) selected from the group consisting of -OH, -CO2H, SO3H, -OPO32, -C(O)OR25, -OC(O)R25, and a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain;

[0059] R25 is selected from the group consisting of Ci-C5 alkyl and C6-Ci2 aryl substituted by one or more CO2H functional groups;

[0060] X2 is selected from the group consisting of -[-C(O)OC(R26)(R27)C(R28)(R29)-]wr and an alkyl Ci-Cio hydrocarbon group optionally bearing one or more -OH, -CO2H or ester(s) group(s); with wl being an integer from 1 to 50, advantageously from 1 to 25, preferably from 1 to 10, in particular from 1 to 5; R26, R27, R28, R29 are independently of each other, independently for each unit wl, selected from the group consisting of H and alkyl Ci-C5;

[0061] p' is 0 or 1;

[0062] R5, R6 and R7 are independently selected from each other from the group consisting of H and Ci-C5 alkyl;

[0063] R8 is CrC5 alkyl;

[0064] R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 and R24 are independently of each other selected from the group consisting of H and Cr C5 alkyl, preferably selected from the group consisting of H and CH3;

[0065] An ester group(s) as defined in this application is of formula -OC(O)R30 with R30 being C1-C5 alkyl and C6-Ci2 aryl substituted by one or more CO2H functional groups.

[0066] Preferably, said PIB polymer comprises residues of a monomer Mlb of formula (I), (II), (III), (IV) or (V) or a mixture thereof

[0067] in which

[0068] R1, R2 and R3 are independently selected from each other from the group consisting of H, CO2H and alkyl Ci-C5;

[0069] R4 is, independently for each unit n, selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 and -OR25 with R25 selected from the group consisting of H and Ci-Cio alkyl optionally substituted by one or more group(s) selected from the group consisting of -OH, -CO2H, SO3H, -OPO32, -C(O)OR25, -OC(O)R25, and a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain;

[0070] R25' is selected from the group consisting of Ci-C5 alkyl and C6-Ci2 aryl substituted by one or more CO2H functional groups;

[0071] X2 is selected from the group consisting of -[-C(O)OC(R26)(R27)C(R28)(R29 )-]wr and a Ci-C5 alkyl hydrocarbon group optionally bearing one or more -OH, -CO2H or ester(s) group(s); with wl being an integer from 1 to 50, advantageously from 1 to 25, preferably from 1 to 10, in particular from 1 to 5;

[0072] R26, R27, R28, R29 are independently of each other, independently for each wl unit, selected from the group consisting of H and CrC3 alkyl;

[0073] p' is 0 or 1;

[0074] R5, R6 and R7 are independently selected from each other from the group consisting of H and CrC3 alkyl;

[0075] R8 is C1-C5 alkyl;

[0076] R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 and R24 are independently of each other selected from the group consisting of H and Cr C3 alkyl, preferably selected from the group consisting of H and CH3;

[0077] In particular, said PIB polymer comprises residues of a monomer Mlb of formula (I), (II), (III), (IV) or (V) or a mixture thereof

[0078] in which

[0079] R1, R2 and R3 are independently selected from each other from the group consisting of H, CO2H and alkyl Ci-C3;

[0080] R4 is, independently for each unit n, selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 and -OR25 with R25 selected from the group consisting in H and CrCi8 alkyl optionally substituted by one or more group(s) selected from the group consisting of -OH, -CO2H, SO3H, -OPO32, -C(O)OR25, -OC(O)R25, and a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain;

[0081] R25 is selected from the group consisting of C1-C5 alkyl and C6-Ci2 aryl substituted by one or more CO2H functional groups;

[0082] X2 is selected from the group consisting of -[-C(O)OC(R26)(R27)C(R28)(R29)-]wr and a Ci-C5 alkyl hydrocarbon group optionally bearing one or more -OH, -CO2H or ester group(s); with wl being an integer from 1 to 5;

[0083] R26, R27, R28, R29 are independently of each other, independently for each wl unit, selected from the group consisting of H and Ci-C3 alkyl;

[0084] p' is 0 or 1;

[0085] R5, R6 and R7 are independently selected from each other from the group consisting of H and Ci-C3 alkyl;

[0086] R8 is CrC3 alkyl;

[0087] R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 and R24 are independently of each other selected from the group consisting of H and CH3;

[0088] More particularly, said monomer Mlb can be selected from the group consisting of acrylic acid, 2-carboxyethyl acrylate, methacrylic acid, maleic acid, maleic anhydride, methacrylic anhydride, tetrahydrophthalic anhydride, fumaric acid, crotonic acid, itaconic 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 acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, methacrylate hydroxybutyl, 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, ureido methacrylate, ethylene glycol methacrylate phosphate and mixtures thereof.

[0089] Said PIB polymer may have a weight-average molecular mass greater than or equal to 10,000 g / mol, advantageously greater than or equal to 25,000 g / mol, preferably greater than or equal to 50,000 g / mol, more preferably greater than or equal to 100,000 g / mol, in particular greater than or equal to 200,000 g / mol. The mass The molecular weight mean was determined by GPC using a Waters 2695e instrument coupled to a Wyatt NEON refractometer equipped with two PL Gel mixed C columns and a guard column (7.8 mm LD x 30 cm, 5 µm) under the following conditions: Temperature: 35°C; flow rate: 1.0 mL / min; injection volume: 100 pL. Samples were prepared at 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 were used as calibration standards.

[0090] PIC Polyethers

[0091] Said PIC polymer has formula (VI) Y2-([CR30R31]mO)nY1 in which R30 and R31 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, C1-C15 alkyl and C6-Ci2 aryl; n is an integer from 10 to 100000; m is an integer from 1 to 10; Y1 and Y2 are independently of each other selected from the group consisting of H, OH, CrC3 alkyl, Si(X')(X2)(X3) with X1, X2 and X3 selected, independently of each other, from the group consisting of Ci-C3 alkyl and CrC3 alkoxy.

[0092] Preferably, Y1 and Y2 are independently selected from the group consisting of Ci-C3 alkyl, Si(X')(X2)(X3) with X1, X2 and X3 selected independently from the group consisting of CrC3 alkyl and CrC3 alkoxy.

[0093] Preferably, n is an integer from 10 to 75000, advantageously from 10 to 50000, preferably from 10 to 25000, in particular from 10 to 10000, more particularly from 10 to 5000.

[0094] Preferably, m is an integer from 1 to 9, advantageously from 1 to 8, preferably from 1 to 7, more preferably from 1 to 6, in particular from 1 to 5, more particularly from 1 to 4.

[0095] Preferably, R30 and R31 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, Ci-Cio alkyl and C6-Ci2 aryl; advantageously H, CrC8 alkyl and C6-Ci0 aryl; preferably H, Ci-C5 alkyl and C6-C8 aryl; in particular H, CrC3 alkyl and C6 aryl.

[0096] According to a preferred embodiment, said PIC polymer comprises monomeric units derived from a MIC monomer of formula (VI) HO-([CR30R31]mO)nH in which R30 and R31 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, Ci-Cio alkyl and C6-Ci2 aryl; n is an integer from 10 to 50000; m is an integer from 1 to 10. Preferably, said PIC polymer comprises monomeric units derived from a MIC monomer of formula (VI) HO-([CR30R31]mO)nH in which R30 and R31 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, Ci-C5 alkyl and C6-Ci0 aryl; n is an integer from 10 to 25000; m is an integer from 1 to 8. In particular, said PIC polymer comprises monomeric units derived from a MIC monomer of formula (VI) HO-([CR30R31]mO)nH in which R30 and R31 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, Ci-C3 alkyl and C6 aryl; n is an integer from 10 to 5000; m is an integer from 1 to 5.

[0097] P1D vinyl polymers

[0098] Said polymer P1D comprises monomeric units derived from a monomer M1D of formula (VII) R32R33C=CR34(CN) or (VIII) R35R36C=CR37(C(O)NR38R39 ) in which R32, R33, R34, R35, R36, R37, R38, R39 are independently selected from the group consisting of H, CrCi8 alkyl and C6-Ci2 aryl optionally substituted by one or more functional group(s) OH, CO2H, SO3H or PO3H. Advantageously, said P1D polymer comprises monomeric units derived from an M1D monomer of formula (VII) RRC=CR (CN) or (VIII) R35R36C=CR37(C(O)NR38R39) in which R32, R33, R34, R35, R36, R, R, R are independently selected from the group consisting of H, C1-C15 alkyl and C6-Ci0 aryl optionally substituted by one or more OH, CO2H, SO3H or PO3H functional group(s).Preferably, said P1D polymer comprises monomeric units derived from an M1D monomer of formula (VII) R32R33C=CR34(CN) or (VIII) R35R36C=CR37(C(O)NR38R39) wherein R32, R33, R34, R35, R36, R37, R38, R39 are independently selected from the group consisting of H, C1-C10 alkyl and C6 aryl optionally substituted by one or more OH, CO2H, SO3H or PO3H functional group(s).

[0099] According to a preferred embodiment, said polymer P1D comprises monomeric units derived from a monomer M1D of formula (VII) RRC=CR (CN) in which R, R, and R are independently selected from the group consisting of H, C1-C5 alkyl, and C6 aryl. Preferably, said polymer P1D comprises monomeric units derived from a monomer M1D of formula (VII) R32 RC=CR (CN) in which R, R, and R are independently selected from the group consisting of H and C1-C3 alkyl.

[0100] According to another embodiment, said polymer P1D comprises monomeric units derived from a monomer M1D of formula (VIII) R35R36C=CR37(C(O)NR 38R39) in which R35, R36, R37, R38, R39 are independently selected from the group consisting of H, C1-C5 alkyl and C6 aryl optionally substituted by one or more OH, CO2H, SO3H or PO3H functional group(s). Advantageously, said P1D polymer comprises monomeric units derived from an M1D monomer of formula (VIII) R35R36C=CR37(C(O)NR38R39) in which R, R, R, R, R are independently selected from the group consisting of H, Ci-C3 alkyl and C6 aryl optionally substituted by one or more OH, CO2H, SO3H or PO3H functional group(s). According to a particularly preferred embodiment, said polymer P1D is selected from the group consisting of acrylonitrile, N-methylol acrylamide, acrylamide and 2-acrylamido-2-methylpropane sulfonic acid or a mixture thereof.

[0101] Alternatively, said P1D polymer comprises monomeric units derived from an M1D monomer selected from the group consisting of conjugated dienes and vinyl or divinyl aromatic hydrocarbon compounds. For example, said P1D polymer comprises monomeric units derived from an M1D monomer selected from the group consisting of 1,3-butadiene, isoprene, styrene, divinylbenzene, and chloroprene, or a mixture thereof.

[0102] Cellulose-based polymers PIE

[0103] Said PIE polymer may be selected from cellulose and a cellulose derivative. In some embodiments, said PIE polymer is selected from at least one of the following: cellulose, cellulose ester, cellulose ether, cellulose nitrate, carboxyalkylcellulose, and cellulose salt. In some embodiments, said PIE polymer is selected from at least one of the following: cellulose, cellulose acetate, methylcellulose, ethylcellulose, hydroxylpropylcellulose (HPC), hydroxyethylcellulose (HEC), cellulose nitrate, carboxymethylcellulose (CMC), carbethylcellulose, carboxypropylcellulose, carboxyisopropylcellulose, sodium cellulose, sodium cellulose nitrate, and sodium carboxyalkylcellulose. In some embodiments, said PIE polymer may be carboxymethylcellulose (CMC).

[0104] Polymers comprising a silane or siloxane functional group PIF

[0105] Said PIF polymers comprising a silane or siloxane functional group may be of the formula (X7)(X8)(X9)Si-Y1-O([CR40R41]mO)nY2-Si(X4)(X5)(X6) or -[-O-Si(R42)(R43)-]p- in which R40 and R41 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, C1-C15 alkyl and C6-Ci2 aryl; n is an integer from 10 to 100000; m is an integer from 1 to 10; Y1 and Y2 are independently of each other selected from the group consisting of Ci-Ci0 alkyl, Ci-Cio urethane and CrC10 carbonyl; X4, X5, X6, X7, X8, X9 with X4, X5, X6, X7, X8, and X9 selected independently of each other from the group consisting of H, OH, C1-C3 alkyl, and Ci-C3 alkoxy; R42 and R43 are independently of each other, and independently for each p unit, selected from the group consisting of C1-C15 alkyl and C6-C12 aryl; p is an integer from 4 to 100,000. The term C1-C10 urethane refers to a C1-C10 alkyl radical functionalized with an -NH-C(O)- group. The term C1-C10 carbonyl refers to a C1-C10 alkyl radical functionalized with a -C(O)- group.Preferably, said PIF polymers (X7)(X8)(X9)Si-Y1-O([CR40R41]mO)nY2-Si(X4)(X5)(X6) or -[-O-Si(R42)(R43)-]p- wherein R40 and R41 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, C1-C10 alkyl and C6-Ci2 aryl; n is an integer from 10 to 50000; m is an integer from 1 to 5; Y1 and Y2 are independently of each other selected from the group consisting of CrC8 alkyl, CrC8 urethane and CrC8 carbonyl; X4, X5, X6, X7, X8, X9 with X4, X5, X6, X7, X8 and X9 selected, independently of each other, from the group consisting of H, OH, Ci-C3 alkyl and Ci-C3 alkoxy; R42 and R43 are independently of each other, and independently for each unit p, selected from the group consisting of C1-C15 alkyl and C6-Ci2 aryl; p is an integer from 4 to 50000.

[0106] In particular, said PIF polymers (X7)(X8)(X9)Si-Y1-O([CR40R41]mO)nY2-Si(X4)(X5)(X6) or -[-O-Si(R42)(R43)-] in which R40 and R41 are independently of each other, and independently for each unit n and independently for each unit m, selected from the group consisting of H, C1-C10 alkyl and C6-Ci2 aryl; n is an integer from 10 to 10000; m is an integer from 1 to 4; Y1 and Y2 are independently of each other selected from the group consisting of C1-C5 alkyl, C1-C5 urethane and CrC5 carbonyl; X4, X5, X6, X7, X8, X9 with X4, X5, X6, X7, X8 and X9 selected, independently of each other, from the group consisting of H, OH, CrC3 alkyl and Ci-C3 alkoxy; R42 and R43 are independently of each other, and independently for each unit p, selected from the group consisting of C1-C15 alkyl and C6-Ci2 aryl; p is an integer from 4 to 10000.

[0107] Alternatively, said PIF polymers comprising a silane or siloxane functional group may be polymers comprising monomeric units derived from a monomer of formula (R44)(R45)C=C(R46)Si(OR47)3 in which R44, R45 and R46 are independently selected from the group consisting of H and C1-C10 alkyl; R47 is selected from the group consisting of H, C1-C10 alkyl and C6-Ci2 aryl.

[0108] Alternatively, said PIF polymers comprising a silane or siloxane functional group may be polymers comprising an amino silane functional group. Alternatively, said PIF polymers comprising a silane or siloxane functional group may be polymers comprising monomeric units derived from a fluorinated monomer as described herein and a -O-SiR'3 or SiR'3 functional group with R' selected from the group consisting of H, OH, Ci-Cio alkyl, C6-Ci2 aryl, Ci-Cio alkoxy.

[0109] Alkaline metal salt SI

[0110] According to a preferred embodiment, said alkali metal salt SI is selected from the group consisting of LiCF3SO3, LiPF6, LiClO4, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2CF2CF3)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2CF2CF3), LiN(SO2CF3)(SO2CF2CF3), LiAsF6, LiBF2C2O4, LiNO3, LiPF3(CF2CF3)3, LiTDI, NaCF3SO3, NaPF6, NaClO4, NaBF4, NaB(C2O4)2, NaN(SO2F)2, NaN(SO2CF3)2, NaN(SO2C2F3)2, NaN(SO2CF2CF3)2, NaN(SO2F)(SO2CF3), NaN(SO2F)(SO2CF2CF3 ), NaN(SO2CF3)(SO2CF2CF3), NaAsF6, NaBF2C2O4, NaNO3, NaPF3(CF2CF3)3, NaTDI, KCF3SO3, KPF6, KC1O4, KBF4, KB(C2O4)2, KN(SO2F)2, KN(SO2CF3)2, KN(SO2C2F3)2, KN(SO2CF2CF3)2, KN(SO2F)(SO2CF3), KN(SO2F)(SO2CF2CF3), KN(SO2CF3)(SO2CF2 CF3), KAsF6, KBF2C2O4, KNO3, KPF3(CF2CF3)3 and KTDI or a mixture of these.

[0111] Preferably, said alkali metal salt SI is selected from the group consisting of LiCF3SO3, LiPF6, LiClO4, LiBF4, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF2CF3)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2CF2CF3), LiN(SO2CF3)(SO2CF2CF3), LiNO3, LiTDI, NaCF3SO3, NaPF6, NaClO4, NaBF4, NaN(SO2F)2, NaN(SO2CF3)2, NaN(SO2CF 2CF3)2, NaN(SO2F)(SO2CF3), NaN(SO2F)(SO2CF2CF3), NaN(SO2CF3)(SO2CF2CF3), NaNO3, NaTDI, KCF3SO3, KPF6, KC1O4, KBF4, KN(SO2F)2, KN(SO2CF3)2, KN(SO2 CF2CF3)2, KN(SO2F)(SO2CF3), KN(SO2F)(SO2CF2CF3), KN(SO2CF3)(SO2CF2CF3), KNO3, and KTDI or a mixture thereof.

[0112] In particular, said alkali metal salt SI is selected from the group consisting of LiCF3SO3, LiPF6, LiClO4, LiBF4, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF2CF3)2, LiNO3, LiTDI, NaCF3SO3, NaPF6, NaClO4, NaBF4, NaN(SO2F)2, NaN(SO2CF3)2, NaN(SO2CF2CF3)2, NaNO3, NaTDI, KCF3SO3, KPF6, KC1O4, KBF4, KN(SO2F)2, KN(SO2CF3)2, KN(SO2CF2CF3)2, KNO3, and KTDI or a mixture thereof.

[0113] Plasticizer

[0114] As mentioned above, said composition may comprise at least one plasticizer. Said plasticizer may be selected from the group consisting of vinylidene carbonate, fluoroethylene carbonate (FEC), 4-fluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolan-2-one, ethylene carbonate (EC), propylene carbonate, (2-cyanoethyl)triethoxysilane, 3-methoxypropionitrile, sulfolane, triethylphosphate, γ-butyrolactone, ethers such as polyethylene glycol dimethyl ethers, including diethylene glycol dimethyl ether (EG2DME), triethylene glycol dimethyl ether (EG3DME), and tetraethylene glycol dimethyl ether (EG4DME), or ionic liquids.

[0115] An ionic liquid is a salt that is liquid at room temperature, meaning it has a melting point below 100°C under atmospheric pressure. It is formed by the association of an organic cation and an anion whose ionic interactions are sufficiently weak to prevent the formation of a solid. Examples of cations in ionic liquids include ammonium, sulfonium, pyridinium, pyrrolidinium, imidazolium, imidazolinium, phosphonium, guanidinium, piperidinium, thiazolium, triazolium, oxazolium, pyrazolium, and mixtures thereof. In one embodiment, this cation may include a Ci-C30 alkyl group, such as 1-butyl-1-methylpyrrolidinium, 1-ethyl-3-methylimidazolium, N-methyl-N-propylpyrrolidinium, or N-methyl-N-butylpiperidinium.

[0116] According to one embodiment, the anions associated with them are chosen from: imides, in particular bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide; borates; phosphates; phosphinates and phosphonates, in particular alkyl-phosphonates; amides, in particular dicyanamide; aluminates, in particular tetrachloroaluminate; halides (such as bromide, chloride, iodide anions); cyanates; acetates (CH3COO), in particular trifluoroacetate; sulfonates, in particular methanesulfonate (CH3SO3), trifluoromethanesulfonate; and sulfates, in particular hydrogen sulfate; an acrylate or a methacrylate.In a preferred embodiment, the anions of the ionic liquid are selected from tetrafluoroborate (BF4-), bis(oxalato)borate (BOB-), hexafluorophosphate (PF6-), hexafluoroarsenate (AsF6-), triflate or trifluoromethylsulfonate (CF3SO3-), bis(fluorosulfonyl)imide (FSI-), bis-(trifluoromethanesulfonyl)imide (TFSI-), nitrate (NO3-), 4,5-dicyano-2-(trifluoromethyl)imidazole (TDI-), an acrylate, or a methacrylate. In a particular embodiment, said anion of the ionic liquid is selected from TDI-, FSI-, TFSI-, PF6-, BF4-, NO3-, BOB-, CH2=CHCOO-. In one embodiment, said anion of the ionic liquid is FSI-.

[0117] According to one embodiment, said plasticizer B2 is a mixture of at least one ionic liquid and at least one SI solvent with a boiling point above 100°C, preferably above 110°C, more preferably above 125°C, in particular above 150°C, more particularly above 160°C.

[0118] Plasticizers enable improved properties of conductivity, electrochemical stability, thermal stability, electrode compatibility, and capacity retention compared to conventional liquid electrolytes.

[0119] Examples of plasticizer B2 according to the invention are the following mixtures:

[0120] - 1-ethyl-3-methylimidazolium-FSI and EC,

[0121] - l-ethyl-3-methylimidazolium-FSI and tetraethylene glycol dimethyl ether,

[0122] - l-ethyl-3-methylimidazolium-FSI and EC and FEC,

[0123] - 1-butyl-l-methylpyrrolidinium-FSI and tetraethylene glycol dimethyl ether, - 1-butyl- 1-methylpyrrolidinium-FSI and EC and FEC,

[0124] - N-propyl-N-methylpyrrolidinium and tetraethylene glycol dimethyl ether

[0125] - l-ethyl-3-methylimidazolium-TFSI and FEC,

[0126] - l-ethyl-3-methylimidazolium-FSI,

[0127] - 1-butyl-l-methylpyrrolidinium-FSI. Negative electrode

[0128] Said negative electrode may include a current collector or electrochemically active material optionally deposited on the current collector. Said coating composition according to the present invention may be deposited on said current collector or on said electrochemically active material.

[0129] Said electrochemically active material is selected from the group consisting of lithium alloy, lithium metal, sodium alloy, potassium alloy, sodium metal, potassium metal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, a silicon alloy, graphite / silicon composite and Li4Ti50i2. Preferably, said electrochemically active material is selected from the group consisting of lithium alloy or lithium metal, sodium alloy, potassium alloy, sodium metal and potassium metal.

[0130] Preferably, when the electrochemically active material is a lithium alloy or lithium metal, said alkali metal salt SI contained in said coating composition comprises at least one of the lithium salts selected from the group consisting of LiPF6, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiNO3 and LiTDI.

[0131] Preferably, when the electrochemically active material is a sodium alloy or sodium metal, said alkali metal salt SI contained in said coating composition comprises at least one of the sodium salts selected from the group consisting of NaPF6, NaBF4, NaB(C2O4)2, NaN(SO2F)2, NaN(SO2CF3)2, NaNO3 and NaTDI.

[0132] Preferably, when the electrochemically active material is a potassium alloy or potassium metal, said alkali metal salt SI contained in said coating composition comprises at least one of the selected potassium salts among the group consisting of KPF6, KBF4, KB(C2O4)2, KN(SO2F)2, KN(SO2CF3)2, KNO3 and KTDI.

[0133] Said current collector may be made of copper, optionally coated with carbon.

[0134] According to one embodiment, when said coating composition is deposited on the current collector or on the electrochemically active material, the latter has a thickness of less than 10 µm. Advantageously, the thickness of said coating composition is less than 8 µm, preferably the thickness of said coating composition is less than 6 µm, more preferably the thickness of said coating composition is less than 4 µm, in particular the thickness of said coating composition is less than 2 µm, more particularly the thickness of said coating composition is less than 1 µm. A thinner coating allows for better conduction of lithium, sodium, or potassium ions. Preparation process

[0135] According to another aspect, the present invention provides a method for preparing a negative electrode according to the present invention. Said method comprises the steps of: a. Preparing a composition comprising said polymer PI, said alkali metal salt SI and a solvent; b. Deposition of the composition prepared in step a) onto a current collector or onto a layer containing an electrochemically active material to form an electrode; c. Consolidation of said electrode formed in step b) by heat treatment.

[0136] In step a), said solvent may be selected, by way of non-limiting example, from the group consisting of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-butanone, 1,2-dimethoxyethane, 1,3-dioxolane, 2,3-butanedione, 2-methylpentan-3-one, 2-methyltetrahydrofuran, tetrahydrofuran, 2-pentanone, methyl cyanide, 3,3-dimethyl-2-butanone, 3-methyl-2-butanone, 3-pentanone, butyl acetate, cyclohexanone, cyclopentanone, 4-methylpentan-2-one, dibutyl ether, dimethyl ether, 1,4-dioxane, dipropyl ether, ethyl acetate, ethyl butanoate or methyl propanoate, tetrahydrofuran, N-butyl-2-pyrrolidone or a mixture thereof;in particular 2-butanone, 1,2-dimethoxyethane, 1,3-dioxolane, 2,3-butanedione, 2-methylpentan-3-one, 2-methyltetrahydrofuran, tetrahydrofuran, 2-pentanone, methyl cyanide, 3,3-dimethyl-2-butanone, 3-methyl-2-butanone, 3-pentanone, butyl acetate, cyclohexanone, cyclopentanone, 4-methylpentan-2-one, dibutyl ether, 1,4-dioxane, dipropyl ether, ethyl acetate, ethyl butanoate or methyl propanoate, or a mixture thereof. Among these-; The preferred compounds are 1,2-dimethoxyethane, 1,3-dioxolane, 2-methyltetrahydrofuran, dibutyl ether, 1,4-dioxane, dipropyl ether, and tetrahydrofuran. Use

[0137] Said negative electrode according to the present invention can be used in a secondary Li-ion, Na-ion or K-ion battery. Said battery also comprises a positive electrode and a separator disposed between said positive electrode and said negative electrode. Examples

[0138] Example 1 - Preparation of a solid electrolyte membrane for a Li-ion battery separator

[0139] 0.400 g of P(VDF-HFP) (containing 11% HFP by weight) are solubilized in 2.46 g of acetone at room temperature. Separately, 0.032 g of LiFSI is dissolved in 0.368 g of EMIM-FSI. This latter solution is added to the P(VDF-HFP) solution and mixed. The resulting solution is then applied as a film using a squeegee and dried at 40°C for 1 h. A transparent, self-supporting film of 15 µm is obtained.

[0140] Example 2 - Deposition of a coating on a lithium metal anode

[0141] 0.24 g of P(VDF-HFP) (containing 11% HFP by weight) are solubilized in 5 g DME is applied at room temperature. Then, 0.36 g of LiFSI is added. The solution is then deposited as a film using a squeegee onto a lithium metal anode. It is then dried at 40°C for 1 hour. This results in a lithium anode with a coating thickness of less than 10 µm.

[0142] Example 3 - Interface resistance measurement

[0143] The interface resistance between the solid electrolyte membrane prepared in Example 1 and lithium metal anodes with different coatings is evaluated. An anode A made solely of lithium metal (reference) is prepared. Anodes B, C, D, E, and F are then prepared, according to the method of Example 2, coated with LiFSI / P(VDF-HFP) coatings having the following mass ratios Sl / Pl, respectively: 0.25; 1; 1.5; 2.3; 4. A solid electrolyte membrane is then placed between two anodes A in a button cell, and the total resistance of the system is measured by electrochemical impedance spectroscopy. The same procedure is followed by placing a solid electrolyte membrane between two anodes B (with the anode coating facing the solid electrolyte membrane), and then for anodes C, D, E, and F.

[0144] Figure 1 compares the total strength of coated Li / membrane / coated Li systems for different types of P(VDF-HFP) / LiFSI coatings. It can be seen that coatings with a mass ratio Sl / Pl less than 0.6 do not provide any additional strength. This represents an improvement over uncoated lithium metal. However, coatings with Sl / Pl mass ratios greater than 0.6 reduce the overall system resistance. Since the membrane is the same in all systems, this means that the interface resistance has been reduced. This reduction is even more significant as the Sl / Pl mass ratio increases.

Claims

Demands

1. Coating composition for a negative electrode comprising at least one PI polymer and at least one SI alkali metal salt characterized in that the mass ratio Sl / Pl is greater than or equal to 0.6; said mass ratio Sl / Pl corresponding to the ratio between the mass of said at least one SI alkali metal salt and the mass of said at least one PI polymer in said composition.

2. Coating composition according to the preceding claim characterized in that said polymer PI is selected from the group consisting of fluorinated polymer P1A, acrylic polymer PIB, polyethers PIC, vinyl polymers P1D, cellulose-based polymers PIE and polymers comprising a silane functional group PIF; or a mixture thereof.

3. Coating composition according to any one of the preceding claims characterized in that said PI polymer is a P1A polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride.

4. Coating composition according to any one of the preceding claims characterized in that said PI polymer is a P1A polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a monomer Mla' selected from the group consisting of vinyl fluoride, 1,2-difluoroethylene, hexafluoropropylene, or a mixture thereof.

5. Coating composition according to any one of the preceding claims characterized in that said alkali metal salt SI is selected from the group consisting of LiCF3SO3, LiPF6, LiC104, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2CF2CF3)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2CF2CF3), LiN(SO2CF3)(SO2CF2CF3), LiAsF6, LiBF2C2O4, LiNO3, LiPF3(CF2CF3)3, LiTDI, NaCF3SO3, NaPF6, NaC104, NaBF4, NaB(C2O4)2, NaN(SO2F)2, NaN(SO2CF3)2, NaN(SO2C2F3)2, NaN(SO2 CF2CF3)2, NaN(SO2F)(SO2CF3), NaN(SO2F)(SO2CF2CF3), NaN(SO2 CF3)(SO2CF2CF3), NaAsF6, NaBF2C2O4, NaNO3, NaPF3(CF2CF3)3, NaTDI, KCF3SO3, KPF6, KC1O4, KBF4, KB(C2O4)2, KN(SO2F)2, KN(SO2CF3)2, KN(SO2C2F3)2, KN(SO2CF2CF3)2, KN(SO2F)(SO2CF3 ), KN(SO2F)(SO2CF2CF3), KN(SO2CF3)(SO2CF2CF3), KAsF6, kbf2c 2O4, KNO3, KPF3(CF2CF3)3 and KTDI or a mixture of these.

6. Coating composition according to any one of the preceding claims characterized in that it comprises at least one plasticizer selected from the group consisting of vinylidene carbonate, fluoroethylene carbonate, 4-fluoro-l,3-dioxolan-2-one, trans-4,5-difluoro-l,3-dioxolan-2-one, ethylene carbonate, propylene carbonate, (2-cyanoethyl)triethoxysilane, 3-methoxypropionitrile, sulfolane, triethylphosphate, γ-butyrolactone, ethers such as polyethylene glycol dimethyl ethers, in particular diethylene glycol dimethyl ether (EG2DME), triethylene glycol dimethyl ether (EG3DME), and tetraethylene glycol dimethyl ether (EG4DME) or ionic liquids.

7. Coating composition according to any one of the preceding claims characterized in that the mass ratio Sl / Pl is greater than or equal to 0.8, preferably greater than or equal to 1.

8. A negative electrode comprising an electrochemically active material, optionally deposited on a current collector, said electrochemically active material being coated with said coating composition according to any one of claims 1 to 7

9. 1 d. / . Negative electrode according to the preceding claim characterized in that said electrochemically active material is selected from the group consisting of lithium alloy, lithium metal, sodium alloy, potassium alloy, sodium metal, potassium metal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, a silicon alloy, graphite / silicon composite and Li4Ti50i2.

10. Negative electrode comprising a current collector coated with said coating composition according to any one of claims 1 to 7.

11. Electrode according to any one of claims 8 to 10 characterized in that said coating composition has a thickness of less than 10 pm.

12. A method for preparing an electrode according to any one of claims 8 to 11 comprising the steps of: a. Preparation of a composition comprising said at least one polymer PI, said at least one alkali metal salt SI and a solvent; b. Deposition of the composition prepared in step a) onto a current collector or onto an electrochemically active material to form an electrode; c. Consolidation of said electrode formed in step b) by heat treatment.

13. Battery comprising a negative electrode according to any one of claims 8 to 11.

14. Battery according to the preceding claim characterized in that it is a secondary lithium-ion, sodium-ion or potassium-ion battery.

15. Battery according to any one of claims 13 or 14 characterized in that it is an all-solid battery.