Composition comprising a fluorinated polymer and an acrylic copolymer and use thereof as an electrode binder

Abstract

The present invention relates to a composition comprising a fluorinated polymer P1 comprising monomer units derived from a fluorinated monomer M1a and a copolymer P2 comprising monomer units derived from a monomer M2a of formula (Ia) R1R2C=C(R3)C(O)R or (Ib) R1R2C=C(R3)R'' and monomer units derived from a monomer M2b of formula (II). The composition is used as an electrode binder.

Description

[0001] Description

[0002] Title: Composition comprising a fluoropolymer and an acrylic copolymer and use thereof as an electrode binder

[0003] Technical field of the invention

[0004] The present invention relates generally to the field of electrical energy storage in rechargeable secondary batteries of the Li-ion type. More specifically, the invention relates to a composition for the preparation of electrodes.

[0005] Technological background of the invention

[0006] Lithium batteries are increasingly used due to higher voltages and higher energy densities than conventional batteries (such as Ni-MH batteries). An elementary cell of a Li-ion storage battery or lithium battery comprises an anode (discharge), and a cathode (also discharge) generally made of a lithium metal oxide insertion compound, such as LiM^C , LiCoÜ2 or LiNiCh, between which is inserted an electrolyte that conducts lithium ions.

[0007] Rechargeable or secondary batteries are more advantageous than primary (non-rechargeable) batteries because the associated chemical reactions that take place at the positive and negative electrodes of the battery are reversible. The electrodes of secondary cells can be regenerated multiple times by applying an electrical charge. Many advanced electrode systems have been developed to store electrical charge. At the same time, much effort has been devoted to developing electrolytes capable of improving the capabilities of electrochemical cells.

[0008] For their part, the electrodes generally comprise at least one current collector on which is coated, in the form of a film, a composite material consisting of a so-called active material because it has electrochemical activity with respect to lithium, a polymer which acts as a binder, plus one or more electroconductive additives which are generally carbon black or acetylene black and possibly a surfactant.

[0009] Binders are considered inactive components because they do not directly contribute to cell capacity. However, their key role in electrode processing and their considerable influence on the electrochemical performance of electrodes have been extensively described. The main relevant physical and chemical properties of binders are thermal stability, chemical and electrochemical stability, tensile strength (strong adhesion and cohesion), and flexibility. The main objective of using a binder is to form stable networks of the solid electrode components, i.e., active materials and conductive agents (cohesion). In addition, the binder must ensure close contact of the composite electrode with the current collector (adhesion).

[0010] Polyvinylidene fluoride (PVDF) is used as a binder in lithium-ion batteries due to its excellent electrochemical stability, good bonding ability, and strong adhesion to electrode materials and current collectors. In wet-slurry processes for electrode preparation, the active materials and binders are dispersed in a liquid solution. The liquid solution is usually based on organic solvents or water. The dispersion is cast onto a current collector and then dried in a high-temperature oven to produce an electrode. Unfortunately, the excellent properties provided by fluoropolymers such as PVDF can also limit the applications in which they can be used. For example, it is difficult to adhere fluoropolymers to other materials.Therefore, organic solvents and other organic additives are generally used in a coating formulation to ensure good adhesion between PVDF-based polymers, a porous separator or an electrode, and optionally the added powder particles. Alternatively, fluoropolymer binders may carry functional groups to promote the adhesive behavior of the polymer. For example, US 2020 / 0407543 describes a polymer binder composition comprising two or more different phases wherein said phases comprise a highly crystalline fluoropolymer phase and an adhesive fluoropolymer phase, said adhesive fluoropolymer functional groups.

[0011] Also described in the art are binder compositions comprising a mixture of vinylidene fluoride polymer and acrylic polymer. For example, US 2013 / 252077 describes an electrode for a lithium-ion battery which operates with a non-aqueous electrolyte. This electrode comprises an active substance and a binder comprising a vinylidene fluoride polymer and an acrylic polymer. EP 2 953 193 describes a binder for a lithium-ion battery comprising a fluoropolymer and an acrylic polymer containing a nitrile group. EP 3796430 describes an electrode mixture comprising a binder composition containing a vinylidene fluoride copolymer and an acrylic polymer of low average molecular weight.

[0012] However, the adhesion of the binder composition is still not satisfactory and can still be improved. Indeed, the electrode material can detach from the current collector, resulting in poor electrochemical performance and reduced cycle life. Therefore, it is important to find a cost-effective and scalable method to improve the adhesion of electrode materials in secondary batteries. Moreover, increasing the mass power density of electric vehicle batteries remains a major challenge for the mass adoption of this technology; therefore, an increase in the high-charge-cycle capacity retention of high-Ni electrodes would help achieve these objectives in terms of cost and fast charge cycle.

[0013] Therefore, there is still a need to develop new binders and electrode compositions for Li-ion batteries to improve the adhesion and high-charge-cycle capacity retention of electrode materials.

[0014] Summary of the invention

[0015] According to a first aspect, the present invention relates to a composition comprising a fluorinated polymer PI comprising monomeric units derived from a fluorinated monomer Mla and a copolymer P2 comprising monomeric units derived from at least one monomer M2a of formula (la) R 1 R 2 C=C(R 3 )C(O)R or (Ib) R 1 R 2 C=C(R 3 )R" and monomeric units derived from a monomer M2b of formula (II) in which the substituents R 1 , R 2 and R 3are, independently of each other, selected from the group consisting of H, C1-C5 alkyl and NH2; R" is selected from the group consisting of Cg-C12 aryl and CN; R is selected from the group consisting of -NHC(CH3hCH2C(O)CH3 or -OR' with R' selected from the group consisting of H and C1-C1s alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'" or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-Cg alkyl or Cg-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H; the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C5 alkyl; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C5 alkyl; the substituent X is selected from the group consisting of C1-C6 alkyl and C4-C18 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0016] The present composition makes it possible to improve the adhesion properties of the electrode composition on the current collector. In addition, the present composition makes it possible to obtain very high performance capacity retention.

[0017] According to a preferred embodiment, the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C3 alkyl and R 7 and R 8 are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C3 alkyl.

[0018] According to a preferred embodiment, the substituents R 1 , R 2 and R 3 are, independently of each other, selected from the group consisting of H and C1-C3 alkyl; R is -OR' with R' selected from the group consisting of H and C1-C10 alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'" or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H.

[0019] According to one embodiment, the substituent X is selected from the group consisting of C1-C10 alkyl and C4-C10 cycloalkyl.

[0020] According to a preferred embodiment, said composition also comprises a copolymer P3 comprising monomeric units derived from at least two monomers M3a and M3b of formula (I) R 1 R 2 C=C(R 3 )C(O)R in which R 1 , R 2 and R 3 are, independently of each other, 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' with R' selected from the group consisting of H and C1-C5 alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'" or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H.

[0021] According to a preferred embodiment, said fluorinated monomer Mla is selected from the group consisting of vinyl fluoride; vinylidene fluoride (VDF); 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); the monomer of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the monomer of formula CF2=CFOCF2CF2SO2F; the monomer of formula F(CF2)nCH2OCF=CF2in which n is 1, 2, 3, 4 or 5; the monomer of formula R 1 CH2OCF=CF2in which R 1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the monomer of formula R 2 OCF=CH2in which R 2is F(CF2)p and p is 1, 2, 3 or 4; trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-trifluoro-l-propene or a mixture thereof.

[0022] According to a preferred embodiment, said fluorinated monomer Mla is vinylidene fluoride and optionally said polymer PI also comprises monomeric units derived from a monomer Mlb selected from the group consisting of vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene; tetrafluoroethylene; hexafluoropropylene; perfluoro(alkyl vinyl) ethers such as perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether and perfluoro(propyl vinyl) ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the monomer of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPC> H; the monomer of formula CF2=CFOCF2CF2SO2F; the monomer of formula F(CF2)nCH2OCF=CF2in which n is 1, 2, 3, 4 or 5; the monomer of formula R 1 CH2OCF=CF2in which R 1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the monomer of formula R 2 OCF=CH2in which R 2is F(CF2)p and p is 1, 2, 3 or 4; trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-trifluoro-l-propene or a mixture thereof.

[0023] According to a preferred embodiment, said fluoropolymer PI has a melt viscosity greater than 1000 Pa.s measured according to the ASTM D-3835 method measured at 232°C and 100 sec 1 This allows for a good electrode coating, i.e. one that adheres well to the current collector.

[0024] According to a preferred embodiment, said copolymer P2 has a number-average molecular mass greater than or equal to 1000 g.mol 1 .

[0025] According to a preferred embodiment, in said composition, the mass ratio Pl / P2 is from 50 / 50 to 99 / 1, preferably from 70 / 30 to 95 / 5. According to another aspect, the present invention provides an electrode binder comprising said composition according to the present invention.

[0026] According to another aspect, the present invention provides an electrode composition comprising said binder according to the present invention, an active material and optionally a conductive agent, an additive or a mixture of both.

[0027] According to a preferred embodiment, said electrode composition comprises a conductive agent being composed of one or more materials selected from the group consisting of carbon black, graphite, carbon fibers, carbon nanotubes, carbon nanofibers, metal powders such as SUS powder and aluminum powder, or mixtures thereof.

[0028] According to a preferred embodiment, said active material is chosen from the group consisting of: LiCoO2, Li(Ni, Co, AQO2, Li(i + X )NiaMnbCo c (x represents a real number of 0 or more, a = 0.9, 0.8, 0.6, 0.5, or 1 / 3, b = 0.05, 0.1, 0.2, 0.3, or 1 / 3, c = 0.05, 0.1, 0.2, or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, LisNiMnsOs, LÎ3Fe2(PO4)3, LÎ3V2(PO4)3, a Li Mn spinel substituted by a different element having a composition represented by Lii +x Mn2-x-yM y O4, M representing at least one metal chosen from Al, Mg, Co, Fe, Ni, and Zn, x and y independently representing a real number between 0 and 2, lithium titanate Li x TiO y - x and y independently representing a real number between 0 and 2, and a lithium metal phosphate having a composition represented by LiMPO4, M representing Fe, Mn, Co, or Ni.

[0029] According to a preferred embodiment, said active material is selected from the group consisting of a lithium alloy, lithium metal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, silicone, a silicon alloy and Li4Ti50i2.

[0030] According to another aspect, the present invention provides an electrode comprising a current collector and a layer consisting of said electrode composition according to the present invention, preferably said layer is in contact with the current collector.

[0031] According to another aspect, the present invention provides a coating for a separator in a Li-ion battery comprising said composition according to the present invention.

[0032] According to another aspect, the present invention provides a separator for Li-ion battery comprising said coating according to the present invention and optionally inorganic particles are selected from the group consisting of: BaTiOs, Pb(Zr,Ti)C>3, Pbi. x There x Zr y 03 (0 <x<l, 0<y<l), PbMg3Nb2 / 3O3,PbTiC> 3, hafnia (HfO or HfCh), SrTiOs, SnC>2, CeC>2, MgO, NiO, CaO, ZnO, Y2O3, bohemite (y-AIO(OH)), AI2O3, TiO2, SiC, ZrC>2, boron silicate, BaSO4, nano-clays, or mixtures thereof. According to another aspect, the present invention provides a Li-ion battery comprising a positive electrode, a negative electrode and a separator characterized in that at least one of the electrodes is an electrode according to the present invention or said separator is a separator according to the present invention.

[0033] In another aspect, said composition according to the present invention is used for the preparation of a conductive polymer, a solid electrolyte for fuel cells, a hydrophilic coating, a hydrophobic coating or a UV-absorbing coating; or as an adhesive for a multi-layer structure extruded in the form of a film, a sheet or a tube; or said copolymer is used as a coating on a metal.

[0034] Detailed description of the invention

[0035] According to a first aspect, a composition comprising a fluoropolymer PI and a copolymer P2 is provided. Said fluoropolymer PI comprises monomeric units derived from a fluoromonomer Mla. Said copolymer P2 comprises monomeric units of a monomer M2a of formula (la) R 1 R 2 C=C(R 3 )C(O)R or (Ib) R 1 R 2 C=C(R 3)R" and monomeric units derived from a monomer M2b of formula (II). The presence of a monomer M2b in said copolymer P2 makes it possible to improve the adhesion properties while maintaining a good level of capacity retention when the composition is used as a binder in an electrochemical device. According to a preferred embodiment, the mass ratio Pl / P2 is from 50 / 50 to 99 / 1, advantageously from 55 / 45 to 98 / 2, preferably from 60 / 40 to 97 / 3, more preferably from 65 / 35 to 96 / 4, in particular from 70 / 30 to 95 / 5, more particularly from 80 / 20 to 95 / 5, preferably from 85 / 15 to 95 / 5.

[0036] According to a preferred embodiment, said fluorinated polymer PI comprises in its chain at least one fluorinated monomer Mla chosen 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.

[0037] Preferably, said fluoropolymer PI comprises monomeric units derived from a monomer Mla selected from the group consisting of vinyl fluoride; vinylidene fluoride (VDF); 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); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPC>3H; the product of formula CF2=CFOCF2CF2SO2F; the product of formula F(CF2)nCH2OCF=CF2in which n is 1, 2, 3, 4 or 5; the product of formula R 1 CH2OCF=CF2in which R 1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the product of formula R 2 OCF=CH2in which R 2is F(CF2)p and p is 1, 2, 3 or 4; perfluorobutylethylene (PFBE); trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-

[0038] 3.3.3-trifluoro-l-propene or a mixture thereof. Among the trifluoropropenes we can cite

[0039] 3,3,3-trifluoropropene. Among the tetrafluoropropenes, we can cite 2, 3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene. Among the pentafluoropropenes, we can cite

[0040] 1.1.3.3.3-pentafluoropropene or 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-

[0041] 3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.

[0042] In particular, said fluoropolymer PI comprises at least monomeric units derived from a monomer Mla being vinylidene fluoride. The fluoropolymer PI may be a homopolymer or a copolymer of vinylidene fluoride.

[0043] According to a particular embodiment, the fluoropolymer PI is a vinylidene fluoride homopolymer.

[0044] According to another particular embodiment, the fluorinated polymer PI is a polymer comprising monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mlb copolymerizable with vinylidene fluoride, or monomeric units derived from a non-fluorinated monomer Mlc or a mixture of the two.

[0045] According to one embodiment, said fluoropolymer PI comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mlb selected from the group consisting of 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); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2=CFOCF2CF2SC>2F; the product of formula F(CF2)nCH2OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R 1 CH2OCF=CF2 in which R 1is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the product of formula R 2 OCF=CH2 in which R 2is 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-1-propene or a mixture thereof. Preferably, the fluoropolymer PI comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mlb selected from the group consisting of vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene, tetrafluoroethylene; 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=CFOCF2CF2SC>2F; 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 fluoropolymer PI comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a fluorinated monomer Mlb selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene and hexafluoropropylene or a mixture thereof.;

[0046] According to another embodiment, said fluorinated polymer PI comprises monomeric units derived from a monomer Mla being vinylidene fluoride and monomeric units derived from a non-fluorinated monomer Mlc of formula R a R b C=C(R c )HORN d in which the substituents R a , R b and R c are independently of each other selected from the group consisting of H and C1-C5 alkyl; R d is selected from the group consisting of - NHC(CH )2CH2C(O)CH OR -OR d ' with R d ' selected from the group consisting of H and Ci-Cis alkyl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H, -OC(O)R d ", -C(O)OR d " or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R d" being selected from the group consisting of C1-C8 alkyl or C6-C12 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H groups. Said heterocycle may be saturated or unsaturated or aromatic. Said heterocycle may be monocyclic or bicyclic. Said heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone ring. Said heterocycle may be substituted by one or more C1-C5 alkyl groups. As mentioned above, the C1-C8 alkyl is optionally substituted by said heterocycle. The latter may be linked to the alkyl chain by the nitrogen atom or any other atom forming the heterocycle. Preferably the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.Said Mlc monomer may be of formula R. a R b C=C(R c )HORN d in which the substituents R a , R b and R c are independently of each other selected from the group consisting of H and C1-C5 alkyl; R d is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR d ' with R d ' selected from the group consisting of H and Ci-Cis alkyl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H, -OC(O)R d ", -C(O)OR d " or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R d" being selected from the group consisting of C1-C8 alkyl or C1-C12 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H group(s). Preferably, the heterocycle is as defined above, in particular the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone. Preferably, the substituent R d ' 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 by a ureido group. In particular, said monomer Mlc is of formula R a R b C=C(R c )HORN d in which the substituents R a and R b are H; R c is H or CH3; R d is-OR d ' with R d' selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, hydroxy propyl, hydroxy butyl, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone. More particularly, said monomer Mlc 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 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(CO2CH2CH2CH2-O- C(O)-CH2CH2CO2H), CH2=CH(CO2CH(CH3)CH2-OC(O)-CH2CH2CO2H),CH2=CH(CO2CH2CH2-OC(O)- C6H4CO2H), CH2=CH(CO2CH2CH2CH2CH(CO2H)CH2CH2CO2H); and mixtures thereof. Among these, said Mlc monomer with an alkyl group having 1 to 8 carbon atoms is preferred, and an alkyl group having 1 to 5 carbon atoms is more preferable. Said fluoropolymer PI may comprise one or more monomeric units derived from said Mlc monomer as defined herein.,

[0047] According to another embodiment, said fluorinated polymer PI comprises monomeric units derived from a monomer Mla being vinylidene fluoride, monomeric units derived from a fluorinated monomer Mlb, monomeric units derived from a non-fluorinated monomer Mlc of formula R a R b C=C(R b )HORN d ; said monomers Mlb and Mlc being as defined above.

[0048] In said fluorinated polymer PI, the mass content 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 content of vinylidene fluoride monomeric units in said fluorinated polymer PI is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.

[0049] According to a particular embodiment, the fluoropolymer PI may be functionalized in whole or in part, which allows it to improve adhesion to metal. Thus, said fluoropolymer PI may comprise monomeric units carrying 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.

[0050] The function is introduced by a chemical reaction which may be grafting, or a copolymerization of the fluorinated monomer with a monomer carrying 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.

[0051] According to one embodiment, the functional group carries a carboxylic acid function which is a group of (meth)acrylic acid type chosen 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.

[0052] According to one embodiment, the units carrying the carboxylic acid function further comprise a heteroatom chosen from oxygen, sulfur, nitrogen and phosphorus.

[0053] 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 carrying functional groups chosen from the groups: 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. An example of a transfer agent of this type 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 can be introduced by an oligomeric or polymeric compound comprising said functional group and mixed with the fluorinated polymer PI.The oligomeric or polymeric compound may be impregnated into or blended with the fluoropolymer PI or intimately blended therewith. In this case, the functional group may 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.According to 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, in particular less than 20,000 g / mol. The weight-average molecular mass 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 LD. x 30 cm, 5 μm) under the following conditions: Temperature: 35°C; flow rate: 1.0 mL / min; injection volume: 100 pL. The samples are prepared at a concentration of 1 mg / ml in THF. Twelve samples of poly(methylmethacrylate) with a molecular weight 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 fluoropolymer PI.The content of functional groups in PVDF is at least 0.01 mol%, preferably at least 0.1 mol%, and at most 15 mol%, preferably at most 10 mol%.

[0054] Said fluoropolymer PI preferably has a high molecular weight. By high molecular weight, as used herein, is meant a fluoropolymer PI having a melt viscosity greater than 100 Pa.s, advantageously greater than 500 Pa.s, preferably greater than 1000 Pa.s, more preferably greater than 2000 Pa.s, in particular greater than 2500 Pa.s, more particularly greater than 3000 Pa.s according to the ASTM D-3835 method measured at 232°C and 100 sec-1.

[0055] Said fluoropolymer PI used in the invention can be obtained by known polymerization methods such as emulsion or suspension polymerization. According to a preferred embodiment, said fluoropolymer PI is prepared by an emulsion polymerization process in the presence of a non-fluorinated surfactant. Thus, said fluoropolymer PI can comprise between 10 ppm and 2% by weight of a non-fluorinated surfactant comprising polyethylene glycol or polypropylene glycol units. Preferably, said 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, said 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 polyethylene glycol segment and at least one polypropylene glycol segment, and has an HLB value of 10 to 15 and a weight average molecular weight of 500 to 2500 g.mol-1.

[0056] According to a preferred embodiment, said fluoropolymer PI is prepared by a suspension polymerization process.

[0057] Said fluoropolymer PI may be in the form of a latex generally having a solids content of 10 to 60% by weight, preferably 10 to 50%, and having 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 having a weight average size of 1 to 30 micrometers, and preferably 2 to 10 micrometers. The agglomerates may break into discrete particles during formulation and application to a substrate.

[0058] Said fluoropolymer PI can be in the form of a powder. This is obtained from the latex which is subjected for example to a drying step and optionally granulation.

[0059] According to certain embodiments, the vinylidene fluoride contained in said PI fluoropolymer is bio-sourced. The term "bio-sourced" means "derived from biomass". This makes it possible to improve the ecological footprint of the polymer. The bio-sourced VDF can be characterized by a renewable carbon content, i.e. carbon of natural origin and originating from a biomaterial or biomass, of at least 1 atomic % 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 originates from a biomaterial (or biomass), as indicated below.According to certain embodiments, the bio-carbon content of the 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%.

[0060] P2 copolymer

[0061] According to a preferred embodiment, said copolymer P2 comprising monomeric units derived from at least one monomer M2a of formula (la) R 1 R 2 C=C(R 3 )C(O)R or (Ib) R 1 R 2 C=C(R 3 )R" and monomeric units derived from a monomer M2b of formula (II) in which the substituents R 1 , R 2 and R 3are, independently of each other, selected from the group consisting of H, C1-C5 alkyl and NH2; R" is selected from the group consisting of C6-C12 aryl and CN; R is selected from the group consisting of -NHC(CH3hCH2C(O)CH3 or - OR' with R' selected from the group consisting of H and C1-C1s alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R"', -C(O)OR"' or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H; the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C5 alkyl;

[0062] R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C5 alkyl;

[0063] X is selected from the group consisting of C1-C18 alkyl and C4-C18 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0064] Said monomer M2a can therefore be of formula (la) R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 , R 2 and R 3are, independently of each other, 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' with R' selected from the group consisting of H and C1-C5 alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'" or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-C8 alkyl or C6-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H. Said heterocycle may be saturated or unsaturated or aromatic. Said heterocycle may be monocyclic or bicyclic.Said heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone ring. Said heterocycle may be substituted by one or more C1-C5 alkyl groups. As mentioned above, the C1-C5 alkyl is optionally substituted by said heterocycle. The latter may be linked to the alkyl chain by the nitrogen atom or any other atom forming the heterocycle. Preferably the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone. Advantageously, said monomer M2a may be of formula (la) R. 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 , R 2 and R 3are independently of each other selected from the group consisting of H and C1-C5 alkyl; R is -OR' with R' selected from the group consisting of H and C1-C5 alkyl optionally substituted with one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'" or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H group(s). Preferably, the heterocycle is as defined above, in particular the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.Said substituent R' may be 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, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone ethyl substituted by a ureido group. Preferably, said monomer M2a is of formula (la) R. 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 and R 2 are H; R 3is H or CH3; R is -OR' with R' selected from the group consisting of H and C1-C18 alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'"; R'" being selected from the group consisting of C1-C8 alkyl or C6-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H. More preferably, said monomer M2a is of formula (la) R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 and R 2 are H; R 3is H or CH3; R is -OR' with R' selected from the group consisting of H and C1-C15 alkyl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'"; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H. In particular, said monomer M2a is of formula (la) R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 and R 2 are H; R 3is H or CH3; R is -OR' with R' selected from the group consisting of H and C1-C10 alkyl optionally substituted with one or more groups -OH, -CO2H, -SO3H, -PO3H, -OC(O)R'", -C(O)O-R'"; R'" being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H. More particularly, said monomer M2a 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, ureido methacrylate, monomers of formula CH2=CH(CO2CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-C6H4CO2H),

[0065] CH2=CH(CO2CH2CH2CH2CH(CO2H)CH2CH2CO2H); and mixtures thereof. Among these, said monomer M2a with an alkyl group having 1 to 8 carbon atoms is preferred, and an alkyl group having 1 to 5 carbon atoms is more preferable. Said copolymer P2 may comprise one or more monomeric units derived from said monomer M2a as defined herein, for example M2a may be a mixture between methyl methacrylate and methacrylic acid.

[0066] Alternatively, said monomer M2a may be of formula (Ib) R 1 R2 C=C(R 3 )R" in which the substituents R 1 , R 2 and R 3 are, independently of each other, selected from the group consisting of H, C1-C5 alkyl and NH2; R" is selected from the group consisting of Cg-Ci2aryl and CN. Preferably, in this embodiment, said monomer M2a may be of formula (Ib) R 1 R 2 C=C(R 3 )R" in which the substituents R 1 , R 2 and R 3 are, independently of each other, selected from the group consisting of H and C1-C3 alkyl and NH2; R" is selected from the group consisting of Cg-Ci2aryl and CN.

[0067] Said monomer M2b is of formula (II) in which the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C5 alkyl; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C5 alkyl; X is selected from the group consisting of C1-C6 alkyl and C4-C18 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0068] The term alkyl or cycloalkyl as used herein refers to linear or branched alkyl or cycloalkyl radicals.

[0069] Advantageously, said monomer M2b is of formula (II) as defined above in which the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C3 alkyl; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C3 alkyl; X is selected from the group consisting of C1-C15 alkyl and C4-C15 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0070] Preferably, said monomer M2b is of formula (II) as defined above in which the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and CH3; R 7 and R 8 are, independently of each other and independently for each unit n, selected from the group consisting of H and CH3; X is selected from the group consisting of C1-C10 alkyl and C4-C10 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0071] More preferably, said monomer M2b is of formula (II) as defined above in which the substituents R 4 , R 5 and R 9 are H; R 6 is H or CH3; R 7 and R 8 are, independently of each other and independently for each unit n, selected from the group consisting of H and CH3; X is selected from the group consisting of C1-C10 alkyl and C4-C10 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0072] In particular, said monomer M2b is of formula (II) as defined above in which the substituents R 4 , R 5 and R 9 are H; R 6 is H or CH3; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and CH3; X is selected from the group consisting of C2-C8 alkyl and C5-C8 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1. More particularly, said monomer M2b is of formula (II) as defined above in which the substituents R 4 , R 5 and R 9 are H; R 6 is H or CH3; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and CH3; X is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, tert-butyl, isobutyl, sec-butyl, isopentyl, neopentyl, tert-pentyl dimethylpropyl, trimethylpentyl, tetramethylcyclobutyl, cyclohexyl, dimethylcyclohexyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

[0073] Preferably, said copolymer P2 comprises at least 50% by weight, advantageously at least 60% by weight, preferably at least 70% by weight, more preferably at least 75% by weight, in particular at least 80% by weight, more particularly at least 85% by weight of monomers M2a based on the total weight of said copolymer P2.

[0074] Preferably, said copolymer P2 comprises less than 50% by weight, advantageously less than 40% by weight, preferably less than 30% by weight, more preferably less than 25% by weight, in particular less than 20% by weight, more particularly less than 15% by weight of monomers M2b based on the total weight of said copolymer P2. Alternatively, said copolymer P2 may comprise at least 50% by mole, advantageously at least 60% by mole, preferably at least 70% by mole, more preferably at least 75% by mole, in particular at least 80% by mole, more particularly at least 85% by mole of monomers M2a based on said copolymer P2. Alternatively, said copolymer P2 may comprise less than 50 mol%, advantageously less than 40 mol%, preferably less than 30 mol%, more preferably less than 25 mol%, in particular less than 20 mol%, more particularly less than 15 mol% of monomers M2b based on said copolymer P2.When said copolymer P2 may also comprise monomeric units derived from a monomer M2c. Said monomer M2c may be.

[0075] - (A) an alkenyl compound containing a functional group, or

[0076] - (B) an alkenyl compound without a functional group.

[0077] The alkenyl compound (A) containing a functional group includes, for example, α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid and the like; vinyl ester compounds such as vinyl acetate, vinyl neodecanoate and the like; amide compounds such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, diacetone acrylamide and the like, sodium 2-acrylamido-2-methyl-1-propanesulfonate; acrylic acid esters such as 2-hydroxyethyl acrylate, N-dialkylaminoethyl acrylate, glycidyl acrylate, n-dodecyl acrylate, fluoroalkyl acrylate and the like;methacrylic acid esters such as dialkylaminoethyl methacrylate, fluoroalkyl methacrylate, 2-hydroxyethyl methacrylate, n-octyl methacrylate, t-butyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate and the like; maleic anhydride, and alkenyl glycidyl ether compounds such as allyl glycidyl ether and the like. Of 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 alone or as a mixture of two or more. The alkenyl compound without a functional group (B) includes, for example, conjugated dienes such as 1,3-butadiene, isoprene and the like;divinyl hydrocarbon compounds such as divinyl benzene and the like; and alkenyl cyanides such as acrylonitrile, methacrylonitrile and the like. Of these, preferred are 1,3-butadiene, and acrylonitrile. These compounds may be used alone or as a mixture of two or more.;

[0078] P3 copolymer

[0079] According to a preferred embodiment, said composition may also comprise a copolymer P3. Said copolymer P3 comprises monomeric units derived from at least two monomers M3a and M3b of formula R 10 R 1:L C=C(R 12 )HORN 13 in which the substituents R 10 , R 11 and R 12 are, independently of each other, selected from the group consisting of H and C1-C5 alkyl; R 13 is selected from the group consisting of -NHCfCHshCFhCfOjCHs or -OR 14 with R 14selected from the group consisting of H and Ci-Cis alkyl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H, -OC(O)R 14 ', -C(O)OR 14 ' or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R 14' being selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more -OH, -CO2H, -SO3H, -PO3H groups. Said heterocycle may be saturated or unsaturated or aromatic. Said heterocycle may be monocyclic or bicyclic. Said heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone ring. Said heterocycle may be substituted by one or more C1-C5 alkyl groups. As mentioned above, the Ci-Cis alkyl is optionally substituted by said heterocycle. The latter may be linked to the alkyl chain by the nitrogen atom or any other atom forming the heterocycle. Preferably the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.

[0080] Said monomers M3a and M3b are different from each other. Said monomers M3a and M3b are preferably of formula R 10 R 1:L C=C(R 12 )HORN 13 in which the substituents R 10 , R 11 and R 12 are independently of each other selected from the group consisting of H and C1-C5 alkyl; R 13 is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR 14 with R 14 selected from the group consisting of H and Ci-Cis alkyl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H, -OC(O)R 14 ', -C(O)OR 14 ' or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R 14' being selected from the group consisting of C1-C8 alkyl or C1-C12 aryl optionally substituted by one or more group(s) -OH, -CO2H, -SO3H, -PO3H. Preferably, the heterocycle is as defined above, in particular the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone. Said monomers M3a and M3b are independently of each other of formula R 10 R 1:L C=C(R 12 )HORN 13 in which the substituents R 10 and R 11 are H; R 12 is H or CH3; R 13 is - OR 14 with R 14selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone. More particularly, said monomers M3a and M3b are independently of each other 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, hydroxypropyl acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxyethyl methacrylate, 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, ureido methacrylate, monomers of formula CH2=CH(CO2CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-CH2CH2CO2H), CH2=CH(CO2CH2CH2-OC(O)-C6H4CO2H),

[0081] CH2=CH(CO2CH2CH2CH2CH(CO2H)CH2CH2CO2H); and mixtures thereof.

[0082] According to a preferred embodiment, the mass ratio Pl / P3 is from 70 / 30 to 99 / 1, more particularly from 80 / 20 to 99 / 1, preferably from 85 / 15 to 99 / 1.

[0083] The copolymers P2 and P3 according to the invention can be obtained by polymerization of the monomers according to known polymerization methods such as emulsion or suspension polymerization.

[0084] Preferably, said copolymers P2 and P3 have, independently of each other, a glass transition temperature of less than or equal to 230°C. Advantageously, said copolymers P2 and P3 have a glass transition temperature of less than or equal to 220°C, preferably less than 200°C, more preferably less than 180°C, in particular less than 160°C, more particularly less than or equal to 150°C. The glass transition temperatures indicated here are calculated using the Fox equation. The Fox equation is an equation used to predict the glass transition temperature of statistical copolymers: 1 / Tg,copo = i coi / Tg,i ; Tg,copo is the glass transition temperature of the copolymer; Tg,i are those of the homopolymers i corresponding to each comonomer; coi are the mass fractions of the monomers i composing this copolymer. The mass fractions are expressed without units.Glass transition temperatures are expressed in degrees Kelvin. The temperature is then converted to degrees Celsius.

[0085] According to a preferred embodiment, said copolymers P2 and P3 have, independently of each other, a number-average molecular mass greater than or equal to 1000 g.mol-1, advantageously greater than or equal to 3000 g.mol-1, preferably greater than or equal to 5000 g.mol-1, more preferably greater than or equal to 10000 g.mol-1, in particular greater than or equal to 50000 g.mol-1, more particularly greater than or equal to 100000 g.mol-1, preferably greater than or equal to 150000 g.mol-1. Thus, said copolymer P2 may have a number-average molecular mass greater than or equal to 1000 g.mol-1, advantageously greater than or equal to 3000 g.mol-1, preferably greater than or equal to 5000 g.mol-1, more preferably greater than or equal to 10000 g.mol-1, in particular greater than or equal to 50000 g.mol-1, more particularly greater than or equal to 100000 g.mol-1, preferably greater than or equal to 150000 g.mol-1.This makes it possible to obtain a good electrode coating, i.e. one that adheres well to the current collector. Said copolymer P3 may have a number-average molecular weight greater than or equal to 1000 g.mol-1, advantageously greater than or equal to 3000 g.mol-1, preferably greater than or equal to 5000 g.mol-1, more preferably greater than or equal to 10000 g.mol-1, in particular greater than or equal to 50000 g.mol-1, more particularly greater than or equal to 100000 g.mol-1, preferably greater than or equal to 150000 g.mol-1. The molecular weight of the copolymers P2 and P3 is determined by Size Exclusion Chromatography (SEC). A test portion of the polymer solution corresponding to 90 mg of dry matter is introduced into a 10 mL bottle. Mobile phase, with 0.04% dimethylformamide (DMF), is added to a total mass of 10 g.The composition of this mobile phase is as follows: NaHCOs: 0.05 mol / L, NaNOs: 0.1 mol / L, triethanolamine: 0.02 mol / L, NaNs 0.03% by mass. The CES chain is composed of a Waters 510 isocratic pump, whose flow rate is set at 0.8 mL / min, a Waters 717+ autosampler, an oven containing a Waters Guard Column Ultrahydrogel precolumn of 6 cm length and 40 mm inner diameter, followed by a Waters Ultrahydrogel linear column of 30 cm length and 7.8 mm inner diameter. Detection is ensured by means of a Waters RI 410 differential refractometer. The oven is brought to the temperature of 60°C and the refractometer is brought to the temperature of 45°C. The CES device is calibrated with a series of sodium polyacrylate standards supplied by Polymer Standards Service with peak molecular weights ranging from 1000 g / mol to 1.10. 6g / mol and a polydispersity index between 1.4 and 1.7. The calibration curve is linear and takes into account the correction obtained using the flow marker: dimethylformamide (DMF).

[0086] Method of preparing the composition

[0087] Said composition can be prepared by different processes. Said fluoropolymer PI and said copolymers P2 and optionally P3 can be mixed with each other in the form of powder or latex.

[0088] Alternatively, said composition may be in the form of an interpenetrating (IPN) or semi-interpenetrating (semi-IPN) polymer network. An interpenetrating (IPN) polymer network is defined as a network in which the polymers are at least partially intertwined at the molecular level but not covalently bonded to each other and which can only be separated if chemical bonds are broken. A semi-interpenetrating (semi-IPN) polymer network comprises one or more polymer networks and one or more linear or branched polymers and is characterized by the molecular-level penetration of at least one of the networks by at least some of the linear or branched macromolecules. A mixture of two or more preformed polymer networks is not an interpenetrating polymer network or a semi-interpenetrating polymer network.In this case, said composition can be prepared by a process comprising the steps of: a) Providing a reactor containing said fluorinated polymer PI, b) Adding at least one monomer M2a, at least one monomer M2b and optionally one monomer M2c as defined above; c) Carrying out the polymerization of said at least one monomer M2a and at least one monomer M2b and optionally said monomer M2c to obtain said composition according to the present invention; d) Optionally drying and grinding the product obtained in step c).

[0089] In step a), said fluorinated polymer PI is preferably in the form of a latex.

[0090] During step b), the polymer PI and said at least one monomer M2a, M2b and optionally said monomer M2c are brought into contact for a sufficiently long time to allow said monomers to impregnate the particles of the fluoropolymer PI before carrying out the polymerization thereof. This contact time may be at least 5 minutes, preferably 10 minutes, in particular at least 15 minutes. The longer the contact time between the monomers and the fluoropolymer PI, the more intimate the mixture between the polymer PI and the copolymer P2; which can make it possible to improve the adhesion properties of the composition.

[0091] Step c) is preferably carried out in the presence of water. Polymerization step c) is carried out in the presence of an initiator. Said initiator may be a persulfate initiator such as sodium persulfate, potassium persulfate, barium persulfate, or ammonium persulfate; alkali metal bisulfites; peroxides such as benzoyl peroxide, or dicumyl peroxide; hydroperoxides such as methyl hydroperoxide or tert-butyl hydroperoxide; acyloins such as benzoin; peracetates such as methyl peracetate, tert-butyl peracetate; perbenzoates such as tert-butyl perbenzoate; peroxalates such as dimethyl peroxalate or di(tert-butyl) peroxalate; azo-type compounds such as azo-bisisobutyronitrile or dimethyl azo-bis-isobutyrate.The initiator is preferably added in a content of 0.005 to 1% by weight based on the weight of said M2a, M2b and optionally M2c. Step c) can be carried out at a temperature of 20°C to 160°C. Step c) can be carried out at a pressure of 280 to 20000 kPa. Preferably, steps b) and c) are carried out with stirring. The polymerization product obtained in step c) is optionally dried in step d) to obtain a powder. The drying step can be carried out by atomization or co-atomization, preferably at a temperature of 50°C to 220°C. If it is desired to obtain said composition in powder form, it can also be obtained by grinding techniques, such as cryo-grinding, where the mixture is brought to a temperature below room temperature, using liquid nitrogen for example, before grinding.At the end of the powder manufacturing step, namely after the drying step, the particle size can be adjusted and optimized by selection or screening processes and / or by grinding to obtain the desired particle size distribution.

[0092] Use

[0093] Said composition as described in the present application can be used in numerous applications. Thus, said composition can be used as a binder for an electrode (cathode or anode) or as a coating for a separator.

[0094] Said composition according to the present invention can be used as a binder for an electrode. Thus, the present invention provides an electrode composition comprising said composition according to the present invention, an active material and optionally a conductive agent.

[0095] In a preferred embodiment, the electrode composition has the following mass composition: a. 50% to 99.95% active material, preferably 50% to 99%, b. 0% to 25% conductive agent, preferably 0.5% to 25%, c. 0.05% to 25% of said binder according to the invention, preferably 0.5% to 25%, d. 0% to 5% of at least one additive selected from the group consisting of a plasticizer, an ionic liquid, a dispersing agent for conductive additive, and a flow aid; the sum of all these percentages being 100%.

[0096] The conductive agents in the electrode are composed of one or more materials that can improve conductivity. Some examples include carbon blacks such as acetylene black, Ketjen black; carbon fibers, such as carbon nanotube, carbon nanofiber, vapor-grown carbon fiber; metal powders such as SUS powder, and aluminum powder.

[0097] Active materials in electrode compositions are materials that are capable of storing and releasing lithium ions.

[0098] In a preferred embodiment, said electrode is a negative electrode. In particular, for a negative electrode, said active material is selected from the group consisting of a lithium alloy, lithium metal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, a silicon alloy, and Li4Ti50i2. The shape of the negative electrode active material is not particularly limited but is preferably particulate.

[0099] In another preferred embodiment, said electrode is a positive electrode. Preferably, for a positive electrode, said active material is selected from the group consisting of LiCoCh, Li(Ni, Co, AI)C>2, Li(i + X )NiaMnbCo c(x represents a real number of 0 or more, a = 0.9, 0.8, 0.6, 0.5, or 1 / 3, b = 0.05, 0.1, 0.2, 0.3, or 1 / 3, c = 0.05, 0.1, 0.2, or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, LisNiMnsOs, LÎ3Fe2(PO4)3, LÎ3V2(PO4)3, a spinel Li Mn substituted by a different element having a composition represented by Lil+xMn2-x-yMyO4, M represents at least one metal selected from Al, Mg, Co, Fe, Ni, and Zn, x and y independently represent a real number between 0 and 2, lithium titanate Li x TiO y- x and y independently representing a real number between 0 and 2, and a lithium metal phosphate having a composition represented by LÎMPO4, M representing Fe, Mn, Co, or Ni. The shape of the positive electrode active material is not particularly limited but is preferably particulate. In addition, the surface of each of the materials described above can be coated. The coating material is not particularly limited as long as it has lithium ion conductivity and contains a material capable of being maintained as a coating layer on the surface of the active material. Examples of the coating material include LiNbOs, Li4TisOi2, and LisPC .

[0100] Said electrode composition can be deposited on at least one face of a current collector to form said electrode. This deposition can be carried out in the presence of an organic solvent, water, a mixture of both or by a solvent-free process, i.e. by a dry coated electrode production process. Said organic solvent can be selected from the group consisting of n-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), N,N- dimethylformamide (DMF), triethylphosphite, triethylphosphate, acetone, cyclopentanone, tetrahydrofuran, methyl ethylketone (MEK), methyl isobutyl ketone (MiBK), ethyl acetate (EA), butyl acetate (BA), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), gamma-butyrolactone and N- butylpyrrolidone; and mixtures thereof.

[0101] Said method of preparing the dry coated electrode comprises the following steps:

[0102] - mixing the active material in powder form, said binder according to the present invention, and optionally the conductive agent in powder form, the additive in powder form or both to form said electrode composition according to the present invention;

[0103] - depositing said electrode composition on said current collector to manufacture an electrode, and

[0104] - optionally consolidation of said electrode by thermomechanical treatment.

[0105] Said dry coated electrode is thus prepared according to a “solvent-free” process, i.e. one which does not require a residual solvent evaporation step after the deposition step because all the constituents are mixed in the dry state, in powder form, and the deposition is also carried out without solvent. A thermomechanical treatment refers to the application of mechanical pressure to the electrode at a given temperature. Such a thermomechanical treatment can be carried out, for example, by a calendering machine comprising rollers which can be heated or a plate press which can also be heated.As solvent-free mixing processes of the various constituents of the electrode composition before the deposition phase on the collector, the following may be mentioned, without being exhaustive: Tl mixing by stirring, air jet mixing, high shear mixing, mixing by V mixer, mixing by screw mass mixer, double cone mixing, drum mixing, conical mixing, double Z arm mixing, fluidized bed mixing, planetary mixer mixing, mechanical melting mixing, extrusion mixing, calendering mixing, grinding mixing.

[0106] According to one embodiment, after the powder mixing step, the electrode is manufactured by a solvent-free spraying process, by depositing the electrode composition on the metal substrate, by a pneumatic spraying process, by electrostatic spraying, by dipping in a fluidized powder bed, by sprinkling, by electrostatic screen printing, by deposition with rotating brushes, by deposition with rotating addition rollers, by calendering. According to one embodiment, the consolidation of the electrode after a deposition process on the metal substrate by solvent-free spraying (pneumatic spraying process, by electrostatic spraying, by dipping in a fluidized powder bed, by sprinkling, by electrostatic screen printing, by deposition with rotating brushes, by deposition with rotating addition rollers) is carried out by a calendering process.This process involves applying pressure to the electrode using two rollers, possibly heated. The consolidation step is optional. Its implementation depends on the technique used to deposit the constituents on the electrode. Thus, when the deposition step has been implemented by calendering, this consolidation step is optional because calendering allows the electrode to be deposited and consolidated simultaneously.

[0107] According to one embodiment, after the powder mixing step, the electrode is manufactured by a two-step solvent-free process. A first step consists of manufacturing a self-supporting film from the premixed formulation with a thermomechanical process such as extrusion, calendering or thermocompression. In a second step, the self-supporting film is laminated onto the metal substrate by a process combining temperature and pressure such as calendering or thermocompression.

[0108] According to one embodiment, after the powder mixing step, the electrode is manufactured by a solvent-free process using a calendering process which makes it possible to carry out the film-forming step and transfer of the coating onto the current collector in a single step, i.e. without going through a step of manufacturing a self-supporting film. To do this, the calender used has several rollers (at least three). The powder obtained after the mixing step is introduced between the first two rollers, most often heated and having differential rotation speeds to shear the powder. The coating formed and remaining stuck on the fastest roller is then directly laminated onto the current collector with a third roller. The electrode thus obtained can be subsequently passed through a calender to adjust its porosity or thickness if necessary.

[0109] According to another aspect of the present invention, said composition according to the present invention can be used as a coating in a separator arranged between two electrodes. Said separator according to the present invention comprises a coating comprising, preferably consisting of, said composition according to the present invention, optionally arranged on one or both faces of a porous support. In this case, the coating is used to coat the support of a separator, on at least one face, in the form of a monolayer or multilayers. There is no particular limitation in the choice of the support which is coated with the coating of the invention, as long as it is a porous substrate having pores. When it comprises several layers, the coating as described in the present invention is arranged on the external face of the support, that is to say on the face which will first be in contact with the electrolytic composition used in the battery.Advantageously, the application of the coating to the support is carried out by aqueous or solvent means. The porous substrate may take the form of a membrane or a fibrous fabric. When the porous substrate is fibrous, it may be a non-woven web forming a porous web, such as a web obtained by direct spinning or melt-blowing (of the "spunbond" or "melt-blown" type) or electro-spinning. Examples of porous substrates useful in the invention as a support include, but are not limited to: polyolefins, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, poly(phenylene oxide), poly(phenylene sulfide), polyethylene naphthalene or mixtures thereof. However, other heat-resistant engineering plastics may be used without particular limitation.Nonwoven materials made of natural and synthetic materials can also be used as the separator substrate. The porous substrate generally has a thickness of 1 to 50 µm, and are typically membranes obtained by extrusion and stretching (wet or dry process) or cast nonwovens. The porous substrate preferably has a porosity of between 5% and 95%. The average pore size (diameter) is preferably between 0.001 and 50 µm, more preferably between 0.01 and 10 µm. The support can also be aluminum or aluminum coated with a polymer layer.

[0110] In addition to said composition, the separator coating may contain inorganic particles that serve to form micropores in the coating (the interstices between inorganic particles). The addition of inorganic particles may also contribute to heat resistance or improve wettability. In one embodiment, said coating comprises from 50 to 99 percent by weight of inorganic particles, based on the weight of the coating. These inorganic particles must be electrochemically stable (not subject to oxidation and / or reduction in the range of voltages used). In addition, powdered inorganic materials preferably have high ionic conductivity. Materials with low density are preferred over materials with higher density, since the weight of the produced battery can be reduced. The dielectric constant is preferably equal to or greater than 5.According to one embodiment, said inorganic particles are chosen from the group consisting of: BaTiOs, Pb(Zr,Ti)Os, Pbi. x LaxZr y O3 (0 <x<l, 0<y<l), PbMg3Nb2 / 3)3,PbTiC> 3, hafnia (HfO or HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2O3, bohemite (y-AIO(OH)), AI2O3, TiO2, SiC, ZrO2, boron silicate, BaSO4, nano-clays, or mixtures thereof. The separator coating may optionally comprise from 0 to 15% by weight based on the polymer, and preferably 0.1 to 10% by weight of additives, selected from thickeners, pH adjusting agents, anti-settling agents, surfactants, wetting agents, fillers, anti-foaming agents and fugitive or non-fugitive adhesion promoters. The fillers mentioned herein in the additives are different from the inorganic particles mentioned above.

[0111] According to an alternative embodiment, said separator does not comprise a porous support. In this case, said separator consists of the coating as described above and comprising said composition; this is deposited directly on the cathode or on the anode of the electrochemical device. The absence of a porous support makes it possible to limit the production costs of the electrochemical device and the dimensions thereof. In this case, said coating replaces the porous support. In this embodiment, said composition preferably has a porosity of 5 to 95%. The separator coating of the invention has an excellent compromise of properties for the application of separator coating: good adhesion in the dry and wet state, good resistance to electrolyte solvent(s) characterized by good retained integrity and moderate swelling.

[0112] According to another aspect of the present invention, a Li-ion battery is provided. Preferably, the Li-ion battery comprises a positive electrode, a negative electrode and a separator. At least one of the electrodes is an electrode according to the present invention or the separator is a separator according to the present invention. Preferably, said Li-ion battery also comprises a lithium salt selected from the group consisting of LiCFsSOs, LiPFg, LiCIO4, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2C2F5)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2C2F5), LÎN(SO2CF3)(SO2C2F5), LiAsFg, LÎBF2C2O4, LÎNO3, LÎPF3(CF2CF3)3, LÏBETI, LÏTDI, or a mixture thereof.

[0113] According to another aspect of the present invention, said composition can be used in the preparation of a conductive polymer, a solid electrolyte for fuel cells, a hydrophilic coating, a hydrophobic coating or a UV absorbing coating. Said composition can be used as an adhesive for a multilayer structure extruded in the form of a film, a sheet or a tube. Said composition can also be used as a coating on a metal.

[0114] Examples

[0115] Method for preparing polymers P2 according to the invention

[0116] P2A polymer

[0117] In a 1000ml glass reactor equipped with mechanical stirring and oil bath heating, 796g of deionized water and 5.9g of sodium dodecyl sulfate are weighed. The mixture is then heated to 78°C. In a first container, 33g of 2 (methacryloyloxy) ethyl acetoacetate and 297.1g of methyl methacrylate are weighed. In a second container, a solution of 0.99g of ammonium persulfate dissolved in 20g of deionized water. In a third container, 3.3g of a 50% solution of sodium 2-acrylamido-2-methyl-l-propanesulfonate (AMPS). The persulfate solution, the sodium 2-acrylamido-2-methyl-l-propanesulfonate solution and 16.5g of the mixture from the first container are then introduced once.

[0118] The mixture is then cooked for 15 minutes, then the remaining contents of the first container are added over two hours at a temperature of 78°C using a peristaltic pump. The pump is then rinsed with 10g of deionized water. A solution consisting of 0.3g of sodium persulfate and 25g of deionized water is then added over an hour at 78°C. The mixture is cooked for another hour at 78°C. A latex containing 26% dry matter is obtained, the particles of which have an average median diameter of 43nm.

[0119] P2B Polymer

[0120] Polymer P2B is prepared in the same manner as polymer P2A except that sodium 2-acrylamido-2-methyl-l-propanesulfonate (AMPS) solution is not introduced.

[0121] Preparation of the P3A polymer In a 1000ml glass reactor equipped with mechanical stirring and oil bath heating, 796g of deionized water and 5.9g of sodium dodecyl sulfate are weighed. The whole is then heated to 78°C.

[0122] In a first container, 33g of acrylic acid and 297.1g of methyl methacrylate are weighed. In a second container, a solution of 0.99g of ammonium persulfate dissolved in 20g of deionized water. In a third container, 3.3g of a 50% solution of sodium 2-acrylamido-2-methyl-l-propanesulfonate are added. The persulfate solution, the sodium 2-acrylamido-2-methyl-l-propanesulfonate solution and 16.5g of the mixture from the first container are then quickly introduced all at once. The mixture is then cooked for 15 minutes and then the remaining contents of the first container are added over two hours at a temperature of 78°C using a peristaltic pump. The pump is then rinsed with 10g of deionized water. A solution of 0.3g of sodium persulfate and 25g of deionized water is then added over 1 hour at 78°C. The process is then cooked for another hour at 78°C. A latex containing 26.4% dry matter is obtained, the particles of which have an average median diameter of 45 nm.

[0123] P3B Polymer

[0124] Polymer P3B is prepared in the same manner as polymer P3A except that sodium 2-acrylamido-2-methyl-l-propanesulfonate (AMPS) solution is not introduced.

[0125] Method of preparing the mixtures

[0126] PI is a homopolymer of vinylidene fluoride having a melt viscosity of 47-53 kPoise according to ASTM D-3835 measured at 232°C and 100 sec 1 .

[0127] P2A is a copolymer of methyl methacrylate, acetoacetoxy-methyl methacrylate and AMPS in a molar ratio of 89.5 / 10 / 0.5. P2B is a copolymer of methyl methacrylate and acetoacetoxy-methyl methacrylate in a molar ratio of 90 / 10. AMPS is optionally used as a comonomer to promote emulsion stability if necessary.

[0128] P3A is a copolymer of methyl methacrylate, AMPS and acrylic acid in a molar ratio of 89.5 / 0.5 / 10. P3B is a copolymer of methyl methacrylate, and acrylic acid in a molar ratio of 90 / 10.

[0129] The latexes P2A, P2B, P3A and P3B were freeze-dried, and then these copolymers were mixed with the polymer PI with a mass ratio P1 / [P2+P3] 90 / 10 and 92% by weight of N-methylpyrrolidone (NMP) as organic solvent to form the binder solution. Table 1 lists the different mixtures studied.

[0130] [Table 1]

[0131] * P2A, P2B, P3A, P3B refers to the polymer used in the example. Ratio refers to the mass ratio

[0132] Preparation of the mud composition for the positive electrode

[0133] 97 wt% LiNi0.gCo0.1Mn0.1O2 (NMC) as the positive electrode active material, 1.5 wt% C65 carbon black as the conductive material, 1.5 wt% binder solution, and an appropriate amount of N-methylpyrrolidone (NMP) as the organic solvent were mixed in a Thinky mixer. The solids concentration was then 72 wt%. Then, NMP was added, so that the viscosity at a shear rate of 10 s-1 was about 4000-6000 mPa-s, to prepare a dispersion for a positive electrode.

[0134] An aluminum foil with a thickness of 20 μm was prepared as a current collector.

[0135] The obtained suspension composition for a positive electrode was applied to one side of the aluminum foil so that the coating amount after drying was 22 mg / cm2, and coated in a coating line with a coating speed of 0.2 m / min and a drying temperature of 50 °C and 90 °C. This positive electrode strip was then rolled by pressing to produce a positive electrode in the form of a sheet composed of an aluminum foil (current collector) and a layer of positive electrode mixed material with a density of 3.4 g / cm3.

[0136] Peel Measurement Method Peel tests were performed on the electrode at 180° according to ASTM D903 at a speed of 25mm / min at 25°C to evaluate the adhesion of the electrode composition coating to the metal foil.

[0137] Lithium half-cell batteries (type CR2032, diameter 20 mm) were prepared in a dry room with a dew point of -40°C by puncturing a small disc (diameter = 12 mm) of the prepared electrode, with lithium metal (diameter = 12 mm) as a counter / reference electrode. Lithium hexafluorophosphate (Li PF6) was dissolved in a mixture of ethylene carbonate and ethyl methyl carbonate (weight ratio = 3:7) so as to obtain a concentration of 1 mol / L of non-aqueous electrolyte solution. The positive electrode and the negative electrode were opposed to each other through a microporous glass microfiber (separator) with a thickness of 300 μm, and 100 μL of the non-aqueous electrolyte solution obtained above was injected; After the non-aqueous electrolytic solution has sufficiently penetrated into the separator or the like, the button cell was sealed, pre-charged and aged to make a lithium-ion half-cell.

[0138] Method of measuring retention capacity

[0139] After the initial charge and discharge cycles at a low current of 0.1C (forming stage), each of the half-cells prepared as described above was subjected to a galvanostatic cycle. Either, charge / discharge cycles were carried out by charging with a constant voltage equivalent to 0.1C (hereinafter referred to as CC / CV charge) (cutoff of 0.05C) up to 4.2V, it is constantly discharged up to 3V with an equivalent current ranging in the order of 0.2C, 0.3C, 0.5C, 1C to 2C where 1C represents the value of the current discharging the reference capacity of the battery in 1 hour, for example, 0.2C represents its current value of 1 / 5 of an hour. The ratio of 2C discharge capacity to 0.1C discharge capacity was calculated as follows: charge characteristic 2C / 0.1C (%) (2C discharge capacity) (0.1C discharge capacity) xl00=2C / 0.1C. The results are reported in Table 2.

[0140] [Table 2]

[0141] *KF WU9700 (Kureha Corporation) is a copolymer of vinylidene fluoride with a monomer comprising an acid group

[0142] As we can see in Table 2, the electrode compositions according to the invention comprising a polymer P2 make it possible to obtain electrodes having both good retention capacity and very good adhesion.

Claims

Claims 1. Composition comprising a fluorinated polymer PI comprising monomeric units derived from a fluorinated monomer Mla and a copolymer P2 comprising monomeric units derived from a monomer M2a of formula (la) R 1 R 2 C=C(R 3 )C(O)R or (Ib) R 1 R 2 C=C(R 3 )R" and monomeric units derived from a monomer M2b of formula (II) in which the substituents R 1 , R 2 and R 3are, independently of each other, selected from the group consisting of H, C1-C5 alkyl and NH2; R" is selected from the group consisting of Cg-Ci2 aryl and CN; R is selected from the group consisting of - NHC(CH3)2CH2C(O)CH3 OR -OR' with R' selected from the group consisting of H and C1-Cis alkyl optionally substituted with one or more groups -OH, CO2H, SO3H, PO3H, -OC(O)R”, -C(O)OR or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; R is selected from the group consisting of C1-C8 alkyl or C1-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H; R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C5 alkyl; R 7 and R 8are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C5 alkyl; X is selected from the group consisting of C1-C18 alkyl and C4-C18 cycloalkyl; n is an integer from 1 to 10, preferably from 1 to 5, in particular n is 1.

2. Composition according to the preceding claim, characterized in that the substituents R 4 , R 5 , R 6 and R 9 are, independently of each other, selected from the group consisting of H and C1-C3 alkyl and R 7 and R 8 are, independently of each other and independently for each unit n, selected from the group consisting of H and C1-C3 alkyl.

3. Composition according to any one of the preceding claims, characterized in that the substituents R 1 , R 2 and R 3are, independently of each other, selected from the group consisting of H and C1-C3 alkyl; R is -OR' with R' selected from the group consisting of H and C1-C10 alkyl optionally substituted with one or more groups -OH, CO2H, SO3H, PO3H, -OC(O)R ”, -C(O)OR with R is selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted with one or more groups -OH, -CO2H, -SO3H, -PO3H.

4. Composition according to any one of the preceding claims, characterized in that the substituent X is selected from the group consisting of C1-C10 alkyl and C4-C10 cycloalkyl.

5. Composition according to any one of the preceding claims, characterized in that said composition also comprises a copolymer P3 comprising monomeric units derived from at least two monomers M3a and M3b of formula (I) R 1 R 2 C=C(R 3 )C(O)R in which the substituents R1 , R 2 and R 3 are, independently of each other, 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' with R' selected from the group consisting of H and C1-C5 alkyl optionally substituted by one or more groups -OH, CO2H, SO3H, PO3H, -OC(O)R”, -C(O)OR or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain; with R selected from the group consisting of C1-C8 alkyl or C8-C12 aryl optionally substituted by one or more groups -OH, -CO2H, -SO3H, -PO3H.

6. Composition according to any one of the preceding claims, characterized in that said fluorinated monomer Mla is selected from the group consisting of vinyl fluoride; vinylidene fluoride (VDF); 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); the monomer of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPC>3H; the monomer of formula CF2=CFOCF2CF2SO2F; the monomer of formula F(CF2)nCH2OCF=CF2in which n is 1, 2, 3, 4 or 5; the monomer of formula R 1 CH2OCF=CF2in which R 1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the monomer of formula R 2 OCF=CH2in which R2 is F(CF2)p and p is 1, 2, 3 or 4; trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-trifluoro-l-propene or a mixture thereof.

7. Composition according to any one of the preceding claims, characterized in that said fluorinated monomer Mla is vinylidene fluoride and optionally said polymer PI also comprises monomeric units derived from a monomer Mlb selected from the group consisting of vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene; tetrafluoroethylene; hexafluoropropylene; perfluoro(alkyl vinyl) ethers such as perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether and perfluoro(propyl vinyl) ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the monomer of formula CF2=CFOCF2CF(CF3)OCF2CF2X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPC>3H; the monomer of formula CF2=CFOCF2CF2SO2F; the monomer of formula F(CF2)nCH2OCF=CF2in which n is 1, 2, 3, 4 or 5; the monomer of formula R 1 CH2OCF=CF2in which R 1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the monomer of formula R2 OCF=CH2in which R 2 is F(CF2)p and p is 1, 2, 3 or 4; trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-trifluoro-l-propene or a mixture thereof.

8. Composition according to any one of the preceding claims, characterized in that said fluoropolymer PI has a viscosity in the molten state greater than 1000 Pa.s according to the ASTM D-3835 method measured at 232°C and 100 sec 1 .

9. Composition according to any one of the preceding claims, characterized in that said copolymer P2 has a number-average molecular mass greater than or equal to 1000 g. mol 1 .

10. Composition according to any one of the preceding claims, characterized in that the mass ratio Pl / P2 is from 50 / 50 to 99 / 1, preferably from 70 / 30 to 95 / 5.

11. Electrode binder comprising said composition according to any one of the preceding claims.

12. Electrode composition comprising said binder according to the preceding claim, an active material and optionally a conductive agent, an additive or a mixture of the two.

13. Electrode composition according to the preceding claim, characterized in that it comprises a conductive agent being composed of one or more materials selected from the group consisting of carbon black, graphite, carbon fibers, carbon nanotubes, carbon nanofibers, metal powders such as an SUS powder and an aluminum powder, or mixtures thereof.

14. Electrode composition according to any one of the preceding claims 10 or 11 wherein said active material is selected from the group consisting of: LiCoO2, Li(Ni, Co, AI)O2, Li(i + X )NiaMnbCo c(x represents a real number of 0 or more, a = 0.9, 0.8, 0.6, 0.5, or 1 / 3, b = 0.05, 0.1, 0.2, 0.3, or 1 / 3, c = 0.05, 0.1, 0.2, or 1 / 3), LiN iO2, LiMn2O4, LiCoMnO4, Li3NiMn3O3, Li3Fe2(PO4)3, Li3V2(PO4)3, a Li Mn spinel substituted by a different element having a composition represented by Lii +x Mn2.x-yMyO4, M representing at least one metal selected from Al, Mg, Co, Fe, Ni, and Zn, x and y independently representing a real number between 0 and 2, lithium titanate Li x TiO y - x and y independently representing a real number between 0 and 2, and a lithium metal phosphate having a composition represented by LiMPO4, M representing Fe, Mn, Co, or Ni.

15. An electrode composition according to any one of the preceding claims 10 or 11 wherein said active material is selected from the group consisting of a lithium alloy, lithium metal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, silicone, a silicon alloy and Li4Ti50i2.

16. Electrode comprising a current collector and a layer consisting of said electrode composition according to any one of the preceding claims 10 to 13, preferably said layer is in contact with the current collector.

17. Coating for a separator in a Li-ion battery comprising said composition according to any one of claims 1 to 8.

18. Separator for Li-ion battery comprising said coating according to the preceding claim and optionally inorganic particles are chosen from the group consisting of: BaTiOs, Pb(Zr,Ti)C>3, Pbi. x LaxZry 03 (0 <x<l, 0<y<l), PbMg3Nb2 / 3O3,PbTiC> 3, hafnia (HfO, HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2O3, bohemite (y-AIO(OH)), AI2O3, TiÜ2, SiC, ZrÜ2, boron silicate, BaSO4, nano-clays, or mixtures thereof.

19. Li-ion battery comprising a positive electrode, a negative electrode and a separator, characterized in that at least one of the electrodes is an electrode according to claim 14 or said separator is a separator according to claim 16.

20. Use of said composition according to any one of claims 1 to 8 for the preparation of a conductive polymer, a solid electrolyte for fuel cells, a hydrophilic coating, a hydrophobic coating or a UV-absorbing coating; or as an adhesive for a multi-layer structure extruded in the form of a film, a sheet or a tube; or said copolymer is used as a coating on a metal.

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