Electrochemical device comprising a separator containing pvdf and a high-viscosity or high-polarity electrolytic composition

Abstract

The present invention relates to an electrochemical device comprising a separator and an electrolytic composition, characterised in that said separator comprises at least one coating comprising a polymer resin comprising vinylidene fluoride monomer units and monomer units of the formula R1R2C=C(R3)C(O)R, wherein the substituents R1, R2 and R3 are independently selected from the group consisting of H and a C1- C5 alkyl; R is selected from the group consisting of –NHC(CH3)2CH2C(O)CH3 or – OR' where R' is selected from the group consisting of H and a C1-C18 alkyl optionally substituted by one or more –OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain, and said electrolytic composition comprises a solvent and a lithium salt; said electrolytic composition having a viscosity greater than 2 cP measured at 20°C and with a shear of 20s-1 or said solvent having a dipole moment greater than 2 Debye at 25°C.

Description

[0001] containing PVDF and one with high viscosity or high

[0002] 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 an electrochemical device comprising a separator specifically adapted to electrolytes with high viscosity or high polarity.

[0003] Technological background of the present invention

[0004] The market for separators for electrochemical devices is dominated by the use of polyolefins (e.g., Celgard® or Hipore®) produced by extrusion and / or stretching via dry or wet processes. Separators must have low thicknesses, sufficient mechanical and temperature resistance, good electrochemical resistance to the voltages to which they are exposed, optimal affinity for the electrolyte, and more generally, excellent ionic conductivity. Among the most interesting alternatives to polyolefins, polymers with better affinity for standard electrolytes have been proposed, in order to reduce the internal resistances of the system, such as poly(methylmethacrylate) (PMMA), poly(vinylidene fluoride) (PVDF), and poly(vinylidene fluoride-hexafluoropropene) (P(VDF-co-HFP)). Another option is to deposit a coating on one or both sides of the polyolefin separator.In the presence of the electrolyte used in electrochemical devices, the separator must have good wettability to enable good efficiency of the device. However, separators based on polyolefins such as polypropylene or polyethylene have poor wettability in the presence of high viscosity electrolyte or in the presence of high polarity electrolyte. The electrochemical device is then penalized by a long induction period to reach its initial performance (negative impact on cell construction and productivity), then more generally shows poor performance both in charge and discharge.

[0005] Polyvinylidene fluoride (PVDF) and its derivatives are of interest as polyolefin separator coatings, due to their electrochemical stability and high dielectric constant, which promotes ion dissociation and therefore conductivity. P(VDF-co-HFP) copolymer (vinylidene fluoride (VDF) and hexafluoropropylene (HFP) copolymer) has lower crystallinity than PVDF. Therefore, the interest of these P(VDF-co-HFP) copolymers is that they promote conductivity.

[0006] Document EP 2 528 141 describes a separator for a secondary battery comprising a porous substrate, an adhesive layer and a polar electrolyte. It was found that the wettability of the separator in the presence of a polar electrolyte was not sufficient.

[0007] There is still a need to develop new coatings for separators that are easy to process and that exhibit a good compromise between dry adhesion, wet adhesion, ionic conductivity and thermal stability while exhibiting good wettability towards high viscosity electrolytes or high polarity electrolytes.

[0008] The invention therefore aims to remedy at least one of the drawbacks of the prior art, namely to propose a polymeric coating for a separator capable of promoting wettability with respect to high viscosity electrolytes or high polarity electrolytes.

[0009] Summary of the invention

[0010] The present invention provides an electrochemical device comprising a separator and an electrolytic composition, characterized in that: i) said separator comprises at least one coating comprising a polymer resin comprising monomeric units of vinylidene fluoride and monomeric units of formula 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 with one or more -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its ring chain, and ii) said electrolyte composition comprises a solvent and a lithium salt; said electrolyte composition having a viscosity greater than 2 cP measured at 20°C and with a shear of 20s 1 or said solvent having a dipole moment greater than 2 Debye at 25°C.

[0011] The use of a specific coating based on a fluoro-acrylic polymer resin allows the implementation of an efficient and effective electrochemical device when the electrolytic composition used has a high viscosity or a high polarity. These performances, particularly in terms of wettability, are highly sought after. Indeed, the good wettability observed makes it possible to reduce the time required to achieve a uniform distribution of the viscous or highly polar electrolyte within the separator and therefore within a lithium-ion battery. The improvement in wettability also makes it possible to increase battery filling rates. This uniform distribution of viscous or highly polar electrolytic compositions is not observed or is difficult to achieve when the separator is based on polyolefins or fluoropolymer without an acrylate or acrylic component.

[0012] According to a preferred embodiment, said electrolytic composition has a viscosity greater than 5 cP, preferably greater than 10 cP, in particular greater than 15 cP measured at 20°C and with a shear of 20 s -1 .

[0013] According to a preferred embodiment, said electrolytic composition has a viscosity of less than 1000 cP measured at 20°C and with a shear of 20 s -1 .

[0014] According to a preferred embodiment, said solvent has a dipole moment greater than 2.5 Debye, preferably greater than 3.0 Debye, more preferably greater than 3.5 Debye, in particular greater than 4.0 Debye at 25°C. According to a preferred embodiment, said polymer resin is a copolymer comprising monomeric units of vinylidene fluoride and monomeric units of formula R 1 R 2 C=C(R 3)C(O)R or said polymer resin is a mixture between a fluoropolymer comprising monomeric units of vinylidene fluoride and an acrylic polymer comprising monomeric units of formula R 1 R 2 C=C(R 3 )C(O)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-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 with one or more -OH groups or a five or six-membered heterocycle comprising at least one nitrogen atom in its ring chain.

[0015] According to a preferred embodiment, said polymer resin is a mixture between a fluoropolymer comprising monomeric units of vinylidene fluoride and an acrylic polymer comprising monomeric units of formula 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 -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its ring chain; and said fluoropolymer is selected from the group consisting of polyvinylidene fluoride homopolymers and copolymers based on polyvinylidene fluoride and at least one comonomer compatible with vinylidene fluoride.

[0016] According to a preferred embodiment, said comonomers are chosen from: vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropenes, tetrafluoropropenes, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes, perfluoroalkylvinylethers, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene, chlorotrifluoropropene and ethylene. According to a preferred embodiment, said fluoropolymer is a polyvinylidene fluoride-hexafluoropropylene copolymer having a weight percentage of hexafluoropropylene monomer units of 2 to 25%, preferably 4 to 15% by weight relative to the weight of the copolymer.

[0017] According to a preferred embodiment, said fluoropolymer comprises monomer units carrying at least one of the following functions: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy, amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolic, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, or phosphonic groups.

[0018] According to a preferred embodiment, said acrylic polymer contains a monomer selected from the group consisting of 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, hydroxybutyl acrylate, hydroxypropyl methacrylate, methyl acrylic acid, methyl methacrylate, ureido methacrylate and combinations thereof.

[0019] According to a preferred embodiment, said coating comprises inorganic particles selected from the group consisting of: BaTiOs, Pb(Zr,Ti)03, Pb i- x There x Zr y03 (0 <x<l, 0<y<l), PBMg3Nb2 / 3)3,PbTiO3, hafnie (HfO (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2Û3, bohémite (y-AIO(OH)), AI2Û3, TiO2, SiC, ZrO2, silicate de bore, BaSÛ4, nano-argiles, ou leurs mélanges.

[0020] According to a preferred embodiment, said device is selected from the group consisting of a Li-ion battery, a capacitor, an electric double-layer capacitor, and a membrane-electrode assembly (MEA) for a fuel cell; preferably a Li-ion battery.

[0021] According to a preferred embodiment, said device is a Li-ion secondary battery and also comprises an anode and a cathode.

[0022] Detailed Description of the Present Invention The present invention relates to an electrochemical device. Said electrochemical device notably comprises a separator and an electrolytic composition which are described in more detail below. In addition to these two components, said electrochemical device comprises an anode and a cathode. Said separator according to the present invention is disposed between the anode and the cathode of said electrochemical device. Preferably, the electrochemical device is selected from the group consisting of a Li-ion battery, a capacitor, an electric double-layer capacitor, and a membrane-electrode assembly (MEA) for a fuel cell. Preferably, said electrochemical device is a Li-ion secondary battery.

[0023] The invention relates to an electrochemical device comprising a separator comprising at least one coating. Said coating contains a polymer resin comprising monomeric units of vinylidene fluoride and monomeric units of formula 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 -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its ring chain. Said polymer resin thus comprises a fluorinated part and an acrylic part. Said resin may be in the form of a mixture between a fluorinated polymer and an acrylic polymer or in the form of a copolymer of fluorinated monomeric units and acrylic monomeric units.

[0024] Preferably, said polymer resin is present in non-crosslinked form in the separator coating. Said polymer resin may be linear or branched.

[0025] According to various embodiments, said coating comprises the following characteristics, where appropriate combined. The contents indicated are expressed by weight, unless otherwise indicated. For all the ranges indicated, the limits are included, unless otherwise indicated. According to a preferred embodiment, said polymer resin is a copolymer comprising monomeric units of vinylidene fluoride and monomeric units of formula R 1 R 2 C=C(R 3 )C(O)R. Said copolymer is described in more detail below.

[0026] According to another embodiment, said polymer resin is a mixture between a fluoropolymer comprising monomeric units of vinylidene fluoride and an acrylic polymer comprising monomeric units of formula 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 with one or more -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its ring chain. The fluoropolymer and the acrylic polymer are described below. i) Fluoropolymer

[0027] Said fluoropolymer is based on a vinylidene difluoride monomer and is generically designated by the abbreviation PVDF.

[0028] According to one embodiment, the fluoropolymer is poly(vinylidene fluoride) homopolymer.

[0029] According to another embodiment, the fluoropolymer is a copolymer of vinylidene difluoride with at least one comonomer compatible with vinylidene difluoride. The comonomers compatible with vinylidene difluoride may be halogenated (fluorinated, chlorinated or brominated) or non-halogenated. Examples of suitable fluorinated comonomers are: vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropenes and in particular 3,3,3-trifluoropropene, tetrafluoropropenes and in particular 2,3,3,3-tetrafluoropropene or 1, 3,3,3-tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes and in particular 1,1,3,3,3-pentafluoropropene or 1, 2, 3,3,3-pentafluoropropene, perfluoroalkylvinylethers and in particular those of general formula Rf-O-CF-CF2, Rf being an alkyl group, preferably C1 to C4 (preferred examples being perfluoropropylvinylether and perfluoromethylvinylether).The fluorinated comonomer may contain a chlorine or bromine atom. It may in particular be chosen from bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene and chlorotrifluoropropene. Chlorofluoroethylene may denote either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene. The 1-chloro-1-fluoroethylene isomer is preferred. Chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.

[0030] The VDF copolymer may also include non-halogenated monomers such as ethylene, and / or acrylic or methacrylic comonomers.

[0031] The fluoropolymer preferably contains at least 50 mol% vinylidene difluoride.

[0032] According to one embodiment, the fluoropolymer is a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) (P(VDF-HFP)), having a percentage by weight of hexafluoropropylene monomer units of 2 to 30%, advantageously of 2 to 25%, preferably of 2 to 20%, preferably of 4 to 15% by weight relative to the weight of the copolymer.

[0033] According to one embodiment, the fluoropolymer is a copolymer of vinylidene fluoride and tetrafluoroethylene (TFE).

[0034] According to one embodiment, the fluoropolymer is a copolymer of vinylidene fluoride and chlorotrifluoroethylene (CTFE).

[0035] According to one embodiment, the fluoropolymer is a VDF-TFE-HFP terpolymer. According to one embodiment, the fluoropolymer is a VDF-TrFE-TFE terpolymer (TrFE being trifluoroethylene). In these terpolymers, the mass content of VDF is at least 10%, the comonomers being present in variable proportions.

[0036] According to one embodiment, the fluoropolymer comprises monomer units carrying at least one of the following functional 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. The function is introduced by a chemical reaction which may be grafting, or a copolymerization of the fluoromonomer with a monomer carrying at least one of said functional groups and a vinyl function capable of copolymerizing with the fluoromonomer, according to techniques well known to those skilled in the art.

[0037] According to one embodiment, the functional group carries a carboxylic acid function which is a (meth)acrylic acid type group chosen from acrylic acid, methacrylic acid, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate and hydroxyethylhexyl(meth)acrylate.

[0038] According to one embodiment, the units carrying the carboxylic acid function further comprise a heteroatom chosen from oxygen, sulfur, nitrogen and phosphorus.

[0039] 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 molar 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.

[0040] The content of functional groups in said fluoropolymer is at least 0.01 mol%, preferably at least 0.1 mol%, and at most 15 mol%, preferably at most 10 mol%.

[0041] More particularly, the transfer agent carrying the functionality is incorporated into said fluorinated polymer at the end of the chain. Thus, said fluorinated polymer may comprise terminal groups consisting of said transfer agent. In particular, the transfer agent is a polymer with a molar mass of less than or equal to 20,000 g / mol and carrying functional groups selected from the group consisting of carboxylic acid or carboxylic acid ester.

[0042] The fluoropolymer preferably has a high molecular weight. By high molecular weight, as used herein, is meant a fluoropolymer having a melt viscosity greater than 100 Pa.s, preferably greater than 500 Pa.s, more preferably greater than 1000 Pa.s, according to ASTM D-3835 method measured at 232°C and 100 sec-1.

[0043] According to one embodiment, the fluoropolymer bearing functional groups can crosslink either by self-condensation of its functional groups or by reaction with a catalyst and / or a crosslinking agent, such as melamine resins, epoxy resins and the like, as well as known low molecular weight crosslinking agents such as di- or higher polyisocyanates, polyaziridines, polycarbodiimides, polyoxazolines, dialdehydes such as glyoxal, acetoacetates, malonates, acetals, di- and trifunctional thiols and acrylates, cycloaliphatic epoxy molecules, organosilanes such as epoxysilanes and amino silanes, carbamates, diamines and triamines, inorganic chelating agents such as certain zinc and zirconium salts, titaniums, glycourils and other aminoplasts.In some cases, functional groups from other polymerization ingredients, such as surfactants, initiators, seed particles, may be involved in the crosslinking reaction. When two or more functional groups are involved in the crosslinking process, the complementary reactive group pairs are, for example, hydroxyl-isocyanate, acid-epoxy, amine-epoxy, hydroxyl-melamine, acetoacetate-acid. Acrylate and / or methacrylate monomers not containing functional groups capable of entering into crosslinking reactions after polymerization should preferably represent 70% or more by weight of the total monomer mixture, and more preferably should be greater than 90% by weight.According to one embodiment, the fluoropolymer comprises a crosslinking agent selected from the group consisting of isocyanates, diamines, adipic acid, dihydrazides and combinations thereof.

[0044] In some embodiments, the PVDF homopolymer and VDF copolymers are composed of bio-based VDF. The term "bio-based" means "derived from biomass". This improves the ecological footprint of the separator. The bio-based VDF may 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%.

[0045] The homopolymeric fluorinated polymers and copolymers of VDF used in the invention can be obtained by known polymerization methods such as emulsion or suspension polymerization.

[0046] According to one embodiment, they are prepared by an emulsion polymerization process in the absence of fluorinated surfactant.

[0047] Polymerization of PVDF results in 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 20 micrometers. The agglomerates may break into discrete particles during formulation and application to a substrate. ii) Acrylic polymer

[0048] As mentioned above, said acrylic polymer comprises monomeric units of formula 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(CH3hCH2C(O)CH3 or -OR' with R' selected from the group consisting of H and Ci-Cis alkyl optionally substituted with one or more -OH groups or a five- or ten-membered heterocycle comprising at least one nitrogen atom in its ring chain. 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 atoms forming the heterocycle. Preferably the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.

[0049] Preferably, said acrylic polymer is based on an alkyl acrylate monomer of formula 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 -OH group(s) a five or ten membered heterocycle comprising at least one nitrogen atom in its ring chain. Preferably, the heterocycle is as defined above, in particular the heterocycle is 2-pyrrolidone, deltalactam, succinimide, 2-imidazolidinone, 4-imidazolidinone.

[0050] According to one embodiment, the substituent R' is selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, n-dodecyl, amyl, isoamyl, hexyl, 2-ethylhexyl, lauryl, n-octyl, hydroxybutyl, hydroxypropyl, ureido-substituted ethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl.

[0051] In particular, said acrylic polymer is based on an alkyl acrylate monomer of formula R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 and R 2 are H; R 3 is H or CH3; R is -OR' with R' 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.

[0052] Thus the alkyl acrylate can be 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, ureido methacrylate. Among these, alkyl acrylates with an alkyl group having 1 to 8 carbon atoms are preferred, and alkyl acrylates with an alkyl group having 1 to 5 carbon atoms are more preferable. These compounds can be used alone or as a mixture of two or more.

[0053] The term "acrylate" herein includes both acrylates and methacrylates.

[0054] The optional ethylenically unsaturated compound copolymerizable with alkyl acrylate and alkyl methacrylate includes:

[0055] - (A) an alkenyl compound containing a functional group, and

[0056] - (B) an alkenyl compound without a functional group.

[0057] The alkenyl compound (A) containing a functional group includes, for example, α,[3-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; 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.;

[0058] It is preferable that the functional alkenyl compound (A) is used in an amount of less than 50% by weight relative to the weight of the monomer mixture and that the functional group-free alkenyl compound (B) is used in an amount of less than 30% by weight relative to the weight of the monomer mixture.

[0059] The acrylic polymer used in the invention can be obtained by polymerization of the alkyl acrylate monomer according to known polymerization methods such as emulsion or suspension polymerization. iii) Mixture of a fluoropolymer and an acrylic polymer Said polymer resin can be prepared according to different methods.

[0060] According to a first embodiment, the fluoropolymer and the acrylic polymer are obtained by known polymerization methods such as emulsion or suspension polymerization independently of each other. The two polymers are then mixed in powder or latex form during the preparation of an aqueous formulation or in the presence of an organic solvent intended for the implementation of the separator.

[0061] Alternatively, according to another preferred embodiment, the polymer resin is synthesized by emulsion polymerization of acrylate / methacrylate monomers using a latex of said fluoropolymer as a seed, which gives a fluoropolymer-acrylic composition in which at least a portion of the fluoropolymer and the acrylic polymer are intimately mixed.

[0062] The fluoroacrylic polymer resin is an aqueous dispersion obtained by emulsion polymerization of 5 to 100, preferably 5-95 parts by weight of a monomer mixture having at least one monomer selected from the group consisting of alkyl acrylates whose alkyl groups have 1-18 carbon atoms and alkyl methacrylates whose alkyl groups have 1-18 carbon atoms and optionally an ethylenically unsaturated compound copolymerizable with the alkyl acrylates and alkyl methacrylates, in an aqueous medium in the presence of 100 parts by weight of particles of a vinylidene fluoride polymer as defined above. The PVDF particles serve as a seed for the polymerization of the acrylic monomers. The PVDF particles can be added in any state to the polymerization system, as long as they are dispersed in an aqueous medium in the form of particles.Since the vinylidene fluoride polymer is generally produced in the form of an aqueous dispersion, it is convenient for the as-produced aqueous dispersion to be used as seed particles. The diameters of the vinylidene fluoride particles are preferably in the range of 0.04 to 2.9 micrometers. In a preferred embodiment, the diameter of the polymer particles is preferably 50 nm to 700 nm.

[0063] The product of the polymerization is a latex that can be used in this form, usually after filtration of the solid by-products of the polymerization process. For use in latex form, the latex may be stabilized by the addition of a surfactant, which may be the same as or different from the surfactant present during the polymerization (if any). This subsequently added surfactant may, for example, be an ionic or non-ionic surfactant.

[0064] The PVDF particles used as seed may have a homogeneous or heterogeneous character or gradient between the core and the surface of the particles, in terms of composition (HFP comonomer content, for example) and / or molecular weight. In the fluoro-acrylic polymer resin, the PVDF / acrylic polymer mass ratio varies from 95 / 5 to 5 / 95, preferably from 75 / 25 to 25 / 75, advantageously from 60 / 40 to 40 / 60.

[0065] In the fluoro-acrylic polymer resin, the average particle diameter is 0.05-3 pm, preferably 0.05-1 pm, more preferably 0.1-1 pm. According to this embodiment, the fluoro-acrylic polymer resin is characterized by an intimate mixture between the fluoro-polymer chains and the acrylic polymer chains in at least a portion of the particle. iv) VDF / AA copolymer

[0066] Alternatively, said polymer resin may be a copolymer comprising vinylidene fluoride monomeric units and monomeric units (A) of formula R 1 R 2 C=C(R 3 )C(O)OR 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; R is selected from the group consisting of H and C1-C5 alkyl optionally substituted with at least one -OH group.

[0067] Preferably, the monomeric units A are of formula R 1 R 2 C=C(R 3 )C(O)OR in which the substituents R 1 , R 2 and R 3are independently selected from the group consisting of H and CH3; R is selected from the group consisting of H, hydroxypropyl and hydroxyethyl or a mixture thereof. The term hydroxypropyl corresponds to -CH2CH(OH)CH3. The term hydroxyethyl corresponds to - CH(CH3)CH2OH.

[0068] Preferably, the monomeric units A of formula R 1 R 2 C=C(R 3)C(O)OR are distributed along the polymer chain mainly formed by monomeric units of vinylidene fluoride. In this embodiment, said polymer resin comprises at least 0.01 mol%, advantageously at least 0.02 mol%, preferably at least 0.03 mol%, in particular 0.04 mol% of monomeric units A. Preferably, said polymer resin comprises at most 5 mol%, advantageously at most 4 mol%, preferably at most 2 mol%, in particular at most 1 mol%, more particularly at most 0.75 mol% of monomeric units A. In this embodiment, said polymer resin may also comprise, in addition to the vinylidene fluoride monomeric units and the monomeric units A, monomeric units derived from one or more fluorinated comonomers B. Said comonomer B is preferably an ethylenically unsaturated comonomer comprising at least one fluorine atom.Non-limiting examples of comonomer B include: C2-C8 perfluorolefins such as tetrafluoroethylene; perfluoroalkylethylene of formula CH2=CHR. 1 in which R 1 is a C2-C6 perfluoroalkyl; chloro- or bromo- or iodo C2- This fluoroolefin such as chlorotrifluoroethylene; perfluoroalkyl vinyl ethers of formula CF2=CFOR 2 in which R 2 is C1-C12 perfluoroalkyl, C1-C12 alkoxy, C1-C12 perfluoroalkoxy; perfluoroalkylvinylether of formula CF2=CFOCF2OR 3 in which R 3 is Ci-Ce perfluoroalkyl or Ci-Ce perfluoroalkoxy; perfluorooxyalkylvinylether of formula CF2=CFOR 4 in which R 4 is C1-C12 alkyl, C1-C12 perfluoroalkyl, C1-C12 perfluoroether and R 4 carries a carboxylic acid or sulfonic acid group or a salt thereof. (v) Inorganic particles and optional additives

[0069] The separator coating according to the invention may contain, in addition to said described polymer resin, inorganic particles which 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. According to 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). Furthermore, powdered inorganic materials preferably have a high ionic conductivity. Materials with a low density are preferred to materials with a 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: BaTiO3, Pb(Zr,Ti)O3, Pb 1-x LaxZryO3 (0 <x<l, 0<y<l), PBMg3Nb2 / 3)3,PbTiO3, hafnie (HfO (HfO2), SrTiO 3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2O3, bohémite (y-AIO(OH)), AI2O3, TiO2, SiC, ZrO2, silicate de bore, BaS04, nano-argiles, ou leurs mélanges. Dans ce cas, le rapport des solides du polymère aux particules inorganiques est de 0,5 à 40 parties en poids de solides de ladite résine polymère pour 60 à 99,5 parties en poids de particules inorganiques. Avantageusement, le rapport des solides du polymère aux particules inorganiques est de 0,5 à 35 pour 65 à 99,5 parties en poids de particules inorganiques. De préférence, le rapport des solides du polymère aux particules inorganiques est de 0,5 à 30 pour 70 à 99,5 parties en poids de particules inorganiques.

[0070] The separator coating of the invention may optionally comprise from 0 to 15% by weight based on the polymer, and preferably 0.1 to 10% by weight of additives, chosen from thickeners, pH adjusting agents, anti-sedimentation agents, surfactants, wetting agents, fillers, anti-foaming agents and fugitive or non-fugitive adhesion promoters.

[0071] Said separator according to the present invention comprises a coating, as described above, 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. Said support may comprise a single layer or several distinct layers. 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. Advantageously, the application of the coating according to the invention to the support is carried out by aqueous means or by 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 nonwoven web forming a porous web, such as a web obtained by direct spinning or melt-blowing (of the "spunbond" or "melt-blown" type) or electrospinning. 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, polyether sulfone, 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 may also be used as the substrate of the separator.The porous substrate generally has a thickness of 1 to 50 µm, and are typically membranes obtained by extrusion and stretching (wet or dry processes) 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.

[0072] According to an alternative embodiment, said separator does not comprise a porous support. In this case, said separator consists of the coating according to the present invention comprising said polymer resin; this is deposited directly on the cathode or on the anode of said 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 polymer resin preferably has a porosity of 5 to 95%. The average pore size of said polymer resin is preferably between 0.001 and 50 μm, more preferably between 0.01 and 10 μm.

[0073] According to another alternative embodiment, said separator does not comprise a porous support and said separator is in the form of a gel. Said separator is as described in the present application. Said separator is formed into a gel by usual techniques such as solvent casting or extrusion.

[0074] The separator coating of the invention exhibits an excellent compromise of properties for separator coating application: good dry and wet adhesion, good resistance to electrolyte solvent(s) characterized by good retained integrity and moderate swelling, and good Gurley permeability. The separator coating of the invention also improves the wettability of the separator when the electrolyte composition has a high viscosity or high polarity as explained in the examples below.

[0075] According to the present invention, said electrochemical device comprises an electrolytic composition. The electrolytic composition impregnates the separator to allow the impregnation of lithium ions within the device. As mentioned above, the electrolytic composition comprises a solvent and a lithium salt. The solvent may be one of the solvents mentioned below or a mixture thereof. According to a first embodiment, said solvent used in the electrolytic composition has a high polarity. The term polarity refers to the dipole moment at 25°C of the solvent used in the electrolytic composition. According to another embodiment, the electrolytic composition has a high viscosity. The viscosity is measured with a Brookfield metek DV2T viscometer at 20°C and a shear of 20 s -1 .

[0076] Preferably, said electrolytic composition has a viscosity greater than 2.0 cP measured according to the method described above.

[0077] According to a preferred embodiment, said electrolyte composition may also have a viscosity greater than 3 cP, greater than 4 cP, greater than 5 cP, greater than 6 cP, greater than 7 cP, greater than 8 cP, greater than 9 cP, greater than 10 cP, greater than 11 cP, greater than 12 cP, greater than 13 cP, greater than 14 cP, greater than 15 cP, greater than 16 cP, greater than 17 cP, greater than 18 cP, greater than 19 cP, greater than 20 cP, greater than 21 cP, greater than 22 cP, greater than 23 cP, greater than 24 cP, greater than 25 cP, greater than 26 cP, greater than 11 cP, greater than 28 cP, greater than 29 cP or greater than 30 cP.

[0078] According to a preferred embodiment, said electrolytic composition may also have a viscosity of between 2 cP and 600 cP, advantageously between 5 and 500 cP, preferably between 10 and 450 cP, more preferably between 15 and 400 cP, in particular between 20 and 350 cP, more particularly between 25 and 300 cP, preferably between 25 and 250 cP, advantageously preferably between 30 and 200 cP. The lithium salt may be present in the electrolytic composition at very variable concentrations. A high concentration of lithium salt will promote a high viscosity of the electrolytic composition. For example, the lithium salt may be present in the electrolytic composition at a concentration of between 0.01 and 20 mol.L 1 , advantageously between 0.01 and 15 mol.L 1 , preferably between 0.01 and 10 mol.L 1. A high concentration of lithium salt in said electrolytic composition will promote the performance of the electrochemical device in terms of capacity.

[0079] Preferably, said electrolytic composition has a viscosity of less than 1000 cP measured according to the method described above, advantageously less than 900 cP, preferably less than 800 cP, more preferably less than 700 cP, in particular less than 600 cP.

[0080] For example, said solvent may be of formula (la), (Ib), (le), (Id), (le), (If), (Ig), (Ih), (li),

[0081] (Ij), (Ik), (II), (Im), (In), (Io), (Ip), (Iq), (Ir), (Is), (It), (lu), (Iv), (Iw), (Ix), (ly) or (Iz): in which R 4 , R 5 and R 18 are independently selected from the group consisting of C1-C10 alkyl, C2-C5 alkenyl, C1-C10 perfluoroalkyl and C1 aryl; R 6 , R 7 , R8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 15 and R 16 are independently selected from the group consisting of H, C1-C10 alkyl, C2-C5 alkenyl, C1-C10 perfluoroalkyl and Cearyl; n is an integer from 1 to 10, preferably from 1 to 5;

[0082] X is O or SO2;

[0083] Y 1 and Y 2 are selected from O or CR 6 R 7 with R 6 and R 7 as defined above provided that Yi and Y2 are not simultaneously O;

[0084] Y 3 is SO2 or S=O;

[0085] R 14 and R 17 are independently selected from the group consisting of H, C1-C5 alkyl, C2-C5 alkenyl, and C1-C5 aryl.

[0086] In the present application, the alkyl and alkenyl substituents described in connection with the above solvent formulas are optionally substituted with one or more fluorine atoms, a C1-C5 alkoxy group, a C1-C10 perfluoroalkyl group, a phenyl group, a CN, OH, NO2 or SO2 functional group. In the present application, the Cearyl substituent described in connection with the above solvent formulas is optionally substituted with one or more fluorine atoms, a C1-C10 alkyl group, a C1-C5 alkoxy group or a C1-C10 perfluoroalkyl group. Said solvent may also be a crown ether such as, for example, but not limited to, 18-crown-6 ether, 15-crown-5 ether, 12-crown-4 ether, dibenzo-18-crown-6 ether, dibenzo-24-crown-8 ether, dicyclohexano-18-crown-6 ether, dibenzo-12-crown-4 ether.

[0087] More preferably, said solvent is of formula (la), (Ib), (le), (Id), (le), (If), (Ig), (Ih), (li), (Ij), (I k), (II), (Im), (In), (Io), (Ip), (Iq), (Ir), (Is), (It), (lu), (Iv), (Iw), (Ix), (ly) or (Iz) in which

[0088] R 4 , R 5 and R 18 are independently selected from the group consisting of C1-C5 alkyl, C2-C3 alkenyl, C1-C5 perfluoroalkyl and C1-C5 aryl;

[0089] R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 15 and R 16 are independently selected from the group consisting of H, C1-C5 alkyl, C2-C3 alkenyl, C1-C5 perfluoroalkyl and Cearyl; n is an integer from 1 to 10, preferably from 1 to 5;

[0090] X is O or SO2;

[0091] Y 1 and Y 2 are selected from O or CR 6 R 7 with R6 and R 7 as defined above provided that Yi and Y2 are not simultaneously O;

[0092] Y 3 is SO2 or S=O;

[0093] R 14 and R 17 are independently selected from the group consisting of H, C1-C5 alkyl, C2-C3 alkenyl, and C1-C5 aryl.

[0094] In particular, said solvent is of formula (la), (Ib), (le), (Id), (le), (If), (Ig), (Ih), (li), (Ij), (Ik), (II), (Im), (In), (Io), (Ip), (Iq), (Ir), (Is), (It), (lu), (Iv), (Iw), (Ix) or (ly) in which

[0095] R 4 , R 5 and R 18 are independently selected from the group consisting of C1-C3 alkyl, C2-C3 alkenyl, C1-C3 perfluoroalkyl and C1-C3 aryl;

[0096] R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 15 , R 16, are selected independently of each other from the group consisting of H, C1-C3 alkyl, C2-C3 alkenyl, C1-C3 perfluoroalkyl and Cearyl; n is an integer from 1 to 10, preferably from 1 to 5;

[0097] X is O or SO2;

[0098] Y 1 and Y 2 are selected from O or CR 6 R 7 with R 6 and R 7 as defined above provided that Yi and Y2 are not simultaneously O; Y 3 is SO2 or S=O;

[0099] R 14 and R 17 are independently selected from the group consisting of H, C1-C3 alkyl, C2-C3 alkenyl, and C1-C3 aryl.

[0100] More particularly, said solvent may be of formula (Ia) in which R 4 and R 5are independently of each other selected from the group consisting of CH3, CH2F, CHF2, C2H5, CH2CH2F, CH2CHF2, CH2CF3, CH2CH2CH3, CH2CH2CH2F, CH2CHFCH3, CH2CH2CF3, CH2CF2CHF2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CF2CF2CF2CF3 and CH(CH3)2; preferably R 4 is CH3, CeHs, or CH2CH3 and R 5 is selected from the group consisting of CH3, CH2F, CHF2, C2H5, CH2CH2F, CH2CHF2, CH2CF3, CH2CH2CH3, CH2CH2CH2F, CH2CHFCH3, CH2CH2CF3, CH2CF2CHF2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CF2CF2CF2CF3 and CH(CH3)2.

[0101] More particularly, said solvent may be of formula (I b) in which R 6 , R 7 , R 8 and R 9are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 6 , R 7 and R 8 are H, CH3, C6H5, or CH2CH3 and R 9 is selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3 and CH=CH2.

[0102] More particularly, said solvent may be of formula (Ic) in which R 6 and R 7 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 6is H, CH3, C6H5, or CH2CH3 and R 7 is selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3 and CH=CH2.

[0103] More particularly, said solvent may be of formula (Id) in which R 4 and R 5 are independently of each other selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CF3, CH2OCH3, CH(CH3)CH2OCH3, CH(CH3)2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CHFCH3 and CH2CH2CH3; preferably R 4 is selected from the group consisting of CH2CH2F, CH3, CeHs, or CH2CH3 and R 5 is selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CF3, CH2OCH3, CH(CH3)CH2OCH3, CH(CH3)2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, CHFCH3and CH2CH2CH3.

[0104] More particularly, said solvent may be of formula (Ic) in which R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 6 , R 7 and R 8 are H, CH3, C6H5, or CH2CH3 and R 9 , R 10 and R 11 are selected independently of each other from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3 and CH=CH2.

[0105] More particularly, said solvent may be of formula (If) in which R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12and R 13 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 6 , R 8 , R 10 and R 12 are H, CH3, C6H5, or CH2CH3 and R 7 , R 9 , R 11 and R 13 are selected independently of each other from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3 and CH=CH2.

[0106] More particularly, said solvent may be of formula (Ig) in which R 6 , R 7 , R 8 , R 9 , R 10 and R 11are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; R 14 is H, CH3, C6H5, CH2CH3 and CH=CH2; preferably R 6 , R 7 and R 8 are H, CH3, CeHs, or CH2CH3 and R 9 , R 10 and R 11 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2; and R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2.

[0107] More particularly, said solvent may be of formula (I h) in which R 7 , R 8 , R 9 and R 11are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3and CH=CH2; R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2; preferably R 7 and R 8 are H, CH3, CeHs, or CH2CH3and R 9 and R 11 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2; and R 14 is H, CH3, C6H5, OR CH2CH3 and CH=CH2.

[0108] More particularly, said solvent may be of formula (li) in which R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3and CH=CH2; R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2; preferably R 6 , R 8 , R 10 and R 12 are H, CH3, CeHs, or CH2CH3and R 7 , R 9 , R 11 and R 13 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2; and R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2.

[0109] More particularly, said solvent may be of formula (Ij) in which R 6 , R 7 , R 8 and R 9are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3),

[0110] CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 6 , R 7 and R 8 are H, CH3, C6H5, or CH2CH3 and R 9 is selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2.

[0111] More particularly, said solvent may be of formula (I k) in which R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 15 and R 16are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2,CH2CH3and CH=CH2; preferably R 6 , R 7 , R 8 , R 9 and R 10 are H, CH3, CeHs, or CH2CH3and R 11 , R 12 , R 13 , R 15 and R 16 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2.

[0112] More particularly, said solvent may be of formula (II) in which R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 15 and R 16are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3and CH=CH2; R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2; preferably R 6 , R 7 , R 8 , R 9 and R 10 are H, CH3, C6H5, or CH2CH3 and R 11 , R 12 , R 13 , R 15 and R 16 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2; and R 14 is H, CH3, C6H5, or CH2CH3and CH=CH2.

[0113] More particularly, said solvent may be of formula (Im) in which R 4 and R 5are independently of each other selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CH2OCH3, CH(CH3)CH2OCH3, CH(CH3)2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CHFCH3and CH2CH2CH3; preferably R 4 is selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CH2OCH3, CH(CH3)CH2OCH3, CH(CH3)2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CHFCH3and CH2CH2CH3and R 5 is selected from the group consisting of CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CH2OCH3, CH(CH3)CH2OCH3, CH(CH3)2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CF2CF2CF2CF3and CHFCH3; R 6 , R 7 , R 8 and R 9are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3and CH=CH2. More particularly, said solvent may be of formula (In) in which R 4 and R 5 are independently of each other selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH(CH3)2, CF3CH2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CHFCH3 and CH2CH2CH3; preferably R 4 is selected from the group consisting of CH3, CH2CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH(CH3)2, CF3CH2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, CeHs, CHFCH3 and CH2CH2CH3; and R 5 is selected from the group consisting of CH2F, CHF2, CH2CH2F, CH2CHF2, CF3CH2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CF2CF2CF2CF3 and CHFCH3.

[0114] More particularly, said solvent may be of formula (lo) in which R 4 is selected from the group consisting of CH3, CH2CH3, CH3OCH2CH2, CH3CH2CH2, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), C6H5, CF3-C6H4, CH2F, CHF2, CH2CH2F, CH2CHF2, CH(CH3)2, CF3CH2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, CHFCH3and CH2CH2CH3.

[0115] More particularly, said solvent may be of formula (Ip) in which R 6 and R 7 are independently of one another selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3, CH3CH2CH2, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3) and CH=CH2; preferably R 6 and R 7are independently selected from the group consisting of H, F, CH3, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CFs)2, CeHs, CH2CH3, CH3CH2CH2, CH(CHS)2, and CH=CH2; and n is an integer from 1 to 10, preferably from 1 to 5.

[0116] More particularly, said solvent may be of formula (Iq) in which R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3, CH3CH2CH2, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3) and CH=CH2; and X is O or SO2; preferably R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH2CH3, CH3CH2CH2, CH(CH3)2and CH=CH2; and X is O or SO2. More particularly, said solvent may be of formula (Ir) in which R 6 is selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; R 14 and R 17 are selected independently of each other from the group consisting of H, CH3, C6H5, CH2CH3 and CH=CH2; preferably R 6 is H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH; and R 14 and R 17are selected independently of each other from the group consisting of H, CH3, CeHs, or CH2CH3 and CH=CH2.

[0117] More particularly, said solvent may be of formula (Is) in which R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably R 8 , R 10 and R 12 are H, CH3, C6H5, or CH2CH3 and R 9 , R 11 and R 13 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CFS)2, CF2CF2CF2CF3, CeHs, CH2CH3 and CH=CH2; and Y 1 and Y 2 are selected from O or CR 6 R7 provided that Yi and Y2 are not simultaneously O with R 6 and R 7 independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH2; preferably H, CH3, CeHs, or CH2CH3.

[0118] More particularly, said solvent may be of formula (It) in which R 6 , R 7 , R 8 and R 9 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CHS)2, CH2CH3 and CH=CH2; R 14 and R 17are independently of each other selected from the group consisting of H, CH3, CeHs, or C^CHset CH=CH2; preferably R 6 and R 8 are independently of each other H, CH3, CeHs, or CH2CH3 and R 7 , R 9 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, CeHs, CH2CH3and CH=CH2; and R 14 and R 17 are independently selected from the group consisting of H, CH3, CeHs, or CH2CH3and CH=CH2.

[0119] More particularly, said solvent may be of formula (lu) in which R 6 , R 7 , R 8 , R 9 , R 10 and R 11are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3and CH=CH2; R 14 and R 17 are independently of each other selected from the group consisting of H, CH3, CeHs, or CH2CH3and CH=CH2; preferably R 6 , R 8 and R 10 are independently of each other H, CH3, CeHs, or CH2CH3 and R 7 , R 9 , R 11 are independently selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, CeHs, CH2CH3and CH=CH2; and R 14 and R 17 are independently selected from the group consisting of H, CH3, CeHs, or CH2CH3and CH=CH2.

[0120] More particularly, said solvent may be of formula (Iv) in which R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are independently of each other selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH2CH3, CH3CH2CH2, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3) and CH=CH2; preferably R 6 , R 7 , R 8 and R 9 are independently of each other selected from the group consisting of H, F, CH3, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH2CH3, CH3CH2CH2, CH(CH3)2, and CH=CH2; and n is an integer from 1 to 10, preferably from 1 to 5.

[0121] More particularly, said solvent may be of formula (Iw) in which R 6is selected from the group consisting of H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, CF2CF2CF2CF3, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CH3CH2CH2, CH(CH3)2, CH2CH3and CH=CH2; R 14 and R 17 are selected independently of each other from the group consisting of H, CH3, C6H5, CH2CH3 and CH=CH2; preferably R 6 is H, F, CH3, CH2F, CHF2, CH2CH2F, CH2CHF2, CH2CF3, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2, CH(CH3)2, CH2CH3 and CH=CH; and R 14 and R 17 are selected independently of each other from the group consisting of H, CH3, CeHs, or CH2CH3 and CH=CH2.

[0122] More particularly, said solvent may be of formula (Ix) in which R 4 , R 5 and R 18are independently of each other selected from the group consisting of CH3, CH2F, CHF2, C2H5, CH2CH2F, CH2CHF2, CH2CF3, CH2CH2CH3, CH2CH2CH2F, CH2CHFCH3, CH2CH2CF3, CH2CF2CHF2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CF2CF2CF2CF3and CH(CH3)2.

[0123] More particularly, said solvent may be of formula (ly) in which R 4 and R 5 are independently of each other selected from the group consisting of CH3, CH2F, CHF2, C2H5, CH2CH2F, CH2CHF2, CH2CF3, CH2CH2CH3, CH2CH2CH2F, CH2CHFCH3, CH2CH2CF3, CH2CF2CHF2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CF2CF2CF2CF3and CH(CH3)2; Y 3 is SO2 or S=O.

[0124] More particularly, said solvent may be of formula (Iz) in which R 4is selected from the group consisting of CH3, CH2F, CHF2, C2Hs, CH2CH2F, CH2CHF2, CH2CF3, CH2CH2CH3, CH2CH2CH2F, CH2CHFCH3, CH2CH2CF3, CH2CF2CHF2, CF3, CF2CF3, CF2CF2CF3, CH(CF3)2, C6H5, CH(CH3)2, CH3CH2CH2CH2, (CH3)2CHCH2, CH3CH2CH(CH3), CF2CF2CF2CF3and CH(CH3)2.

[0125] In a non-limiting manner, said solvent is for example selected from the group consisting of propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxyethane, gamma-butyrolactone, 3-fluoro-gamma-butyrolactone, delta-valerolactone, gamma-valerolactone, epsilon-caprolactone, gamma-caprolactone, butyrolactam, valerolactam, N-methyl-butyrolactam, N-methyl-valerolactam, fluoroethylene carbonate, fluoropropylene carbonate, monofluoromethyl methyl carbonate, methyl 2,2,2-trifluoroethyl carbonate, trifluoroethyl ethyl carbonate, bis(2,2,2-trifluoroethyl carbonate), propyl 2,2,2-trifluoroethyl carbonate, methylnonafluorobutyl ether, hexafluoroisopropyl methyl ether, bis(2,2,2-trifluoroethyl)ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, methyl isopropyl carbonate, ethyl isopropyl carbonate, propyl ethyl carbonate, methyl propyl carbonate, 1-fluoropropyl methyl carbonate,2-fluoropropyl methyl carbonate, 1,1,1-trifluoropropyl methyl carbonate, 1,1,1,2,2-pentafluoropropyl methyl carbonate, 1,1,2,2-tetrafluoropropyl methyl carbonate, 1,1,1-trifluoroethyl methyl carbonate, 1,1-difluoroethyl methyl carbonate, 1-fluoroethyl methyl carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl fluoromethyl carbonate, 1-fluoroethyl ethyl carbonate, 1,1-difluoroethyl ethyl carbonate, 1,1,1-trifluoroethyl ethyl carbonate, vinyl ethylene carbonate, vinylene carbonate, ethyl ethanoate, ethyl 1-fluoroethanoate, ethyl 1,1-difluoroethanoate, 1-fluoroethyl ethanoate, methyl, 1-methoxy isopropyl ethanoate, 1-fluoroethyl propanoate, ethyl 2-fluoropropanoate, methyl butanoate, ethyl butanoate, methyl methoxyethanoate, N-methyl-2-oxazolidinone, ethylene glycol diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2,6-dimethyltetrahydrofuran, tetrahydropyran,triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,4-dioxane, 1,3-dioxolane, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, diphenyl carbonate, methyl phenyl carbonate, ethylene,

[0126] 2,3-Dimethylcarbonate, vinylene carbonate, ethylene 2-vinylcarbonate, methyl benzoate, ethyl benzoate, 5-valerolactone, trimethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, triethyl phosphate, acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, 2-methylglutaronitrile, valeronitrile, butyronitrile, isobutyronitrile, N-methylformamide, N-ethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, N-methylpyrrolidone, N-vinylpyrrolidone, dimethylsulfone, ethylmethylsulfone, diethylsulfone, sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dimethyl sulfoxide, methyl ethyl sulfoxide, diethyl sulfoxide, benzonitrile, tolunitrile,

[0127] 1,3-Dimethyl-2-imidazolidinone, l,3-dimethyl-3,4,5,6-tetrahydro-2(l,H)-pyrimidinone, 3-methyl-2-oxazolidinone, nitromethane, nitroethane, nitropropane, nitrobutane. These solvents can be used individually or in combination. Alternatively, said solvent can be an ionic liquid. Preferably, the ionic liquid is of the formula (Cation)FSI or (cation)TFSI where FSI is bis(fluorosulfonyl)imide and TFSI is bis(trifluoromethanesulfonyl)imide. Preferably, the cation is of the ammonium, imidazolium, pyrrolidinium, piperidinium, phosphonium, sulfonium, oxonium type. In a non-limiting manner, mention may be made of (l-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide), (l-Butyl-3-methylimidazolium bis(fluorosulfonyl)imide), (1-

[0128] Butyl-l-methylpyrrolidinium bis(fluorosulfonyl)imide), (l-Propyl-3-methylpyrrolidinium bis(fluorosulfonyl)imide), (1-butyl-l-methylpiperidinium bis(fluorosulfonyl)imide), (1- methyl-l-propylpiperidinium bis(fluorosulfonyl)imide), (Methyl(tri-n- butyl)phosphonium bis(fluorosulfonyl)imide), (Methyl(tri-n-ethyl)phosphoium bis(fluorosulfoyl)imide), (l-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide), (l-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide), (1-Butyl-l-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide), (l-Propyl-3-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide), (1-butyl-l-methylpiperidinium bis(trifluoromethanesulfonyl)imide), (1-methyl-l-propylpiperidinium bis(trifluoromethanesulfonyl)imide), (Methyl(tri-n-butyl)phosphonium bis(trifluoromethanesulfonyl)imide), (Methyl(tri-n-ethyl)phosphoium bis(trifluoromethanesulfonyl)imide).

[0129] Alternatively, said solvent used in the present electrolytic composition has a dipole moment greater than 2 Debye at 25°C. Preferably, said solvent has a dipole moment greater than 2.5 Debye, preferably greater than 3.0 Debye, more preferably greater than 3.5 Debye, in particular greater than 4.0 Debye at 25°C.

[0130] For example, but not limited to, said electrolyte may be selected from the group consisting of propylene carbonate, 1-fluoroethyl methyl carbonate, 1-fluoroethyl ethyl carbonate, 1,1-difluoroethyl methyl carbonate, 1,1-difluoroethyl ethyl carbonate, 1,1,1-trifluoroethyl methyl carbonate, 1,1,1-trifluoroethyl ethyl carbonate, perfluoroethyl methyl carbonate, perfluoroethyl ethyl carbonate, propyl methyl carbonate, propyl ethyl carbonate, dimethoxymethane, ethylene carbonate, isopropyl methyl carbonate, isopropyl ethyl carbonate, fluoroethylene carbonate, vinylidene carbonate, butylene carbonate, vinyl ethylene carbonate, fluoropropylene carbonate, fluoro-gamma-butyrolactone, delta-valerolactone, gamma-butyrolactone, fluoropropyl methyl carbonate, 2-fluoropropyl methyl carbonate, 1,1,1-trifluoropropyl methyl carbonate, 1,1,2,2-tetrafluoropropyl methyl carbonate, 1,1,1,2,2-pentafluoropropyl methyl carbonate, fluoropropyl ethyl carbonate,2-fluoropropyl ethyl carbonate, 1,1,1-trifluoropropyl ethyl carbonate, 1,1,2,2-tetrafluoropropyl ethyl carbonate, 1,1,1,2,2-pentafluoropropyl ethyl carbonate, nitromethane, 18-crown-6 ether, 15-crown-5 ether, 12-crown-4 ether, dibenzo-18-crown-6 ether, dibenzo-24-crown-8 ether, dicyclohexano-18-crown-6 ether, dibenzo-12-crown-4 ether, nitromethane, nitroethane, nitropropane, nitrobutane, trimethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, triethyl phosphate, acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, 2-methylglutaronitrile, valeronitrile, butyronitrile, isobutyronitrile, N-methylformamide, N-ethylformamide, N,N- dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidinone, N- methylpyrrolidone, N-vinylpyrrolidone, dimethylsulfone, ethylmethylsulfone, diethylsulfone, sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, dimethyl sulfoxide, methyl ethyl sulfoxide, diethyl sulfoxide, benzonitrile,tolunitrile, l,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone.,

[0131] As mentioned above, said electrolyte composition also comprises a lithium salt. For example, the lithium salt may be LiPFe, IJOSO2CF3, LilX^SOzCFsh, LiN(SO2F)2, LiBF4, UCIO4, lithium 2-trifluoromethyl-4,5-dicyanoimidazolate, lithium difluorophosphate (UPO2F2), lithium bis(oxalato)borate (LiB(C2O4)2), lithium difluoro(oxalato)borate (LiF2B(C2O4)2) or UNO3.

[0132] The following examples illustrate in a non-limiting manner the scope of the invention. The examples according to the invention and comparative examples described below were carried out according to the same protocol. Preparation of the latexes:

[0133] The 3 different latexes are indicated in Table 1 below with their main characteristics: HFP content in the P(VDF-HFP) copolymer, PVDF / acrylic ratio, dry extract. The polymer resins used for tests 3 and 4 are according to the present invention. The polymer resins according to the present invention were prepared from a P(VDF-HFP) copolymer latex used as a seed to synthesize the corresponding fluoro-acrylic polymer composition by an emulsion polymerization process following the protocol described in WO 2007 / 018783.

[0134] Preparation of a PVDF / acrylic polymer blend: The P(VDF-HFP) copolymer latex and the acrylic latex of similar composition to the acrylic part of the polymer resin in Test 4 are prepared independently of each other by an emulsion polymerization process as indicated above. The two latexes are then mixed in a ratio of 70 / 30.

[0135] Preparation of coating compositions:

[0136] For each of tests 2 to 4, the indicated latex is added to a thickening agent (CMC 250k in 3.5% solution in water) plus, if necessary, the addition of demineralized water to obtain the same dry extract close to 25.4% independently of the initial dry extract of the latex alone. Mix under moderate shear in a Thinky mixer 200rpm / 10min. Then add the other additives - wetting agent (BYK 349), adhesion promoter (BYK LPC-22346, already supplied in 50% solution) only for the composition not already containing acrylic in the latex (= Test 2) - then mix again at 200rpm / 10min.

[0137] Application of coatings:

[0138] Each coating composition is applied to a porous PE separator (Gelon, 12 micron thickness) with a coater equipped with a spiral bar depositing 6 pm (wet thickness) at a speed of approximately 25 mm / sec, then dried at room temperature for 24 hours. [Table 1]

[0139] Wettability test

[0140] A 2 ml drop of the electrolytic composition is placed on the separator. A visual inspection confirms whether good wettability is observed, i.e., whether the electrolytic composition impregnates the separator, or, on the contrary, whether no wettability is observed, i.e., the drop of electrolytic composition does not impregnate the separator. The visual inspection is carried out after 30 minutes for all samples. Very good wettability is rated 2, good wettability is rated 1, and no wettability is rated 0.

[0141] The electrolytic composition is prepared by mixing the solvent and the lithium salt considered in quantities calculated to reach the desired concentration. In the examples below, the lithium salt concentration is 4 mol.L 1 for the two solvents considered, i.e. propylene carbonate (PC) and diethyl carbonate (DEC).

[0142] Test 1 is carried out in the presence of a separator made solely of a polyethylene support, without coating. Test 2 is carried out in the presence of a separator comprising a polyethylene support coated with a PVDF film without an acrylic part. Test 3 and Test 4 are carried out in the presence of a separator comprising a polyethylene support coated with a fluoro-acrylic polymer latex (prepared by emulsion as indicated above). The results are shown in Table 2 below.

[0143] [Table 2] : Debye dipole moment; î: viscosity measured at 20°C at a shear rate of 20s-l with a Brookfield metek DV2T viscometer; PC: propylene carbonate; DEC: diethyl carbonate. As shown in the results above, the polymer resins according to the present invention (test 3 and test 4) impregnate the separator more easily compared to a polymer resin without an acrylic component.

Claims

Demands 1. An electrochemical device comprising a separator and an electrolytic composition, characterized in that: i) said separator comprises at least one coating comprising a polymer resin comprising vinylidene fluoride monomeric units and monomeric units of formula R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 , R 2 and R 3are independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR' with R' selected from the group consisting of H and Ci-Cis alkyl groups optionally substituted with one or more -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain, and ii) said electrolytic composition comprises a solvent and a lithium salt; said electrolytic composition having a viscosity greater than 2 cP measured at 20°C and with a shear rate of 20 s 1 or said solvent having a dipole moment greater than 2 Debye at 25°C.

2. An electrochemical device according to the preceding claim, characterized in that said electrolytic composition has a viscosity greater than 5 cP, preferably greater than 10 cP, in particular greater than 15 cP measured at 20°C and with a shear rate of 20 s -1 .

3. Electrochemical device according to claim 1 characterized in that said solvent has a dipole moment greater than 2.5 Debye, preferably greater than 3.0 Debye, more preferably greater than 3.5 Debye, in particular greater than 4.0 Debye at 25°C. An electrochemical device according to any one of the preceding claims, characterized in that said polymer resin is a copolymer comprising vinylidene fluoride monomeric units and monomeric units of formula R 1 R 2 C=C(R 3 )C(O)R or said polymer resin is a mixture of a fluorinated polymer comprising monomeric units of vinylidene fluoride and an acrylic polymer comprising monomeric units of formula R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 , R 2 and R 3are independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', with R' selected from the group consisting of H and Ci-Cis alkyl groups optionally substituted by one or more -OH groups or a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain. An electrochemical device according to any one of the preceding claims, characterized in that said polymer resin is a mixture of a fluorinated polymer comprising vinylidene fluoride monomeric units and an acrylic polymer comprising monomeric units of formula R 1 R 2 C=C(R 3 )C(O)R in which the substituents R 1 , R 2 and R 3are independently selected from the group consisting of H and C1-C5 alkyl; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR' with R' selected from the group consisting of H and Ci-Cis alkyl optionally substituted by one or more -OH group(s) or a five- or six-membered heterocycle comprising at least one nitrogen atom in its cyclic chain; and said fluorinated polymer is selected from the group of polyvinylidene fluoride homopolymers and copolymers based on polyvinylidene fluoride and at least one comonomer compatible with vinylidene fluoride. An electrochemical device according to the preceding claim, characterized in that said comonomers are selected from the group consisting of vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropenes, tetrafluoropropenes, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes, perfluoroalkylvinyl ethers, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene, chlorotrifluoropropene, and ethylene. An electrochemical device according to claim 5 or claim 6, characterized in that said fluorinated polymer is a polyvinylidene fluoride-hexafluoropropylene copolymer having a weight percentage of hexafluoropropylene monomer units of 2 to 25%, preferably 4 to 15% by weight relative to the weight of the copolymer.Electrochemical device according to any one of the preceding claims 5 to 7 characterized in that said fluorinated polymer comprises monomeric units bearing at least one of the following functions: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy, amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolic, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, or phosphonic groups. Electrochemical device according to any one of the preceding claims 5 to 8 characterized in that said acrylic polymer contains a monomer selected from the group consisting of 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. Hydroxybutyl acrylate, hydroxypropyl methacrylate, methyl acrylate, methyl methacrylate, ureido methacrylate and their combinations.

10. An electrochemical device according to any one of the preceding claims, characterized in that said coating comprises inorganic particles selected from the group consisting of: BaTiO3, Pb(Zr,Ti)O3, Pb i- x La x Zr y O3(0 <x<l, 0<y<l), pbmg3nb2 3)3,pbtio3, hafnie (hfo (hfo2), srtio3, sno2, ceo2, mgo, nio, cao, zno, y2o3, bohémite (y-aio(oh)), ai2o3, tio2, sic, zro2, silicate de bore, basû4, nano-argiles, ou leurs mélanges.

11. Device according to any one of the preceding claims characterized in that said device is selected from the group consisting of Li-ion battery, capacitor, double-layer electrical capacitor, and membrane-electrode assembly (MEA) for fuel cell; preferably the Li-ion battery.

12. Device according to any one of the preceding claims characterized in that said device is a secondary Li-ion battery and also comprises an anode and a cathode.

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