Water-soluble polymer as battery binding material

Abstract

This invention relates to a method for preparing a binder for an electrode ink, a binder composition and a battery comprising said binder.

Description

[0001] WATER-SOLUBLE POLYMERAS BATTERY BINDING MATERIAL

[0002] TECHNICAL SCOPE OF THE INVENTION

[0003] This invention relates to a method for preparing a binder for an electrode ink, said binder consisting of a water-soluble polymer, a binder composition and a battery comprising said binder.

[0004] PRIOR ART

[0005] Lithium-ion batteries are used in a wide range of products, including medical devices, electric cars, aircraft and, above all, consumer products such as laptops, cell phones and cameras. Due to their high energy density, high operating voltage, and low self-discharge, lithium-ion batteries have invaded the secondary battery market and continue to find novel uses in developing industries and products.

[0006] In general, lithium-ion batteries (LIBs) comprise an anode, a cathode and an electrolyte material such as an organic solvent containing a lithium salt. More specifically, the anode and cathode (collectively, the "electrodes") are formed by mixing one or more active electrode materials, such as lithium oxides (cathode) or graphite (anode) with a polymer (called and used as a binder) and a solvent to form a paste or ink, which is then applied and dried on a current collector, such as aluminum or copper, to form a film. The anode and cathode are then stacked and wound before being housed in a pressurized case containing electrolyte material, which together form a lithium- ion cell.

[0007] In a lithium cell, the binder plays several important roles in both mechanical and electrochemical performance. Firstly, it helps to disperse the other components in the solvent during the manufacturing process (some also acting as thickeners), enabling homogeneous distribution. Secondly, it holds the other components together, including the active components, conductive additives, and current collector, ensuring that all these parts remain in contact. Through chemical or physical interactions, the binder connects these separate components, holding them together and ensuring the mechanical integrity of the electrode without significantly impacting electronic or ionic conductivity. Thirdly, it must contribute to the formation of a stable solid electrolyte interface (SEI), thus preventing continuous depletion of the electrolyte's lithium reservoir and protecting the electrode from corrosion.

[0008] Another important point is that binders must have a certain degree of elasticity if they are not to crack or develop defects. Brittleness can lead to problems during battery manufacture or assembly.

[0009] Given all the roles it plays in an electrode (and in the battery as a whole), the choice of binder is crucial to ensuring good battery performance.

[0010] Today, the two most widely used water-based commercial binders are polyacrylic acids and the sodium carboxymethyl cellulose / styrene-butadiene rubber (CMC / SBR) system.

[0011] Amphoteric diblock copolymers composed of anionic (poly(sodium p-styrenesulfonate) and cationic poly(vinylbenzyl trimethylammonium chloride) blocks, prepared via a controlled radical polymerization method, have been reported (Fukumoto et al., “Polystyrene-based amphoteric diblock copolymers with upper critical solution temperature (UCST) in aqueous solutions”, Chemistry Letters, vol. 50, no. 6, 2021, pages 1114-1117).

[0012] Ampholytic diblock copolymers of poly(2-(dimethylamino)ethyl methacrylate)-b- poly(methacrylic acid) have been described (Gohy et al., “Aggregates formed by amphoteric diblock copolymers in water”, Macromolecules, vol. 33, no. 17, 2000, pages 6378-6387).

[0013] Amphoteric diblock copolymers composed of poly(2-acrylamido-2-methylpropanesulfonic acid sodium salt) with poly(3-(acrylamido)propyl trimethylammonium chloride) blocks, synthesized via reversible addition-fragmentation chain transfer radical polymerization, have been reported (Kawata et al., “Thermo-responsive behavior of amphoteric diblock copolymers bearing sulfonate and quaternary amino pendant groups”, Langmuir, vol. 35, no. 5, 2018, pages 1458-1464).

[0014] Poly(2-(dimethylamino)ethyl methacrylate)-b-poly(acrylic acid) diblock copolymers, synthesized by atom transfer radical polymerization have been described (Zhiying et al., “Dual-stimuli responsive behaviors of diblock polyampholyte PDMAEMA-b-PAA in aqueous solution”, Journal of Colloid and Interface Science, vol. 356, no. 2, 2011, pages 557-565).

[0015] EP 4 130 077 describes multiblock copolymers of 2-acrylamido-2-methylpropanesulfonic acid and cationic monomers such as N-vinylpyrrolidone, N-vinylformamide or diallyldimethylammonium chloride obtained by addition-fragmentation chain transfer radical polymerization.

[0016] US 2010 / 280169 describes ampholytic diblock copolymers of diallyldimethylammonium chloride and acrylic acid, obtained by addition-fragmentation chain transfer radical polymerization.

[0017] CN 109 935 476 describes an amphoteric gel polymer electrolyte.

[0018] More than ever, there is a need for novel binders that can meet the specifications of manufacturers, in order to provide batteries with better performance and thus meet present and future societal and environmental challenges. Surprisingly, the Applicant has discovered that the polymer according to the invention offers good performance, giving the ink better properties in terms of dispersion, adhesion, stability, flexibility, and capacity retention, thus meeting the needs of industrialists without any inconvenience to them. Even more surprisingly, there appears to be a synergistic effect between the use of the polymer according to the invention and flexibility agents such as CMC, SBR or combinations thereof.

[0019] The resulting polymers and their use are part of a general principle of improving product performance, and more specifically the properties of binders in batteries. The improved performance of the polymers obtained by the method according to the invention makes it possible to reduce the quantity of product required for the application, which therefore implies a reduction in the release of greenhouse gases such as CO2 associated with the manufacture and use of synthetic polymers.

[0020] DESCRIPTION OF THE INVENTION

[0021] This invention relates to a method for preparing a binder for an electrode ink, said binder consisting of a water-soluble polymer.

[0022] More precisely, this invention relates to a method for preparing a binder for an electrode ink, said binder consisting of a water-soluble polymer comprising:

[0023] - at least one cationic hydrophilic monomer A;

[0024] - at least one anionic hydrophilic monomer B.

[0025] At least 30 mol% of the cationic hydrophilic monomers A of this water-soluble polymer are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol.

[0026] This invention also relates to a composition for an electrode ink comprising:

[0027] - at least one binder consisting of a water-soluble polymer comprising:

[0028] * at least one cationic hydrophilic monomer A;

[0029] * at least one anionic hydrophilic monomer B;

[0030] * at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;

[0031] - at least one electrode-active material;

[0032] - optionally at least one flexibility agent chosen from polysaccharides, styrene-butadiene rubber and mixtures thereof.

[0033] Finally, this invention also relates to a battery, preferably a lithium-ion battery, comprising an electrode comprising:

[0034] - at least one binder consisting of a water-soluble polymer comprising:

[0035] * at least one cationic hydrophilic monomer A;

[0036] * at least one anionic hydrophilic monomer B;

[0037] * at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;

[0038] - at least one electrode-active material.

[0039] DESCRIPTION OF THE INVENTION

[0040] By "polymer" we mean a polymer obtained from at least one cationic monomer A and at least one anionic monomer B. It may also comprise other monomers chosen from non-ionic hydrophilic monomers, zwitterionic hydrophilic monomers and hydrophobic monomers.

[0041] By "water-soluble polymer" we mean a polymer which gives an aqueous solution without insoluble particles when dissolved with stirring at 25°C and a concentration of 10 g.L'1in deionized water.

[0042] In the following, and above, “molecular weight” and “weight average molecular weight”, also noted Mw, are synonyms and are used indiscriminately.

[0043] By "hydrophilic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, less than or equal to 1, wherein the partition coefficient Kowis determined at 25°C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH of between 6 and 8.

[0044] By "hydrophobic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, greater than 1, wherein the partition coefficient Kowis determined at 25°C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH of between 6 and 8.

[0045] The octanol / water partition coefficient, Kow, represents the ratio of concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is defined as follows: [ monomer]octanol[monomer]water

[0046] According to the invention, "X and / or Y" means "X" or "Y", or "X and Y".

[0047] The invention also includes all possible combinations of the other than disclosed embodiments, whether they are preferred embodiments or given by way of example. In addition, when ranges of values are indicated, the terminals are part of these ranges. The disclosure also includes all combinations between the bounds of these value ranges. For example, the value ranges "1-20, preferably 5-15", imply disclosure of the ranges " 1-5", " 1-15", "5-20" and " 15-20" and the values 1, 5, 15 and 20.

[0048] By "macromonomer" we mean a macromolecule with at least one end group that enables it to behave as a monomer and to be incorporated into a polymer chain in such a way that each macromolecule contributes only one monomer unit to the polymer formed.

[0049] By "macromolecule" we mean a molecule with a weight-average molecular weight advantageously of at least 300 g / mol, preferably between 300 and 5,000 g / mol, even more preferably between 500 and 3,000 g / mol.

[0050] By "macro-transfer agents and macro-initiators", we mean a macromolecule possessing at least one functional group enabling it to ensure its function as transfer agent or initiator respectively. Advantageously, these molecules have a number of functions capable of ensuring their respective function of at least 2, preferably at least 5, more preferably at least 10 and advantageously less than 100, preferably less than 50, more preferably less than 20.

[0051] By "crosslinking macro-agents", we mean a macromolecule possessing at least two groups enabling it to ensure its crosslinking function. Advantageously, these molecules have a number of functions able to ensure their respective function of at least 5, preferably at least 10 and advantageously less than 100, preferably less than 50, more preferably less than 20.

[0052] Water-soluble polymer

[0053] According to the invention, the water-soluble polymer represents 100% by weight of the binder.

[0054] The water-soluble polymer according to the invention is a synthetic polymer.

[0055] By "block polymer" we mean di-block, tri-block or multi-block, grafted block polymers, branched block polymers (also known as linear star polymers).

[0056] Block-by-block polymers are polymers composed of at least two blocks of other than the same monomer. Di-block polymers have two distinct blocks; tri-block polymers have three, etc... They are advantageously obtained by successively polymerizing different monomer species.

[0057] In one particular embodiment, the polymer has an X-Y structure when composed of two different monomers. Thus, a first block comprises only monomers X, a second block comprises only monomers Y. In other words, the first fraction comprises X monomers only. These are first polymerized, and when all the monomers X have reacted, the second fraction comprising monomers Y is added.

[0058] In one particular embodiment, the polymer has an X-Y-Z structure when composed of three different monomers. In other words, the first fraction comprises only monomers X. These are first polymerized, and when all the monomers X have reacted, the second fraction comprising monomers Y is added. When all monomers Y have reacted, the third fraction comprising monomers Z is added.

[0059] This polymerization system may be extended to obtain so-called multi-block polymers with the structure Xi-Yi-...-Xn-i-Yn-i-Xn-Yn, n being an integer greater than or equal to 2 representing the number of blocks.

[0060] In one particular embodiment, the water-soluble polymer is a comb polymer wherein the blocks are on the backbone and / or on the side chains of the water-soluble polymer. In this embodiment, the water-soluble polymer is obtained by polymerization of at least one macromonomer, in addition to monomers.

[0061] The water-soluble polymer according to the invention comprises at least:

[0062] - a cationic hydrophilic monomer A;

[0063] - an anionic hydrophilic monomer B;

[0064] - optionally a monomer C chosen from non-ionic hydrophilic monomers, zwitterionic hydrophilic monomers, hydrophobic monomers, macromonomers, and mixtures thereof.

[0065] The cationic hydrophilic monomers A constitute the cationic blocks of the water-soluble polymer.

[0066] Advantageously, the number of cationic blocks in the water-soluble polymer is at least 2, preferably at least 3, more preferably at least 5, most preferably at least 8.

[0067] Advantageously, the number of cationic blocks in the water-soluble polymer is less than 30, preferably less than 25, more preferably less than 15 and most preferably less than 12.

[0068] Advantageously, the water-soluble polymer comprises a number of cationic blocks of between 2 and 10.

[0069] The number of cationic blocks can be adjusted by one skilled in the art, as it depends on the weightaverage molecular weight of the polymer, to achieve the desired properties.

[0070] The number of blocks in the water-soluble polymer can be determined by methods widely known by those skilled in the art, in particular Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared spectroscopy (FTIR) or Mass Spectrometry (MS).

[0071] Advantageously, the water-soluble polymer has a ratio between the number of anionic charges and the number of cationic charges of between 1.01 and 24, preferably between 1.01 and 20, more preferably between 1.1 and 12.5, more preferably between 1.5 and 8, even more preferably between 2 and 5 and even more preferably between 2.5 and 3.2.

[0072] The water-soluble polymer according to the invention may comprise one or more cationic hydrophilic monomers designated as "monomer A".

[0073] Hydrophilic cationic monomer A

[0074] Advantageously, the hydrophilic cationic monomer(s) which can be used in the context of the invention are chosen, in particular, from monomers of the vinyl type, in particular acrylamide, acrylic, allylic or maleic monomers possessing a protonable amine or ammonium function, advantageously quaternary ammonium. In particular and without limitation, diallyldialkyl ammonium salts such as diallyldimethyl ammonium chloride (DADMAC); acidified or quatemized salts of dialkyl-aminoalkyl(meth)acrylamides such as methacrylamido propyltrimethyl ammonium chloride (MAPTAC), acrylamido propyltrimethyl ammonium chloride (APTAC); acidified or quatemized salts of dialkylaminoalkyl acrylate, such as quatemized or salified dimethylaminoethyl acrylate (DMAEA); acidified or quatemized salts of dialkylaminoalkyl methacrylate, such as quatemized or salified dimethylaminoethyl methacrylate (DMAEMA); acidified or quatemized salts of N,N-dimethylallylamine; acidified or quatemized salts of diallylmethylamine; acidified or quatemized salts of diallylamine; vinylamine obtained by the hydrolysis (basic or acid) of an amide group-N(R2)-CO-R‘ with R1and R2being, independently, a hydrogen atom or an alkylated chain of 1 to 6 carbons, for example vinylamine obtained from the hydrolysis of vinylformamide; vinylamine obtained by Hofmann degradation; and mixtures thereof.

[0075] Advantageously, the alkyl groups are Ci-C7, preferably Ci-C3and can be linear, cyclic, saturated or unsaturated chains. Preferably quatemized dimethylaminoethyl acrylate.

[0076] The hydrophilic cationic monomer A is preferably selected from the group consisting of quatemized or salified dimethylaminoethyl acrylate, quatemized or salified dimethylaminoethyl methacrylate, diallyldimethyl ammonium chloride, acrylamido propyltrimethyl ammonium chloride, methacrylamido propyltrimethyl ammonium chloride, quatemized or salified N,N- dimethylallylamine, quatemized or salified diallylmethylamine, quatemized or salified diallylamine, vinylamine derived from vinylformamide hydrolysis or Hofmann degradation, and mixtures thereof.

[0077] The water-soluble polymer advantageously comprises between 4 and 49 mol% of cationic hydrophilic monomer(s) A, preferably between 10 and 49 mol%, more preferably between 10 and 40 mol%, most preferably between 10 and 25 mol%.

[0078] One skilled in the art will know how to prepare quaternized monomers, for example using a quatemizing agent of the R-X type, where R is an alkyl group and X is a halogen or sulfate.

[0079] By “quatemizing agent” we refers to a molecule capable of alkylating a tertiary amine.

[0080] The quatemizing agent may be selected from dialkyl sulfates containing 1 to 6 carbon atoms or alkyl halides containing 1 to 6 carbon atoms. Preferably, the quatemizing agent is chosen from methyl chloride, benzyl chloride, dimethyl sulfate or diethyl sulfate. In addition, this invention also covers DADMAC, APTAC and MAPTAC monomers whose counterion is a sulfate, fluoride, bromide, or iodide instead of chloride.

[0081] The water-soluble polymer according to the invention may comprise one or more anionic hydrophilic monomers designated as "monomer B".

[0082] Hydrophilic anionic monomer B

[0083] Advantageously, the anionic hydrophilic monomer(s) B which can be used in the context of the invention can be selected from a wide group. The monomers may have vinyl functions (advantageously acrylic, maleic, fumaric, malonic, itaconic, or allylic) and contain a carboxylate, phosphonate, phosphate, sulfate, sulfonate, or other anionically charged group.

[0084] Advantageously, the hydrophilic anionic monomer(s) B are selected from the group consisting of acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; 3-acrylamido 3 -methylbutanoic acid; C1-C3 itaconic acid hemi-esters; acryloyl chloride; strong acid monomers with, for example, a sulfonic acid or phosphonic acid function, such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2- methylidenepropane-l,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid, ethylene glycol methacrylate phosphate, 3-allyloxy-2-hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyl acrylate; water-soluble salts of these monomers, such as alkali metal, alkaline earth metal or ammonium salts; and mixtures thereof. Preferably acrylic acid and / or 2-acrylamido-2- methylpropanesulfonic acid (ATBS), more preferably acrylic acid.

[0085] Preferably, the anionic hydrophilic monomer(s) are acrylic acid and / or 2-acrylamido-2- methylpropane sulfonic acid and / or the water-soluble salts of these monomers, more preferably acrylic acid and / or its water-soluble salts.

[0086] In one particular embodiment, the anionic hydrophilic monomer(s) can be partially or fully salified.

[0087] By salified, we mean the substitution of a proton of at least one acid function of the-R(=O)-OH type (with R representing P, S or C) of the anionic monomer by a metal or ammonium cation to form a salt of the-R(=O)-OX type (X being a metal cation or an organic cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example R-C(=O)-OH in the case of the carboxylic acid function, whereas the salified form of the monomer corresponds to the R-C(=0)-0 form' X+, X+corresponding to an alkaline cation or an organic cation. The acid functions of the polymer may be partially or fully salified.

[0088] The salified form advantageously corresponds to salts of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (e.g., ammonium ion or tertiary ammonium), or mixtures thereof. Preferred salts are sodium and lithium salts.

[0089] Salification can be carried out, either fully or partially, before, during, or after polymerization.

[0090] In one particular embodiment, advantageously between 0 and 100 mol% of the anionic hydrophilic monomers of the water-soluble polymer are in salified form, preferably between 10 and 90 mol%, more preferably between 30 and 80 mol%.

[0091] The water-soluble polymer according to the invention advantageously comprises between 5 and 96 mol% of anionic hydrophilic monomers B, preferably between 10 and 80 mol%, more preferably between more than 25 and 50 mol%.

[0092] In one preferred embodiment, the water-soluble polymer has a greater number of anionic charges than cationic charges.

[0093] The water-soluble polymer according to the invention may comprise one or more non-ionic hydrophilic monomers and / or zwitterionic hydrophilic monomers and / or hydrophobic monomers and / or macromonomers and mixtures thereof designated as "monomer C".

[0094] Non-ionic C monomer

[0095] Advantageously, the non-ionic hydrophilic monomer or monomers which can be used in the context of the invention are chosen from the group comprising water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N,N-dialkyl acrylamides (e.g., N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N- dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactam, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glycidyl methacrylate, glyceryl methacrylate, vinyl acetate, diacetone acrylamide, methacrylic anyhydride, acrylonitrile, maleic anydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and their alkoxylated derivatives, hydroxypropylacrylate and its alkoxylated derivatives, and mixtures thereof. Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C 1-C3. Linear alkyl groups are preferred. Preferably, the non-ionic monomer is acrylamide.

[0096] The water-soluble polymer according to the invention advantageously comprises between 0 and less than 91 mol% non-ionic hydrophilic monomers, preferably between 20 and 75 mol%, and more preferably between 25 and 65 mol%.

[0097] Zwitterionic monomer C

[0098] Advantageously, the zwitterionic hydrophilic monomer or monomers which can be used in the context of the invention are chosen, in particular, from derivatives of a vinyl-type unit (advantageously acrylamide, acrylic, allylic or maleic), this monomer having an amine or quaternary ammonium function and an acid function of the carboxylic (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate) type.

[0099] Preferably, this monomer comprises an amine or quaternary ammonium function and an acid function of the carboxylic (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate) type.

[0100] Dimethylaminoethyl acrylate derivatives, such as 2-((2-9(acryloyloxy)ethyl)dimethylammonio) ethane- 1 -sulfonate, may be mentioned in particular and non-limitingly, examples of zwitterionic monomers are for example: 3-((2-(acryloyloxy)ethyl)dimethylammonio)propane-l-sulfonate; 4- ((2-(acryloyloxy)ethyl)dimethylammonio)butane- 1 -sulfonate; [2-(acryloyloxy)ethyl]

[0101] (dimethylammonio)acetate; dimethylaminoethyl methacrylate derivatives such as 2-((2- (methacryloyloxy)ethyl)dimethylammonio)ethane-l -sulfonate, 3-((2-(methacryloyloxy)ethyl) dimethylammonio)propane- 1 -sulfonate, 4-((2-(methacryloyloxy)ethyl)dimethylammonio)butane- 1 -sulfonate, [2-(methacryloyloxy)ethyl] (dimethylammonio)acetate; dimethylamino propylacrylamide derivatives such as 2-((3-acrylamidopropyl)dimethylammonio)ethane-l- sulfonate, 3 -((3 -acrylamidopropyl)dimethylammonio)propane-l -sulfonate, 4-((3- acrylamidopropyl)dimethylammonio)butane-l -sulfonate, [3-(acryloyl)oxy)propyl]

[0102] (dimethylammonio)acetate, dimethylamino propyl methylacrylamide, 2-((3- methacrylamidopropyl)dimethylammonio)ethane-l -sulfonate, 3-(dimethylammonio) propane-1- sulfonate 4- ((3-methacrylamidopropyl)dimethylammonio) butane- 1 -sulfonate, propyl [3- (methacryloyloxy)](dimethylammonio)acetate; and mixtures thereof.

[0103] Other hydrophilic zwitterionic monomers can be used, in particular those described by the Applicant in document WO2021 / 123599.

[0104] The water-soluble polymer according to the invention advantageously comprises between 0 and 30 mol% zwitterionic hydrophilic monomers, preferably between 0.01 and 20 mol% and more preferably between 0.1 and 15 mol%.

[0105] Hydrophobic C monomer C

[0106] The water-soluble polymer according to the invention may comprise one or more hydrophobic monomers.

[0107] Advantageously, the monomer or monomers with a hydrophobic character which can be used in the context of the invention can be chosen, in particular, from esters of (meth)acrylic acid with a (i) C4-C30 alkyl chain, or (ii) arylalkyl (C4-C30 alkyl, C4-C30 aryl), or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; alkyl aryl sulfonates (C4-C30 alkyl, C4-C30 aryl); mono- or di-substituted amides of (meth)acrylamide with a (i) C4-C30 alkyl chain, or (ii) arylalkyl chain (alkyl C4-C3o, aryl C4-C30 ), or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; anionic or cationic monomer derivatives of (meth)acrylamide or (meth)acrylic acid carrying a hydrophobic chain, vinylpyridine and mixtures thereof. Hydrophobic monomers can include halogen atoms, such as chlorine.

[0108] Among these hydrophobic monomers:

[0109] - alkyl groups are preferably C4-C20, more preferably C4-C8. The C6-C20 alkyls are preferably linear alkyls, while the C4-C5 alkyls are preferably branched,

[0110] - the arylalkyl groups are advantageously C7-C25, preferably C7-C15,

[0111] - the ethoxylated chains advantageously comprise from 1 to 2OO-CH2-CH2-O- groups, more preferably from 10 to 40,

[0112] - the propoxylated chains advantageously comprise from 1 to 50 -CH2-CH2-CH2-O- groups, preferably from 1 to 20.

[0113] Preferred monomers belonging to these classes are, for example:

[0114] - n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylate, erucyl (meth)acrylamide, N-tert- Butyl (meth)acrylamide, vinylpyridine, 2-ethylhexyl acrylate, C4-C22 itaconic acid hemi-esters, acidified or quaternized salts of C4-C22 dialkylaminoalkyl (meth)acrylate, acidified or quaternized salts of C4-C22, dialkylaminoalkyl (meth)acrylamides, acrylamido undecanoic acid, and combinations thereof.

[0115] - cationic allyl derivatives of formula (I) or (II): in which:

[0116] R: independently an alkyl chain containing 1 to 4 carbons;

[0117] Ri: an alkyl or arylalkyl chain containing 8 to 30 carbons;

[0118] X: a halide selected from the group consisting of bromides, chlorides, iodides, fluorides and any negatively charged counterion; and, preferably, hydrophobic cationic derivatives of the methacryloyl type corresponding to formula (III):

[0119] in which:

[0120] - A represents O or N-R5 (preferably A represents N-R5),

[0121] - R2, R3, R4, Rs, s, R7: independently a hydrogen atom or an alkyl chain containing 1 to 4 carbons,

[0122] - Q: an alkyl chain containing 1 to 20 carbons,

[0123] - Rs: an alkyl or arylalkyl chain containing 8 to 30 carbons,

[0124] - X: a halide selected from the group consisting of bromides, chlorides, iodides, fluorides and any negatively charged counterion.

[0125] The water-soluble polymer according to the invention generally comprises less than 3 mol% hydrophobic monomers.

[0126] When the water-soluble polymer according to this invention comprises hydrophobic monomers, they are present in such quantities that the polymer remains soluble in water.

[0127] In one preferred embodiment, the polymer comprises no hydrophobic monomer.

[0128] Macromonomer C

[0129] In one particular embodiment, the water-soluble polymer may be obtained by polymerizing the hydrophilic cationic A and anionic B monomers and at least one macromonomer bearing an unsaturated function. In other words, the hydrophilic cationic A and anionic B monomer(s) and the macromonomer(s) are polymerized simultaneously in a reactor. The polymer chain is gradually formed in the presence of the hydrophilic monomers and macromonomers.

[0130] The water-soluble polymer according to the invention advantageously comprises between 0 and 20 mol% macromonomer, preferably between 0.1 and 15 mol%, more preferably between 1 and 10 mol%.

[0131] Ethoxylated macromonomer C In one particular embodiment, the macromonomer is a macromonomer of formula (IV):

[0132] CH2=CR9-Z-(EO)n-(PO)m-Rio (IV) in which:

[0133] - R9 is hydrogen or methyl;

[0134] - n is a number between 1 and 200, preferably between 6 and 100, and more preferably between 10 and 40;

[0135] - Z is the divalent group-C(=O)-O-,-C(=O)-NH-, or (CH2)qwhere q is a number between 1 and 3;

[0136] - m is a number between 0 and 50, preferably between 0 and 20;

[0137] - EO is an ethylene oxide group (-CH2-CH2-O-);

[0138] - PO is a propylene oxide group (-CH2-CH(CH3)-O-);

[0139] - Rio is a hydrogen atom or a saturated or unsaturated, optionally aromatic, linear, branched or cyclic carbon radical comprising 1 to 30 carbon atoms, comprising 0 to 4 heteroatoms, selected from the group comprising O, N, and S.

[0140] In one preferred embodiment, n is greater than or equal to m.

[0141] In one preferred embodiment, the sum n+m is between 6 and 100, preferably between 10 and 40.

[0142] The hydrophilic monomer(s) that can be used to prepare the macromonomer are advantageously chosen from the anionic hydrophilic and / or non-ionic hydrophilic and / or cationic hydrophilic and / or zwitterionic hydrophilic and / or hydrophobic monomers described preceding.

[0143] One skilled in the art may consult "Macroinitiator and Macromonomer: Preparation and Application", Kaoru Adachi & Yasuhisa Tsukahara, Encyclopedia of Polymeric Nanomaterials, if required.

[0144] Thermosensitive macromonomer C

[0145] In one particular embodiment, the macromonomer is a thermosensitive macromonomer. By thermosensitive macromonomer we mean a macromolecule composed of monomers that change the physical properties of the polymer as a function of temperature.

[0146] Examples include Lower Critical Solution Temperature (LCST) groups and Upper Critical Solution Temperature (UCST) groups.

[0147] One skilled in the art knows these types of monomers from his general knowledge, if need be he will be able to consult the Applicant's document WO2016162532. If necessary, he may also consult the document "How to manipulate the upper critical solution temperature (UCST)?", J.Niskanen & H.Tenhu, Polymer Chemistry, 2017, 8, 220.

[0148] In one preferred embodiment, the heat-sensitive macromonomer has a molecular weight of between 500 g / mol and 200,000 g / mol, preferably between 1,000 g / mol and 100,000 g / mol, more preferably between 1,500 g / mol and 100,000 g / mol. Molecular weight refers to weight-average molecular weight.

[0149] Advantageously, the molar percentage of units derived from heat-sensitive macromonomers in the water-soluble polymer is greater than 10'4mol% relative to the total number of moles of heatsensitive monomers and macromonomers, preferably greater than 10'3mol%, even more preferably greater than 5.1 O'3mol%. The molar percentage of units derived from heat-sensitive macromonomers in the water-soluble polymer is preferably less than 9.1 O'2mol% relative to the total number of moles of heat-sensitive monomers and macromonomers, preferably less than 8.10"2mol%, more preferably less than 6.10'2mol%, even more preferably less than 5.10'2mol%, even more preferably less than 4.10'2mol%.

[0150] The heat-sensitive macromonomer is a monomer. Thus, unless otherwise indicated, when the weight of monomers is mentioned, it includes the weight of any heat-sensitive macromonomer(s).

[0151] Branching agent

[0152] The polymer may also be structured with a branching agent. A structured polymer is a non-linear polymer with side chains.

[0153] The branching agent is advantageously chosen from:

[0154] - structural agents, which may be chosen from the group comprising polyethylenically unsaturated compounds (having at least two unsaturated functions) different from monomer A, such as vinyl functions, in particular allyl or acrylic functions, and may include, for example, methylene bis acrylamide (MBA), triallylamine, or tetraallylammonium chloride or 1,2 dihydroxy ethylene bis- (N-acrylamide),

[0155] - compounds with at least two epoxy functions,

[0156] - compounds with at least one unsaturated function and one epoxy function,

[0157] - macroinitiators such as polyperoxides, polyazoids and transfer polyagents such as polymercaptant polymers, and polyols,

[0158] - functionalized polysaccharides,

[0159] - water-soluble metal complexes composed of:

[0160] * a metal with a valence greater than 3, such as, by way of example and without limitation, aluminum, boron, zirconium or titanium, and * a ligand bearing a hydroxyl function.

[0161] The amount of branching agent in the water-soluble polymer, according to the invention, is advantageously between 5 and 10,000 ppm relative to the total weight of the monomers of the water-soluble polymer, preferably between 10 and 5,000 ppm, more preferably between 15 and 1,000 ppm.

[0162] In one particular embodiment, the branching agent is a macro-branching agent, for example polyethylene oxide diacrylate.

[0163] The use of these branching macro-agents enables the polymer to be structured, for example in a star or comb-like, dendritic fashion.

[0164] When the water-soluble polymer according to the invention includes a branching agent, the polymer remains water-soluble. One skilled in the art will know how to adjust the amount of crosslinking agent, and possibly the amount of transfer agent, to achieve this result.

[0165] In one preferred embodiment, the water-soluble polymer does not comprise a branching agent.

[0166] In one particular embodiment, the water-soluble polymer comprises at least one transfer agent.

[0167] The transfer agent is advantageously selected from methanol; isopropyl alcohol; sodium hypophosphite; calcium hypophosphite; magnesium hypophosphite; potassium hypophosphite; ammonium hypophosphite; formic acid; sodium formate; calcium formate; magnesium formate; potassium formate; ammonium formate; 2-mercaptoethanol; 3 -mercaptopropanol; dithiopropylene di thiopropanol; dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene dithiopropylene magnesium formate; potassium formate; ammonium formate; 2-mercaptoethanol; 3- mercaptopropanol; dithiopropylene glycol; thioglycerol; thioglycolic acid; thiohydracrylic acid; thiolactic acid; thiomalic acid; cysteine; and aminoethanethiol; thioglycolates; allyl phosphites; allyl mercaptans, such as n-dodecyl mercaptan; sodium methallysulfonate; calcium methallysulfonate; magnesium methallysulfonate; potassium methallysulfonate; ammonium methallysulfonate; alkyl phosphites such as trialkyl (C12-C15) phosphites, di-oleyl-hydrogen phosphites, dibutyl phosphite, dialkyldithiophosphates such as dioctyl phosphonate, tertiary nonylmercaptan, 2-ethylhexyl thioglycolate, n-octyl mercaptan, n-dodecyl mercaptan, tertiary-dodecyl mercaptan, isooctylthioglycolate, 2-Ethylhexyl thioglycolate, 2-Ethylhexyl mercaptoacetate, polythiols and mixtures thereof. Preferably sodium hypophosphite or sodium formate.

[0168] The quantity of transfer agent in the water-soluble polymer according to the invention is advantageously between 100 and 50,000 ppm relative to the total weight of the monomers of the water- soluble polymer, preferably between 200 and 10,000 ppm, more preferably between 300 and 5,000 ppm.

[0169] In one particular embodiment, the water-soluble polymer does not comprise a specific transfer agent, and this role may be ensured by the polymerization solvent (such as isopropanol).

[0170] In one particular embodiment, the water-soluble polymer does not comprise a transfer agent.

[0171] In one particular embodiment, the transfer agent is a macro -transfer agent chosen from polymercaptants and polyols.

[0172] The use of these macro -transfer agents enables the polymer to be structured in a dendritic manner, for example in the form of a star or comb.

[0173] Molecular weight of water-soluble polymer

[0174] Advantageously, the water-soluble polymer according to the invention has a weight average molecular weight advantageously between 50,000 and 5 million g / mol, preferably between 100,000 and 3,000,000 g / mol, more preferably between 300,000 and 800,000 g / mol, even more preferably between 400,000 and 600,000 g / mol.

[0175] The weight average molecular weight is advantageously determined by the intrinsic viscosity of the polymer. Intrinsic viscosity may be measured by methods known to one skilled in the art and can be calculated from the reduced viscosity values for different polymer concentrations, using a graphical method consisting of plotting the reduced viscosity values (y-axis) against the concentration (x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity value is plotted on the y-axis or using the least-squares method. The molecular weight may then be determined by the Mark-Houwink equation:

[0176] [r|] = K M“

[0177] [q] represents the intrinsic viscosity of the polymer as determined by the solution viscosity method. K is an empirical constant.

[0178] M represents the molecular weight of the polymer. a represents the Mark-Houwink coefficient.

[0179] K and a depend on the particular polymer-solvent system.

[0180] This water-soluble polymer has at least 30 mol% of its cationic hydrophilic monomers A in the form of cationic blocks. The cationic blocks have a molecular weight of between 500 and 50,000 g / mol, preferably between 1,000 and 40,000 g / mol, more preferably between 5,000 and 30,000 g / mol.

[0181] There are several polymerization methods for introducing blocks with a molecular weight of between 500 and 50,000 g / mol into a polymer.

[0182] The molecular weight of the blocks in the water-soluble polymer can be determined by methods widely known by those skilled in the art, in particular nuclear magnetic resonance (NMR), Fourier Transform Infrared spectroscopy (FTIR) or Mass Spectrometry (MS).

[0183] The invention is therefore not limited to the methods described below.

[0184] Polymerization method

[0185] In a particular embodiment, the water-soluble polymer is obtained by polymerization in the presence of at least one anionic template.

[0186] Template

[0187] In template polymerization, polymer formation takes place in the presence of another low- molecular-weight polymer template. Before and during polymerization, some of the monomers are spatially distributed around these templates by electrostatic interactions, Van der Waals forces or hydrogen bonds, so that, once polymerization has begun, blocks with a well-defined structure in terms of size, polarity and functionality are formed. The simultaneous or delayed addition of a comonomer produces a polymer with block inclusions whose properties are other than those of a polymer obtained by conventional polymerization. Interactions / bonds with the template are reversible, enabling them to be recycled once polymerization is complete.

[0188] One skilled in the art may refer to "Template polymerisation and co-polymerisalion". Stefan Polowinski, Prog. Polym. Sci. 27 (2002) 537-577, or to "Monitoring Polymerization Reactions: From Fundamentals to Applications" , Wayne F. Reed and Alina M. Alb, John Wiley & Sons. 2014.

[0189] The template(s) are prepared from anionic monomers, in particular and without limitation vinylfunctional monomers such as acrylic, maleic, fumaric, itaconic or allylic monomers. Monomers with a carboxylate, phosphonate, phosphate, sulfonate, sulfate or other anionically charged group. Preferred monomers belonging to this class are, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, acrylamido undecanoic acid, 3-acrylamido 3 -methylbutanoic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrene sulfonic acid, 2- acrylamido-2-methylpropane disulfonic acid, and mixtures thereof. Preferably acrylic acid and / or 2-acrylamido-2-methylpropane sulfonic acid (ATBS). More preferably, the anionic template(s) are prepared from acrylic acid.

[0190] The molecular weight of the anionic template is between 500 and 50,000 g / mol. Molecular weight is defined as weight-average molecular weight.

[0191] In another embodiment, the water-soluble polymer is obtained by radical polymerization controlled by reversible deactivation (RDRP).

[0192] RDRP polymerization

[0193] The polymerization is advantageously a reversible deactivation controlled radical polymerization (RDRP).

[0194] Polymerization can take place in solution, by precipitation, in emulsion (aqueous or inverse), in suspension, or water-in-water, preferably in solution.

[0195] Radical polymerization includes free-radical polymerization using UV, azo, redox or thermal initiators, as well as controlled radical polymerization (CRP) or matrix polymerization techniques.

[0196] RDRP includes techniques such as Iodine Transfer Polymerization (ITP), Nitroxide Mediated Polymerization (NMP), Atom Transfer Radical Polymerization (ATRP), Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT), which includes MADIX technology (Macromolecular Design by Interchange of Xanthates), various variations of Organometallic Mediated Radical Polymerization (OMRP), and OrganoHeteroatom-mediated Radical Polymerization (OHRP).

[0197] All these techniques are based on a reversible equilibrium between a dormant and an active species. This activation-deactivation process enables the chains to grow at the same rate until the monomer is fully consumed, making it possible to control polymer molecular weights and obtain narrow polymer distributions. Reversible deactivation of growing chains minimizes irreversible termination reactions. The vast majority of polymer chains remain in dormant form and can therefore be reactivated. It is then possible to functionalize the chain ends in order to initiate other polymerization modes or to make chain extensions. This is the key to achieving high molecular weights, controlled compositions and architectures.

[0198] Controlled radical polymerization may therefore have the following distinctive aspects: 1. the number of polymer chains is fixed throughout the reaction,

[0199] 2. the polymer chains all grow at the same rate, resulting in:

[0200] * a linear increase in molecular weight,

[0201] * a narrow molecular weight distribution,

[0202] 3. the average molecular weight is controlled by the monomer / precursor molar ratio.

[0203] The controlled character is all the more pronounced when the rate of chain radical reactivation is so much greater than the rate of chain growth. However, in some cases, the rate of chain radical reactivation is greater than or equal to the rate of chain propagation. In these cases, conditions 1 and 2 are not observed and, consequently, molecular weight control is not possible.

[0204] Using RDRP, it is therefore possible to obtain a polymer with a block structure, by adding the monomers in the melt and alternating the composition of the melt according to molecular weight and the desired water-soluble polymer composition.

[0205] In other words, a first fraction of cationic monomer constituting the water-soluble polymer, sufficient to achieve a molecular weight of between 500 and 50,000 g / mol, is polymerized. When all the cationic monomers have reacted, a second fraction of the water-soluble polymer monomers is added and polymerized. And so on, alternating fractions constituting the blocks and the remainder of the monomers constituting the water-soluble polymer, until the desired molecular weight is achieved.

[0206] In one preferred embodiment, the reversible deactivation-controlled radical polymerization technique is selected from reversible addition-fragmentation chain transfer (RAFT), nitroxide- controlled polymerization (NMP) and atom transfer radical polymerization (ATRP).

[0207] In the case of reversible addition-fragmentation chain transfer polymerization (RAFT) and nitroxide-controlled polymerization (NMP), the polymerization initiator(s) used are advantageously chosen from compounds which dissociate into radicals under polymerization conditions, for example: organic peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and redox catalysts. The use of water-soluble initiators is preferred. In some cases, it is advantageous to use mixtures of various polymerization initiators, for example mixtures of redox catalysts and azo compounds.

[0208] According to the invention, the quantity of initiator is advantageously between 2,000 and 20,000 ppm relative to the total weight of monomer, preferably between 4,000 and 10,000 ppm.

[0209] In one particular embodiment, the initiator is a macroinitiator. The use of macroinitiators enables the polymer to be structured, resulting in star-shaped, combshaped or dendritic structures.

[0210] Advantageously, the macroinitiator(s) that can be used in the context of the invention can be chosen from polyperoxides and polyazoics. In particular, the initiator may be 2,2'-Azobis[2-(2-imidazolin- 2-yl)propane]dihydrochloride.

[0211] RAFT polymerization

[0212] In one preferred embodiment of the invention, the technique for controlled radical polymerization by reversible deactivation is reversible addition-fragmentation chain transfer (RAFT) polymerization.

[0213] RAFT is based on a reversible chain transfer mechanism consisting of two addition-fragmentation equilibria involving a control agent. Initiation and termination between radicals are the same as in conventional radical polymerization. After decomposition of the initiator into radicals, the first radical species produced adds to the monomer to form a carbon radical, which then reacts rapidly with the control agent to form the corresponding radical entity. The latter will fragment into an initiator and a novel radical capable of re-initiating polymerization.

[0214] Reversible addition-fragmentation chain transfer polymerization requires the presence of at least one control agent, advantageously of formula (V): in which

[0215] - Z represents O, S, NR3 or is a direct bond to Ri;

[0216] - Ri, R2 and R3, which may be identical or different, represent:

[0217] * an optionally substituted alkyl, acyl, alkenyl or alkynyl group (i), or

[0218] * an optionally substituted or aromatic, saturated or unsaturated carbon ring (ii), or

[0219] * an optionally substituted or aromatic, saturated or unsaturated heterocycle (iii), these groups and rings (i), (ii) and (iii) may be substituted by substituted aromatic groups or by alkoxycarbonyl or aryloxycarbonyl (-COOR), carboxy (-COOH), acyloxy (-O2CR), carbamoyl (- C0N(R)2), cyano (-CN) groups, alkylcarbonyl, alkyl aryl carbonyl, arylcarbonyl, arylalkylcarbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (-OH), amino (-N(R)2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups of hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), cationic substituents (quaternary ammonium salts);

[0220] - R is an alkyl or aryl group C1-C20;

[0221] - R3 may also represent a hydrogen atom;

[0222] - Q is a linear or structured polymer chain comprising n identical or different monomers comprising at least one ethylenic function;

[0223] - n is an integer between 0 and 500, advantageously between 1 and 500, more advantageously between 1 and 100. When n is equal to 0, Q is a single bond between the sulfur atom and the R2 group.

[0224] The monomer or monomers used to form Q are advantageously chosen from the same monomers as those described for forming the branched water-soluble polymer (monomers A and / or B and / or C). Examples include acrylamide, acrylic acid and mixtures thereof.

[0225] In NR2 functions, the two R groups may be identical or different from each other.

[0226] In one preferred embodiment, the control agent is of formula V in which Z represents O.

[0227] In another preferred embodiment, the control agent is of formula V in which:

[0228] - Z represents O,

[0229] - Q is a linear or structured polymer chain obtained from 1 to 100 monomers comprising at least one non-ionic hydrophilic monomer and / or at least one anionic hydrophilic monomer and / or at least one cationic hydrophilic monomer described preceding.

[0230] In another preferred embodiment, the control agent is of formula (VI): in which Q is a linear or structured polymeric chain obtained from 1 to 100 monomers chosen from acrylamide, acrylic acid or quatemized or salified dimethylaminoethyl acrylate, preferably between 1 and 50.

[0231] In another preferred embodiment, the control agent is of formula V in which Z represents S. In another preferred embodiment, the control agent is of formula (VII): in which the groups R3, which are identical or different, independently represent a hydrogen atom or a CH3 or a cation, the cation being advantageously chosen from alkali metal cations (Li, Na, K...), alkaline earth metal cations (Ca, Mg...) or ammonium cations (e.g., ammonium ion or tertiary ammonium), preferably sodium.

[0232] In another preferred embodiment, the control agent is of formula (VIII): in which:

[0233] - the groups R3 are identical or different and independently represent a hydrogen atom or a CH3 or a cation, the cation advantageously being chosen from alkali metal cations (Li, Na, K...), alkaline earth metal cations (Ca, Mg...) or ammonium cations (e.g., ammonium ion or tertiary ammonium), preferably sodium;

[0234] - Q is a linear or structured polymeric chain obtained from 1 to 100 monomers chosen from acrylamide, acrylic acid or quatemized or salified dimethylaminoethyl acrylate, preferably between 1 and 50.

[0235] In another preferred embodiment, the control agent is of formula (IX): in which the R3 are identical or other than, independently represent a hydrogen atom or a CH or a cation, the cation being advantageously chosen from alkali metal cations (Li, Na, K...), alkaline earth metal cations (Ca, Mg...) or ammonium cations (e.g., ammonium ion or tertiary ammonium), preferably sodium.

[0236] In another preferred embodiment, the control agent is of formula (X): in which

[0237] - the groups R3, which may be identical or different, independently represent an H or a CH3 or a cation, the cation advantageously being chosen from alkali metal cations (Li, Na, K...), alkaline earth metal cations (Ca, Mg...) or ammonium cations (e.g., ammonium ion or tertiary ammonium), preferably sodium; and

[0238] - Q is a linear or structured polymeric chain obtained from 1 to 100 monomers chosen from acrylamide, acrylic acid or quatemized or salified dimethylaminoethyl acrylate, preferably between 1 and 50.

[0239] The molar ratio between monomers and control agent is advantageously between 700: 1 and 42,000:1, preferably between 1,400: 1 and 14,000: 1, more preferably between 2,800: 1 and 11,500:1, even more preferably between 5,600: 1 and 11,500: 1.

[0240] NMP polymerization

[0241] In one particular embodiment, the reversible deactivation-controlled radical polymerization technique is nitroxide polymerization (NMP).

[0242] NMP's reversibility principle is based on a family of compounds known as alkoxyamines.

[0243] An alkoxyamine is a compound of formula (XI): in which:

[0244] - R4 and R5 are identical or different, independently represent an H or an alkyl group which may be linear, branched, cyclic, saturated or unsaturated, and may comprise one or more heteroatoms, advantageously C1-C30, preferably C1-C20, more preferably Ci-Cs; - Re represents an alkyl group which may be linear, branched, cyclic, saturated or unsaturated and may comprise one or more heteroatoms, advantageously from C1-C30, preferably from C1-C20, more preferably from Ci-Cs.

[0245] The usefulness of this functional group is that under certain conditions, homolysis of the C-0 bond may occur, yielding a stable radical in the form of a 2-center, 3 -electron N-0 system and a carbon radical that serves as an initiator for radical polymerization.

[0246] For NMP purposes, nitrogen-bonded R groups are always bulky, sterically troublesome groups, and oxygen-bonded R groups must allow mesomerization of the radical to form a stable radical (e.g., a benzyl, t-butyl, ester-type group) for successful polymerization to occur.

[0247] NMP provides excellent control of chain length and structure, as well as a relative absence of true termination, allowing polymerization to continue as long as monomer is available.

[0248] Alkoxyamines suitable for NMP are listed in documents W02002 / 48109, WO99 / 46261 or W02010 / 015599.

[0249] The molar ratio between monomers and alkoxyamine is advantageously between 700: 1 and 42,000:1, preferably between 1,400: 1 and 14,000: 1, more preferably between 2,800: 1 and 11,500:1, even more preferably between 5,600: 1 and 11,500: 1.

[0250] One skilled in the art may also refer to “New Polymer Synthesis by Nitroxide Mediated Living Radical Polymerizations" by C. J. Hawker et al, Chemical Reviews, 2001, pp. 3661-3688, if required.

[0251] ATRP polymerization

[0252] In one particular embodiment, the reversible deactivation controlled radical polymerization technique is atom transfer polymerization (ATRP).

[0253] ATRP uses a transition metal complex as catalyst with an alkyl halide as initiator (R-X). Various transition metal complexes, including those of Cu, Fe, Ru, Ni and Os, can be used. In ATRP, the dormant species is activated by the transition metal complex to generate radicals via an electron transfer process. Simultaneously, the transition metal is oxidized to a higher oxidation state. This reversible process rapidly establishes an equilibrium, with each growing chain having the same probability of propagating with monomers to form living or dormant polymer chains (R-Pn-X). As a result, polymers with similar molecular weights and a narrow molecular weight distribution can be prepared. The number of polymer chains is determined by the amount of initiator. The initiator(s) are advantageously chosen from alkyl halides whose structures are similar to that of the radical being propagated. Alkyl halides such as alkyl bromides are more reactive than alkyl chlorides, the alkyl being advantageously Ci-Cs, preferably C1-C4.

[0254] Suitable primers for ATRP are listed in documents W02002 / 48109, WO99 / 46261 or W02010 / 0015599.

[0255] The molar ratio between monomers and initiator is advantageously between 700: 1 and 42,000: 1, preferably between 1,400: 1 and 14,000: 1, more preferably between 2,800: 1 and 11,500: 1, most preferably between 5,600: 1 and 11,500: 1.

[0256] In another embodiment, the water-soluble polymer is obtained by polymerization with a macromonomer.

[0257] Macromonomer

[0258] In one particular embodiment, the water-soluble polymer of the invention may be obtained by polymerizing at least one type of anionic hydrophilic monomer B and at least one macromonomer. According to this embodiment, the water-soluble polymer is obtained by polymerization of at least one anionic hydrophilic monomer B and at least one macromonomer, the macromonomer comprising the cationic hydrophilic monomer A and constituting the blocks of the water-soluble polymer.

[0259] Relating to macromonomer synthesis, telomerization may be mentioned, which is a method for synthesizing oligomers with low molecular weights (known as telomers).

[0260] Telomerization agents can be selected from thiols, alcohols, disulfides, phosphorus, boron and halogen derivatives. In particular, they can be used to introduce specific functions at the end of telomer chains, such as silane, trialkoxysilane, amine, epoxy, hydroxyl, phosphonate or acid functions.

[0261] Once these oligomers have been formed, in a second step, a vinyl double bond (R'iR'2 C=CR'3-, R'I, R'2 and R'3 being independently of each other a hydrogen atom or a hydrocarbon or nonhydrocarbon group which may include heteroatoms) may be introduced at the end of the chain so that they serve as macromonomers which may in turn be polymerized.

[0262] In another macromonomer synthesis method, a water-soluble polymer (the backbone) is first obtained by polymerizing the water-soluble monomers, then oligomers are grafted onto said water- soluble polymer. In this embodiment, the oligomers are cationic blocks.

[0263] Surprisingly, the Applicant discovered that the structure of the polymer according to the invention enabled it to offer good performance by giving the ink better properties, whether in terms of dispersion, adhesion, stability or flexibility, and thus meet the needs of industrialists without any disadvantages for them.

[0264] The performance provided by the polymer according to the invention is enhanced when used in combination with a flexibility agent such as carboxymethylcellulose CMC, styrene-butadiene rubber SBR, or combinations thereof.

[0265] Composition

[0266] This invention also relates to a composition for an electrode ink comprising:

[0267] - at least one binder consisting of a water-soluble polymer comprising:

[0268] * at least one cationic hydrophilic monomer A;

[0269] * at least one anionic hydrophilic monomer B;

[0270] * at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;

[0271] - at least one electrode-active material;

[0272] - optionally at least one flexibility agent chosen from polysaccharides, styrene-butadiene rubber and mixtures thereof.

[0273] Advantageously, the solvent is water.

[0274] This composition comprises a quantity of water-soluble polymer advantageously between 0.5 and 15% by weight relative to the total weight of the composition, preferably between 0.7 and 10% by weight, more preferably between 0.9 and 7% by weight and even more preferably between 1 and 5% by weight.

[0275] Preferably, the flexibility agent is a polysaccharide, advantageously chosen from the group comprising carboxymethylcellulose, alginates, xanthan gums, diutan gum, welan gum, their salts and mixtures thereof. Preferably, the flexibility agent is carboxymethylcellulose.

[0276] This composition has a quantity of flexibility agent advantageously between 0.5 and 10% by weight relative to the total weight of the composition, preferably between 0.5 and 5% by weight, more preferably between 1 and 3% by weight.

[0277] Advantageously, the composition has a weight ratio between the at least one water-soluble polymer and the at least one flexibility agent of between 0.1 and 30, preferably between 0.1 and 14, and more preferably between 0.33 and 5.

[0278] Battery

[0279] This invention also relates to a battery, preferably a lithium-ion battery, comprising an electrode comprising:

[0280] - at least one binder consisting of a water-soluble polymer comprising:

[0281] * at least one cationic hydrophilic monomer A;

[0282] * at least one anionic hydrophilic monomer B;

[0283] * at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;

[0284] - at least one electrode-active material.

[0285] The invention and its advantages will be better illustrated by, but not limited to, the following examples.

[0286] EXAMPLES

[0287] List of abbreviations:

[0288] ADC: Dimethylaminoethyl acrylate quaternized with methyl chloride

[0289] Na A: Sodium acrylate

[0290] AA: Acrylic acid

[0291] SBR: Styrene Butadiene Rubber (from Zeon BM 400)

[0292] CMC: Carboxymethylcellulose (from Sigma Aldrich Mw= 700,000 g / mol, DS = 0.7)

[0293] Example 1- Synthesis of an ADC and NaA (30 / 70 mol%) block polymer (Pl) using a G1 template

[0294] G1 template summary

[0295] 190.0 g of deionized water are added to a one-liter jacketed reactor equipped with a refrigerant and mechanical stirrer with a half-moon module and nitrogen inlet, and heated to 80°C under a nitrogen atmosphere (nitrogen flow).

[0296] A sodium persulfate solution is prepared in a dropping funnel, by dissolving 17.0 g of sodium persulfate in 100.0 g of deionized water. A second ampoule is filled with 690.0 g of 2-acrylamido- 2-methylpropane sulfonic acid sodium salt solution 50% by weight in water).

[0297] The sodium persulfate solution is added to the reactor over 20 minutes, keeping the reactor at 80°C. In parallel, the sodium salt solution of 2-acrylamido-2-methylpropane sulfonic acid is added over 90 minutes. Once the sodium persulfate solution has been added, the solution is kept stirring at 80°C for 60 minutes. A G1 polymer with a weight-average molecular weight equal to 41,000 g / mol, determined from the intrinsic viscosity, is thus obtained.

[0298] Synthesis of polymer Pl according to the invention

[0299] In a one-liter reactor, equipped with coolant, temperature probe, and mechanical stirrer with halfmoon module, monomer feed and nitrogen inlet, 863.9 g deionized water, 50.5 g 80% wt ADC solution in water, 18.4 g AA, 115.0 g 40% wt G1 polymer solution in water and 0.1 g sodium hypophosphite are added.

[0300] The resulting solution is heated to 45°C. Nitrogen bubbles are then applied for 30 minutes to remove all traces of dissolved oxygen.

[0301] A solution of 0.1 g of 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA-044® from the Wako company) in 5 mL of deionized water and a solution of 0.1 g of 2,2'-Azobis(2- methylpropionamidine)dihydrochloride (V-50® from the Wako company) in 5 mL deionized water are prepared in parallel and added to the reactor once the temperature has stabilized at 45°C.

[0302] When peak temperature is reached, the medium is left to stir for a further 1 hour. 1.2 g of a 40% wt. sodium metabisulfite solution in water is then added, and the medium is left to stir for 30 min. The pH of the solution is then adjusted to 6.5. Polymer Pl is thus obtained.

[0303] Example 2- Synthesis of a polymer (P2) with successive blocks of ADC and NaA (45 / 55 mol%) by RAFT

[0304] To a one-liter reactor equipped with a cooler, temperature probe, mechanical stirrer with half-moon module, monomer feed, and nitrogen inlet are added 679.6 g of deionized water.

[0305] A solution of propanic acid 2-[(ethoxythioxomethyl)thio]-methyl ester is prepared by mixing 2.0 g of propanic acid 2-[(ethoxythioxomethyl)thio]-methyl ester in 30 mL of deionized water and 70 mL of acetone. 1 mL of this solution is added to the reactor.

[0306] The medium is degassed for 20 minutes and heated to 60°C.

[0307] A solution of 5.1 mg 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) in 5 mL deionized water is prepared and added to the reactor.

[0308] 8.4 g of 80% ADC (by weight in water) is injected into the reactor, and the medium is left to stir for 30 min. The ADC polymerization is controlled gravimetrically.

[0309] If polymerization is below 80mol%, the medium is left to stir until this value is reached.

[0310] If polymerization is above 80mol%, 6.1 g of AA and 8.4 g of 80% ADC (by weight in water) are added to the reactor, and the medium is left to stir for 30 min.

[0311] If polymerization is below 80mol%, the medium is left to stir until this value is reached. These 2 successive additions of ADC on the one hand and AA and ADC on the other are repeated 3 times. Once the additions are complete, the medium is left to stir for a further 1 hour. 1.2 g of a 40% sodium metabisulfite solution (by weight in water) is added to the medium and the medium is left to stir for 30 min. The pH of the solution is then adjusted to 6.5. Polymer P2 is thus obtained.

[0312] Example 3- Synthesis of a comb polymer (P3) with a NaA backbone (55 mol%) and 10,000 g / mol ADC side chains (representing 45 mol%)

[0313] Synthesis of macromonomer Ml

[0314] In a one-liter reactor, equipped with a condenser, a temperature probe and mechanical stirring with a half-moon module and a nitrogen inlet, 403.8 g of water are added, deionized and 100.0 g of an 80% by weight ADC solution in water. The medium is degassed for 30 min, the pH adjusted to 3.5 (+ / - 0.5) using a 10M hydrochloric acid solution, and the temperature adjusted to 60°C.

[0315] 1.0 g 2-aminoethanethiol (95% purity) is added to the reactor and dissolved in 5 mL deionized water, and 0.2 g 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) dissolved in 5 mL deionized water is added to the reactor. The medium is left to stir at 50°C for 24 hours. Telomer T1 is thus obtained.

[0316] 4.8 g of 10% sodium hydroxide (by weight in water) are prepared for addition via a syringe pump.

[0317] 1.8 g methacrylic anhydride is prepared for addition via syringe pump.

[0318] The medium containing telomer T1 is cooled to 10°C and the pH maintained between 7 and 9. Sodium hydroxide solution and methacrylic anhydride are then added.

[0319] Syringe pump flow rates are adjusted to control the exothermicity of the reaction and maintain a pH between 7 and 9. The result is a macromonomer Ml .

[0320] Synthesis of the P3 polymer according to the invention

[0321] In a one-liter reactor, equipped with a condenser, a temperature probe and mechanical stirring with a half-moon module, a monomer supply and a nitrogen inlet, are added 196.8 g of deionized water,

[0322] 23.8 g of AA, 261.6 g of a 20% by weight solution of macromonomer Ml in water and 0.2 g of sodium hypophosphite.

[0323] The medium is degassed for 20 minutes and heated to 60°C.

[0324] A solution containing 0.1 g of 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA- 044® from the Wako company) dissolved in 5 mL of deionized water and a solution containing 0.1 g of 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) dissolved in 5 mL of deionized water are prepared in parallel and added to the reactor.

[0325] Once peak temperature has been reached, the medium is left to stir for a further 1 hour. 1.2 g of 40% wt. sodium metabisulfite solution in water is then added to the medium, and the medium is left to stir for 30 min. The pH of the solution is then adjusted to 6.5. The P3 polymer is thus obtained.

[0326] Example 4- Synthesis of a comb polymer (P4) with a NaA backbone (85 mol%) and 10,000 g / mol ADC side chains (15 mol%) and incorporating a hydrophobic link.

[0327] 308.2 g of deionized water, 51.7 g of AA, 122.4 g of a 20% by weight solution of macromonomer Ml in water and 23.0 mg of dodecylmercaptan dissolved in 5 mL of acetone are added to a one- liter reactor equipped with a cooler, temperature probe and mechanical stirrer with half-moon module, monomer feed and nitrogen inlet.

[0328] The medium is degassed for 20 minutes and heated to 60°C.

[0329] A solution containing 0.1 g of 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA- 044® from the Wako company) dissolved in 5 mL of deionized water and a solution containing 0.1 g of 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) dissolved in 5 mL of deionized water are prepared in parallel and added to the reactor.

[0330] Once peak temperature has been reached, the medium is left to stir for a further 1 hour. 1.2 g of 40% wt. sodium metabisulfite solution in water is then added to the medium, and the medium is left to stir for 30 min. The pH of the solution is then adjusted to 6.5. P4 polymer is thus obtained.

[0331] Counter-example 1- Synthesis of a statistical polymer (PCI) of ADC and NaA (45 / 55 mol%)

[0332] In a one-liter reactor, equipped with a condenser, a temperature probe and mechanical stirring with a half-moon module, a monomer supply and a nitrogen inlet, 664.5 g of deionized water, 23.8 g of AA, a solution of 65.4 g of ADC at 80% by weight in water and 0.2 g of sodium hypophosphite are introduced.

[0333] The medium is degassed for 20 minutes and heated to 60°C.

[0334] A solution containing 0.1 g of 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VA- 044® from the Wako company) dissolved in 5 mL of deionized water and a solution containing 0.1 g of 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) dissolved in 5 mL of deionized water are prepared in parallel and added to the reactor.

[0335] Once peak temperature has been reached, the medium is left to stir for a further 1 hour. 1.2g of 40% sodium metabisulfite solution (by weight) in water is then added to the medium, and the medium is left to stir for 30 min. The pH of the solution is then adjusted to 6.5. The PCI polymer is then obtained.

[0336] Counter-example 2- Synthesis of a comb polymer (PC2) with a NaA backbone (55 mol%) and 400 g / mol ADC side chains (45 mol%) The method described in Example 3 is repeated, adjusting the quantities so that the M2 macromonomer has side chains of 400 g / mol, to obtain the PC2 polymer.

[0337] Counter-example 3- Synthesis of a comb polymer (PC3) with a NaA backbone (55 mol%) and 90,000 g / mol ADC side chains (45 mol%)

[0338] The method described in Example 3 is repeated, adjusting the quantities so that the M2 macromonomer has side chains of 90,000 g / mol, to obtain the PC3 polymer.

[0339] Counter Example 4- Synthesis of a polymer (PC4) of ADC and NaA with 20% cationic charges in the form of 10,000 g / mol blocks.

[0340] In a one liter reactor, equipped with a condenser, a temperature probe and mechanical stirring with a half-moon module, a monomer supply and a nitrogen inlet, are added 679.6 g of deionized water. 103 mg propanic acid 2-[(ethoxythioxomethyl)thio]-methyl ester is dissolved in 2 mL acetone, then diluted in 529.1 g deionized water. 1 mL of this solution is added to the reactor.

[0341] The medium is degassed for 20 minutes and heated to 60°C.

[0342] Amonomer solution A comprising 10.1 g of80% ADC (by weight in water) is prepared. In parallel, a monomer solution B comprising 18.4 g AA and 40.4 g 80% ADC (by weight in water) is prepared.

[0343] An initiator solution of 5 mg of 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (V-50® from the Wako company) in 10 g of deionized water is prepared.

[0344] The initiator solution and a third of solution A are added to the reactor and left to react for 45 min. One third of solution B is then added and the medium is left to react for 80 min.

[0345] The addition of solution A followed by solution B is repeated a further 2 times. An initiator solution may be re-injected if polymerization slows down.

[0346] Once dropping is complete, the medium is left to stir for a further 1 hour. 1.20 g of a 40% sodium metabisulfite solution (by weight in water) is added to the medium and left to stir for 30 min. The pH of the solution is then adjusted to 6.5. The PC4 polymer is then obtained.

[0347] Characterization of the polymers obtained

[0348] The characteristics of the polymers thus obtained are summarized in Table 1.

[0349] Table 1 : Polymer properties

[0350] % block cationicity = percentage of cationic monomers in block form.

[0351] Molecular weights are determined by steric exclusion chromatography. They are measured by an Agilent 1260 Infinity system equipped with a Dawn HELOS, OPtilab T-Rex multi-angle light scattering detector and 3 columns in series: Shodex SB 807-G, Shodex SB 807-HQ and Shodex 805-HQ.

[0352] The percentage of block-by-block cationicity corresponds to the percentage of cationic charges involved in cationic triads. This percentage is determined by proton NMR. It is measured by a Bruker 400 MHz ASCEND (TM) Avance III HD equipped with a 10 mm BBO 400 MHz Z-G radiating probe.

[0353] MWBC corresponds to the molecular weight by weight of the cationic blocks. It is measured in different ways depending on the one particular embodiment employed:

[0354] - For Pl, integration of the signals corresponding to the AA / ADC / ADC triads enables us to determine the number of cationic blocks Nb. Knowing the molecular weight by number, the mole fraction in ADC, the percentage of block cationicity and Nb, we can determine MWBC.

[0355] - For P2, the ratio [ADC] / [Agent RAFT] corrected by the actual conversion (polymerization) leads to the molecular weight by number of the blocks. The molecular weight MWBC is obtained by applying the poly dispersity index of the copolymer.

[0356] - For P3, the molecular weight of the macromonomer Ml corresponds to MWBC. This is determined directly by steric exclusion chromatography.

[0357] Application examples

[0358] The polymers obtained are then used as anode binders.

[0359] Ink preparation Inks composed of 83.5% GHDR 15-4 graphite from Imerys, 3% C-Energy Super C65 carbon black from Imerys, 10% SiQC 99 from Nanomakers and 3.5% active polymer are produced.

[0360] The powders are first introduced into a 150 mL flask adapted to the Thinky ARM 310 stirrer. They are shaken for 1 minute at 1,100 rpm to homogenize the powder mixture. The polymer is diluted in the appropriate amount of deionized water. The latter is adjusted to obtain a viscosity at 10 s'1of between 5,000 and 10,000 cP.

[0361] The proportion of ink solids with a viscosity within this range is denoted TS. The powders and polymer solution are mixed at 1,100 rpm for 2 min, then at 2,000 rpm for 5 min.

[0362] Preparing negative electrodes

[0363] The inks thus prepared are deposited on a 20 pm-thick copper foil using an RK Print K303 lab coater. The thickness of the layer is adjusted using the other than bars supplied to achieve between 3.8 and 4.3 mAh / cm2(5.2- 6.0 mg / cm2).

[0364] The electrode is then dried for 12 hours at 60°C in a vacuum oven. The electrode is then calendered to achieve a porosity of 30% + / - 3%.

[0365] Preparing button cells

[0366] For each electrode, 4 disks of 13 mm diameter are cut and dried overnight in a vacuum oven heated to 110°C, then placed in a glove box (EE O < 0.1 ppm; O2 < 0.1 ppm).

[0367] CR 2032 button cells are used. The cathode is NMC 622 from Customcells (3.5 mAh / cm2), the separator is a 16.5 mm Celgard 2,500 disk and the electrolyte is LP 57 from E-Lyte ( IM LiPFe in EC:EMC (30:70% by weight + 10% FEC)) added at 20 pL to the anode and cathode.

[0368] Button cell cycling

[0369] Button cell capacity retention is assessed using BCS 805 galvanostatic cyclers from the Biologic company. Batteries are cycled at 25°C between 2.5 and 4.2 V at C / 10 for 100 cycles, with a 5- minute rest period between each charge / discharge cycle.

[0370] Ink evaluation

[0371] * Solids content

[0372] Solids content (SC) represents the amount of dry matter in the ink. The higher the value, the better the ink, as less energy is required to evaporate the solvent.

[0373] * Dispersion quality

[0374] The quality of mineral particle dispersion is assessed using a fineness gauge. 2 mL of ink are placed on the gauge and the ink is squeegeed off. Any agglomerates present leave streaks from a certain depth, which we note as P. This depth determines the size of the powder agglomerates and should therefore be as small as possible, or even zero.

[0375] * Stability

[0376] One of the roles of the polymer is to guarantee ink stability. 30 mL of ink is stored at 25°C in a transparent tube 10 cm high and 1.5 cm in diameter for 12 hours. The amount of water recovered from the surface is weighed and noted as E. The lower the water content, the greater the stability of the mixture. If the mixture remains homogeneous, no water is removed.

[0377] * Flexibility

[0378] A 1 cm wide strip of dry electrode is cut and wound around a 2 mm diameter cylinder and held for 5 min. The strip is then unfolded, and if any cracks are present, the polymer is assigned a value of 1. If no cracks are present, a value of 0 is assigned. Flexibility is rated C.

[0379] * Adhesion

[0380] A pull-off measurement is performed on 5 cm strips of dry electrode using a Testometric M250 tensile tester equipped with a 2.5 kN cell. The measurement is performed at 180°C at a speed of 10 mm / s and repeated 3 times. The average pull-out force is denoted F. The higher the average pull-out force, the greater the electrode's ability to withstand the mechanical stresses experienced during charging and discharging cycles.

[0381] * Retention capacity

[0382] The percentage retention capacity after 100 cycles is calculated as follows ((Qioo- Qo ) / Qo ) x 100, where Qioo: capacity after 100 cycles; and Qo: capacity before the cycles. The higher the latter, the more efficient the binder. Retention capacity is given by RCioo.

[0383] Results

[0384] The results of the various tests carried out are summarized in Table 2.

[0385] Table 2: Results of the other tests performed

[0386] When used on their own, the binders of this invention lead to inks with fewer defects and greater stability than the proposed counter-examples. Once dried, the electrodes are easy to handle, and no cracking was observed in our test. The composite layer adheres better than the CMC and SBR reference and the counter-examples. Capacity retention is also significantly improved when the polymers of the invention are used. Furthermore, the binders of the invention combined with CMC and / or SBR see their application performance significantly improved, which is not the case with the counter-examples.

Claims

CLAIMS1. Method for preparing a binder for an electrode ink, said binder consisting of a water-soluble polymer comprising:- at least one cationic hydrophilic monomer A;- at least one anionic hydrophilic monomer B; at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol.

2. Method for preparing a binder for an electrode ink according to claim 1, characterized in that the water-soluble polymer comprises a number of cationic blocks of between 2 and 10.

3. Method for preparing a binder for an electrode ink according to claim 1 or 2, characterized in that the cationic hydrophilic monomer A is selected from the group consisting of quatemized or salified dimethylaminoethyl acrylate, quaternized or salified dimethylaminoethyl methacrylate, diallyldimethyl ammonium chloride, acrylamido propyltrimethyl ammonium chloride, methacrylamido propyltrimethyl ammonium chloride, quaternized or salified N,N- dimethylallylamine, quatemized or salified diallylmethylamine, quatemized or salified diallylamine, vinylamine derived from vinylformamide hydrolysis, vinylamine obtained by Hofmann degradation, and mixtures thereof.

4. Method for preparing a binder for an electrode ink according to any of claims 1 to 3, characterized in that the water-soluble polymer comprises between 4 and 49 mol% cationic hydrophilic monomers A.

5. Method for preparing a binder for an electrode ink according to any of claims 1 to 4, characterized in that the anionic hydrophilic monomer B is selected from the group consisting of acrylic acid, methacrylic acid, dimethylacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, acrylamido undecanoic acid, 3-acrylamido 3 -methylbutanoic acid, C1-C3 itaconic acid hemi-esters, acryloyl chloride, vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-l,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrene sulfonic acid, 2- acrylamido-2-methylpropane sulfonic acid, 2-acrylamido-2-methylpropane disulfonic acid, ethylene glycol methacrylate phosphate, 3 -allyloxy -2-hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyl acrylate; water-soluble salts of these monomers, such as alkali metal, alkaline earth metal or ammonium salts; and mixtures thereof.

6. Method for preparing a binder for an electrode ink according to any of claims 1 to 5,characterized in that the water-soluble polymer comprises between 5 and 96 mol% anionic hydrophilic monomers B.

7. Method for preparing a binder for an electrode ink according to any of claims 1 to 6, characterized in that the water-soluble polymer does not comprise a branching agent.

8. Method for preparing a binder for an electrode ink according to any of claims 1 to 7, characterized in that the water-soluble polymer is obtained by radical polymerization controlled by reversible deactivation.

9. Method for preparing a binder for an electrode ink according to claim 8, characterized in that the reversible deactivation-controlled radical polymerization is selected from reversible addition-fragmentation chain transfer polymerization, nitroxide-controlled polymerization or atom transfer polymerization.

10. Method for preparing a binder for an electrode ink according to claim 8 or 9, characterized in that the radical polymerization controlled by reversible deactivation is reversible additionfragmentation chain transfer polymerization.

11. Method for preparing a binder for an electrode ink according to any of claims 1 to 10, characterized in that the water-soluble polymer is obtained by polymerization of at least one anionic hydrophilic monomer B and at least one macromonomer, the macromonomer comprising the cationic hydrophilic monomer A and constituting the blocks of the water-soluble polymer.

12. A composition for an electrode ink comprising:- at least one binder consisting of a water-soluble polymer comprising:* at least one cationic hydrophilic monomer A;* at least one anionic hydrophilic monomer B;* at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;- at least one electrode-active material;- optionally at least one flexibility agent selected from polysaccharides, styrene-butadiene rubber and mixtures thereof.

13. The composition according to claim 12, characterized in that the composition comprises a quantity of water-soluble polymer of between 0.5 and 15% by weight relative to the total weight of the composition.

14. The composition according to claim 12 or 13, characterized in that the flexibility agent isa polysaccharide selected from the group comprising carboxymethylcellulose, alginates, xanthan gums, diutan gum, welan gum, their salts and mixtures thereof, wherein the composition comprises an amount of flexibility agent of between 0.5 and 10% by weight relative to the total weight of the composition, and wherein the composition has a weight ratio between the at least one water-soluble polymer and the at least one flexibility agent of between 0.1 and 30.

15. Battery, preferably lithium-ion battery, comprising an electrode comprising:- at least one binder consisting of a water-soluble polymer comprising:* at least one cationic hydrophilic monomer A; * at least one anionic hydrophilic monomer B;* at least 30 mol% of the cationic hydrophilic monomers A are in form of cationic blocks, the cationic blocks having a molecular weight of between 500 and 50,000 g / mol;- at least one electrode-active material.

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