Silicon Anode Binder

Abstract

The present invention relates to a binder for a non-aqueous electrolyte rechargeable battery, a negative electrode slurry for a rechargeable battery, a negative electrode for a rechargeable battery, and a rechargeable battery containing the same.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application No. 21306620.2, filed November 22, 2022, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to a binder for a non-aqueous electrolyte rechargeable battery, a negative electrode slurry for a rechargeable battery, a negative electrode for a rechargeable battery, and a rechargeable battery containing the same. [Background technology]

[0003] Non-aqueous electrolyte rechargeable batteries, such as lithium-ion rechargeable batteries, are widely used as power sources for electronic devices. Although high capacity and long cycle life characteristics are desirable, current lithium-ion batteries are limited in their charge storage by the capacity of the negative electrode.

[0004] As an example of a method for increasing the capacity of a lithium-ion rechargeable battery, an active material containing silicon atoms can be used in the negative electrode.

[0005] Silicon has a theoretical capacity of about 4,200 mAh / g and is therefore important for high capacity battery applications from a capacity standpoint. However, the volume of silicon expands by about four times when charged during charging and discharging, which causes irreversible reactions such as the breakdown of electrical connections between active materials, the separation of active materials from current collectors, and the formation of solid electrolyte interfaces (SEIs) due to the erosion of active materials by electrodes, as well as the associated deterioration of service life. Furthermore, current binders can only accommodate limited silicon loadings (10 wt. % or less) before battery life is significantly reduced due to reduced stability of charging cycles.

[0006] Currently, there is a lot of activity dedicated to the development of new binders for silicon-containing anodes to enable higher energy density storage.

[0007] The binder, typically an organic polymer, acts as a bonding matrix between the active materials throughout the anode layer and to maintain contact with the current collector onto which the anode is deposited during manufacture.

[0008] There are many approaches being pursued to develop next generation binders to accommodate silicon anodes.

[0009] There are several polycarboxylate binders and derivatives being pursued, including polyacrylic acid, polyamic acid, polyacrylamide, and other hydrogen bonding structures.

[0010] Miranda, A. et al. ("A Comprehensive Study of Hydrolyzed Polyacrylamide as a Binder for Silicon Anodes" Appl. Mater. Interfaces, 2019, 11, 44090-44100) disclose the use of partially hydrolyzed polyacrylamide in the fabrication of composite silicon anodes with good adhesion, high strength and high electrochemical storage capacity.

[0011] It is also well documented that for polycarboxylates, particularly polyacrylic acids, there is an advantage to first converting them to lithium salts by neutralization with a base such as lithium hydroxide. This is done primarily to avoid sequestration of lithium ions by free acid groups in the cell, which can reduce the initial capacity.

[0012] WO 2015 / 163302 discloses that the capacity retention after 10 cycles of charging and discharging can be improved by using an aqueous solution of crosslinked sodium polyacrylate copolymer. Sodium polyacrylate has been used as a water-soluble, high-strength, high-elasticity binder. It is expected that the use of sodium polyacrylate can suppress or reduce the volume change accompanying the charging and discharging of a battery containing a silicon-containing active material, and improve the cycle characteristics. However, it is considered difficult in practice to apply an aqueous solution of a copolymer containing sodium polyacrylate, since cracks will occur in the electrode during the coating and drying process of the negative electrode slurry when using an aqueous solution of a copolymer containing sodium polyacrylate as the main component.

[0013] Despite current strategies to prevent degradation of silicon-rich anodes, they appear to be limited in their effectiveness, and there has not yet been a clear breakthrough to reach the higher levels of silicon required to achieve meaningful progress in this field. Numerous disclosures of mixed binder systems exist to exploit intermolecular cooperative effects to enhance binder performance.

[0014] US Patent Publication No. 2020 / 0343556 provides a binder for a non-aqueous electrolyte rechargeable battery, comprising a blend of a first copolymer comprising units derived from a (meth)acrylic acid-based monomer and units derived from a (meth)acrylonitrile monomer, and a second copolymer comprising units derived from an aromatic vinyl-based monomer and units derived from an ethylenically unsaturated monomer comprising a carboxylic acid moiety. The binder can suppress or reduce electrode expansion of the negative electrode, improving cycle characteristics.

[0015] The applicant has unexpectedly found that certain polymers obtained by copolymerization of at least one monomer having an unsaturated heterocycle carrying at least one nitrogen atom with at least one monomer selected from monomers having a carboxylic acid group and acrylamide can be used to prepare binders for electrodes, in particular for silicon-rich anodes, exhibiting high cycle stability and electrochemical stability. Summary of the Invention

[0016] The object of the present invention is to provide an aqueous electrode-forming composition [Composition (Comp)] for use in the preparation of electrodes for electrochemical devices, comprising a)Below: (A) A repeating unit derived from at least one monomer (M) which is an ethylenically unsaturated monomer having an unsaturated heterocyclic group having at least one nitrogen atom, and the monomer (M) is represented by the following formula (I): [ka] [In formula: R 1 is H or an alkyl group, where the alkyl group is preferably a methyl group; R 2 is H or an alkyl group; R 3 and R 4 may be selected from a hydrogen atom or from a linear or branched alkyl group having 1 to 6 carbon atoms; A is, i) a single covalent bond; and ii) a spacer, such as -CO-NH-(CH2) n -, -CO-O-(CH2) n - and -CO-O-(CH2) n -O-CO- (wherein n is an integer from 1 to 5, typically equal to 3 or 4). A group selected from the group consisting of is a bond selected from the group consisting of: X, Y and Z are independently selected from carbon atoms or nitrogen atoms; a, b and c are each independently selected from integers 1 to 2; Each dashed dotted line represents an optional double bond. A repeat unit having the formula: (B) The following: (B1) at least one α,β-ethylenically unsaturated carboxylic acid monomer [monomer (AA)]; and (B2) Formula (II): [ka] (In the formula, R 5 R represents a hydrogen atom or a methyl group, which may be the same or different from each other. 6 and R 7 may be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other, R 8 and R 9 may be selected from a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a carboxylic acid group, or an amide group. At least one (meth)acrylamide [monomer (AM)] A repeating unit derived from at least one monomer selected from the group consisting of At least one polymer (P*) comprising b) an electrode active material; c) an aqueous solvent; d) optionally, at least one conductivity-imparting additive; The composition (Comp) is characterized by comprising:

[0017] In another object, the present invention provides a process for the preparation of an electrode [electrode (E)], said process comprising: (i) providing a metal substrate having at least one surface; (ii) providing a composition (Comp) as defined above; (iii) applying the composition (Comp) provided in step (ii) onto at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate coated on at least one surface with said composition (Comp); (iv) drying the assembly obtained in step (iii); (v) subjecting the dried assembly obtained in step (iv) to a compression step to obtain the electrode (E) of the invention. The present invention provides a process including:

[0018] In a further aspect, the present invention relates to an electrode [electrode (E)] obtainable by the process of the present invention.

[0019] In a still further object, the present invention relates to an electrochemical device comprising at least one electrode (E) of the present invention.

[0020] A further object of the present invention is to (A) A repeating unit derived from at least one monomer (M) which is an ethylenically unsaturated monomer having an unsaturated heterocyclic group having at least one nitrogen atom, and the monomer (M) is represented by the following formula (I): [ka] [In formula: R 1 is H or an alkyl group, where the alkyl group is preferably a methyl group; R 2 is H or an alkyl group; R 3 and R 4 may be selected from a hydrogen atom or from a linear or branched alkyl group having 1 to 6 carbon atoms; A is, i) a single covalent bond; and ii) a spacer, such as -CO-NH-(CH2) n -, -CO-O-(CH2) n- and -CO-O-(CH2) n -O-CO- (wherein n is an integer from 1 to 5, typically equal to 3 or 4). A group selected from the group consisting of is a bond selected from the group consisting of: X, Y and Z are independently selected from carbon atoms or nitrogen atoms; a, b and c are each independently selected from integers 1 to 2; Each dashed dotted line represents an optional double bond. A repeat unit having the formula: (B1) a repeat unit derived from at least one ethylenically unsaturated carboxylic acid monomer [monomer (AA)]; and (B2) Formula (II): [ka] (In the formula, R 5 R represents a hydrogen atom or a methyl group, which may be the same or different from each other. 6 and R 7 may be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other, R 8 and R 9 may be selected from a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a carboxylic acid group, or an amide group. Repeating units derived from at least one (meth)acrylamide [monomer (AM)] The polymer (P) comprises: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In the context of the present invention, the term "weight percent" (wt%) indicates the content of a particular component in a mixture, calculated as the ratio between the weight of the component and the total weight of the mixture. When referring to the total solids content (TSC) of a liquid composition, weight percent (wt%) indicates the ratio between the weights of all non-volatile components in the liquid.

[0022] The term "electrochemical cell" is intended herein to mean an electrochemical cell comprising a positive electrode, a negative electrode and a liquid electrolyte, with a monolayer or multilayer separator adhered to at least one surface of one of the electrodes.

[0023] Non-limiting examples of electrochemical cells include batteries, preferably secondary batteries, and electric double layer capacitors, among others.

[0024] For the purposes of the present invention, "secondary battery" is intended to mean a rechargeable battery. Non-limiting examples of secondary batteries include, inter alia, alkaline or alkaline earth secondary batteries.

[0025] As is known in the art, an electrode-forming composition is a composition, typically a fluid composition, in which solid components are dissolved or dispersed in a liquid, that can be applied onto a metal substrate and then dried, thus forming an electrode in which the metal substrate acts as a current collector. Electrode-forming compositions typically include at least an electroactive material and at least a binder.

[0026] The electrode-forming composition of the present invention [composition (Comp)] contains at least one polymer (P), which functions as a binder.

[0027] Polymer (P*) The polymer (P*) is obtainable by radical copolymerization of a mixture of at least one monomer (M) as defined above and at least one monomer chosen from at least one α,β-ethylenically unsaturated carboxylic acid monomer [monomer (AA)] and at least one (meth)acrylamide monomer [monomer (AM)] as defined above.

[0028] The "unsaturated heterocyclic group having at least one nitrogen atom" in the monomer (M) of formula (I) is preferably a 5- to 6-membered aromatic cyclic group having at least one N in the ring, for example: [ka] (wherein * represents the point of bond A) etc.

[0029] Bond A and Residue R 2 may be attached to the heterocyclic group at any position, either at a carbon atom or at a nitrogen atom.

[0030] The monomer (M) can be, for example: - Formula (Ia): [ka] Vinylimidazole (VIm) - Formula (Ib): [ka] 2-Methyl-1-vinylimidazole - Formula (Ic): [ka] 1-vinyl-1,2,4-triazole - Expression (Id): [ka] 2-Vinylpyrazine Formula (Ie): [ka] 4-Vinylpyridine - Expression (If): [ka] of 2-vinylpyridine - Formula (Ig): [ka] Hydroxyl-(meth)acrylate imidazole derivatives of It could be.

[0031] The divalent spacer group A in formula (I) is typically a group -CO-NH-(CH2) n -, -CO-O-(CH2) n or -CO-O-(CH2) n -O-CO-, for example, formula (IX): [ka] (In the formula, R 6 , R 8 and R 9 is as defined above) and Formula (IY): [ka] (In the formula, R 2 is as defined above, and A 1 and A 2 are two groups that react together to form a covalent bond) Any other covalent linker group resulting from reaction with a compound of formula (I) may be considered.

[0032] For example, A 2 is -(CH2) m -NH2 group, where m is 1 to 4, preferably 2 or 3. In that case, A 1 can be, for example, a carboxylic acid, an acid chloride, an acid anhydride, or an epoxy.

[0033] According to another variant, A 2 is -(CH2) m In the formula, m is 1 to 4, preferably 2 or 3. In this case, A 1 can be, for example, a carboxylic acid, an acid chloride, an acid anhydride or an ester.

[0034] The polymer (P*) is a polymer having a structure as obtained by copolymerizing the monomers (M), (AA) and / or (AM), i.e. obtained by such polymerization, although the polymer (P*) is not necessarily obtained by this process. Alternatively, the polymer (P*) can be obtained, for example, by a first step (E1) of copolymerizing the monomers (AA), (AM) and the compound of formula (IX) to give the polymer (P0), and then a second step (E2) of post-grafting of the polymer (P0) by reaction with the compound (IY).

[0035] A in compound (IY) used in step (E2) 2 Ga-(CH2) m When it is an -NH2 group, the compound (IX) used in step (E1) may advantageously be chosen from additional acrylic or methacrylic acid, or esters thereof; maleic anhydride; vinylbenzyl chloride; glycidyl methacrylate; and (blocked) isocyanatoethyl methacrylate.

[0036] A in compound (IY) used in step (E2) 2 Ga-(CH2) m When it is an --OH group, compound (IX) used in step (E1) may advantageously be chosen from additional acrylic acid, methacrylic acid, maleic anhydride or esters thereof.

[0037] In addition, quaternization of all or part of the imidazole functional groups of the polymer (P*) may occur and may result from the quaternization of all or part of the monomers and / or from the post-quaternization of all or part of the imidazole functional groups of the polymer.

[0038] The at least one α,β-ethylenically unsaturated carboxylic acid monomer (AA) preferably has the formula (III): [ka] (wherein Ra , R b and R c are independently selected from a hydrogen atom and a C1-C3 hydrocarbon group. It is a compound of the formula:

[0039] More preferably, monomer (AA) is a compound of formula (III) as defined above, selected from the group consisting of acrylic acid, methacrylic acid, Sipomer ΒCEA (sold by Solvay), ethacrylic acid, croton, methyl (meth)acrylic acid, ethyl (meth)acrylic acid, propyl (meth)acrylic acid, isopropyl (meth)acrylic acid, n-butyl (meth)acrylic acid, 2-ethylhexyl (meth)acrylic acid, n-hexyl (meth)acrylic acid and n-octyl (meth)acrylic acid.

[0040] The metha(acryl)amide monomer of formula (II) [monomer (AM)] is preferably selected from the group consisting of metha(acryl)amide or N-substituted metha(acryl)amides such as N-alkylacrylamides, N,N-dialkylacrylamides.

[0041] The at least one polymer (P*) may further comprise less than 10 mol % of one or more further monomers (M') selected from the group consisting of hydrophobic and amphiphilic monomers, with the proviso that the total amount of monomers (AA) and / or monomers (AM) is at least 60 mol % relative to the total moles of repeating units of the polymer (P*).

[0042] In this embodiment in which an additional monomer (M') is present in (P*), said hydrophobic and / or amphiphilic monomer is a monoethylenically unsaturated monomer: - alkyl esters of maleic anhydride and (meth)acrylic acid, such as monomethyl maleic anhydride, dimethyl maleic anhydride, monoethyl maleic anhydride, diethyl maleic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, etc. - hydroxyalkyl esters of maleic anhydride and (meth)acrylic acid, such as monohydroxyethyl maleic anhydride, dihydroxyethyl maleic anhydride, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, etc. - ethoxylates and propoxylates derived from maleic anhydride, such as, for example, poly(propylene oxide)-b-poly(ethylene oxide) maleic acid half-esters or diesters, alkyl-poly(ethylene oxide) maleic acid half-esters or diesters, - ethoxylates and / or propoxylates derived from the ethoxylation and / or propoxylation of hydroxyalkyl (meth)acrylic acids, such as poly(propylene oxide)-b-poly(ethylene oxide)-ethyl (meth)acrylate. - ethoxylates and / or propoxylates derived from the (trans)esterification of (meth)acrylic acid and esters, such as poly(propylene oxide)-b-poly(ethylene oxide) (meth)acrylates and alkyl-poly(ethylene oxide) (meth)acrylates. - vinyl esters, such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, 2-ethylhexyl vinyl ether, vinylcyclohexyl ether, dodecyl vinyl ether, 2-(diethylamino)ethyl vinyl ether, 2-(di-n-butylamino)ethyl vinyl ether, etc. Allyl ethers, such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, 2-ethylhexyl vinyl ether, etc. - vinyl esters, such as vinyl acetate or vinyl propionate Alkyl-substituted acrylamides, such as N-tert-butylacrylamide or N-methyl(meth)acrylamide is selected from the group consisting of:

[0043] Preferably, the additional monomer (M') present in the polymer (P*) is - Monoethyl maleic anhydride, diethyl maleic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate - Monohydroxyethyl maleic anhydride, dihydroxyethyl maleic anhydride, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate - Poly(propylene oxide)-b-poly(ethylene oxide) maleic acid half ester - Poly(propylene oxide)-b-poly(ethylene oxide)-ethyl (meth)acrylate - Poly(propylene oxide)-b-poly(ethylene oxide) (meth)acrylate, alkyl-poly(ethylene oxide) (meth)acrylate - Vinyl acetate, vinyl propionate is selected from the group consisting of:

[0044] The proportion in moles of monomer (M') cannot exceed 10% by mole of the total moles of monomers (AA+AM+M+M') present in polymer (P*). Advantageously, the proportion in moles of monomer (M') is less than 5% by mole.

[0045] The at least one polymer (P) may further comprise less than 1 mol % of one or more further crosslinking monomers (XL-M) containing at least two ethylenic unsaturations.

[0046] In this embodiment in which an additional monomer (XL-M) is present in the polymer (P*), said crosslinking monomers are N,N'-methylenebisacrylamide (MBA), N,N'-ethylenebisacrylamide, polyethylene glycol (PEG) diacrylates, triacrylates, divinyl ethers, typically trifunctional divinyl ethers, such as tri(ethylene glycol) divinyl ether (TEGDE), N-diallylamine, N,N-diallyl-N-alkylamines, their acid addition salts and their quaternization products (wherein alkyl as used here is preferentially (C1-C3) alkyl); compounds of N,N-diallyl-N-methylamine and of N,N-diallyl-N,N-dimethylammonium, such as chloride. and bromides; or alternatively may be selected from ethoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate (DiTMPTTA), divinylbenzene (DVB), ethoxylated or propoxylated bisphenol A diacrylate, dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), propoxylated di(meth)acrylates, butyloxylated di(meth)acrylates, dimethylacrylamide, 1,4-butanediol dimethacrylate (BDDMA), 1,6-hexanediol dimethacrylate (HDDMA), 1,3-butylene glycol dimethacrylate (BGDMA), and derivatives thereof.

[0047] The proportion in molar terms of monomer (XL-M) cannot exceed 1 mol % of the total moles of monomers (AA+AM+M+M'+XL-M) present in polymer (P*), in order to avoid gel formation and viscosity increase. Advantageously, the proportion in molar terms of monomer (M') is less than 0.5 mol %.

[0048] According to said embodiment, the polymer (P*) obtained by polymerization further comprising monomers (XL-M) is at least partially crosslinked.

[0049] In one preferred embodiment of the present invention, no further monomers (M') or (XL-M) are present in the polymer (P*), since the polymer (P*) (A) at least a monomer (M) as defined above, (B) The following: (B1) at least one [monomer (AA)] as defined above; and (B2) at least one [monomer (AM)] as defined above At least one monomer selected from the group consisting of It means that it is obtained by radical copolymerization of, in particular of, a mixture consisting essentially of,

[0050] Typically, the polymer (P*) is reacted in the presence of a free radical source with at least one monomer (M), at least one monomer (AA) and / or at least one monomer (AM), - optionally at least one monomer (M') and - optionally at least one monomer (XL-M) It is obtained by radical copolymerization of a mixture of

[0051] Any free radical source can be used. It is particularly possible to generate free radicals spontaneously, for example by increasing the temperature, with a suitable monomer, such as styrene. It is possible to generate free radicals by irradiation, in particular by UV irradiation, preferably in the presence of a suitable UV-sensitive initiator. It is possible to use radical or redox type initiators or initiator systems. The free radical source may be water-soluble or not. It may be preferable to use water-soluble or at least partially water-soluble initiators.

[0052] In general, the higher the amount of free radicals, the more easily the polymerization is initiated (it is accelerated), but the lower the molar mass of the resulting copolymer. peroxides, such as hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctoate, t-butyl peroxyneodecanoate, t-butyl peroxyisobutyrate, lauroyl peroxide, t-amyl peroxypivalate, t-butyl peroxypivalate, dicumyl peroxide, benzoyl peroxide, sodium persulfate, potassium persulfate or ammonium persulfate, azo compounds, such as: 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-butanenitrile), 4,4'-azobis(4-pentanoic acid), 1,1'-azobis(cyclohexanecarbonitrile), 2-(t-butylazo)-2-cyanopropane, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2'-azobis[2-methyl-N-(hydroxyethyl)propionamide], 2,2'-azobis(N,N'-dimethyleneisobutylamine), 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutyramide), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide}, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], or 2,2'-azobis(isobutyramide) dihydrate, - redox systems, including combinations such as: hydrogen peroxide, alkyl peroxides, peresters, percarbonates, persulfates, etc., and any mixture of iron salts, titanium salts, zinc formaldehyde sulfoxylate or sodium formaldehyde sulfoxylate with reducing sugars, etc. - alkali metal bisulfites, such as sodium metabisulfite, and alkali metal or ammonium persulfates, perborates or perchlorates in combination with reducing sugars; - aryl phosphinic acids and others of a similar nature, such as benzene phosphonic acid, and alkali metal persulfates in combination with reducing sugars; may in particular be used.

[0053] The polymerization temperature can be in particular between 25° C. and 95° C. The temperature can depend on the source of free radicals. If it is not a source of UV initiator type, it will be preferable to operate at between 50° C. and 95° C., more preferably between 60° C. and 80° C. In general, the higher the temperature, the more easily the polymerization is initiated (it is accelerated), but the lower the molar mass of the copolymer obtained.

[0054] According to a preferred embodiment of the invention, the polymer (P*) is obtained by radical polymerization of one monomer (AA), one monomer (AM) and one monomer (M) in the presence of a free radical source to obtain a polymer comprising repeat units derived from monomer (AA), repeat units derived from monomer (AM) and repeat units derived from monomer (M).

[0055] The polymer (P*) according to this embodiment is hereinafter referred to as "polymer (P)".

[0056] According to a more preferred embodiment, the polymer (P) is obtained by radical polymerization of acrylic acid, acrylamide and vinylimidazole of formula (Ia).

[0057] The polymer (P*) can also be prepared by any controlled radical polymerization technique, among which we can mention reversible addition-fragmentation chain transfer (RAFT) and macromolecular design using exchange reactions of xanthates (MADIX).

[0058] The use of RAFT or MADIX controlled radical polymerization agents (hereinafter referred to as "RAFT / MADIX agents") has been disclosed, for example, in WO 98 / 058974 A (RHODIA CHIMIE) December 30, 1998 and WO 98 / 01478 A (EIDUPONT DE NEMOURS AND COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANIZATION) January 15, 1998.

[0059] Preferably, the polymer (P*) has the following molar ratios, based on the total amount of monomers (AA), (AM) and (M): Monomer (AA): 0 to 95%, in particular 5 to 50%, preferably 20 to 40%, - Monomer (AM): 0 to 90%, preferably 25 to 90%, more preferably 60 to 80%, Monomer (M): 0.1 to 50%, for example 1 to 30%, in particular 1 to 20%, further preferably 2 to 15%. (wherein at least one of monomer (AA) and monomer (AM) is not in an amount of 0%) The compound is obtained by radical copolymerization of a mixture having

[0060] As a result, the polymer (P*) preferably has - 0 to 95%, in particular 5 to 50%, preferably 20 to 40% of repeat units derived from monomer (AA), - 0 to 90%, preferably 25 to 90%, more preferably 50 to 80% of repeating units derived from monomer (AM), and - 1 to 50%, for example 1 to 30%, in particular 1 to 20%, or even more preferably 2 to 15%, of repeat units derived from monomer (M) (wherein at least one of the monomers (AA) and (AM) is not in an amount of 0% All the above mole percentages are based on the total moles of repeat units of the polymer (P*). Includes.

[0061] In a preferred embodiment of the invention, the polymer (P*) is - 5 to 50%, preferably 20 to 40%, of repeat units derived from monomer (AA), - 25 to 90%, more preferably 50 to 80%, of repeat units derived from monomer (AM), and - 1 to 50%, for example 1 to 30%, in particular 1 to 20%, or even more preferably 2 to 15%, of repeat units derived from monomer (M) (All the above mole % are based on the total moles of repeat units of the polymer (P*).) The polymer (P) comprises:

[0062] In addition, the polymer (P*) according to the invention preferably has a number average molecular weight (Mn) of at least 90 kDa, for example from 90 to 5000 kDa, preferably from 850 kDa to 2000 kDa.

[0063] According to a preferred embodiment, the polymer (P*) is a statistical (random) copolymer having a weight average molecular weight of about 100 kDa to 10000 kDa, preferably 1000 kDa to 3000 kDa, of monomers (AA), (AM) and (M), preferably about: - 20-40% monomer (AA), - 50-80% monomer (AM), and - 2-15% monomer (M) It is a copolymer obtained by radical polymerization of a mixture in a molar ratio of

[0064] According to one embodiment of the invention, the polymer (P*) is a block copolymer obtained by controlled radical polymerization using a RAFT / MADIX agent.

[0065] As used herein, "block copolymer" refers to any controlled architecture copolymer, including, but not limited to, true block polymers, which can be diblock, triblock, or multiblock; branched block copolymers, also known as linear star polymers; comb; and gradient polymers. Gradient polymers are linear polymers whose composition varies gradually along the polymer chain, potentially ranging from random to block-like structures. Each block of a block copolymer can itself be a homopolymer, a random copolymer, a random terpolymer, or a gradient polymer.

[0066] The polymer (P*) can be provided in solid or dry form or in vectorized form, for example in the form of a solution or emulsion or suspension, in particular in the form of an aqueous solution. A vectorized form, for example an aqueous solution, can in particular contain 3 to 50% by weight, for example 5 to 30% by weight, of the polymer (P*). The aqueous solution containing the polymer (P) can in particular be a solution obtained by aqueous phase preparation at the end of a radical polymerization process.

[0067] The polymer (P) as defined above is novel and represents a further object of the present invention.

[0068] When the polymer (P*) is a polymer (P) and thus comprises repeat units derived from at least one monomer (AA), it may suitably be converted into its neutralized form polymer (PN) and thus comprises repeat units derived from at least an α,β-ethylenically unsaturated carboxylic acid in neutralized form.

[0069] In one embodiment, the invention therefore provides a polymer (PN), said polymer comprising (A) A repeating unit derived from at least one monomer (M) which is an ethylenically unsaturated monomer having an unsaturated heterocyclic group having at least one nitrogen atom, and the monomer (M) is represented by the following formula (I): [ka] [In the formula, R 1 is H or an alkyl group, preferably a methyl group; R 2 is H or an alkyl group; R 3 and R 4 may be selected from a hydrogen atom or from a linear or branched alkyl group having 1 to 6 carbon atoms; A is, i) a single covalent bond; and ii) a spacer, such as -CO-NH-(CH2) n -, -CO-O-(CH2) n - and -CO-O-(CH2) n -O-CO- (wherein n is an integer from 1 to 5, typically equal to 3 or 4). A group selected from the group consisting of is a bond selected from the group consisting of: X, Y and Z are independently selected from carbon atoms or nitrogen atoms; a, b and c are each independently selected from integers 1 to 2; Each dashed dotted line represents an optional double bond. and a repeat unit having the formula: (B1) repeat units derived from at least one α,β-ethylenically unsaturated carboxylic acid monomer [monomer (AA)] in neutralized form; (B2) Formula (II): [ka] (In the formula, R 5 R represents a hydrogen atom or a methyl group, which may be the same or different from each other. 6 and R 7 may be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other, R 8 and R 9may be selected from a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a carboxylic acid group, or an amide group. and a repeating unit derived from at least one (meth)acrylamide [monomer (AM)] of Includes.

[0070] The polymer (PN) can be prepared by neutralizing the acid groups of the repeating units derived from the monomers (AA) of the polymer (P) as defined above, where the neutralization of the acid groups is carried out with a salt containing a monovalent cation [salt (S)], preferably an alkali metal salt, or with ammonia, in a suitable solvent.

[0071] The salt (S) can be any salt capable of neutralizing an acid group. In some embodiments, the salt (S) is a lithium salt selected from the group consisting of lithium carbonate, lithium hydroxide, lithium bicarbonate, and combinations thereof, preferably lithium carbonate. In some embodiments, the lithium salt does not include lithium hydroxide.

[0072] The solvent for use in the step of neutralizing the polymer (P) can be any solvent capable of dissolving the salt (S) or ammonia and the resulting polymer (PN). Preferably, the solvent is selected from at least one of aqueous solvents, such as water, NMP, and alcohols, such as, for example, methanol, isopropanol, and ethanol. Most preferably, the solvent is an aqueous solvent. Even more preferably, the solvent is water.

[0073] Preferably, the content of the salt (S) in the solvent is in the range of 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total weight of the solvent and the salt (S).

[0074] In some embodiments where the salt (S) is a lithium salt, the concentration of the lithium salt in the solvent provides at least 0.25, 0.5, 0.8, 1, 1.5, 2, 2.5, 3, 4 equivalents of lithium to the acid groups, in some embodiments, the concentration of the lithium salt in the solvent provides at most 5 equivalents, preferably at most 4 equivalents of lithium to the acid groups.

[0075] According to said embodiment, the polymer (PN) comprises repeat units derived from the lithiated form of at least one α,β-ethylenically unsaturated carboxylic acid monomer.

[0076] The content of the polymer (PN) in the solution after neutralization is in the range of 0.5 to 40% by weight, preferably 2 to 30% by weight, and more preferably 4 to 20% by weight, based on the total weight of the solvent and the polymer (PN).

[0077] The polymer (PN) can be isolated as a solid from the solution after neutralization and optionally stored for later use. The solid polymer (PN) can also be dissolved (or redissolved) in water to prepare the electrode-forming composition described below. However, preferably, the solution containing the polymer (PN) after neutralization is an aqueous solution that can be used directly, optionally with further dilution with water, in preparing the binder composition as described below.

[0078] In a preferred embodiment, the lithium salt of polymer (P), i.e., polymer (P-Li), was prepared by adding an amount of LiOH to completely neutralize an aqueous solution containing about 10 wt.% of polymer (P). The resulting solution had a pH in the range of 6.5-9 and contained approximately 10 wt.% of polymer (P-Li).

[0079] Neutralized polymer solutions advantageously have advantages in terms of slurry processing and dispersion capabilities since the neutralized polymer exhibits increased viscosity. Furthermore, the polymer (P-Li) has a pH that is more compatible with lithiated silicon types that typically perform better when processed in slurries with a pH higher than 7. An additional advantage is that the salified form of the repeating unit derived from the monomer (AA) avoids sequestration of lithium ions by free acid groups within the cell, which can reduce first cycle coulombic efficiency and therefore initial capacity.

[0080] Electrode forming composition [Composition (Comp)] The amount of polymer (P*) that can be used in the electrode-forming composition (Comp) is influenced by various factors. One such factor is the surface area and amount of the active material, as well as the surface area and amount of any conductivity-imparting additives added to the electrode-forming composition. These factors are believed to be important because the binder particles provide a bridge between the conductive material particles, keeping them in contact.

[0081] The electrode-forming composition of the invention [Composition (Comp)] comprises one or more electrode active materials. For the purposes of the present invention, the term "electrode active material" is intended to mean a compound capable of incorporating or inserting into its structure and subsequently releasing therefrom alkali or alkaline earth metal ions during the charging and discharging phases of an electrochemical device. The electrode active material is preferably capable of incorporating or inserting and releasing lithium ions.

[0082] The nature of the electrode active material in the electrode-forming composition (Comp) of the present invention depends on whether the composition is used to manufacture a negative electrode (anode) or a positive electrode (cathode).

[0083] When forming a positive electrode for a lithium-ion secondary battery, the electrode active material may include a composite metal chalcogenide of the formula LiMQ2 (where M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr, and V, and Q is a chalcogen such as O or S). Among these, it is preferable to use a lithium-based composite metal oxide of the formula LiMO2 (where M is the same as defined above). Preferred examples thereof include LiCoO2, LiNiO2, LiNi x Co 1-x O2 (0 < x < 1) and spinel-structured LiMn2O4 may be mentioned.

[0084] As an alternative, when forming a positive electrode for a lithium-ion secondary battery, further, the electrode active material is of the formula M1M2(JO4) f E 1-f (where M1 is lithium, which may be partially substituted by another alkali metal representing less than 20% of the M1 metal, M2 is a transition metal at a +2 oxidation level selected from Fe, Mn, Ni, or a mixture thereof, which may be partially substituted by one or more additional metals representing less than 35% of the M2 metal, including at oxidation levels of +1 to +5 and 0, JO4 is any oxyanion, where J is any of P, S, V, Si, Nb, Mo, or a combination thereof, E is a fluoride, hydroxide, or chloride anion, and f is the molar fraction of the JO4 oxyanion, generally included in the range of 0.75 to 1) of a lithiated or partially lithiated transition metal oxyanion-based electroactive material.

[0085] M1M2(JO4) as defined above f E 1-f The electrode active material is preferably phosphate-based and may have an ordered or modified olivine structure.

[0086] More preferably, the electrode active material when forming the positive electrode is of the formula Li 3-x M’ y M’’ 2-y(JO4)3, where 0≦x≦3 and 0≦y≦2, M′ and M″ are the same or different metals, at least one of which is a transition metal, JO4 is preferably PO4, which may be partially substituted with another oxyanion, and J is any of S, V, Si, Nb, Mo, or a combination thereof. Even more preferably, the electrode active material has the formula Li(Fe x Mn 1-x )PO4, where 0≦x≦1, and x is preferably 1 (i.e., lithium iron phosphate of formula LiFePO4).

[0087] When forming a negative electrode for a lithium ion secondary battery, the electrode active material may preferably include one or more carbon-based materials and / or one or more silicon-based materials.

[0088] In some embodiments, the carbon-based material may be selected from graphite, graphene, or carbon black, such as natural or artificial graphite. These materials may be used alone or as a mixture of two or more of them.

[0089] The carbon-based material is preferably graphite.

[0090] The silicon-based compound may be one or more selected from the group consisting of chlorosilanes, alkoxysilanes, aminosilanes, fluoroalkylsilanes, silicon, silicon chloride, silicon carbide, silicon oxide, and lithium silicon oxide.

[0091] More particularly, the silicon-based compound may be silicon oxide or silicon carbide.

[0092] When present in the electrode active material, the silicon-based compound is included in an amount ranging from 1 to 70% by weight, preferably from 5 to 30% by weight, based on the total weight of the electroactive compound.

[0093] One or more optional conductivity-imparting additives may be added to improve the electrical conductivity of the resulting electrodes made from the compositions of the present invention. Conductive agents for batteries are known in the art.

[0094] Examples of these may include: carbonaceous materials such as carbon black, graphite fine powder, carbon nanotubes, graphene, or fibers, or fine powders or fibers of metals such as nickel or aluminum. The optional conductive agent is preferably carbon black. Carbon black is available, for example, under the brand names Super P® or Ketjenblack®.

[0095] If present, the conductive agent is different from the carbon-based material described above.

[0096] The amount of the optional conductive agent is preferably 0 to 30% by weight of the total solids in the electrode-forming composition. In particular, for the cathode-forming composition, the optional conductive agent is typically 0 to 10% by weight, more preferably 0 to 5% by weight, of the total solids in the composition.

[0097] For anode-forming compositions that do not include a silicon based electroactive compound, the optional conductive agent is typically present in an amount of from 0% to 5% by weight, more preferably from 0% to 2% by weight, of the total amount of solids in the composition, whereas for anode-forming compositions that include a silicon based electroactive compound, it has been found beneficial to incorporate a larger amount of the optional conductive agent, typically from 0.5 to 30% by weight of the total amount of solids in the composition.

[0098] Furthermore, the electrode-forming composition of the present invention may contain at least one thickener; when present, the amount of thickener (also called rheology modifier) ​​is not particularly limited and generally ranges from 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the total weight of the composition (Comp). The thickener is generally added to prevent or slow down settling of the powdered electrode material from the aqueous composition of the present invention, while providing the appropriate viscosity of the composition for the casting process.

[0099] Non-limiting examples of suitable thickening agents include organic thickening agents, such as carboxylated alkyl celluloses, such as carboxylated methyl cellulose, and inorganic thickening agents, such as natural clays, such as montmorillonite and bentonite, man-made clays, such as laponite, and others, such as silica and talc.

[0100] The total solids content (TSC) of the composition (Comp) of the invention is typically comprised between 15 and 70% by weight, preferably between 40 and 60% by weight, relative to the total weight of the composition (Comp). The total solids content of the composition (Comp) is understood to be the accumulation of all its non-volatile components, including in particular the polymer (P), the electrode active material and any solid, non-volatile additional additives, such as thickeners.

[0101] When the aqueous binder solution is prepared separately and then combined with the electrode active material and optional conductive material and other additives to prepare the composition (Comp), a sufficient amount of water is used to produce a stable solution. The amount of water used can range from the minimum amount required to produce a stable solution to the amount required to achieve the desired total solids content in the electrode mixture after the electrode active material, optional conductive material, and other solid additives have been added.

[0102] Electrode (E) The electrode-forming composition (Comp) of the present invention can be used in a process for the manufacture of an electrode [electrode (E)], said process comprising: (i) providing a metal substrate having at least one surface; (ii) providing an electrode-forming composition [Composition (Comp)] as defined above; (iii) applying the composition (Comp) provided in step (ii) onto at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate coated on at least one surface with said composition (Comp); (iv) drying the assembly provided in step (iii); (v) subjecting the dried assembly obtained in step (iv) to a compression step to obtain the electrode (E) of the invention. Includes.

[0103] The metal substrate is generally a foil, mesh or net made of a metal such as copper, aluminum, iron, stainless steel, nickel, titanium or silver.

[0104] Under step (iii) of the process of the present invention, the electrode-forming composition (Comp) is typically applied onto at least one surface of the metal substrate by any suitable procedure such as casting, printing and roll coating.

[0105] Optionally, step (iii) may be repeated, typically one or more times, by applying the electrode-forming composition (Comp) provided in step (ii) onto the assembly provided in step (iv).

[0106] Under step (iv) of the process of the invention, drying can be carried out either under atmospheric pressure or under vacuum, or alternatively, drying can be carried out under a modified atmosphere, for example under an inert gas, typically especially devoid of moisture (water vapour content less than 0.001% v / v).

[0107] The drying temperature will be selected to achieve evaporative removal of the aqueous medium from the electrode (E) of the present invention.

[0108] In step (v), the dried assembly obtained in step (iv) is subjected to a compression step, such as a calendering process, to achieve the target porosity and density of the electrode (E) of the present invention.

[0109] Preferably, the dried assembly obtained in step (iv) is hot pressed, the temperature during the pressing step being comprised between 25°C and 130°C, preferably about 60°C.

[0110] The preferred target density for the electrode (E) is comprised between 1.4 and 2 g / cc, preferably at least 1.55 g / cc. The density of the electrode (E) is calculated as the sum of the products of the densities of the electrode's components multiplied by their mass ratio in the electrode formulation.

[0111] In a further aspect, the present invention relates to an electrode [electrode (E)] obtainable by the process of the present invention.

[0112] Therefore, the present invention provides a method for producing a composition comprising the steps of: - a metal substrate having at least one surface; - directly adhered onto at least one surface of said metal substrate; a) at least one polymer (P*), b) electrode active material; c) an aqueous solvent, and d) optionally at least one conductivity-imparting additive; At least one layer comprising a composition comprising The present invention relates to an electrode (E) comprising:

[0113] The composition directly applied onto at least one surface of the metal substrate corresponds to the electrode-forming composition (Comp) of the invention from which the aqueous medium has been at least partially removed during the manufacturing process of the electrode, for example in step (iv) (drying) and / or in the compression step (v). Therefore, all preferred embodiments described with respect to the electrode-forming composition (Comp) of the invention are also applicable to the composition directly applied onto at least one surface of the metal substrate in the electrode of the invention, except for the aqueous medium removed during the manufacturing process.

[0114] In a preferred embodiment of the present invention, the electrode (E) is a negative electrode. More preferably, the negative electrode comprises a silicon-based electrode active material.

[0115] In a further preferred embodiment, the present invention comprises, based on the total weight of the electrode: - 0.5 to 15% by weight, preferably 0.5 to 10% by weight, of a polymer (P*), - 45 to 95% by weight, preferably 70 to 90% by weight, of a carbon-based material, - 3 to 50% by weight, preferably 10 to 50% by weight, of silicon-based material; - 0 to 5% by weight, preferably 0.5 to 2.5% by weight, more preferably about 1% by weight of a conductivity imparting additive; The present invention relates to a negative electrode comprising:

[0116] The electrode (E) of the present invention is particularly suitable for use in electrochemical devices, in particular in secondary batteries.

[0117] The secondary battery of the present invention is preferably an alkaline or alkaline earth secondary battery.

[0118] The secondary battery of the present invention is more preferably a lithium ion secondary battery.

[0119] Electrochemical devices according to the present invention can be fabricated by standard methods known to those skilled in the art.

[0120] To the extent that the disclosure of any patents, patent applications, and publications incorporated herein by reference conflicts with the statements of this application to the extent that any term may be unclear, the statements of this application shall control.

[0121] To the extent that the disclosure of any patents, patent applications, and publications incorporated herein by reference conflicts with the statements of this application to the extent that any term may be unclear, the statements of this application shall control.

[0122] The present invention will now be described with reference to the following examples, the purposes of which are merely illustrative and are not intended to limit the scope of the invention. EXAMPLES

[0123] raw materials AA: acrylic acid available from Aldrich; AM: Acrylamide monomer (50% in water) available from SNF; VIm: vinylimidazole monomer available from Aldrich; 4-Vinylpyridine available from Aldrich; Transfer agent: a freshly prepared 1 wt% solution in ethanol of a MADIX type transfer agent available as Rhodixan A1 from Solvay; Sodium persulfate in powder form available from VWR; (a 10 wt % aqueous solution was prepared immediately prior to polymerization experiments); Sodium formaldehyde sulfoxylate in powder form available from Aldrich; (a 10 wt % solution in water was prepared immediately prior to polymerization experiments); V-50 initiator: (2,2'-azobis(2-methyl-propionamidine) dihydrochloride) available in powder form from Aldrich; (10 wt % aqueous solution prepared immediately prior to polymerization experiments); Lithium hydroxide monohydrate (98% purity) available from Sigma-Aldrich; Silicon oxide, KSC-1064, commercially available from Shin-Etsu Chemical Co., Ltd., with a theoretical capacity of about 2100 mAh / g; graphite, ACTILION2 by Imerys SA; Carbon black, available as SC45 from Imerys SA; Carboxymethyl cellulose (CMC), available from Nippon Paper Industries as MAC 500LC; Styrene-butadiene rubber (SBR) suspension (40% by weight in water), available from Zeon Corporation as Zeon® BM-480B; Electrolyte mixture of LiPF6 1M in EC / DMC 1 / 1 v / v with 2 wt% VC and 10 wt% F1EC from Solvionic.

[0124] General procedure for the synthesis of polymer (P) The synthesis process was carried out in an adiabatic reactor (thermos-like flask) to minimize heat exchange with the surroundings.

[0125] The reactor was equipped with a lid containing multiple inlets into which a small reflux system was installed, a mechanical stirring system, a nitrogen purge line, and raw material supply lines.

[0126] In the first step, all the monomers, solvent (water) and optional transfer agent were charged into the reactor and kept under stirring and nitrogen purge at room temperature for approximately 1 hour. Then, the redox type initiator was added to the reaction mixture. The thermal initiator was also added into the reaction mixture at the same time. The initiator was homogenized in the reaction mixture with mechanical stirring for a few minutes, and then the stirring and nitrogen purge were stopped.

[0127] An exothermic effect occurred within approximately half to an hour, increasing the reaction mixture temperature from room temperature to approximately 80-90° C. The reaction mixture was then maintained in the reaction flask for an additional 24 hours.

[0128] The reagent charges used for specific polymer synthesis examples are shown in Table 1.

[0129] [Table 1]

[0130] The corresponding molar ratios of monomers used for polymers P-1, P-2, P-3, P-4 and P-5 are provided in Table 2.

[0131] [Table 2]

[0132] The flowable, highly viscous, gel-like products were then discharged from the flask and analyzed for their solids content (1 gram sample heated at 130° C. to stable mass), residual monomer (HPLC analysis) and molecular weight distribution (SEC MALS analysis).

[0133] The properties of polymers P-1 to P-5 are summarized in Table 3.

[0134] [Table 3]

[0135] Molecular weight determination The mass distribution of the polymers was measured by SEC MALS analysis (SEC: size exclusion chromatography - MALS: multi-angle laser scattering) to obtain real values, expressed in g / mol.

[0136] SEC MALS analysis uses two detectors: - Differential Refractometer RI-Concentration Detector - MALS detector (Multi-angle Laser Dispersion) - Mass Detector The analysis was carried out on an HPLC chain equipped with

[0137] For each slice of the chromatogram (for the polymer species), the software: Concentration of polymer, RI signal = constant * dn / dc * concentration Mass of the slice Mi Calculate. From the given Mi data, the software calculates the mass distribution: Mw, Mn and the polydispersity index Ip=Mw / Mn Calculate.

[0138] The calculation of the molar mass requires the increment of the refractive index of the polymer, dn / dc, which is a constant depending, among other things, on the nature of the mobile phase, the temperature of the experimental conditions and the wavelength of the laser.

[0139] The value "dn / dc" is calculated by the software according to the mass recovery of the eluted fractions: for the polymer of the invention dn / dc is 0.17 mL / g, leading to a mass recovery of 95-100 wt.%. The molar mass was calculated based on the actual Mi points, without any adjustment of the log(M) curve.

[0140] Detailed analysis conditions are as follows: - Analytical equipment: SEC system with MALS detector (Mini Dawn TREOS) and Agilent Differential Refractometer (RI) - Pump: Agilent 1100 - Mobile phase: 1M NH4NO3 and 100ppm NaN3 in water - Column (manufacturer, model no.): Shodex OHpak SB 806M HQ (30 cm guard column for three columns) - Temperature: 35℃ - Flow rate: 1.0mL / min - Injection volume and sample concentration: 100 μL, 0.1% (expressed as dry polymer)

[0141] General procedure for the preparation of aqueous solutions of Li-polymers Approximately 40 g of 5 wt% aqueous polymer solution was titrated with aqueous LiOH solution (4.25 wt% LiOH in water) using a Mettler Toledo titrator T5 to the desired pH value. Binder Solution The exact amounts of LiOH solution and total solids of the final lithiated binder solution are reported in Table 4.

[0142] [Table 4]

[0143] Preparation of electrode-forming composition and negative electrode The electrode-forming composition and negative electrode were prepared as detailed below using the following equipment: Mechanical mixers: planetary mixers (Speedmixer) and high shear mechanical mixers of the Dispermat® series with pitched impellers; Film coater / doctor blade: electric Elcometer® 4340 / Zehntner ZUA2000; Vacuum oven: Vacuum BINDER VD 23; and Roll press: Precision 4 inch hot rolling press / calendaring up to 100℃.

[0144] Example 1 - Terpolymer Anode 5% Binder An aqueous composition was prepared by mixing 20.0 g of a 2 wt% CMC solution in water, 0.40 g of carbon black, 7.52 g of silicon oxide, 30.08 g of graphite, and 10.127 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 31.873 g of a 5% solids aqueous solution of polymer P-1 was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0145] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by doctor blade, and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 18.8% by weight of silicon oxide, 75.2% by weight of graphite, 4% by weight of P-1, 1% by weight of CMC and 1% by weight of carbon black. Electrode E1 was thus obtained.

[0146] Example 2 - Terpolymer Anode 3% Binder An aqueous composition was prepared by mixing 22.0 g of a 2 wt% CMC solution in water, 0.44 g of carbon black, 8.448 g of silicon oxide, 33.792 g of graphite, and 17.790 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 17.753 g of a 5% solids aqueous solution of polymer P-1 was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0147] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by doctor blade, and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 19.2% by weight of silicon oxide, 76.8% by weight of graphite, 2% by weight of P-1, 1% by weight of CMC and 1% by weight of carbon black. Electrode E2 was thus obtained.

[0148] Example 3 - Terpolymer Anode 3% Binder An aqueous composition was prepared by mixing 22.0 g of a 2 wt% CMC solution in water, 0.44 g of carbon black, 8.448 g of silicon oxide, 33.792 g of graphite, and 17.790 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 17.753 g of a 5% solids aqueous solution of polymer P-3 was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0149] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by a doctor blade, and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 19.2% by weight of silicon oxide, 76.8% by weight of graphite, 2% by weight of P-3, 1% by weight of CMC, and 1% by weight of carbon black. Electrode E3 was thus obtained.

[0150] Example 4 - Terpolymer Anode 3% Binder An aqueous composition was prepared by mixing 22.0 g of a 2 wt% CMC solution in water, 0.44 g of carbon black, 8.448 g of silicon oxide, 33.792 g of graphite, and 17.790 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 17.753 g of a 5% solids aqueous solution of polymer P-2 was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0151] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by a doctor blade, and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 19.2% by weight of silicon oxide, 76.8% by weight of graphite, 2% by weight of P-2, 1% by weight of CMC, and 1% by weight of carbon black. Electrode E4 was thus obtained.

[0152] Example 5 - Terpolymer Anode Lithiated at pH 8.5 5% Binder An aqueous composition was prepared by mixing 19.0 g of a 2 wt% CMC aqueous solution, 0.38 g of carbon black, 7.14 g of silicon oxide, 28.58 g of graphite, and 10.72 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 34.18 g of a 4.47% solids polymer P-1-Li-1 aqueous solution was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0153] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by doctor blade and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 18.8% by weight of silicon oxide, 75.2% by weight of graphite, 4% by weight of polymer P-1-Li-1, 1% by weight of CMC and 1% by weight of carbon black. Electrode E5 was thus obtained.

[0154] Example 6 - Terpolymer Anode Lithiated at pH 7.5 5% Binder An aqueous composition was prepared by mixing 19.0 g of a 2 wt% CMC aqueous solution, 0.38 g of carbon black, 7.14 g of silicon oxide, 28.58 g of graphite, and 12.56 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 32.34 g of a 4.48% solids polymer P-1-Li-2 aqueous solution was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0155] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by a doctor blade, and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 18.8% by weight of silicon oxide, 75.2% by weight of graphite, 4% by weight of polymer P-1-Li-2, 1% by weight of CMC, and 1% by weight of carbon black. Electrode E6 was thus obtained.

[0156] Example 7 - Terpolymer Anode Lithiated at pH 6.5 5% Binder An aqueous composition was prepared by mixing 19.0 g of a 2 wt% CMC aqueous solution, 0.38 g of carbon black, 7.14 g of silicon oxide, 28.58 g of graphite, and 11.13 g of deionized water. After gentle stirring with a planetary mixer for 10 minutes, 33.78 g of a 4.54% solids polymer P-1-Li-3 aqueous solution was added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour. After 1 hour, the shear force was reduced and the slurry was mixed again by slow stirring.

[0157] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by doctor blade and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 18.8% by weight of silicon oxide, 75.2% by weight of graphite, 4% by weight of polymer P-1-Li-3, 1% by weight of CMC and 1% by weight of carbon black. Electrode E7 was thus obtained.

[0158] Comparative Example CE1: Anode containing styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) An aqueous composition was prepared by mixing 25.0 g of a 2 wt% aqueous solution of CMC and 0.50 g of carbon black; after gentle stirring with a planetary mixer for 10 minutes, 9.60 g of silicon oxide, 38.4 g of graphite, and 23.861 g of deionized water were added. The mixture was homogenized by gentle stirring with a planetary mixer for 10 minutes, and then mixed again by gentle stirring for 1 hour.

[0159] After approximately 1 hour of mixing, 2.639 g of SBR suspension was added to the composition and mixed again with slow stirring for 1 hour.

[0160] The binder composition thus obtained was cast on a copper foil having a thickness of 18.5 μm by doctor blade and the coating layer was dried in an oven at a temperature of 90° C. for about 70 minutes to obtain a negative electrode. The thickness of the dried coating layer was about 60 μm. The electrode was then hot pressed at 60° C. in a roll press to achieve a target density of 1.6 g / cc. The resulting negative electrode had the following composition: 19.2% by weight of silicon oxide, 76.8% by weight of graphite, 2% by weight of SBR, 1% by weight of CMC and 1% by weight of carbon black. Electrode CE1 was thus obtained.

[0161] Adhesion Test A peel test was performed to evaluate the adhesion of the electrode composition coating on the metal substrate. The test was performed on the electrodes prepared as described above according to the procedure of ASTM D903, operating at a speed of 300 mm / min at 25° C. The results are shown in Table 5.

[0162] [Table 5]

[0163] Battery manufacturing Coin cells (CR2032 type, 20 mm diameter) were fabricated in a glove box under Ar gas atmosphere by punching small disks of negative electrodes prepared according to Ex1, Ex2, Ex3, Ex4, Ex5, Ex6, Ex7 and CE1 together with equilibrated NMC positive disks purchased from CUSTOMCELLS. The electrolyte used to fabricate the coin cells was a mixture of 1 M LiPF6, 2 wt% VC and 10 wt% F1EC in EC / DMC 1 / 1 v / v from Solvionic; polyethylene separators (commercially available from Tonen Chemical Co., Ltd.) were used as received.

[0164] Capacity Retention Test Cycling stability of full cells at a C-rate of 1C (open capacity was measured in triplicate and is shown in Table 6 below):

[0165] [Table 6]

[0166] The results show that the discharge capacity retention in the batteries including the electrodes of the present invention is much higher than that of the batteries made by using the electrodes of Comparative Example 1, while at the same time showing good adhesion to the metal substrate, in some cases even higher than that of the reference composition obtained by using the polymer of Comparative Example 1.

Claims

1. 1. An aqueous electrode-forming composition [Composition (Comp)] for use in fabricating an electrode for an electrochemical device, comprising: a) the following: (A) A repeating unit derived from at least one monomer (M), which is an ethylenically unsaturated monomer having an unsaturated heterocyclic group having at least one nitrogen atom, wherein the monomer (M) is represented by the following formula (I): 【Chemical 1】 [In the formula: R １ is H or an alkyl group, wherein said alkyl group is preferably a methyl group; R ２ is H or an alkyl group; R ３ and R ４ may be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms; A is, i) a single covalent bond; and ii) spacers, such as —CO—NH—(CH ２ ) ｎ -, -CO-O-(CH ２ ) ｎ - and -CO-O-(CH ２ ) ｎ -O-CO- where n is an integer from 1 to 5, typically equal to 3 or 4. a group selected from the group consisting of is a bond selected from the group consisting of: X, Y and Z are independently selected from carbon atoms or nitrogen atoms; a, b and c are independently selected from the integers 1 to 2; Each dashed dotted line represents an optional double bond. A repeat unit having the formula: (B) The following: (B1) at least one α,β-ethylenically unsaturated carboxylic acid monomer [monomer (AA)]; and (B2) Formula (II): 【Chemistry 2】 (In the formula, R ５ represents a hydrogen atom or a methyl group, and may be the same or different from each other; R ６ and R ７ can be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and are the same or different from each other, R ８ and R ９ may be selected from a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a carboxylic acid group or an amide group. At least one (meth)acrylamide monomer [monomer (AM)] A repeating unit derived from at least one monomer selected from the group consisting of and at least one polymer (P*) comprising b) an electrode active material; and c) an aqueous solvent; d) optionally at least one conductivity-imparting additive; A composition (Comp) characterized by comprising:

2. 10. The composition (Comp) of claim 1, further comprising at least one thickener.

3. The monomer (M) is Formula (Ia): 【Chemistry 3】 vinylimidazole (VIm) - Formula (Ib) 【Chemistry 4】 2-methyl-1-vinylimidazole - Formula (Ic) 【Chemistry 5】 1-vinyl-1,2,4-triazole Formula (Id) 【Chemistry 6】 2-vinylpyrazine Formula (Ie) 【Chemistry 7】 of 4-vinylpyridine Formula (If) 【Chemistry 8】 of 2-vinylpyridine - Formula (Ig) 【Chemistry 9】 Hydroxyl-(meth)acrylate imidazole derivatives of The composition (Comp) according to claim 1, selected from the group consisting of:

4. Monomer (AA) has formula (III): 【Chemistry 10】 (wherein R ４ , R ５ and R6 is a hydrogen atom and C １ ~C ３ independently selected from hydrocarbon groups The composition (Comp) according to claim 1, which is a compound of the formula:

5. 2. The composition (Comp) of claim 1, wherein the monomer (AA) of formula (III) is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, croton, methyl(meth)acrylic acid, ethyl(meth)acrylic acid, propyl(meth)acrylic acid, isopropyl(meth)acrylic acid, n-butyl(meth)acrylic acid, 2-ethylhexyl(meth)acrylic acid, n-hexyl(meth)acrylic acid and n-octyl(meth)acrylic acid.

6. The composition (Comp) according to claim 1, wherein the (meth)acrylamide monomer [monomer (AM)] of formula (II) is selected from the group consisting of (meth)acrylamide or N-substituted meth(acryl)amides such as N-alkylacrylamides, N,N-dialkylacrylamides.

7. Polymer P(*) is - 0 to 95%, in particular 5 to 50%, preferably 20 to 40% of repeat units derived from monomer (AA), - 0 to 90 mol %, preferably 25 to 90%, more preferably 50 to 80% of repeat units derived from monomer (AM), - 1 to 50%, for example 1 to 30%, in particular 1 to 20%, or even 2 to 15% of repeat units derived from the monomer (M); Including, wherein at least one of the monomers (AA) and (AM) is present in an amount other than 0%; All of the foregoing mole percentages are based on the total moles of repeating units of said polymer (P). The composition (Comp) according to claim 1.

8. (A) A repeating unit derived from at least one monomer (M), which is an ethylenically unsaturated monomer having an unsaturated heterocyclic group having at least one nitrogen atom, wherein the monomer (M) is represented by the following formula (I): 【Chemistry 11】 [In the formula: R １ is H or an alkyl group; R ２ is H or an alkyl group; R ３ and R ４ may be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms; A is, i) a single covalent bond; and ii) spacers, such as —CO—NH—(CH ２ ) ｎ -, -CO-O-(CH ２ ) ｎ - and -CO-O-(CH ２ ) ｎ -O-CO- where n is an integer from 1 to 5, typically equal to 3 or 4. a group selected from the group consisting of is a bond selected from the group consisting of: X, Y and Z are independently selected from carbon atoms or nitrogen atoms; a, b and c are independently selected from the integers 1 to 2; Each dashed dotted line represents an optional double bond. A repeat unit having the formula: (B1) a repeating unit derived from at least one α,β-ethylenically unsaturated carboxylic acid monomer [monomer (AA)]; and (B2) Formula (II): 【Chemistry 12】 (In the formula, R ５ represents a hydrogen atom or a methyl group, and may be the same or different from each other; R ６ and R ７ can be selected from a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and are the same or different from each other, R ８ and R ９ may be selected from a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a carboxylic acid group or an amide group. A repeating unit derived from at least one (meth)acrylamide monomer [monomer (AM)] of A polymer (P) comprising:

9. The polymer (P) according to claim 8, - 5 to 95%, in particular 5 to 50%, preferably 20 to 40% of repeat units derived from monomer (AA), - 25 to 90%, preferably 50 to 80%, of repeat units derived from monomer (AM), - 0.1 to 50%, for example 1 to 30%, in particular 1 to 20%, or even 2 to 15% of repeat units derived from the monomer (M); Including, All of the foregoing mole percentages are based on the total moles of repeat units of said polymer (P). Polymer (P).

10. A process for preparing an electrode [electrode (E)], said process comprising: (i) providing a metal substrate having at least one surface; (ii) providing a composition (Comp) according to any one of claims 1 to 7; (iii) applying the composition (Comp) provided in step (ii) onto at least one surface of the metal substrate provided in step (i), thereby providing an assembly comprising a metal substrate having at least one surface coated with said composition (Comp); (iv) drying the assembly provided in step (iii); (v) subjecting the dried assembly obtained in step (iv) to a compression step to obtain the electrode (E) of the present invention. Including, processes.

11. An electrode [electrode (E)] obtained by the process according to claim 10.

12. Electrochemical device comprising at least one electrode (E) according to claim 11.

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