Powdered binder for preparing electrodes using a solvent-free method.

Abstract

The present invention relates to an electrode binder comprising polymer P1 and polymer P2 that form an interpenetrating polymer network or a semi-interpenetrating polymer network.

Description

[Technical Field]

[0001] This invention generally relates to the field of electrical energy storage in lithium-ion type batteries. More specifically, this invention relates to binders for dry-coated electrodes for lithium-ion batteries. Another subject of this invention is a method for preparing electrodes using the binder. This invention also relates to lithium-ion batteries manufactured by incorporating the electrodes. [Background technology]

[0002] The basic cell of a lithium-ion battery or lithium battery generally comprises an anode (for discharge) and a cathode (which also serves as a discharge component) composed of a metal oxide type lithium-intercalated compound such as LiMn2O4, LiCoO2, or LiNiO2, with an electrolyte that conducts lithium ions inserted between them.

[0003] Rechargeable or secondary cells have advantages over primary cells (non-rechargeable) because the related chemical reactions occurring at the positive and negative electrodes of the battery are reversible. The electrodes of secondary cells can be regenerated several times by applying a charge. Many advanced electrode systems for storing charge have been developed. At the same time, considerable effort has been devoted to developing electrolytes that can improve the capacity of electrochemical cells.

[0004] Regarding electrodes, the electrodes generally include at least one current collector, on which a composite material is deposited in the form of a film, comprising a material called an active material because it has electrochemical activity toward lithium, a polymer that acts as a binder, one or more conductive additives which are generally carbon black or acetylene black, and optionally a surfactant.

[0005] Binders are classified as inert components because they do not directly contribute to the cell's capacity. However, their important role in electrode processing and their considerable influence on the electrode's electrochemical performance are widely described. The main relevant physical and chemical properties of binders are thermal stability, chemical and electrochemical stability, tensile strength (strong adhesion and strong aggregation), and flexibility. The primary purpose of using binders is to form a stable network (aggregation) of the solid components of the electrode, namely the active material and conductive agent. Furthermore, the binder must ensure close contact (adhesion) between the composite electrode and the current collector.

[0006] The current method for manufacturing electrodes for lithium-ion batteries, the "slurry" method, requires the use of a solvent. This method involves preparing an ink by mixing an active material, a conductive filler, and a polymer binder in a solvent. This ink is then deposited onto a current collector, and the solvent is evaporated. The majority of the energy consumed by this method comes from the step of evaporating the solvent. A strong trend in the field of lithium-ion batteries is to reduce manufacturing costs, which includes limiting the costs associated with energy consumption for manufacturing.

[0007] Compared to conventional wet suspension methods for manufacturing electrodes, dry (solvent-free) manufacturing methods are simpler. Such methods eliminate the emission of volatile organic compounds and offer the possibility of producing electrodes with greater thickness (>120 μm) and higher energy density in the final energy storage device. Changes in manufacturing technology have little effect on the electrode's active material. However, the polymer additives responsible for the electrode's mechanical integrity must be suitable for the new manufacturing conditions.

[0008] The adhesion of coatings to current collectors obtained by solvent-free methods is often inferior to that obtained by slurry methods. To improve adhesion to current collectors, one solution involves relying on current collectors covered with a conductive coating that contributes to adhesion to the current collector and ensures electron transfer between the current collector and the electrode coating. However, this solution is expensive and incurs considerable additional costs.

[0009] As a result, a binder is needed that provides good electrochemical resistance and contributes to good adhesion to metal current collectors via a solvent-free manufacturing method. It is also essential that the binder has high affinity to other components of the solvent-free formulation, and therefore causes close aggregation during pressing. [Overview of the project]

[0010] According to the first aspect, the present invention relates to a polymer P1 comprising monomer units derived from a fluoromonomer, and a polymer of formula R 1 R 2 C=C(R 3 Polymer P2 (wherein substituent R) contains at least one monomer unit derived from monomer M2 of C(O)R. 1 , R 2 and R 3 R is independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is H and C1-C5 alkyl groups optionally substituted with one or more -OH, CO2H, SO3H or PO3H groups. 18 The present invention relates to a binder in powder form comprising an alkyl group (selected from the group consisting of a 5- or 6-membered heterocycle having at least one nitrogen atom in its ring chain), wherein polymers P1 and P2 form an interpenetrating polymer network or a semi-interpenetrating polymer network, and have a particle size distribution Dv50 of 25 μm or less.

[0011] An interpenetrating polymer network is defined as a network in which polymers are at least partially entangled at the molecular level but are not covalently bonded to each other, and can only be separated if the chemical bonds are broken. A semi-interpenetrating polymer network comprises one or more polymer networks and one or more linear or branched polymers, characterized by molecular-scale interpenetration between at least one network and at least several linear or branched macromolecules. A mixture of two or more pre-formed polymer networks is not an interpenetrating polymer network or a semi-interpenetrating polymer network.

[0012] The present invention has one or more advantages. Among these, the present invention enables improved electrode cohesiveness because no solvent is present during its manufacture, which limits cracking, improves adhesion to metal substrates, i.e., current collectors, eliminates the need for expensive coated current collectors, limits the use of toxic organic solvents, and increases productivity by eliminating the drying step after electrode manufacturing.

[0013] According to a preferred embodiment, the binder has a particle size distribution Dv50 of 10 μm or less.

[0014] According to a preferred embodiment, the binder has a particle size distribution Dv90 of 100 μm or less, preferably 25 μm or less.

[0015] The binder according to the present invention, having the size distribution described in this patent application, improves the performance of electrodes containing it.

[0016] According to a preferred embodiment, the polymer P1 is a homopolymer of vinylidene fluoride or a copolymer containing monomer units derived from vinylidene fluoride and monomer units of a monomer M1 selected from the group consisting of: vinyl fluoride; trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkyl vinyl) ethers, such as perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE) and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); products of the formula CF2=CFOCF2CF(CF3)OCF2CF2X (where X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H); products of the formula CF2=CFOCF2CF2SO2F; products of the formula F(CF2)nCH2OCF=CF2 (where n is 1, 2, 3, 4 or 5); 1 products of the formula R 1 CH2OCF=CF2 (where R 2 is hydrogen or F(CF2)m and m is equal to 1, 2, 3 or 4); products of the formula R 2 OCF=CH2 (where R

[0017] <0000According to a preferred embodiment, polymer P1 is a homopolymer of vinylidene fluoride, or a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from monomer M1 selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, or mixtures thereof.

[0018] According to a preferred embodiment, the polymer P1 comprises a monomer unit having at least one of the following functional groups selected from the group consisting of epoxy groups such as carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, and glycidyls, amides, hydroxyls, carbonyls, mercaptos, sulfides, oxazolines, phenols, esters, ethers, siloxanes, sulfonic acids, sulfuric acids, phosphoric acids, and phosphonic acids or mixtures thereof.

[0019] According to a preferred embodiment, the monomer M2 is of formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is H and C1-C5 alkyl groups optionally substituted with one or more -OH, CO2H, SO3H or PO3H groups. 18 It has (selected from the group consisting of alkyl groups).

[0020] According to a preferred embodiment, the polymer P2 is -50% to 100% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is C1-C 18 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 30% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is H and one or more functional groups selected from the group consisting of CO2H, PO3H and SO3H, C1-C5 alkyl groups. 18 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 20% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is a C1-C5 alkyl group having one or more -OH functional groups. 18 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); Includes.

[0021] In another aspect, the present invention provides an electrode composition in powder form for preparing a dry-coated electrode, comprising the binder, active material, and optionally a conductive agent, additive, or a mixture thereof, characterized in that it has a tap density of at least 70% of the tap density of the active material as measured according to standard ISO 1068:1975. Tap density is the increased bulk density obtained after mechanically tapping a container containing the powder sample. Tap density is obtained by mechanically tapping a graduated cylinder or container containing the powder sample. Tap density is measured according to standard ISO 1068:1975.

[0022] According to a preferred embodiment, the composition has the following mass composition: a. 50% to 99.9%, preferably 50% to 99% active material, b. A binder according to the present invention in an amount of 0.1% to 25%, preferably 0.5% to 25%. c. 0% to 25%, preferably 0.5% to 25% conductive agent, d. At least one additive selected from the group consisting of plasticizers, ionic liquids, dispersants for conductive additives, and flow aids, in an amount of 0% to 5%. It has all of these percentages, and the sum of all these percentages is 100%.

[0023] According to a preferred embodiment, the composition comprises a conductive agent containing one or more materials selected from the group consisting of carbon black, graphite, carbon fibers, carbon nanotubes, carbon nanofibers, metal powders such as SUS powder and aluminum powder, or mixtures thereof.

[0024] According to a preferred embodiment, in the electrode composition, the active material is LiCoO2, Li(Ni,Co,Al)O2, Li (1+x) Ni a Mn b Co c (x represents a real number greater than or equal to 0, a=0.8, 0.6, 0.5 or 1 / 3, b=0.1, 0.2, 0.3 or 1 / 3, c=0.1, 0.2 or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, Li3NiMn3O3, Li3Fe2(PO4)3, Li3V2(PO4)3, Li 1+x Mn 2-x-y M y LiMn spinel substituted with different elements having a composition represented as O4 (where M represents at least one metal selected from Al, Mg, Co, Fe, Ni, and Zn, and x and y independently represent real numbers between 0 and 2), lithium titanate Li x TiO y The group consists of lithium metal phosphates having compositions represented by (x and y independently represent real numbers from 0 to 2) and LiMPO4 (where M represents Fe, Mn, Co, or Ni).

[0025] According to another embodiment, in the electrode composition, the active material is a carbon material such as lithium alloy, lithium metal, metal oxide, graphite or hard carbon, silicon, silicon and Li4Ti5O12 It is selected from the group consisting of alloys.

[0026] In another embodiment, the present invention provides a dry-coated electrode comprising a current collector and a layer comprising an electrode composition according to the present invention, preferably in contact with the current collector. Not limited to, the current collector may be made of copper or aluminum.

[0027] In another embodiment, the present invention is - A step of mixing the active material in powder form, the binder according to the present invention, and optionally the conductive agent in powder form, the additive in powder form, or both, to form the electrode composition according to the present invention; - The steps of depositing the electrode composition onto the current collector to form an electrode, and -Optionally, a step of solidifying the electrodes by thermomechanical treatment, The present invention provides a method for preparing the dry-coated electrode described in the above item, characterized by including the above.

[0028] In another aspect, the present invention provides a lithium-ion battery comprising a positive electrode, a negative electrode, and a separator, wherein at least one electrode is a dry-coated electrode according to the present invention. [Modes for carrying out the invention]

[0029] According to a first aspect of the present invention, a binder is provided. The binder according to the present invention is in powder form. The binder comprises polymer P1 and polymer P2 as described in the present invention. Polymers P1 and P2 form an interpenetrating polymer network or a semi-interpenetrating polymer network as defined above.

[0030] According to a preferred embodiment, the binder has a particle size distribution Dv50 of 25 μm or less. Dv50 is the particle size at the 50th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by laser particle size analysis. This applies to all Dv50 values ​​described herein. This parameter is determined by laser particle size analysis. A Malvern Insitec System type particle size analyzer is used for measurement. This is performed via dry laser diffraction on the powder at a focal length of 100 mm. The binder can have a particle size distribution Dv50 of 24 μm or less, advantageously 23 μm or less, preferably 22 μm or less, more preferably 21 μm or less, particularly 20 μm or less, more specifically 19 μm or less, preferably 18 μm or less, advantageously 17 μm or less, more preferably 16 μm or less, more preferably 15 μm or less, particularly 14 μm or less, more specifically 13 μm or less. According to a particular embodiment, the binder has a particle size distribution Dv50 of 12 μm or less, preferably 11 μm or less, and particularly 10 μm or less.

[0031] According to a preferred embodiment, the binder has a particle size distribution Dv90 of 100 μm or less. Dv90 is the particle size at the 90th percentile (by volume) of the cumulative particle size distribution. This parameter can be determined by laser particle size analysis. This applies to all Dv90 values ​​described herein. This parameter is determined by laser particle size analysis. A Malvern Insitec System type particle size analyzer is used for measurement. This is performed by dry laser diffraction on the powder at a focal length of 100 mm. The binder may have a particle size distribution Dv50 of 90 μm or less, advantageously 80 μm or less, preferably 70 μm or less, more preferably 60 μm or less, particularly 50 μm or less, more specifically 40 μm or less, preferably 30 μm or less, and advantageously preferably 25 μm or less.

[0032] Polymer P1 The polymer P1 contains monomer units derived from a fluoromonomer. The fluoromonomer is a vinyl compound containing at least one fluorine atom.

[0033] Preferably, the polymer P1 contains at least one monomer unit derived from a monomer selected from the group consisting of: vinyl fluoride; vinylidene fluoride (VDF); trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkyl vinyl) ethers, e.g., perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether Perfluoro(PEVE) and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); products of formula CF2=CFOCF2CF(CF3)OCF2CF2X (wherein X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H); products of formula CF2=CFOCF2CF2SO2F; products of formula F(CF2)nCH2OCF=CF2 (wherein n is 1, 2, 3, 4 or 5); formula R 1 CH2OCF=CF2(in the formula, R 1 Products of hydrogen or F(CF2)m (where m is 1, 2, 3, or 4); formula R 2 OCF=CH2(wherein, R 2Products of (where p is F(CF2)p, and p is 1, 2, 3, or 4); perfluorobutylethylene (PFBE); trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, and 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or mixtures thereof. Among trifluoropropenes, 3,3,3-trifluoropropene can be mentioned. Among tetrafluoropropenes, 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene can be mentioned. Among pentafluoropropenes, 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene can be mentioned. Chlorofluoroethylene may represent either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene. 1-chloro-1-fluoroethylene isomers are preferred. The chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.

[0034] In particular, the polymer P1 contains at least monomer units derived from vinylidene fluoride. The polymer P1 may be a homopolymer or a copolymer. The copolymer may also contain non-fluoromonomers.

[0035] According to one embodiment, polymer P1 is a vinylidene fluoride homopolymer.

[0036] According to an alternative embodiment, polymer P1 is a polymer comprising units derived from vinylidene fluoride, and is preferably selected from polyvinylidene fluoride homopolymers and copolymers comprising vinylidene fluoride units and units derived from at least one other comonomer that can copolymerize with vinylidene fluoride.

[0037] Therefore, the polymer P1 comprises monomer units derived from vinylidene fluoride and monomer units derived from monomers selected from the group consisting of: vinyl fluoride; trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkyl vinyl) ethers, e.g., perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether Tel(PEVE) and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); products of formula CF2=CFOCF2CF(CF3)OCF2CF2X (wherein X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H); products of formula CF2=CFOCF2CF2SO2F; products of formula F(CF2)nCH2OCF=CF2 (wherein n is 1, 2, 3, 4 or 5); formula R 1 CH2OCF=CF2(in the formula, R 1 Products of hydrogen or F(CF2)m (where m is 1, 2, 3, or 4); formula R 2 OCF=CH2(wherein, R 2 Products of F(CF2)p (where p is 1, 2, 3 or 4); perfluorobutylethylene (PFBE); trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, and 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or mixtures thereof.

[0038] According to a preferred embodiment, polymer P1 is a copolymer comprising units of vinylidene fluoride (VDF) and units resulting from one or more monomers selected from the group consisting of: vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ethers, e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether or perfluoro(propyl vinyl) ether, perfluoro(1,3-dioxole), perfluoro(2,2-dimethyl-1,3-dioxole), products of formula CF2=CFOCF2CF(CF3)OCF2CF2X (wherein X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H), products of formula CF2=CFOCF2CF2SO2F; formula F(CF2) n Products of CH2OCF=CF2 (wherein n is 1, 2, 3, 4, or 5), formula R'CH2OCF=CF2 (wherein R' is hydrogen or F(CF2) z The product of (where z is 1, 2, 3, or 4); formula R''OCF=CH2(where R'' is F(CF2) z Products of (where z is 1, 2, 3 or 4), trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene, and 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or mixtures thereof.

[0039] Preferably, polymer P1 is a copolymer comprising monomer units derived from vinylidene fluoride and monomer units derived from monomers selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, and hexafluoropropylene or mixtures thereof. In polymer P1, the mass content of vinylidene fluoride units is at least 50%, preferably at least 60%, more preferably more than 70%, and advantageously more than 80%.

[0040] According to certain embodiments, polymer P1 is functionalized in whole or in part, thereby improving its adhesion to metals. Accordingly, polymer P1 may contain monomer units having at least one, preferably at least one carboxylic acid or hydroxyl functional group, selected from the group consisting of carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, epoxy such as glycidyl, amides, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, or phosphonic acid.

[0041] The functional groups are introduced by a chemical reaction that allows for grafting or copolymerization of a fluorinated monomer with a monomer having at least one of the functional groups and a vinyl functional group copolymerizable with the fluorinated monomer, in accordance with techniques well known to those skilled in the art.

[0042] According to one embodiment, the functional group is supported by a carboxylic acid functional group which is a (meth)acrylic acid type group selected from acrylic acid, methacrylic acid, methylacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, and acryloyloxypropyl succinate.

[0043] According to one embodiment, the unit supporting the carboxylic acid functional group further comprises a heteroatom selected from oxygen, sulfur, nitrogen, and phosphorus.

[0044] According to one embodiment, the functionality is introduced via a transfer agent used during the synthesis process. The transfer agent is a polymer having a molar mass of 20,000 g / mol or less and having a functional group selected from the following groups: carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, epoxy (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, or phosphonic acid. Acrylic acid oligomers are an example of this type of transfer agent. According to a preferred embodiment, the transfer agent is an acrylic acid oligomer having a molar mass of 20,000 g / mol or less. Alternatively, the functional group may be introduced by an oligomer or polymer compound containing the functional group and mixed with polymer P1. The oligomer or polymer compound may be impregnated into polymer P1, mixed with polymer P1, or closely mixed with polymer P1. In this case, the functional group may be derived from a (meth)acrylic acid compound selected from acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, and acryloyloxypropyl succinate. For example, the functional group may be an oligomer or polymer containing monomer units derived from monomers selected from the group consisting of acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, and acryloyloxypropyl succinate. According to one embodiment, the oligomer or polymer has a weight-average molecular weight of 100,000 g / mol or less, preferably less than 80,000 g / mol, preferably less than 60,000 g / mol, more preferably less than 40,000 g / mol, and particularly less than 20,000 g / mol. The weight-average molecular weight is determined by GPC using a Waters2695e instrument connected to a Wyatt NEON refractometer equipped with two PL gel mixed C columns and a guard column (inner diameter 7.8 mm × 30 cm, 5 μm), under the following conditions: temperature: 35°C; flow rate: 1.0 mL / min; injection volume: 100 μL. The sample is prepared to a concentration of 1 mg / mL in THF.Twelve samples of poly(methyl methacrylate) with molecular masses ranging from 535 to 2,210,000 g / mol were used as calibration standards.

[0045] The functional group content in PVDF is at least 0.01 mol%, preferably at least 0.1 mol%, and 15 mol% or less, preferably 10 mol% or less.

[0046] The PVDF homopolymers and VDF copolymers used in the present invention can be obtained by known polymerization methods such as emulsion polymerization or suspension polymerization.

[0047] According to one embodiment, they are prepared by an emulsion polymerization method in the absence of a fluorinated surfactant.

[0048] Polymerization of PVDF generally yields latex having a solid content of 10% to 60% by weight, preferably 10% to 50%.

[0049] According to certain embodiments, PVDF homopolymers and VDF copolymers are composed of bio-based VDF. The term "bio-based" means "derived from biomass." This makes it possible to improve the ecological footprint of the polymer. Bio-based VDF conforms to the standard NF EN 16640. 14 The content of carbon is determined by the carbon content and can be characterized by the content of at least 1 atomic percent of renewable carbon, i.e., naturally occurring carbon derived from biomaterials or biomass. The term “renewable carbon” indicates that the carbon is of natural origin and derived from biomaterials (or biomass), as shown below. According to certain embodiments, the biocarbon content of VDF is more than 5%, preferably more than 10%, preferably more than 25%, preferably more than 33%, preferably more than 50%, preferably more than 66%, preferably more than 75%, preferably more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, and advantageously equal to 100%.

[0050] The polymer P1 may have a melting temperature of 80°C to 180°C, preferably 100°C to 170°C, as measured according to ASTM D3418.

[0051] Polymer P2 As described above, the polymer P2 is of formula R 1 R 2 C=C(R 3 ) Containing at least one monomer unit derived from the monomer M2 of C(O)R (wherein substituent R 1 , R 2 and R 3 R is independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is H and C1-C5 alkyl groups optionally substituted with one or more -OH, CO2H, SO3H or PO3H groups. 18 (Selected from the group consisting of alkyl groups, or 5- or 6-membered heterocycles containing at least one nitrogen atom in their ring chain).

[0052] The heterocycle may be saturated, unsaturated, or aromatic. The heterocycle may be monocyclic or bicyclic. The heterocycle may be a pyrrole, pyrrolidine, pyridine, piperidine, pyrimidine, pyrazine, 1,4-dihydropyridine, indole, oxyindole, isatin, quinoline, isoquinoline, quinazoline, imidazoline, pyrazolidine, 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone ring. The heterocycle may be substituted with one or more C1-C5 alkyl groups. 18 The alkyl group is optionally substituted on the heterocycle. The latter can be bonded to the alkyl chain via a nitrogen atom or any other atom forming the heterocycle. Preferably, the heterocycle is 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone.

[0053] Preferably, the polymer P2 is of formula R 1 R 2 C=C(R 3)Contains monomer units derived from the monomer M2 of C(O)R (wherein substituent R 1 , R 2 and R 3 R is independently selected from the group consisting of H and C1-C5 alkyl groups; R is selected from the group consisting of -NHC(CH3)2CH2C(O)CH3 or -OR', and R' is C1-C5 alkyl groups optionally substituted with one or more -OH, CO2H, SO3H or PO3H groups. 18 (Selected from the group consisting of alkyl groups or 5- or 10-membered heterocycles containing at least one nitrogen atom in their ring chain). Preferably, the heterocycle is defined as above, and in particular the heterocycle is 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, or 4-imidazolidinone. The term "alkyl(meth)acrylate" encompasses alkyl acrylates and alkyl methacrylates.

[0054] Preferably, the monomer M2 is of formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is H and C1-C5 alkyl groups optionally substituted with one or more -OH, CO2H, SO3H or PO3H groups. 18 It has (selected from the group consisting of alkyl groups).

[0055] According to a preferred embodiment, the substituent R' is selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, n-dodecyl, amyl, isoamyl, hexyl, 2-ethylhexyl, lauryl, n-octyl, hydroxybutyl, hydroxypropyl, and ethyl, which are substituted with a ureido, hydroxyethyl, hydroxypropyl, or hydroxybutyl group.

[0056] In particular, the polymer P2 is of formula R 1 R 2 C=C(R 3)C(O)R monomer M2 (wherein substituent R 1 and R 2 H is R 3 is H or CH3, and R contains a monomer unit derived from -OR' (where R' is selected from the group consisting of H, methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, hydroxypropyl, hydroxybutyl, 2-pyrrolidone, δ-lactam, succinimide, 2-imidazolidinone, and 4-imidazolidinone).

[0057] Therefore, monomer M2 may be methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-dodecyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide, lauryl acrylate, n-octyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-dodecyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, n-octyl methacrylate, or ureido methacrylate. Among these, alkyl acrylates having 1 to 8 carbon atoms in the alkyl group are preferred, and alkyl acrylates having 1 to 5 carbon atoms in the alkyl group are more preferred. These may be used individually or as a mixture of two or more. Therefore, the polymer P2 may be a homopolymer of the monomer M2 defined above or a copolymer derived from a mixture of one or more monomers M2 defined above.

[0058] P2 polymer also, -(A) Alkenyl compounds containing a functional group, and -(B) Alkenyl compounds that do not have functional groups It may contain monomer units derived from it.

[0059] Examples of alkenyl compounds (A) containing functional groups include α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, crotonic acid, and itaconic acid; vinyl ester compounds such as vinyl acetate and vinyl neodecanoate; and amide compounds such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, and diacetoneacrylamide. Examples include: acrylic acid esters such as 2-hydroxyethyl acrylate, N-dialkylaminoethyl acrylate, glycidyl acrylate, n-dodecyl acrylate, and fluoroalkyl acrylate; and methacrylic acid esters such as dialkylaminoethyl methacrylate, fluoroalkyl methacrylate, 2-hydroxyethyl methacrylate, n-octyl methacrylate, t-butyl methacrylate, glycidyl methacrylate, and ethylene glycol dimethacrylate; maleic anhydride; and alkenyl glycidyl ether compounds such as allyl glycidyl ether. Among these, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, N-methylolacrylamide, N-methylolmethacrylamide, diacetoneacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and allyl glycidyl ether. These may be used individually or as a mixture of two or more.

[0060] Examples of alkenyl compounds (B) that do not have functional groups include conjugated dienes such as 1,3-butadiene and isoprene; divinyl hydrocarbon compounds such as divinylbenzene; and alkenyl cyanides such as acrylonitrile and methacrylonitrile. Among these, preferred compounds are 1,3-butadiene and acrylonitrile. These may be used individually or as a mixture of two or more.

[0061] The functional alkenyl compound (A) is preferably used at a ratio of less than 50% by weight based on the weight of the monomer mixture, and the alkenyl compound (B) having no functional group is preferably used at a ratio of less than 30% by weight based on the weight of the monomer mixture.

[0062] According to a specific embodiment, the polymer P2 is - 50% to 100% by weight of monomer units derived from at least one monomer of the formula R 1 R 2 C=C(R 3 )C(O)OR’ (where the substituents R 1 , R 2 and R 3 are independently selected from the group consisting of H and C1-C5 alkyl, and R’ is selected from the group consisting of C1-C 18 alkyl); - 0% to 30% by weight of monomer units derived from at least one monomer of the formula R 1 R<了 2 C=C(R 3 )C(O)OR’ (where the substituents R 1 , R 2 and R 3 are independently selected from the group consisting of H and C1-C5 alkyl, and R’ is selected from the group consisting of C1-C 18 alkyl having one or more functional groups selected from the group consisting of H, and CO2H, PO3H and SO3H); - 0% to 20% by weight of monomer units derived from at least one monomer of the formula R 1 R 2 C=C(R 3 )C(O)OR’ (where the substituents R 1 , R 2 ' and R 3 are independently selected from the group consisting of H and C1-C5 alkyl, and R’ is selected from the group consisting of C1-C 18 alkyl having one or more -OH functional groups); and includes.

[0063] <着 Preferably, the polymer P2 is -50% to 100% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is C1-C 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 30% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is H and one or more functional groups selected from the group consisting of CO2H, PO3H and SO3H, C1-C5 alkyl groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 20% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C5 alkyl groups, and R' is a C1-C5 alkyl group having one or more -OH functional groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); Includes.

[0064] In particular, the polymer P2 is -50% to 100% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is C1-C 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 30% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is H and one or more functional groups selected from the group consisting of CO2H, PO3H and SO3H, having C1-C3 alkyl groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 20% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is a C1-C3 alkyl group having one or more -OH functional groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); Includes.

[0065] More specifically, the polymer P2 is -50% to 99% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is C1-C 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0.5% by weight to 30% by weight, formula R 1 R 2 C=C(R 3)C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is H and one or more functional groups selected from the group consisting of CO2H, PO3H and SO3H, having C1-C3 alkyl groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0.5% by weight to 20% by weight, formula R 1 R 2 C=C(R 3 )C(O)OR' (wherein, the substituent R 1 , R 2 and R 3 R' is independently selected from the group consisting of H and C1-C3 alkyl groups, and R' is a C1-C3 alkyl group having one or more -OH functional groups. 10 A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); Includes.

[0066] <Method for preparing the binder> The aforementioned binder is, a) A step of preparing a reactor containing the polymer P1 which includes monomer units derived from fluoromonomers, b) Formula R as defined in this patent application 1 R 2 C=C(R 3 The steps include adding at least one monomer M2 of C(O)R to the reactor and placing the polymer P1 in contact with the at least one monomer M2; c) The step of carrying out polymerization of the at least one monomer M2; d) A step of drying the product obtained in step c) and optionally shredding it to prepare the binder according to the present invention; It can be manufactured by a method that includes the following:

[0067] In step a), the polymer P1 is preferably in the form of latex.

[0068] During step b), formula R as defined in this patent application 1 R 2 C=C(R 3 Add at least one monomer M2 of C(O)R to the reactor. During step b), polymer P2 of formula R 1 R 2 C=C(R 3 )If different monomer units of C(O)R are included, preferably all constituent monomers of polymer P2 are added. Adding all of the at least one constituent monomer M2 of polymer P2 in step b) allows for an improvement in the tightness of the mixture between polymer P1 and all of the constituent monomer units of polymer P2.

[0069] During step b), the polymer P1 and the at least one monomer M2 are brought into contact for a sufficiently long time to impregnate the polymer P1 particles with the monomer M2 before polymerization takes place. This contact time may be at least 5 minutes, preferably 10 minutes, and particularly at least 15 minutes. The longer the contact between monomer M2 and polymer P1, the tighter the mixture between polymer P1 and polymer P2 becomes (after polymerization of monomer M2).

[0070] The method also includes step c) in which the at least one monomer M2 is polymerized. Step c) is preferably carried out in the presence of water. Step c) of polymerization of the at least one monomer M2 is carried out in the presence of an initiator. The initiator may be a persulfate type such as sodium persulfate, potassium persulfate, barium persulfate or ammonium persulfate; alkali metal bisulfites; peroxides such as benzoyl peroxide or dicumyl peroxide; hydroperoxides such as methyl hydroperoxide or tert-butyl hydroperoxide; acyloins such as benzoin; peracetates such as methyl peracetate or tert-butyl peracetate; perbenzoates such as tert-butyl perbenzoate; peroxalates such as dimethyl peroxalate or di(tert-butyl) peroxalate; or an initiator of an azo compound such as azobisisobutyronitrile or dimethyl azobisisobutyrate. The initiator is preferably added in a content of 0.005% to 1% by weight, based on the weight of at least one monomer M2 and optionally, the weight of alkenyl compounds (A) and (B) if present.

[0071] Optionally, step c) is carried out in the presence of a chain transfer agent. The chain transfer agent may be an oxygen-containing compound such as an alcohol, carbonate, ketone, ester, or ether; a halocarbon or hydrohalocarbon compound such as a chlorocarbon, hydrochlorocarbon, chlorofluorocarbon, or hydrochlorofluorocarbon; or ethane or propane. Alternatively, the chain transfer agent may be a polymer having a molar mass of 20,000 g / mol or less and having a functional group selected from the following groups: carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, epoxy (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenol, ester, ether, siloxane, sulfonic acid, sulfuric acid, phosphoric acid, and phosphonic acid. Acrylic acid oligomers are an example of this type of transfer agent. Preferably, if present, the chain transfer agent is added in a content of 0.05% to 5% by weight based on the weight of at least one monomer M2 and, optionally, the weight of the alkenyl compounds (A) and (B) if present.

[0072] Other compounds may also be present in the implementation of the composition by the method described in the protocol in WO2007 / 018783.

[0073] Step c) can be carried out at a temperature of 20°C to 160°C. Step c) can be carried out at a pressure of 280 to 20000 kPa.

[0074] Preferably, steps b) and c) are carried out while stirring.

[0075] The polymerization product obtained in step c) is dried in step d). The drying step can be carried out by spray drying or co-spray drying, preferably at a temperature of 100°C to 220°C. The powder can also be obtained by grinding techniques such as cryogenic grinding, in which the mixture is brought to a temperature below ambient temperature, for example, by liquid nitrogen, before grinding. At the end of the powder production steps, i.e., after the drying step, the particle size can be adjusted and optimized by selection or screening steps and / or shredding to obtain the desired particle size distribution.

[0076] <Electrode composition, electrode, and preparation method> According to another aspect of the present invention, an electrode composition is provided. The electrode composition is in powder form. The electrode composition is used to prepare a dry-coated electrode. The electrode composition comprises the binder, active material, and optionally a conductive agent, additive, or a mixture of both, and is characterized by having a tap density of at least 70% of the tap density of the active material as measured according to standard ISO 1068:1975.

[0077] In a preferred embodiment, the dry-coated electrode has the following mass composition: a. 50% to 99.9%, preferably 50% to 99% active material, b. A binder according to the present invention in an amount of 0.1% to 25%, preferably 0.5% to 25%. c. 0% to 25%, preferably 0.5% to 25% conductive agent, d. At least one additive selected from the group consisting of plasticizers, ionic liquids, dispersants for conductive additives, and flow aids, in an amount of 0% to 5%. It has all of these percentages, and the sum of all these percentages is 100%.

[0078] In a particular embodiment, the dry-coated electrode has the following mass composition: a. Active material comprising 65% to 99.9%, preferably 70% to 99%. b. A binder according to the present invention in an amount of 0.1% to 25%, preferably 0.5% to 25%. c. 0% to 10%, preferably 0.5% to 5% conductive agent, d. At least one additive selected from the group consisting of plasticizers, ionic liquids, dispersants for conductive additives, and flow aids, in an amount of 0% to 5%. It has all of these percentages, and the sum of all these percentages is 100%.

[0079] The conductive agent in the dry-coated electrode is composed of one or more materials that can improve conductivity. According to a preferred embodiment, the electrode composition includes a conductive agent. The conductive agent may be selected from the group consisting of carbon black, graphite, carbon fibers, carbon nanotubes, carbon nanofibers, metal powders such as SUS powder and aluminum powder, or mixtures thereof. Carbon black may be, for example, acetylene black or Ketjen black.

[0080] The active material is a material capable of storing and releasing lithium ions.

[0081] In a preferred embodiment, the electrode is a negative electrode. In particular, with respect to the negative electrode, the active material is a carbon material such as lithium alloy, lithium metal, metal oxide, graphite or hard carbon, silicon, silicon and Li4Ti5O 12 It is selected from the group consisting of alloys. The form of the negative electrode active material is not particularly limited, but it is preferably particulate.

[0082] In another preferred embodiment, the electrode is a positive electrode. Preferably, with respect to the positive electrode, the active material is LiCoO2, Li(Ni,Co,Al)O2, Li (1+x) NiaMn b Co c (x represents a real number greater than or equal to 0, a=0.8, 0.6, 0.5 or 1 / 3, b=0.1, 0.2, 0.3 or 1 / 3, c=0.1, 0.2 or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, Li3NiMn3O3, Li3Fe2(PO4)3, Li3V2(PO4)3, Li 1+x Mn 2-x-y M y LiMn spinel substituted with different elements having a composition represented as O4 (where M represents at least one metal selected from Al, Mg, Co, Fe, Ni, and Zn, and x and y independently represent real numbers between 0 and 2), lithium titanate Li x TiO y The group consists of lithium metal phosphates having compositions represented by (x and y independently represent real numbers from 0 to 2) and LiMPO4 (where M represents Fe, Mn, Co, or Ni).

[0083] Furthermore, the surfaces of each of the above materials can be coated. The coating material is not particularly limited as long as it contains a material that is conductive to lithium ions and can be maintained on the surface of the active material in the form of a coating layer. Examples of coating materials include LiNbO3 and Li4Ti5O 12 and includes Li3PO4.

[0084] The form of the positive electrode active material is not particularly limited, but it is preferably particulate.

[0085] According to a preferred embodiment of the present invention, a dry-coated electrode is provided. The electrode comprises a current collector and a layer comprising an electrode composition according to the present invention, preferably in contact with the current collector.

[0086] According to another aspect of the present invention, a method for preparing a dry-coated electrode is provided. The method for preparing the dry-coated electrode includes the following steps: - A step of mixing the active material in powder form, the binder according to the present invention, and optionally the conductive agent in powder form, the additive in powder form, or both, to form the electrode composition according to the present invention; - The steps of depositing the electrode composition onto the current collector to form an electrode, and -Optionally, a step of solidifying the electrodes by thermomechanical treatment.

[0087] Thus, the dry-coated electrode is prepared using a "solvent-free" method, in which all components are mixed in powder form in a dry state, and deposition is also carried out without a solvent, thus eliminating the need for a residual solvent evaporation step after the deposition step.

[0088] Thermomechanical treatment refers to applying mechanical pressure to an electrode at a given temperature. Such thermomechanical treatment can be performed, for example, using a calendering apparatus equipped with a heatable roll, or using a heatable plate press.

[0089] As methods for solvent-free mixing of various components of the electrode composition before the deposition stage on the current collector, some methods, though not exhaustive, include stirring, air jet mixing, high shear mixing, V-mixer mixing, screw mixer mixing, double cone mixing, drum mixing, conical mixing, double Z-arm mixing, fluidized bed mixing, planetary mixer mixing, mechanofusion mixing, extrusion mixing, calendering mixing, and grinding mixing.

[0090] According to one embodiment, after the powder mixing step, the electrode is manufactured by a solvent-free spraying method, deposition of the electrode composition onto a metal substrate, pneumatic spraying method, electrostatic spraying, immersion in a fluidized powder bed, spraying, electrostatic screen printing, deposition by a rotating brush, deposition by a rotating weighing roll, and calendering.

[0091] According to one embodiment, after deposition on a metal substrate by solvent-free spraying (air pressure spraying method, electrostatic spraying, immersion in a fluidized powder bed, spraying, electrostatic screen printing, deposition by a rotating brush, deposition by a rotating weighing roll), the electrode is solidified by a calendering method. This method consists of applying pressure to the electrode using two optionally heated rolls. The solidification step is optional. Its implementation depends on the technique used to deposit the components onto the electrode. Therefore, if the deposition step is performed by calendering, this solidification step is optional because calendering allows for simultaneous deposition and solidification of the electrode.

[0092] According to one embodiment, after the powder mixing step, the electrode is manufactured by a two-step solvent-free method. The first step consists of manufacturing a self-supporting film from a premixed formulation by a thermomechanical method such as extrusion, calendering, or thermal compression. In the second step, the self-supporting film is laminated onto a metal substrate by a method combining temperature and pressure, such as calendering or thermal compression.

[0093] According to one embodiment, after the powder mixing step, the electrode is manufactured by a solvent-free method using a calendering method, thereby enabling the steps of film formation and coating transfer onto the current collector to be carried out in a single step, i.e., without going through the step of manufacturing a self-supporting film. To do this, the calender used has several rolls (at least three). The powder obtained after the mixing step is usually heated and introduced between the first two rolls having different rotation speeds to shear the powder. The formed coating, which remains attached to the fastest roll, is then directly laminated onto the current collector by the third roll. The electrode thus obtained can then be passed through the calender again to adjust its porosity or thickness as needed.

[0094] The mass ratio of the conductive agent to the active material is preferably 0% to 10%, and more preferably 0% to 7%.

[0095] The mass ratio of the binder to the active material is preferably 0.1% to 10%, and more preferably 0.5% to 7%.

[0096] According to one embodiment, all electrode components are mixed in a single step according to a conventional method to obtain an electrode composition.

[0097] According to one embodiment, electrode components are sequentially mixed according to a conventional method to obtain an electrode composition. In one embodiment, the electrode composition is applied to a substrate by electrostatic screen printing. Some examples of substrates are current collectors such as metal sheets or metal meshes, polymer films, or layers of solid electrolytes for solid-state batteries.

[0098] The preferred thickness of the electrode is 0.1 μm to 1000 μm, preferably 0.1 μm to 300 μm.

[0099] According to another aspect of the present invention, a lithium-ion battery is provided. Preferably, the lithium-ion battery comprises a positive electrode, a negative electrode, and a separator, wherein at least one electrode is a dry-coated electrode according to the present invention. [Examples]

[0100] The following examples illustrate the present invention without limiting it.

[0101] <Preparation of the anode> Polymer P1a is a copolymer of vinylidene fluoride and hexafluoropropylene, with a measured melting temperature of 145°C when the hexafluoropropylene content is 5% by weight. Polymer P1b is also a copolymer of vinylidene fluoride and hexafluoropropylene, with a measured melting temperature of 145°C when the hexafluoropropylene content is 6% by weight. The melting temperatures were measured according to standard ASTM D3418. The active material used is C-NERGY Actilion GHDR 15-4 graphite, sold by Imerys.

[0102] The binder used to prepare the electrodes is prepared according to the method detailed in this patent application. The binder has the following composition, as shown in Table 1:

[0103] [Table 1]

[0104] The binder according to the present invention has a particle size distribution Dv50 of 25 μm or less, as determined by laser particle size analysis.

[0105] <Electrode preparation> Graphite lithium-ion battery anodes were manufactured using solvent-free methods and electrostatic spraying methods.

[0106] The anode consists of X wt% of the polymer binder according to the present invention and (100-X) wt% of graphite. Each electrode is prepared according to the following protocol:

[0107] - Mixing of ingredients: The graphite and binder powders are weighed and placed in a 250 ml metal pot. The graphite / binder mixture is mixed for 1 minute and 30 seconds using a Minimix type vibrating mixer sold by Merris. The binder-containing mixture according to the present invention has a tap density of at least 70% of the tap density of the active material (in this case, graphite) measured according to standard ISO 1068:1975.

[0108] - Accumulation of compounding material on the current collector After mixing, the powdered formulation is deposited onto a copper current collector to a thickness of 18 μm. Deposition is performed by electrostatic spraying using an Optiselect Pro spray gun controlled by an Optiflex Pro control unit, both commercially available from Gema. The deposition area is 10 × 5 cm. 2 10-15 mg / cm³ across the surface area 2 It is between these two points.

[0109] - Electrode solidification Once the deposition step is performed, the electrodes are solidified using a table calendar (model CA3 / 200-SP, sold by Sumet GmbH). The roller speed is set to 0.1 m / min. The compressive force is controlled to apply a force of 44 N / mm per unit length, with a maximum calendar solidification temperature of 150°C.

[0110] Table 2 shows approximately 12 mg / cm³ 2 This summarizes the composition of anodes prepared at the given basis weight.

[0111] [Table 2] Composition by mass %

[0112] <Measuring adhesive strength> The adhesion between the coating and the copper foil is evaluated by measuring the peel strength at 180° using a dynamometer. To do this, a 25 mm wide electrode strip is cut out. This strip is then bonded to a rigid aluminum plate using double-sided adhesive, depositing the adhesive on the graphite / binder coating side. The peel test is performed using a Synergie 200H type MTS Systems dynamometer, with a rigid aluminum plate fixed to one jaw and a flexible aluminum sheet with the deposit fixed to the other jaw. In this configuration, the peel angle is 180°. The jaw displacement velocity is set to 100 mm / min. Table 3 summarizes the electrode peel strength values.

[0113] [Table 3]

[0114] As can be seen, the binder according to the present invention enables the production of anodes with significantly improved adhesion between the binder and the current collector.

Claims

1. A polymer P1 containing monomer units derived from a fluoromonomer, and a polymer P2 containing at least one monomer unit derived from a monomer M2 of the formula R １ R ２ C═C(R ３ )C(O)R (wherein the substituents R １ , R ２ and R ３ are independently selected from the group consisting of H and C １ -C ５ alkyl; R is selected from the group consisting of -NHC(CH ３ ) ２ CH ２ C(O)CH ３ or -OR', where R' is selected from the group consisting of H and optionally C ２ -C ３ alkyl substituted with one or more -OH, CO ３ H, SO １ H or PO １８ H groups, or a 5- or 6-membered heterocycle containing at least one nitrogen atom in its ring chain), and the polymer P1 and the polymer P2 form an interpenetrating polymer network or a semi-interpenetrating polymer network A powder-type binder characterized by having a particle size distribution Dv50 of 25 μm or less.

2. The binder according to claim 1, characterized in that it has a particle size distribution Dv50 of 10 μm or less.

3. A binder according to claim 1 or 2, characterized by having a particle size distribution Dv90 of 100 μm or less, preferably 25 μm or less.

4. The polymer P1 is a homopolymer of vinylidene fluoride, or monomer units derived from vinylidene fluoride, and vinyl fluoride; trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkyl vinyl) ethers, such as perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole) (PDD); formula CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ X (where X is SO) ２ F, CO ２ H, CH ２ OH, CH ２ OCN or CH ２ OPO ３ Products of H; formula CF ２ = CFOCF ２ CF ２ SO ２ Products of F; formula F(CF) ２ ) nCH ２ OCF = CF ２ Products of formula R (wherein n is 1, 2, 3, 4, or 5); formula R １ CH ２ OCF = CF ２ (In the formula, R １ is hydrogen or F(CF) ２ The product of formula R (where m is equal to 1, 2, 3, or 4); ２ OCF=CH ２ (In the formula, R ２ is F(CF ２ A binder according to any one of claims 1 to 3, comprising a copolymer of a product of (where p is 1, 2, 3 or 4); perfluorobutylethylene (PFBE); and monomer units of monomer M1 selected from the group consisting of trifluoropropene, tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoropropene and 2-trifluoromethyl-3,3,3-trifluoro-1-propene, or mixtures thereof.

5. The binder according to any one of claims 1 to 4, characterized in that the polymer P1 is a copolymer comprising a homopolymer of vinylidene fluoride, or monomer units derived from vinylidene fluoride, and monomer units derived from monomer M1 selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, or mixtures thereof.

6. The binder according to any one of claims 1 to 5, characterized in that the polymer P1 comprises a monomer unit having at least one functional group selected from the group consisting of epoxy groups such as carboxylic acids, carboxylic acid anhydrides, carboxylic acid esters, and glycidyl groups, and groups such as amides, hydroxyls, carbonyls, mercaptos, sulfides, oxazolines, phenols, esters, ethers, siloxanes, sulfonic acids, sulfuric acids, phosphoric acids, and phosphonic acids, or mixtures thereof.

7. The monomer M2 is, １ R ２ C = C(R ３ )C(O)OR' (wherein the substituent R １ , R ２ and R ３ H and C １ ~C ５ R' is independently selected from the group consisting of alkyl groups, and R' is H, and optionally one or more -OH groups, CO ２ H, SO ３ H or PO ３ C substituted with H group １ ~C １８ A binder according to any one of claims 1 to 6, characterized by having (selected from the group consisting of alkyl groups).

8. The aforementioned polymer P2 -50% by weight to 100% by weight, formula R １ R ２ C = C(R ３ )C(O)OR' (wherein the substituent R １ , R ２ and R ３ H and C １ ~C ５ R' is C, independently selected from the group consisting of alkyl groups. １ ~C １８ A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); -0% by weight to 30% by weight, formula R １ R ２ C = C(R ３ )C(O)OR' (wherein the substituent R １ , R ２ and R ３ H and C １ ~C ５ R' is independently selected from the group consisting of alkyls, and R' is H, as well as CO ２ H, PO ３ H and SO ３ C having one or more functional groups selected from the group consisting of H １ ~C １８ A monomer unit derived from at least one monomer (selected from the group consisting of alkyl groups); - 0% to 20% by weight of a compound of formula R １ R ２ C═C(R ３ )C(O)OR' (wherein the substituents R １ , R ２ and R ３ are each independently selected from the group consisting of H and C １ - ５ alkyl, and R' is selected from the group consisting of C １ - １８ alkyl having one or more -OH functional groups); monomer units derived from at least one monomer of​​ A binder according to any one of claims 1 to 7, characterized by containing the following.

9. A powder-form electrode composition for preparing a dry-coated electrode, comprising the binder, active material, and optionally a conductive agent, additive, or a mixture thereof, wherein the tap density is at least 70% of the tap density of the active material as measured in accordance with standard ISO 1068:1975.

10. The following mass composition: a. 50% to 99.9%, preferably 50% to 99% active material, b. A binder according to any one of claims 1 to 8, in an amount of 0.1% to 25%, preferably 0.5% to 25%. c. A conductive agent in an amount of 0% to 25%, preferably 0.5% to 25%. d. At least one additive selected from the group consisting of plasticizers, ionic liquids, dispersants for conductive additives, and flow aids, in an amount of 0% to 5%. The electrode composition according to claim 9, wherein the total percentages of all of these are 100%.

11. The electrode composition according to any one of claims 9 and 10, characterized by comprising a conductive agent containing one or more materials selected from the group consisting of carbon black, graphite, carbon fibers, carbon nanotubes, carbon nanofibers, metal powders such as SUS powder and aluminum powder, or mixtures thereof.

12. where the active material is LiCoO ２ , Li(Ni,Co,Al)O ２ , Li （１＋ｘ） Ni ａ Mn ｂ Co ｃ (x represents a real number of 0 or more, a = 0.8, 0.6, [0.5]] or 1 / 3, b = 0.1, 0.2, 0.3 or 1 / 3, c = 0.1, 0.2 or 1 / 3), LiNiO ２ , LiMn ２ O ４ , LiCoMnO ４ , Li <000--0101>NiMn ３ O ３ , Li ３ Fe ２ (PO ４ ) ３ , Li ３ V ２ (PO<00--0110>) ３ , Li １＋ｘ Mn ２－ｘ－ｙ M ｙ O ４ (M represents at least one metal selected from Al, Mg, Co, Fe, Ni and Zn, and x and y independently represent real numbers of 0 to 2), LiMn spinel substituted with different elements having a composition represented by, lithium titanate Li ｘ TiO ｙ (x and y independently represent real numbers of 0 to 2), and LiMPO[[ID=--5]] ４ (M represents Fe, Mn, Co or Ni), the electrode composition according to any one of claims 9 to 11, selected from the group consisting of lithium metal phosphates having a composition represented by. It should be noted that there seems to be a small error in the original text where "a = 0.5" was written as "a = 0.5]]", and there is a "0--0" in the tag "<00--0101>" and "<00--0110>" which should be corrected to normal tags like " ３ " and " ４ " for accurate translation. The above translation is based on the content as provided with these corrections in mind for better understanding of the text structure.

13. The active material is a carbon material such as lithium alloy, lithium metal, metal oxide, graphite or hard carbon, silicon, silicon and Li ４ Ti ５ O １２ An electrode composition according to any one of claims 9 to 12, selected from the group consisting of the following alloys.

14. A dry-coated electrode comprising a current collector preferably made of copper, and a layer comprising the electrode composition according to any one of claims 9 to 13, preferably in contact with the current collector.

15. - A step of mixing the active material in powder form, the binder according to any one of claims 1 to 8, and optionally the conductive agent in powder form, the additive in powder form, or both, to form the electrode composition according to any one of claims 9 to 13; - The steps of depositing the electrode composition onto the current collector to form an electrode, and -Optionally, a step of solidifying the electrodes by thermomechanical treatment, A method for preparing a dry-coated electrode according to claim 14, characterized by including the following:

16. A lithium-ion battery comprising a positive electrode, a negative electrode, and a separator, wherein at least one electrode is the dry-coated electrode described in claim 14.

Images