Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
  • H01M4/623—Binders being polymers fluorinated polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/624—Electric conductive fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/661—Metal or alloys, e.g. alloy coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/027—Negative electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/028—Positive electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention generally relates to the field of the storage of electrical energy in secondary batteries of the Li-ion type. More specifically, the invention relates to a binder in powder form based on an intimate mixture of fluorinated polymers. The invention also relates to several processes for preparing said binder. The invention finally relates to an electrode comprising said binder, as well as to energy storage devices comprising at least one such electrode, such as Li-ion secondary batteries and supercapacitors.
• a Li-ion battery includes at least a negative electrode or anode coupled to a copper current collector, a positive electrode or cathode coupled to an aluminum current collector, a separator, and an electrolyte.
• the electrolyte consists of a lithium salt, generally lithium hexafluorophosphate, mixed with a solvent which is a mixture of organic carbonates, chosen to optimize the transport and dissociation of ions.
• a high dielectric constant favors the dissociation of ions, and therefore the number of ions available in a given volume, while a low viscosity favors ionic diffusion which plays an essential role, among other parameters, in the velocities of charging and discharging of the electrochemical system.
• the electrodes generally comprise at least one current collector on which is deposited, in the form of a film, a composite material which consists of: a so-called active material because it has an electrochemical activity with respect to the lithium, a polymer which acts as a binder, plus one or more electronically conductive additives which are generally carbon black or acetylene black, and optionally a surfactant.
• Binders are counted among the so-called inactive components because they do not directly contribute to cell capacity. However, their key role in electrode processing and their considerable influence on the electrochemical performance of electrodes have been widely described.
• the main relevant physical and chemical properties of binders are: thermal stability, chemical and electrochemical stability, tensile strength (strong adhesion and cohesion), and flexibility.
• the main purpose of using a binder is to form stable networks of the solid components of the electrodes, i.e. the active materials and the conductive agents (cohesion). In addition, the binder must ensure close contact of the composite electrode to the current collector (adhesion).
• PVDF Poly(vinylidene fluoride)
• NMP N-methyl pyrrolidone
• the manufacturing processes in the dry way are simpler; these processes eliminate the emission of volatile organic compounds, and offer the possibility of manufacturing electrodes having higher thicknesses (>120 ⁇ m), with a higher energy density of the final energy storage device.
• PTFE Polytetrafluoroethylene
• the fibrillation of PTFE improves the mechanical properties of the electrode, and increases its cohesion.
• PTFE has two limitations: it does not always make it possible to develop a sufficient level of adhesion to the cathode (on aluminum foil) and must be combined with other binders; at the anode, there is a reduction reaction of the PTFE, which strongly limits its use.
• Document WO 2015/161289 describes an energy storage device having a cathode, an anode and a separator between the anode and the cathode, where at least one of the electrodes comprises a composite binder material based on polytetrafluoroethylene (PTFE).
• the PTFE composite binder material can comprise PTFE and at least one of the following materials: polyvinylidene fluoride (PVDF), PVDF copolymer and poly(ethylene oxide) (PEO).
• Example 6 describes a manufacturing process for forming the cathode electrode film, said process comprising first mixing activated carbon with powdered PVDF, in a mass ratio of 2:1 for 10 minutes, followed by a spray milling step under approximately 80 psi pressure, then adding a mixed powder including NMC, activated carbon and carbon black, and finally adding the PTFE and mixing for 10 minutes .
• the object of the invention is therefore to provide compositions and methods for manufacturing binders and films, based on solid particles, for battery electrodes.
• Another object of the present invention is to provide an electrode which comprises a relatively low mass content of binder in order to make it possible to increase the active charge content in the cathode in order to maximize the capacity of the batteries.
• the invention also aims to provide a process for manufacturing an electrode for a Li-ion battery using said compositions, by a technique of deposition without solvent on a metallic substrate.
• the invention finally relates to an electrode obtained by this process.
• the invention aims to provide energy storage devices comprising at least one such electrode, such as Li-ion secondary batteries and supercapacitors comprising at least one such electrode.
• the present invention relates to a binder which can be used in a lithium-ion battery. It is a composite binder formed from an intimate mixture of two fluorinated polymers, PTFE and PVDF.
• the invention relates firstly to a fluoropolymer binder for a lithium-ion battery, consisting of a mixture of a PTFE phase formed of PTFE particles having a size ranging from 10 nm to 1 mih, and a PVDF phase formed of PVDF particles having a size ranging from 10 nm to 1 mih, said binder being in powder form.
• the PVDF is chosen from poly(vinylidene fluoride) homopolymers and copolymers of vinylidene difluoride with at least one comonomer chosen from the list: vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, 3,3,3- trifluoropropene, 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, 1, 1,3,3,3-pentafluoropropene, 1,2,3,3,3-pentafluoropropene, perfluoropropylvinylether, perfluoromethylvinylether, bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene, chlorotrifluoropropene, ethylene, and mixtures thereof.
• the invention also relates to various methods of manufacturing said binder.
• said binder is prepared by coatomization of PVDF and PTFE latex, the method comprising the following steps: a. mixing a PVDF latex with a PTFE latex, b. add water to the mixture of PVDF and PTFE latexes to bring the dry extract to a content between 10 and 50% by weight of polymer. vs. coatomizing the mixture thus obtained to obtain a composite powder formed of particles of PTFE and particles of PVDF.
• said binder is prepared by polymerization of PVDF in the presence of a seed of PTFE.
• said binder is prepared by polymerization of PTFE in the presence of a seed of PVDF.
• Another object of the invention is an Fi-ion battery electrode comprising an active filler for anode or cathode, an electronically conductive filler, and a fluorinated polymer binder as described above.
• the Applicant has demonstrated that it is possible to manufacture electrodes for lithium-ion batteries which contain a mass content of binder equal to or greater than 1% and equal to or less than 5%; this represents a lower amount of binder compared to a technique that does not allow the two types of binders to be combined intimately, which translates into the need to have to increase the amount of binder to be used to obtain handling properties, flexibility and equivalent membership.
• the decrease in the quantity of binder makes it possible to increase the rate of active charge in the cathode and thus to increase the charge capacity of the latter.
• the invention also relates to a process for manufacturing a Fi-ion battery electrode, by a solvent-free process.
• Another object of the invention is an Fi-ion secondary battery comprising a negative electrode, a positive electrode and a separator, in which at least one electrode is as described above.
• the present invention makes it possible to overcome the drawbacks of the state of the art. More specifically, it provides technology that makes it possible to:
• the invention relates to a fluoropolymer binder for a lithium-ion battery, consisting of a mixture of a polytetrafluoroethylene (PTFE) phase and a polyvinylidene fluoride (PVDF) phase.
• PTFE polytetrafluoroethylene
• PVDF polyvinylidene fluoride
• said binder is in the form of a powder consisting of a mixture of primary particles of PTFE having a size ranging from 10 nm to 1 mhi, and primary particles of PVDF having a size ranging from 10 nm to 1 mhi.
• said electrode comprises the following characters, possibly combined. The contents indicated are expressed by weight, unless otherwise indicated.
• said PTFE particles have a size ranging from 50 nm to 500 nm, preferably from 100 nm to 300 nm.
• said PVDF particles have a size ranging from 50 nm to 500 nm, preferably from 100 nm to 300 nm.
• Primary particles are defined herein as particles having a size of less than 1 mhi.
• the size of the polymer particles is expressed in volume average diameter (Dv50).
• Dv50 is the particle diameter at the fiftieth percentile of the cumulative particle size distribution. This parameter can be measured by laser granulometry.
• the mass ratio in the binder between PVDF and PTFE varies from 10:90 to 90:10.
• the binder is fibrillizable, due to the presence of the PTFE.
• the fluorinated polymer used in the invention is a polymer based on vinylidene difluoride.
• the PVDF is a poly(vinylidene fluoride) homopolymer or a mixture of homopolymers of vinylidene fluoride.
• the PVDF is a poly(vinylidene fluoride) homopolymer or a copolymer of vinylidene difluoride with at least one comonomer compatible with vinylidene difluoride.
• Comonomers compatible with vinylidene difluoride can be halogenated (fluorinated, chlorinated or brominated) or non-halogenated.
• fluorinated comonomers examples include: vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, trifluoropropenes and in particular 3,3,3-trifluoropropene, tetrafluoropropenes and in particular 2,3,3,3-tetrafluoropropene or 1 , 3,3,3-tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes and in particular 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene, perfluoroalkylvinylethers and in particular those of general formula Rf-0-CF-CF2, Rf being an alkyl group, preferably C1 to C4 (preferred examples being perfluoropropylvinylether and perfluoromethylvinylether).
• the fluorinated comonomer can contain a chlorine or bromine atom. It can in particular be chosen from bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene and chlorotrifluoropropene.
• Chlorofluoroethylene can denote either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene.
• the 1-chloro-1-thioroethylene isomer is preferred.
• the chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.
• the VDF copolymer can also comprise non-halogenated monomers such as ethylene, and/or acrylic or methacrylic comonomers.
• the fluoropolymer preferably contains at least 50 mole percent vinylidene difluoride.
• the PVDF is a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP)) (P(VDF-HFP)), having a percentage by weight of hexafluoropropylene monomer units of 2 to 23%, preferably from 4 to 15% by weight relative to the weight of the copolymer.
• the PVDF is a mixture of a poly(vinylidene fluoride) homopolymer and a VDF-HFP copolymer.
• the PVDF is a copolymer of vinylidene fluoride and tetrafluoroethylene (TFE). According to one embodiment, the PVDF is a copolymer of vinylidene fluoride and chlorotrifluoroethylene (CTFE).
• TFE tetrafluoroethylene
• CTFE chlorotrifluoroethylene
• the PVDF is a VDF-TFE-HFP terpolymer.
• the PVDF is a VDF-TrFE-TFE terpolymer (TrFE being trifluoroethylene).
• the mass content of VDF is at least 10%, the comonomers being present in variable proportions.
• the PVDF is a mixture of two or more VDF-HFP copolymers.
• the PVDF comprises monomer units bearing at least one of the following functions: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolics, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, phosphonic.
• Fa function is introduced by a chemical reaction which may be grafting, or copolymerization of the fluorinated monomer with a monomer bearing at least one of said functional groups and a vinyl function capable of copolymerizing with the fluorinated monomer, according to techniques well known by the man of the trade.
• the functional group bears a carboxylic acid function which is a group of (meth)acrylic acid type chosen from acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth) acrylate and hydroxyethylhexyl (meth)acrylate.
• a carboxylic acid function which is a group of (meth)acrylic acid type chosen from acrylic acid, methacrylic acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth) acrylate and hydroxyethylhexyl (meth)acrylate.
• the units carrying the carboxylic acid function also comprise a heteroatom chosen from oxygen, sulphur, nitrogen and phosphorus.
• the functionality is introduced via the transfer agent used during the synthesis process.
• the transfer agent is a polymer with a molar mass less than or equal to 20,000 g/mol and carrying functional groups chosen from the groups: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolics, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, phosphonic.
• An example of such a transfer agent are acrylic acid oligomers.
• the content of functional groups of the PVDF is at least 0.01 molar, preferably at least 0.1% molar, and at most 15% molar, preferably at most 10% molar.
• the PVDF preferably has a high molecular weight.
• high molecular weight as used herein, is meant a PVDF having a melt viscosity greater than 100 Pa.s, preferably greater than 500 Pa.s, more preferably greater than 1000 Pa.s, preferably greater than at 2000 Pa.s.
• the viscosity is measured at 232° C., at a shear rate of 100 s 1 using a capillary rheometer or a parallel plate rheometer, according to standard ASTM D3825. Both methods give similar results.
• PVDF homopolymers and the VDF copolymers used in the invention can be obtained by known polymerization methods such as emulsion polymerization.
• they are prepared by an emulsion polymerization process in the absence of fluorinated surfactant.
• Polymerization of PVDF results in a latex generally having a solids content of 10 to 60% by weight, preferably 10 to 50%, and having a weight average particle size of less than 1 micrometer, preferably less than 1000 nm , preferably less than 800 nm, and more preferably less than 600 nm.
• the weight average size of the particles is generally at least 10 nm, preferably at least 50 nm, and advantageously the average size is in the range of 100 to 400 nm.
• the polymer particles can form agglomerates, called secondary particles, the average size of which by weight is less than 5000 ⁇ m, preferably less than 1000 ⁇ m, advantageously between 1 to 80 micrometers, and preferably from 2 to 50 micrometers. Agglomerates can break down into discrete particles during formulation and application to a substrate.
• the PVDF homopolymer and the VDF copolymers are composed of bio-based VDF.
• bio-based VDF means “derived from biomass”. This improves the ecological footprint of the membrane.
• Bio-based VDF can be characterized by a renewable carbon content, i.e. carbon of natural origin and coming from a biomaterial or from biomass, of at least 1 atomic % as determined by the content of 14C according to standard NF EN 16640.
• renewable carbon indicates that the carbon is of natural origin and comes from a biomaterial (or biomass), as indicated below.
• the bio-carbon content of the VDF can be greater than 5%, preferably greater than 10%, preferably greater than 25%, preferably greater than or equal to 33%, preferably greater than 50% , preferably greater than or equal to 66%, preferably greater than 75%, preferably greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, advantageously equal to 100% .
• the fluorinated polymer used in the invention generically designated by the abbreviation PTFE, is a polymer based on tetrafluoroethylene (TFE).
• the PTFE is a poly(tetrafluoroethylene) homopolymer or a mixture of tetrafluoroethylene homopolymers.
• the PTFE is a poly(tetrafluoroethylene) homopolymer or a copolymer of tetrafluoroethylene with at least one comonomer compatible with tetrafluoroethylene, such as vinylidene fluoride or hexafluoropropylene.
• the polytetrafluoroethylene which enters into the composition of the binder according to the invention, mixed with the PVDF, is a polymer obtained by polymerization of TFE in emulsion, according to the conditions known to those skilled in the art.
• the TFE can be copolymerized with at least one other monomer, such as vinylidene fluoride or hexafluoropropylene.
• Polymerization of PTFE results in a latex generally having a solids content of 10 to 60% by weight, preferably 10 to 50%, and having a weight average particle size of less than 1 micrometer, preferably less than 1000 nm , preferably less than 800 nm, and more preferably less than 600 nm.
• the weight average size of the particles is generally at least 10 nm, preferably at least 50 nm, and advantageously the average size is in the range of 100 to 400 nm.
• the PTFE used in the invention has a high molecular weight, preferably greater than 100,000 g/mole
• the invention also relates to various methods of manufacturing the fluoropolymer binder.
• said binder is prepared by coatomization of the PVDF and PTFE latexes described above.
• Atomization (or coatomization) is known in itself.
• the fluoropolymers are always in the form of particles of size less than 1 mih.
• an aqueous dispersion is prepared by mixing, with stirring, the mixture of fluoropolymer latexes (PVDF latex and PTFE latex, as described above), in order to bring the dry extract to a content between 10 and 50% by mass of polymers PVDF+PTFE.
• This aqueous dispersion is then atomized, preferably in the presence of an antifoaming agent of the siloxane-modified polyether type, to produce a composite powder which can then be used in the preparation of the electrodes.
• the particle size can be adjusted and optimized by selection or sieving methods.
• PVDF Polymerization of PVDF in the presence of a PTFE seed (PVD F shell/PTFE core)
• said binder is prepared by polymerization of PVDF in the presence of a seed of PTFE.
• water is added to obtain a dry extract ranging from 10 to 50%, to which vinylidene fluoride and a polymerization initiator are added.
• a stable latex is obtained, the particle size of which is in the range 200 to 400 nm (Dv50).
• the PVDF:PTFE mass composition of this latex varies from 10:90 to 90:10.
• the solid content obtained is between 10 and 60%.
• the PTFE latex is obtained in a first reactor, it is transferred to another reactor, optionally after a storage time, then the polymerization of the PVDF is started.
• said binder is prepared by polymerization of PTFE in the presence of a seed of PVDF.
• water is added to obtain a dry extract ranging from 10 to 50%, to which tetrafluoroethylene and a polymerization initiator are added.
• a stable latex is obtained, the particle size of which is in the range 200 to 400 nm (Dv50).
• the PVDF:PTFE mass composition of this latex varies from 10:90 to 90:10.
• the solid content obtained is between 10 and 60%.
• the PVDF latex is obtained in a first reactor, it is transferred to another reactor, optionally after a storage time, then the polymerization of the PTFE is started.
• Another object of the invention is a Li-ion battery electrode comprising an active charge for the anode or cathode, an electronically conductive charge, and a fluorinated polymer binder as described above.
• the PTFE is fibrillated.
• the extent of fibrillation and the quality of fibrils formed influence certain properties of the electrode, such as its flexibility and manipulability.
• the fibrils are visible by scanning electron microscopy (SEM).
• the active materials at the negative electrode are generally lithium metal, graphite, graphene, silicon/carbon composites, silicon, fluorinated graphites of CL X type with x between 0 and 1 and LiTisOn type titanates.
• the active materials at the positive electrode are generally of the L1MO2 type, of the L1MPO4 type, of the L12MPO3P type, of the LUMSiCL type where M is Co, Ni, Mn, Le or a combination of these, of the LiM C ⁇ type, of the Sx, and lithium polysulfides represented by the formula LUSn with n >1.
• the conductive fillers are chosen from carbon blacks, graphites, natural or synthetic, carbon fibers, carbon nanotubes, metal fibers and powders, and conductive metal oxides. Preferably, they are chosen from carbon blacks, graphites, natural or synthetic, carbon fibers and carbon nanotubes.
• a mixture of these conductive fillers can also be produced.
• the use of carbon nanotubes in combination with another conductive filler such as carbon black can have the advantages of reducing the rate of conductive fillers in the electrode and of reducing the rate of polymer binder due to a lower specific surface compared to carbon black.
• a polymeric dispersant which is distinct from said binder, is used mixed with the conductive filler to disaggregate the agglomerates present and to help its dispersion in the final formulation with the polymeric binder and the active filler.
• the polymeric dispersant is chosen from poly(vinyl pyrrolidone), poly(phenyl acetylene), poly(meta-phenylene vinylidene), polypyrrole, poly(para-phenylene benzobisoxazole, poly(vinyl alcohol), and mixtures thereof.
• the mass composition of the electrode is:
• At least one additive chosen from the list: plasticizer, ionic liquid, dispersing agent for conductive fillers, and flow agent for the formulation, the sum of all these percentages being 100%.
• the invention also relates to a solvent-free method of manufacturing a Li-ion battery electrode, said method comprising the following steps:
• thermo- consolidation of said electrode by heat treatment (application of a temperature up to 50°C above the melting point of the polymer, without mechanical pressure), and/or thermo-mechanical treatment such as calendering or thermo-compression.
• solventless process means a process that does not require a residual solvent evaporation step downstream of the deposition step.
• thermo-mechanical process such as extrusion, calendering or thermo-compression
• the metallic supports of the electrodes are generally aluminum for the cathode and copper for the anode.
• Metallic supports can be surface treated and have a conductive primer with a thickness of 5 ⁇ m or more.
• the supports can also be wovens or nonwovens made of carbon fiber.
• Said electrode is consolidated by heat treatment by passing it through an oven, under an infrared radiation lamp, in a calender with heated rollers or in a press with heated platens.
• Another alternative is a two-step process.
• the electrode undergoes heat treatment in an oven, under an infrared radiation lamp or in contact with pressureless heating plates. Then a compression stage at room temperature or hot is carried out using a calender or a plate press. This step makes it possible to adjust the porosity of the electrode and to improve the adhesion on the metallic substrate.
• the invention also relates to a Li-ion battery electrode manufactured by the method described above.
• said electrode is an anode.
• said electrode is a cathode.
• Another object of the invention is a Li-ion secondary battery comprising a negative electrode, a positive electrode and a separator, in which at least one electrode is as described above.
• Another object of the invention is a supercapacitor comprising at least one such electrode.
• the latex of sample 1 is then dried by atomization and makes it possible to obtain a powder of PTFE.
• a reactor water, an initiator, a chain transfer agent, a non-fluorinated emulsifier and vinylidene fluoride are introduced.
• the polymerization is carried out at a temperature of 85° C. and under a pressure of 9000 kPa. After 180 min a latex containing 37% solid content is obtained.
• the size of the primary particle is 225 nm (D50).
• the latex corresponding to sample 3 is dried by atomization and makes it possible to obtain a PVDF powder
• Sample 5 Preparation of a mixture of PVDF and PTFE powders
• 750 g of PTFE powder corresponding to sample 2 and 250 g of PVDF powder corresponding to sample 2 are introduced.
• Stirring is done for 2 min at a speed of rotation such that the speed at the end of the blades is 20 ms 1 .
• Sample 6 Preparation of a PTFE/PVDF composite binder by coatomization
• An antifoam product (Byk 019) is also added. The addition is made with moderate stirring in a container at 5 (10 rpm) and at room temperature 20°C. The aqueous dispersion obtained is easily pumpable).
• the PTFE latex/PVDF latex mixture thus prepared is then pumped with moderate stirring (10 rpm) and then coatomized using the following operating conditions:
• Coatomizer inlet temperature 175°C
• Coatomizer outlet temperature 55°C
• Compressed air 220 kPa
• the coatomization of the PVDF latex particles and the PTFE particles allows the preparation of 400 g of PVDF/PTFE composite powder.
• This composite powder contains 25% by mass of PVDF and 75% by weight of PTFE.
• the size of the secondary particles thus formed is 23 ⁇ m (D50).
• Sample 7 Preparation of a core-shell structure, PTFE core/PVDF shell Water, an initiator, a chain transfer agent, a non-fluorinated emulsifier and ethylene tetrafluoride are introduced into a reactor.
• the polymerization is carried out at a temperature of 68° C. and under a pressure of 3000 kPa.
• the total reaction volume is 2 1.
• the latex thus obtained is then reduced to a dry extract of 20% by adding water (900 g).
• the temperature is then increased to 90°C and the pressure is increased to 4500 kPa by continuously adding VF2 to the reactor.
• Adding potassium persulfate initiator starts the polymerization of a PVDF shell around the PTFE core. After 60 minutes of polymerization, a stable latex is obtained, the particle size of which is 280 nm (D50). The mass composition is 75% PTFE and 25% PVDF. The solid content obtained is 25%. The total amount consumed of 193 g of VF2.
• Sample 8 Preparation of a core-shell structure, PVDF core / PTFE shell Water, an initiator, a chain transfer agent, a non-fluorinated emulsifier and PVDF are introduced into a reactor.
• the polymerization is carried out at a temperature of 90° C. and under a pressure of 4500 kPa.
• the total reaction volume is 21.
• a latex containing 37% solids content is obtained, with a primary particle size D50 of 225 nm.
• the latex thus obtained is then reduced to a dry extract of 15% by adding water (2933 g).
• the temperature is then reduced to 70°C and the pressure is reduced to 3000 kPa by continuously adding TFE to the reactor.
• Adding potassium persulfate initiator starts the polymerization of a PTFE shell around the PVDF core. After 200 minutes of polymerization, a stable latex is obtained, the particle size of which is 338 nm (D50). The mass composition is 75% PTFE and 25% PVDF. The solid content obtained is 37.5%.
• Electrode formulation active material, conductive filler such as carbon black (but also graphene, carbon nanotubes, carbon fibers obtained by growth in the vapor phase (VGCF)), and PVDF binder.
• conductive filler such as carbon black (but also graphene, carbon nanotubes, carbon fibers obtained by growth in the vapor phase (VGCF))
• PVDF binder PVDF binder
• the active material binder/conductive filler mixture is produced in two stages. First, an active filler is mixed with a conductive filler by a solvent-free process. In a second step, the binder is mixed with the active filler and the pre-mixed conductive filler. As a process for mixing the various constituents of the formulation without solvent, a mixer with fast blades of the Henschel FM10 type was used for 2 minutes at a speed of rotation such that the speed at the end of the blades is 20 ms 1 .
• the composition is then prepared in the form of a self-supporting film by compression using a heated parallel platen press.
• the formulation is deposited on a silicone film so as to obtain a basis weight of 25 mg/cm 2 .
• a second film of silicone paper is deposited on the surface of the deposit.
• the assembly consisting of the first layer of silicone paper, the formulation and the second layer of silicone paper is then compressed at 200° C. under 700 kPa for 5 minutes. After the compression step, the assembly is removed from the press and left to cool to room temperature.
• a self-supporting film is obtained after removing the layers of silicone paper.
• the self-supported film is compressed on the aluminum current collector under the same conditions as the production of the self-supported film.
• the preparation conditions of the films and the final cathode were adjusted to obtain a thickness of 75 ⁇ m, and a porosity of 32-34% calculated indirectly according to the surface weight on the theoretical weight per unit surface.
• An elongation at break test is carried out on the film and a classification is carried out to determine its handling.
• the classification varies from HO (immediate rupture) to H3 (elongation at rupture greater than 3%).
• the peel force is determined by pulling at a speed of the order of 100 to 200 mm/min. This makes it possible to establish the following classification - the values are indicative, as they depend on the measuring device, the peel force, the peel speed and the adhesive supplier.
• the classification ranges from AO (no adhesion) to A4 (excellent adhesion).
• Test specimens 5cm long and at least 2cm wide are cut from the 5 electrodes. These specimens are then rolled up around a metal bar of imm in diameter or folded on themselves. The surface is then visually observed to identify any cracks and establish the following classification

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• Manufacturing & Machinery (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Electric Double-Layer Capacitors Or The Like (AREA)

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• 2021
  • 2021-05-03 FR FR2104641A patent/FR3122528B1/fr active Active
• 2022
  • 2022-04-28 TW TW111116263A patent/TW202247513A/zh unknown
  • 2022-05-02 JP JP2023567978A patent/JP2024519717A/ja active Pending
  • 2022-05-02 US US18/558,551 patent/US20240222635A1/en active Pending
  • 2022-05-02 CN CN202280032432.3A patent/CN117280484A/zh active Pending
  • 2022-05-02 EP EP22727960.1A patent/EP4334983A1/fr active Pending
  • 2022-05-02 WO PCT/FR2022/050845 patent/WO2022234227A1/fr not_active Ceased
  • 2022-05-02 KR KR1020237040966A patent/KR20240004687A/ko active Pending

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