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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • 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
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D185/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon; Coating compositions based on derivatives of such polymers
  • C09D185/02—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon; Coating compositions based on derivatives of such polymers containing phosphorus
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/002—Priming paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J185/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon; Adhesives based on derivatives of such polymers
  • C09J185/02—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon; Adhesives based on derivatives of such polymers containing phosphorus
• • 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
• • 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
  • H01M4/043—Processes of manufacture in general involving compressing or compaction
• • 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
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
  • H01M4/40—Alloys based on alkali metals
  • H01M4/405—Alloys based on lithium
• • 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
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
  • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• • 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
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
  • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
• • 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
• • 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
• • 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
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/665—Composites
  • H01M4/667—Composites in the form of layers, e.g. coatings
• • 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 relates to a primer that improves the adhesiveness between a composition comprising an electro active material and a current collector, and to an electrode comprising the same.
• An electrochemical cell typically comprises a cathode and an anode, collectively referred to as electrodes.
• electro active materials are deposited onto a conductive support, acting as current collector for the electrode. Maintaining an efficient electrical contact between the electro active material and the conductive support is necessary for the functioning of the electrochemical cell.
• Such electrical contact can be provided, for example, via the use of at least one primer, which is deposited between the electro active material and the conductive support.
• Primers suitable for the manufacture of electrodes have been disclosed for example in WO 2009/054987 (Sion Power Corporation).
• EP 2639863 discloses a positive electrode for secondary cell comprising a current collector, which is comprised of aluminium or an aluminium alloy, and a positive electrode active material layer, wherein the positive electrode active material layer contains a positive electrode active material, a water-based binder, an organic phosphonic acid compound, and a polyvalent metal compound.
• a copolymer [copolymer (A)] obtained by radical polymerization of at least one phosphorus-containing unsaturated monomer with acrylic acid and/or methacrylic acid can be advantageously used as primer to provide an outstanding adhesion between the electro active material and the current collector of a cathode.
• the present invention relates to an electrode [electrode (E)] comprising:
• composition comprising at least one electrode active material [compound (AM)] and at least one binder [binder (B)].
• Said electrode (E) can be either a cathode (positive electrode) or an anode (negative electrode).
• said electrode (E) is a cathode (positive electrode).
• the present invention relates to a method for manufacturing an electrode (E) as defined above, said method comprising: step (1) of providing a metal substrate having at least one surface; step (1b) of surface treatment of said at least one surface of said metal substrate to provide a surface-modified metal substrate having at least one side that is at least partially chemically modified; step (2) of contacting at least one copolymer (A) with said at least one surface of said metal substrate, thus providing a first layer; step (3) contacting an electrode-forming composition [composition (CE)] comprising at least one electrode active material [compound (AM)], at least one binder [binder (B)] and at least one solvent [solvent (S)] with said first layer.
• composition (CE) comprising at least one electrode active material [compound (AM)], at least one binder [binder (B)] and at least one solvent [solvent (S)] with said first layer.
• the present invention relates to an electrochemical device, preferably a secondary battery, comprising a positive electrode and a negative electrode, wherein at least one of said positive electrode and said negative electrode is the electrode (E) as defined above.
• the present invention relates to the use of said copolymer (A) as a primer in a current collector of an electrochemical device.
• electro-active material is intended to denote a compound which is able to incorporate or insert into its structure and substantially release therefrom alkaline or alkaline-earth metal ions during the charging phase and the discharging phase of an electrochemical device.
• the compound (AM) is preferably able to incorporate or insert and release lithium ions;
• secondary battery is intended to denote a rechargeable battery
• cathode and “positive electrode” are used as synonyms;
• the nature of said metal substrate depends on whether the final electrode thereby provided is a positive electrode or a negative electrode.
• the metal substrate comprises, preferably consists of, at least one metal selected from the group consisting of aluminium (Al), nickel (Ni), titanium (Ti), and alloys thereof. Aluminium being preferred.
• the metal substrate comprises, preferably consists of, silicon (Si) or at least one metal selected from the group consisting of lithium (Li), sodium (Na), zinc (Zn), magnesium (Mg), copper (Cu) and alloys thereof. Copper being preferred.
• said copolymer (A) is obtained by radical polymerization of:
• copolymer (A) has a molecular weight of at least 7,500 Da, more preferably from 10 kDa to 1500 kDa, even more preferably from 10 kDa to 150 kDa, notably between 10 kDa and 100 kDa.
• said copolymer (A) is obtained by radical copolymerization of the phosphorus-containing unsaturated monomer of formula (b) above with acrylic acid.
• the phosphorus-containing unsaturated monomer of formula (b) and the acrylic acid are in a molar ratio from 40:60 to 20:80, preferably 35:65 to 25:75 and even more preferably 30:70.
• copolymer (A) has a molecular weight of from 25 kDa to 85 kDa.
• said copolymer (A) is obtained by radical copolymerization of a mixture of 2-hydroxyethyl methacrylate phosphate, complying with formula (a) above wherein n is 1 and 2, with acrylic acid and methacrylic acid.
• said copolymer (A) is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of acrylic acid, methacrylic acid and 2-hydroxyethyl methacrylate phosphates of Formula (a):
• - acrylic acid from 65 to 90%, preferably from 80 to 90%, more preferably 83-85%,
• - methacrylic acid from 5 to 30%, preferably from 5 to 15%, more preferably 11-13%,
• - 2-hydroxyethyl methacrylate phosphates from 2 to 12%, preferably from 2 to 10%, more preferably from 2 to 6% and even more preferably about 4%.
• copolymer (A) has a molecular weight of from 15 kDa to 35 kDa.
• Average molecular weights are measured by Size Exclusion Chromatography (SEC).
• said first layer comprising compound (A) has a thickness below 1 pm.
• composition (CEA) depends on whether said composition is used in the manufacture of a positive electrode [electrode (Ep)] or a negative electrode [electrode (En)].
• the compound (AM) may comprise a composite metal chalcogenide of formula LiMQ2, wherein M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr and V or a metal such as Al and a mixture of thereof and Q is a chalcogen such as O or S.
• M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr and V or a metal such as Al and a mixture of thereof and Q is a chalcogen such as O or S.
• M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr and V or a metal such as Al and a mixture of thereof and Q is a chalcogen such as O or S.
• M is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr and V or a metal such as Al and a mixture of thereof
• Q is a chalcogen such as O or S.
• the compound (AM) may comprise a lithiated or partially lithiated transition metal oxyanion-based electro-active material of formula M1 M2(JO4)fE1-f, wherein M1 is lithium, which may be partially substituted by another alkali metal representing less than 20% of the M1 metals, M2 is a transition metal at the oxidation level of +2 selected from Fe, Mn, Ni or mixtures thereof, which may be partially substituted by one or more additional metals at oxidation levels between +1 and +5 and representing less than 35% of the M2 metals, including 0, JO4 is any oxyanion wherein J is either P, S, V, Si, Nb, Mo or a combination thereof, E is a fluoride, hydroxide or chloride anion, f is the molar fraction of the JO4 oxyanion, generally comprised between 0.75 and 1.
• the M1 M2(JO4)fE1 -f electro-active material as defined above is preferably phosphate-based and may have an ordered or modified olivine structure.
• the compound (AM) in the case of forming a positive electrode (Ep) has formula Li3-xM’yM”2-y(JO4)3 wherein 0 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 2, M’ and M” are the same or different metals, at least one of which being a transition metal, JO4 is preferably PO4 which may be partially substituted with another oxyanion, wherein J is either S, V, Si, Nb, Mo or a combination thereof.
• the compound (AM) is a phosphate-based electro-active material of formula Li(FexMn1-x)PO4 wherein 0 ⁇ x ⁇ 1 , wherein x is preferably 1 (that is to say, lithium iron phosphate of formula LiFePO4).
• the compound (AM) may preferably comprise:
• Lithium typically existing in forms such as powders, flakes, fibers or spheres (for example, mesocarbon microbeads) hosting Lithium;
• Lithium alloy compositions including notably those described in US 6203944 (3M INNOVATIVE PROPERTIES CO.) and/or in WO 00/03444 (MINNESOTA MINING AND MANUFACTURING CO );
• Lithium titanates generally represented by formula Li4TisOi2; these compounds are generally considered as “zero-strain” insertion materials, having low level of physical expansion upon taking up the mobile ions, i.e. Li + ;
• - Lithium-silicon alloys generally known as Lithium silicides with high Li/Si ratios, in particular Lithium silicides of formula Li ⁇ Si;
• Li ⁇ Ge Li ⁇ Ge
• the carbon-based material may be, for example, graphite, such as natural or artificial graphite, graphene, carbon black or mixtures thereof.
• the carbon-based material is preferably graphite.
• the silicon-based compound may be one or more selected from the group consisting of chlorosilane, alkoxysilane, aminosilane, fluoroalkylsilane, silicon, silicon chloride, silicon carbide and silicon oxide. More particularly, the silicon-based compound may be silicon oxide or silicon carbide.
• the at least one silicon-based compound is comprised in the compound (AM) in an amount ranging from 1 to 30 % by weight, preferably from 5 to 20 % by weight with respect to the total weight of the compound (AM).
• said binder (B) is selected from aqueous solutions of polyacrylic acid (PAA), carboxymethyl cellulose with styrene butadiene (CMC-SBR).
• PAA polyacrylic acid
• CMC-SBR carboxymethyl cellulose with styrene butadiene
• said binder (B) is selected from semi-crystalline polymers or elastomers. Semi-crystalline polymers being more preferred.
• the term “semi-crystalline” means a fluoropolymer that has, besides the glass transition temperature Tg, at least one crystalline melting point on DSC analysis.
• a semi-crystalline fluoropolymer is hereby intended to denote a fluoropolymer having a heat of fusion determined according to ASTM D 3418 of advantageously at least 0.4 J/g, preferably of at least 0.5 J/g, more preferably of at least 1 J/g.
• the term "elastomer” is intended to designate a true elastomer or a polymer resin serving as a base constituent for obtaining a true elastomer.
• True elastomers are defined by the ASTM, Special Technical Bulletin, No. 184 standard as materials capable of being stretched, at room temperature, to twice their intrinsic length and which, once they have been released after holding them under tension for 5 minutes, return to within 10 % of their initial length in the same time.
• the intrinsic viscosity of copolymer (A), measured in dimethylformamide at 25 °C, is comprised between 0.05 l/g and 0.60 l/g, more preferably between 0.15 l/g and 0.50 l/g even more preferably between 0.20 l/g and 0.45 l/g.
• the copolymer (A) of the present invention usually has a melting temperature (Tm) in the range from 120 to 200°C.
• the melting temperature may be determined from a DSC curve obtained by differential scanning calorimetry (hereinafter, also referred to as DSC).
• DSC differential scanning calorimetry
• Tm melting temperature
• said binder (B) is selected from VDF-based polymers, more preferably VDF homopolymer or a copolymer of VDF with at least one (per)fluorinated monomer different from VDF and/or at least one (meth)acrylic monomer.
• Non limitative examples of suitable (per)fluorinated monomers different from VDF are notably:
• C2-C8 partially or fully fluorinated olefins, such as tetrafluoroethylene (TFE), hexafluoropropylene (HFP), pentafluoropropylene and hexafluoroisobutylene;
• TFE tetrafluoroethylene
• HFP hexafluoropropylene
• CH2 CH-Rf, wherein Rf is a C-i-Ce perfluoroalkyl group
• C2-C8 chloro and/or bromo and/or iodo-fluoroolefins such as chlorotrifluoroethylene (CTFE);
• (d) (per)fluoroalkylvinylethers (PAVE) of formula CF2 CFORf, wherein Rf is a C-i-Ce (per)fluoroalkyl group, e.g. CF3, C2F5, C3F7.
• said at least one (meth)acrylic monomer complies with the following formula: wherein each of R1 , R2, R3, equal or different from each other, is independently a hydrogen atom or a C1-C3 hydrocarbon group, and
• ROH is a hydrogen atom or a C1-C5 hydrocarbon moiety comprising at least one hydroxyl group.
• binder (B) is selected from the group comprising: VDF homopolymer and copolymer of VDF with at least one (meth)acrylic monomer as defined above.
• Suitable binders (B) are commercially available for example from Solvay Specialty Polymers under the trade name Solef (R) PVDF.
• said step (1b) of surface treatment comprises any surface treatment applied at least partly on the surface, wherein the surface treatments are selected from the group consisting of chemical modification, chemical etching, electrochemical etching, electrodeposition, chemically oxidized processes, coating, corona discharge.
• chemical etching can effectively roughen the surface of current collectors, which is favourable for improving adhesion and interfacial conductivity between electrodes and current collectors.
• Chemical modification can suitably be obtained by treatment with chemicals such as acids.
• Coating is another effective way to modify the surface of the metal substrate to achieve better performance in terms of enhanced electronic conductivity, adhesion towards the electrode and reduction of the corrosion. Reducing the corrosion is expected to improve the general performance of the battery by improving the good contact with the paste of the electrode by improving the electronic conductivity.
• Good results have been obtained by performing said step (1b) via chemical etching, more preferably by contacting said at least one surface of said metal substrate in an acid solution, preferably nitric acid solution.
• said step of contact is performed by dipping said at least one surface into said acid solution.
• said contacting step can be performed by applying said acid solution onto at least one part of said at least one surface of said metal substrate.
• said area of said at least one surface of said metal surface subjected to etching can comprise the whole surface or at least a part of said surface.
• step (1b) and before step (2) at least one step of cleaning and/or rinsing said at least one surface of said metal substrate is/are performed.
• said step of cleaning is performed with an organic solvent. More preferably, acetone.
• said step of rinsing is performed with water.
• said step (2) is performed by techniques known in the art, for example dip coating, spray coating, and the like.
• step (2) Preferably, after said step (2) and before step (3), at least one step of rinsing is performed.
• said step (3) is performed by contacting an electrode-forming composition [composition (CE)] to said first layer.
• said composition (CE) comprises at least one electroactive material [compound (AM)] as defined above, at least one binder (B) as defined above and at least one solvent [solvent (S)].
• the solvent (S) may preferably be an organic polar one, examples of which may include: N-methyl-2-pyrrolidone (NPM), N,N- dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphamide, dioxane, tetrahydrofuran, tetramethylurea, triethyl phosphate, trimethyl phosphate and mixtures thereof; and isobutylnitrile, isobutyl-butyrate, dibutylether, methyl isobutyl ketone, dibutyl carbonate, tert-butyl acetoacetate.
• NPM N-methyl-2-pyrrolidone
• N,N- dimethylformamide N,N-dimethylacetamide
• dimethylsulfoxide hexamethylphosphamide
• dioxane tetrahydrofuran
• tetramethylurea triethyl
• step (3) at least one step of drying is performed.
• step of drying is performed at a temperature from 50°C to 150°C and/or for a time from 30 seconds to 30 minutes.
• the solvent to be evaporated is water.
• a step of compression can be performed, for example via a calendaring process. This additional step is useful to achieve the target porosity and density of the final electrode (E) of the invention.
• said step of compression can be performed by hot pressing, at a temperature from 25°C and 130°C.
• composition directly adhered onto he first layer corresponds to the electrode-forming composition, also referred to as composition (CE), wherein the solvent has been at least partially removed during the manufacturing process of the electrode, for example in the step of drying as disclosed herein above and/or in the subsequent compression step.
• the secondary battery of the invention is preferably an alkaline or an alkaline-earth metal secondary battery.
• the secondary battery of the invention is more preferably a Lithium-ion secondary battery.
• the electrochemical device according to the present invention being preferably a secondary battery, comprises: a positive electrode, a negative electrode and a separator interposed between said positive electrode and said negative electrode, wherein at least one of the positive electrode and the negative electrode is the electrode (E) of the present invention.
• An electrochemical device according to the present invention can be prepared by standard methods known to a person skilled in the art.
• LCO-based cathode slurry was prepared as follows. Solef (R) 5130 was dissolved at 6 wt.% in NMP. Once the dissolution was complete, LCO as active material and carbon additive SC65 (both in powder form) were added to the polymer solution. The relative amounts of the components [LCO:binder:SC65], as wt.%, are 97:1 :2. The total solid content of the slurry was set at 75%.
• the dying step consisted of 50 minutes at 90°C in a vacuum oven, with the first 25 minutes in dynamic vacuum and the last 25 minutes in static vacuum.
• Each of said Al current collectors was subjected to etching with 5 wt.% HNO3 solution, for 4 minutes at 40°C. A suitable amount of a LCO-based cathode slurry was casted onto each of said collectors and then drying was performed. Peeling test was performed as disclosed below. The average results are reported in Table 1 .
• Al current collectors were prepared according to the present invention. Each of said Al current collectors was subjected to etching with 5 wt.% HNO3 solution, for 4 minutes at 40°C.
• Copolymer (A)-1 random copolymer obtained from copolymerization of a mixture of acrylic acid and vinyl phosphoric acid, in a molar ratio 70:30.
• Copolymer (A)-1 had a weight average molecular weight (Mw) in the range from about 30 to 80 kDa, as measured by GPC using the following conditions:
• SEC was eguipped with a MultiAngle Laser Light Scattering (MALLS) Mini Dawn TREOS detector and an Agilent concentration detector (Rl detector).
• MALLS MultiAngle Laser Light Scattering
• Rl detector Agilent concentration detector
• Absolute molar masses were obtained with the dn/dC of the poly(acrylic acid) egual to 0.1875 mL/g.
• As detector the following was used: Rl (Agilent concentration detector) + MALLS (MultiAngle Laser Light Scattering) Mini Dawn TREOS.
• Copolymer (A)-2 random copolymer obtained from copolymerization of a mixture of acrylic acid, methacrylic acid, and 2-hydroxyethy methacrylate phosphates of Formula (a), in a molar ratio of about 83:13:4.
• Copolymer (A)-2 had a Mw in the range from about 20 to 30 kDa, measured by SEC chromatography using the following conditions:
• SEC was equipped with a MultiAngle Laser Light Scattering (MALLS) Mini Dawn TREOS detector and an Agilent concentration detector (Rl detector).
• MALLS MultiAngle Laser Light Scattering
• Rl detector Agilent concentration detector
• the SEC-MALLS system run on three columns Varian Aquagel OH mixed H, 8 pm, 3*30 cm at a flow rate of 1 mL / min and with the following mobile phase: 85 % water, 100mM NaCI, 25mM NaH2PO4, 25Mm Na2HPO4 - 15% methanol.
• Polymer samples were diluted down to 0.5 active wt% in the mobile phase for at least 4 hours then filtered in a Millipore filter 0.45 pm and 100 microliters were injected in the mobile phase flow. Absolute molar masses were obtained with the dn/dC of the poly(acrylic acid) equal to 0.1875 mL/g.
• the dipping was performed for 2 minutes at 45°C. Then, rinsing was then performed, followed by drying for 5 minutes starting from room temperature up to 100°C. A suitable amount of a standard LCO-based cathode slurry was casted on each treated Al current collector and then drying was performed.
• Collectors (A) were obtained using copolymer (A)-1 and collectors (B) were obtained using copolymer (A)-2 above defined.
• Peeling test was performed as disclosed below. The average results are reported in Table 1 .
• the coefficient of variation was also calculated as the ratio between the average load and the standard deviation.

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