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
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  • 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
  • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
• • H—ELECTRICITY
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  • 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
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  • 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
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
  • H01M10/0562—Solid materials
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  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
• • 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
  • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
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  • 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
  • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
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  • 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
  • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
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  • 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
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  • 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
  • H01M4/625—Carbon or graphite
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
  • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
• • 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
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/44—Methods for charging or discharging
• • H—ELECTRICITY
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  • 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
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  • 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
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  • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/0065—Solid electrolytes
  • H01M2300/0068—Solid electrolytes inorganic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0088—Composites
  • H01M2300/0094—Composites in the form of layered products, e.g. 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
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0421—Methods of deposition of the material involving vapour deposition
  • H01M4/0423—Physical vapour deposition
• • 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
  • H01M4/0421—Methods of deposition of the material involving vapour deposition
  • H01M4/0428—Chemical vapour deposition
• • 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 the field of energy storage, and more specifically to accumulators, in particular of the lithium type.
• Rechargeable lithium-ion batteries indeed offer excellent energy and volume densities and today occupy a prominent place in the market for portable electronics, electric and hybrid vehicles and stationary energy storage systems.
• the electrode negative or positive, generally consists of a conductive support used as a current collector coated with a layer containing an active material and generally in addition a binder and an electronically conductive material.
• Solid electrolytes also offer a significant improvement in terms of safety as they present a much lower risk of flammability than liquid electrolytes.
• the solid sulphide electrolytes reach sufficient maturity to envisage their industrial use.
• Their high values of ionic conductivity associated with their ductility and limited density make them serious candidates for new generations of all-solid-state batteries that can compete with the energy densities of current Li-ion batteries with liquid electrolytes.
• Solid sulfide electrolytes cause electrode deterioration problems.
• Highly reactive, sulphide electrolytes react with the materials constituting the electrodes, in particular with the active material and the carbonaceous material. This deterioration of the electrodes then results in a decrease in the performance of the electrochemical cell as it operates.
• the active material of the electrode is protected.
• the other constituents of the electrode, in particular the electronically conductive material are always in direct contact with the electrolyte and continue to deteriorate during the operation of the electrochemical cell
• one of the aims of the invention is to solve these objectives by providing an electrode covered, over all or part of its surface, with a coating layer of an electronically insulating and ionic conductor material.
• the layer of electronic insulating and ionic conductor material makes it possible to limit and / or prevent the reactions that may occur between the materials of the electrode and the sulphide electrolyte, while making it possible to maintain good electrochemical performance.
• the Applicant has also discovered that the presence of a layer of electronic insulating and ionic conductor material makes it possible to widen the accessible potential window. Applied to the surface of the positive electrode (cathode), the layer of electronic insulating material and ionic conductor lowers the value of the accessible potentials. Applied to the surface of the negative electrode (anode), the layer of electronic insulating material and ionic conductor increases the value of the accessible potentials.
• the invention relates firstly to an electrode which can be used in an energy storage device comprising at least one active material and at least one carbonaceous electronic material, said electrode being covered, over all or part of its surface, with a layer coating in an electronically insulating and ionic conductor material, said electrode being such that A1 ⁇ 6 and A2> 10, with: e / where: e represents the thickness of the coating layer (in m), s ⁇ represents the ionic conductivity of the electronic insulating material and ionic conductor (in S.nr 1 ),
• S represents the ratio of the area developed by the active material to the total area of the electrode (in m 2 of active material per cm 2 of electrode), ae represents the electronic conductivity of the electronic insulating material and ionic conductor (in S.nr 1 ), and
• said electrode is such that A1 ⁇ 6 and A2> 10, with: e represents the thickness of the coating layer (in m), a ⁇ represents the ionic conductivity, measured at 25 ° C, of the electronic insulating material and ionic conductor (in S.nr 1 ),
• S represents the ratio of the area developed by the active material over the total area of the electrode (in m 2 of active material per cm 2 of electrode), ae represents the electronic conductivity, measured at 25 ° C, electronic insulating material and ionic conductor (in S.nr 1 ), and
• the electronic insulating and ionic conductor material has an electronic conductivity, measured at 25 ° C., less than or equal to 10 _1 ° S.nr 1 , preferably less than or equal to 10 -12 S.nr 1 .
• the electronically insulating and ionic conductor material exhibits an ionic conductivity, measured at 25 ° C., greater than or equal to 10 8 S.nr 1 , preferably greater than or equal to 10 6 S.nr 1 .
• the electronically insulating and ionic conductor material is chosen from halides, oxides, phosphates, sulfides, polymers and any one of their mixtures.
• the electronically insulating and ionic conductor material has an electronic conductivity less than or equal to 10 _1 ° S.nr 1 , preferably less than or equal to 10 -12 S.nr 1 .
• the electronically insulating and ionic conductor material has an ionic conductivity greater than or equal to 10 -8 S.nr 1 , preferably greater than or equal to 10 -6 S.nr 1 .
• the electronically insulating and ionic conductive material has an electronic conductivity, measured at 25 ° C., less than or equal to 10 10 S.nr 1 , preferably less than or equal to 10 -12 S.nr 1 .
• the electronically insulating and ionic conductor material exhibits an ionic conductivity, measured at 25 ° C., greater than or equal to 10 8 S.nr 1 , preferably greater than or equal to 10 6 S.nr 1 .
• the electronic insulating and ionic conductor material is chosen from halides, oxides, phosphates, sulfides, polymers and any of their mixtures.
• the thickness of the coating layer is 2 to 50nm, preferably 5 to 10nm
• the coating layer covers at least 50% of the surface of the electrode, preferably at least 75%, more preferably at least 90%, even more preferably at least 95%.
• the electrode is porous and at least part of the pores of the electrode is at least partially filled with a solid electrolytic material, preferably a sulfur-containing solid electrolytic material.
• the electrode coated with the coating layer is porous and at least part of the pores of the coated electrode is at least partially filled with a solid electrolytic material, preferably a sulfur-containing solid electrolytic material.
• the invention also relates to a method of manufacturing an electrode as defined above, and in detail below, this method comprising: a) providing an electrode, b) depositing mainly or part of the surface of the electrode of a coating layer as defined above, and in detail below, c) optionally, the deposition by infiltration in at least part of the pores of the coating layer of a solid electrolytic material, preferably of a sulfur-containing solid electrolytic material, and d) optionally, a treatment allowing the solidification of the electrolyte, in particular by heat treatment or by ultraviolet radiation.
• the subject of the invention is also an electrochemical element comprising a stack between two electronically conductive current collectors, said stack comprising:
• a layer comprising a solid electrolytic composition separating said positive electrode and said negative electrode, the electrolytic composition comprising at least one solid electrolytic compound, preferably chosen from solid electrolytic sulfur compounds and polymers;
• Said element being characterized in that at least one of said positive electrode and said negative electrode is as defined above, and in detail below.
• both said positive electrode and said negative electrode are covered, over all or part of their surface, with a coating layer, identical or different, as defined above. above and in detail below.
• the invention further relates to a method of manufacturing an electrochemical element as defined above and in detail below, this method comprising: i) providing a positive electrode and a negative electrode, 'at least one of said positive electrode and of said negative electrode being as defined above, and in detail below, or having been obtained by implementing the method described above, in detail below - below, and ii) forming, between said positive electrode and said negative electrode, a layer comprising a solid electrolytic composition.
• the invention further relates to an electrochemical module comprising the stack of at least two elements as defined above and in detail below, each element being electrically connected with one or more other element (s). .
• the invention relates to a battery comprising one or more module (s) as defined above and in detail below. Detailed description of the invention
• the invention relates first of all to an electrode that can be used in an energy storage device, said electrode being covered, especially or part of its surface, with a coating layer of an electronically insulating and ionic conductor material.
• An electrode according to the invention typically comprises a current collector on which is deposited an electrode material.
• electrode material is meant within the meaning of the invention a mixture comprising at least one active material, cathodic or anode depending on the nature of the electrode considered, at least one carbonaceous electronic material and optionally a binder.
• the electrode according to the invention can be a positive electrode (also called a cathode) or a negative electrode (also called an anode).
• positive electrode designates the electrode where electrons enter, and where cations (Li + ) arrive in discharge.
• negative electrode designates the electrode from which the electrons leave, and from which the cations (Li + ) are released in discharge
• the electrode according to the invention is a negative electrode.
• the positive electrode can be of any known type.
• the cathode typically consists of a conductive support used as a current collector on which is deposited the cathodic active material and a carbonaceous electronic material.
• a binder can also be incorporated into the mixture.
• the cathodic active material is not particularly limited. It can be chosen from the following groups or their mixtures:
• M 'and M being different from each other, and 1 £ x £ 1.4; 0 £ y £ 0.6; 0 £ z £ 0.2; - a compound (c) of formula Li x Fei-yM y P0 4 (LFMP) where M is chosen from the group consisting of B, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb and Mo; and £ 0.8 x £ 1.2; 0 £ y £ 0.6;
• M represents at least one element chosen from the group consisting of Na, K, Mg, Ca, B, Sc, Ti, V, Cr , Mn, Fe, Co, Ni, Cu, Zn, Al, Y, Zr, Nb, Mo, Ru, Ag, Sn, Sb, Ta, W, Bi, La, Pr, Eu, Nd and Sm and where 0 ⁇ x ⁇ 0.5 and 0 ⁇ y ⁇ 1.
• the current collector is preferably a two-dimensional conductive support such as a solid or perforated strip, made of carbon or of metal, for example of nickel, of steel, of stainless steel or of aluminum, preferably aluminum.
• the current collector can be coated on one or both sides with a carbon layer.
• the negative electrode can be of any known type.
• the anode typically consists of a conductive support used as a current collector on which is deposited the anode active material and a carbonaceous electronic material.
• a binder can also be incorporated into the mixture.
• a negative electrode is also present (generally initially limited to the single current collector).
• the anodic active material is not particularly limited. It can be chosen from the following groups and their mixtures:
• M and M' each represent at least one element selected from the group consisting of Li, Na, K, Mg, Ca, B, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Y, Zr, Nb, Mo, Ru, Ag, Sn, Sb, Ta, W, Bi, La, Pr, Eu, Nd and Sm;
• X represents at least one element selected from the group consisting of S, F, Cl and Br.
• the d index represents an oxygen deficiency.
• the index d can be less than or equal to 0.5.
• Said at least one oxide of titanium and niobium can be chosen from TiNb 2 0, Ti2Nb207, Ti2Nb20g and Ti2Nbio02 9 .
• a lithiated titanium oxide or a titanium oxide capable of being lithiated is chosen from the following oxides: i) Li xa M a Tiy- b M ' b C ) 4-cd X c in which 0 ⁇ x £ 3; £ 1 y £ 2.5; 0 £ to 1; 0 £ b £ 1; 0 £ c £ 2 and - 2.5 £ d £ 2.5; M represents at least one element selected from the group consisting of Na, K, Mg, Ca, B, Mn, Fe, Co, Cr, Ni, Al, Cu, Ag, Pr, Y and La;
• M represents at least one element selected from the group consisting of B, Mo, Mn, Ce, Sn, Zr, Si, W, V, Ta, Sb, Nb, Ru, Ag, Fe, Co, Ni, Zn, Al , Cr, La, Pr, Bi, Sc, Eu, Sm, Gd, Ti, Ce, Y and Eu;
• X represents at least one element selected from the group consisting of S, F, Cl and Br;
• the index d represents an oxygen deficiency.
• the index d can be less than or equal to 0.5. ii) H x TiyC where £ 0 x £ 1; 0 £ y £ 2, and iii) a mixture of compounds i) to ii).
• lithiated titanium oxides belonging to group i) are the spinel Li Ti 5 0i2, Li 2 TiC> 3, laramsdellite Li 2 Ti 3 07, LiTi 2 C> 4, Li x Ti 2 04, with 0 ⁇ x ⁇ 2 and Li 2 Na2Ti 6 0i4.
• a preferred compound has the formula LTO LU-a M a TIS b M 'b C, e.g. Li Ti 5 0i2 which still written Li 4/3 Ti 5/3 0 4.
• the binder present at the cathode and the anode has the function of reinforcing the cohesion between the particles of active materials as well as of improving the adhesion of the mixture according to the invention to the current collector.
• the binder may contain one or more of the following: polyvinylidene fluoride (PVDF) and its copolymers, polytetrafluoroethylene (PTFE) and its copolymers, polyacrylonitrile (PAN), poly (methyl) - or (butyl) methacrylate, polyvinyl chloride (PVC ), poly (vinyl formai), polyester, block polyetheramides, polymers of acrylic acid, methacrylic acid, acrylamide, itaconic acid, sulfonic acid, elastomer and cellulose compounds.
• PVDF polyvinylidene fluoride
• PTFE polytetrafluoroethylene
• PAN polyacrylonitrile
• PVC poly (methyl) - or (butyl) methacryl
• the elastomer (s) which can be used as binder can be chosen from styrene-butadiene (SBR), butadiene- acrylonitrile (NBR), hydrogenated butadiene-acrylonitrile (HNBR), and a mixture of several thereof.
• SBR styrene-butadiene
• NBR butadiene- acrylonitrile
• HNBR hydrogenated butadiene-acrylonitrile
• the carbonaceous electronic material or conductive material is generally chosen from graphite, carbon black, acetylene black, soot, graphene, carbon nanotubes or a mixture of these.
• the carbonaceous electronic material is distributed throughout the active material particles and the current collector.
• current collector is understood to mean an element such as a pad, plate, sheet or other, made of a conductive material, connected to the positive or negative electrode, and ensuring the conduction of the flow of electrons between the electrode and the terminals of the battery. .
• the electrode according to the invention is covered over all or part of its surface with a coating layer of an electronically insulating and ionic conductor material.
• the coating layer preferably covers at least 50% of the surface of the electrode, preferably at least 75%, more preferably at least 90%, still more preferably at least 95%.
• the thickness of the coating layer is preferably 2 to 50 nm, more preferably 5 to 10 nm.
• only the surface of the electrode material is covered by the coating layer.
• the coating layer covers at least 50% of the surface of the electrode material, more preferably at least 75%, still more preferably at least 90%, typically at least 95%.
• the surface of the electrode material and at least part of the surface of the current collector are covered by the coating layer.
• At least 50% of the surface of the collector is covered by the coating layer, more preferably at least 75%, even more preferably from 90% to 95%.
• electrode is used in an equivalent manner to denote the electrode material taken alone or else the assembly consisting of the electrode material and the current collector.
• electrode electronic insulating material means a material incapable of transporting electrons. The electronically conductive behavior of a material is evaluated by measuring its electronic conductivity oe.
• the electronic conductivity of a material can be determined using any method known to those skilled in the art. It can for example be measured as follows:
• a pellet of the material for which the value of the electronic conductivity is to be determined is prepared by pressing powder of said material under 5t / cm 2 then by carrying out sintering at a temperature 30% lower than its melting temperature (expressed in K) for 2h.
• a gold film is then deposited on the surface of the pellet, in order to improve the contact between the current collectors and the sample.
• the pellet is finally placed between 2 nickel collectors on the surface.
• a voltage is applied to the terminals of the electrodes in order to measure the evolution of the current flowing in the pellet as a function of time.
• the graph obtained plotting the evolution of this current as a function of the applied voltage is a straight line the slope of which corresponds to the electronic resistance Re of the pellet.
• the electronic conductivity of the material is finally calculated by applying the following formula: where oe represents the electronic conductivity of the material (in S.nr 1 ), e represents the thickness of the pellet (in m), S the surface of the pellet (in m 2 ) and Re the electronic resistance of the material (in Ohm ).
• the electronically insulating and ionic conductor material has an electronic conductivity, measured at 25 ° C, less than or equal to 10 10 S.nr 1 , preferably less than or equal to 10 12 S.nr 1 .
• ionically conductive material is meant within the meaning of the invention a material capable of transporting ions.
• the ionic conductive behavior of a material is evaluated by measuring its ionic conductivity oi.
• the ionic conductivity of a material can be determined using any method known to those skilled in the art. It can for example be measured as follows:
• a pellet of the material whose ionic conductivity value is to be determined is prepared according to the protocol described above before being placed between 2 nickel collectors on the surface.
• the electronically insulating and ionic conductor material exhibits an ionic conductivity, measured at 25 ° C., greater than or equal to 10 8 S.nr 1 , preferably greater than or equal to 10 6 S.nr 1 .
• the electronically insulating and ionically conductive material can be selected from azides, halides, oxides, phosphates, sulfides, polymers, and any of their mixtures.
• the electronically insulating and ionic conductor material is chosen from azides, it is preferably lithium azide U 3 N.
• the electronic insulating and ionic conductor material is chosen from halides, it is preferably chosen from materials of formula:
• M Zn, V, Ti, Mn, Mg, Cd, Fe or Cr, 0 £ z £ 1 and X is a halogen, in particular chosen from Cl, Br and I.
• the electronically insulating and ionic conductor material is chosen from oxides, it is preferably chosen from metal oxides.
• NAICON sodium-based superionic conductors
• lithium-based superionic conductors (LISICON for "Li Super Ionie Conductor” in English) of formula Li 2 + 2X Zni- x Si x GeC> 4 with 0 ⁇ x ⁇ 1,
• the electronically insulating and ionic conductor material is chosen from phosphates, it is preferably chosen from metal phosphates, more preferably from lithiated metal phosphates, even more preferably from lithiated thio-phosphates such as for example Lii 0 GeP 2 Si 2 and its derivatives obtained by doping and / or substitution of one or more lithium Li atoms, or germanium Ge atoms with one or more metallic elements, in particular tin Sn.
• the sulphide compounds present in the coating layer differ from the sulphide compounds present in the electrolytic composition.
• the sulphide compounds forming the coating layer exhibit a higher electronic conductivity than the sulphide compounds present in the electrolyte.
• the electronically insulating and ionic conductor material is chosen from sulphides, it is preferably chosen from sulphides having an electronic conductivity less than or equal to 10 -10 S.nr 1 .
• Such sulphide compounds are in particular chosen from the materials of formula [(Li2S) y (P2S 5 ) ly] (1-z) (LiX) z where:
• X is a halogen, in particular chosen from Cl, Br and I, or an oxygen atom,
• the electronically insulating and ionic conductor material is chosen from polymers, it is preferably chosen from homopolymers and copolymers of poly (oxyethylene) (POE) or polyethylene glycol; poly (propylene) (PP); poly (propylene) carbonate (PPC); polymers of alkyl (meth) acrylate type, in particular of poly (meth) acrylates (PMA and PMMA); poly (meth) acrylonitrile (PAN); poly (dimethylsiloxane) (PDMS); cellulose and their derivatives, in particular cellulose acetates; poly (vinylidene fluoride) (PVdF); polyvinylpyrrolidone (PVP); polystyrenes sulfonate (PSS); poly (vinyl chloride) (PVC); polyethylenes, especially poly (ethylene terephthalate) (PET); polyimides and mixtures thereof.
• copolymers which can be used, mention may in particular be made of copolymers
• These various polymers can comprise lithium salts such as LiTFSI, LiFSI, LiPF 6 , UCIO 4 .
• these polymers may contain traces or significant amounts of organic solvents, and in particular ethylene carbonate (EC), diethyl carbonate (DEC), dimethoxyethane (DME), dioxolane (DOL), etc.
• the electronically insulating and ionic conductor material is chosen from metal oxides; metal phosphates, preferably from lithiated metal phosphates; and any of their mixtures.
• the electronically insulating and ionic conductor material is chosen from lithium niobate LiNbC> 3, substituted lithium phosphates, compounds of LIPON type (Li3 , 2PO3 , 8No , 2) and any one of their mixtures.
• the electronically insulating and ionic conductor material is chosen from lithium niobate LiNbC> 3, compounds of LIPON type (Li 3, 2PO3.8N 0, 2) and any one of their mixtures.
• the electrode according to the invention is such that A1 ⁇ 6, the parameter A1 being calculated as follows: e
• S represents the ratio of the area developed by the active material to the total area of the electrode (in m 2 of active material per cm 2 of electrode).
• the electrode is such that A1 £ 4, preferably A1 £ 1.5, more preferably A1 £ 0.
• the electrode according to the invention is such that A2> 10, the parameter A2 being calculated as follows:
• A2 in sb XS (cond.) where: e represents the thickness of the coating layer (in m), sb represents the electronic conductivity, measured at 25 ° C, of the electronic insulating material and ionic conductor (in S.nr 1 ), and
• the electrode is such that A2 3 12, preferably A2 3 13.0.
• surface developed by a material is meant within the meaning of the invention the actual surface area of the material, measured on a microscopic scale, so as to take into account any roughness of the material and in particular its porosity.
• the developed surface thus differs from the apparent surface of the material measured on a macroscopic scale without taking into account any roughness.
• the developed area of a material can be calculated from the value of the specific surface area of the material expressed in n / kg of material.
• the specific surface of a material is typically measured by the BET method developed by Brunauer, Emett and Teller in 1938 by gas adsorption. This method is described by Alcade et al. (2013) and based on determining the amount of gas required to cover the outer surface and inner pores of a solid with a complete monolayer of gas. The method is applicable to a solid sample in powder form, the particle diameter of which does not exceed 2 mm and the specific surface of which is greater than 0.2 m 2 .g _1 .
• the sample is placed in an oven at 105 ° C, crushed and placed in a glass sample holder.
• the powdered sample is degassed at 105 ° C for 120 minutes and cooled in a liquid nitrogen bath at a temperature of 77 K, to prevent gas condensation with increasing temperature.
• Helium a gas that does not attach to the sample surface, is injected into the sample holder to measure the volume unoccupied by the sample. After the helium has been evacuated, the nitrogen is injected in successive stages, thus allowing the device to measure the pressure in the sample holder. The regularly measured partial pressure makes it possible to determine the quantity of nitrogen adsorbed.
• the quantity is represented as a function of the relative pressure Ps / PO.
• Ps / PO is between 0.05 and 0.35
• the volume of the monolayer is given by the expression:
• the developed surface area of a material sample is finally calculated by multiplying the specific surface area value obtained by the mass of the sample considered.
• the surface of the electrode is porous.
• the electrode has a porosity greater than or equal to 30%, more preferably greater than or equal to 40%, advantageously ranging from 40 to 60%.
• the deposition of the coating layer does not affect the porosity of the electrode. Indeed, the coating layer having a very small thickness, the total volume of the coating is negligible compared to the pore volume.
• the electrode covered with the coating layer is also porous.
• the electrode coated with the coating layer has a porosity greater than or equal to 25%, more preferably greater than or equal to 40%, advantageously ranging from 40 to 60%.
• At least part of the pores of the electrode, in particular the pores of the electrode coated with the coating layer, are at least partially filled with a solid electrolytic material, preferably chosen from electrolytic materials. solid conductors of lithium.
• the solid electrolyte can be of any known type. It is chosen in particular from sulfur-containing electrolytes, oxide-type electrolytes, polymer electrolytes, polymer / ceramic hybrid electrolytes and any of their mixtures.
• the solid electrolyte is chosen from sulfur-containing electrolytes and polymers.
• the solid electrolyte is chosen from sulfur-containing electrolytes, that is to say comprising sulfur, more preferably from sulfide electrolytes, alone or as a mixture with other constituents, such as polymers or gels. Mention may thus be made of partially or completely crystallized sulphides as well as amorphous ones.
• the sulphides forming the electrolytic layer differ from the sulphide compounds forming the coating layer in that they have an ionic conductivity greater than 10 _2 S.nr 1 and an electronic conductivity of between 10 -8 and 10 10 S.nr 1 .
• the electrolytic materials may also include oxysulphides, oxides (garnet, phosphate, anti-perovskite, etc.), hydrides, polymers, gels or ionic liquids which conduct lithium ions.
• the pores of the electrode are filled with a solid electrolytic material, preferably at least 70% by volume, more preferably at least 80% by volume.
• a solid electrolytic material preferably at least 70% by volume, more preferably at least 80% by volume.
• the coating layer and the electrolytic composition are made of different materials.
• a subject of the invention is also a method of manufacturing an electrode as defined above, this method comprising: a) providing an electrode, positive or negative, b) depositing all or part of the surface of said electrode with a coating layer of an electronically insulating and ionic conductor material as defined above, c) optionally, the deposition by infiltration in at least part of the pores of the electrode of a solid electrolytic material such as as defined above, and d) optionally, a treatment allowing the solidification of the electrolyte, preferably by heat treatment or by ultraviolet radiation.
• the heat treatment (optional step d) is carried out at a temperature ranging from 100 ° C to 250 ° C.
• the deposition of the coating layer on the surface of the electrode can be carried out by any method known to those skilled in the art.
• the coating layer is deposited by atomic layer deposition (ALD for “Atomic Layer Deposition”), by molecular layer deposition (MLD for “Molecular Layer Deposition”), by chemical deposition in vapor phase (CVD in English for “Chemical Vapor Deposition”), by physical vapor deposition (PVD in English for “Physical Vapor Déposition”), by soaking (in English “dip coating”) or by impregnation.
• ALD atomic layer deposition
• MLD molecular layer deposition
• CVD in English for “Chemical Vapor Deposition” chemical deposition in English for “Chemical Vapor Deposition”
• PVD in English for “Physical Vapor Déposition” physical vapor deposition
• soaking in English “dip coating” or by impregnation.
• the coating layer is formed from a precursor composition comprising at least one precursor compound of the electronic insulating material and ionic conductor and at least one solvent.
• the precursor compound of the electronic insulating and ionic conductor material is chosen from a source or target compound of the targeted electronic insulating and ionic conductor material or of a similar composition making it possible, in a reactive atmosphere, to obtain the desired composition profile by PVD or PLD (deposition of LiPON from a U3PO4 target under a partial nitrogen atmosphere) or, precursors making it possible to obtain the compositions targeted by ALD or MLD.
• PVD or PLD deposition of LiPON from a U3PO4 target under a partial nitrogen atmosphere
• precursors making it possible to obtain the compositions targeted by ALD or MLD.
• lithium tert-butoxide LiO'Bu lithium hexamethyldisilazide LiN (SiMe3) 2, niobium ethanolate Nb (OEt ) 5 , diethyl phosphoramidate H 2 NP (0) (0C2H 5 ) 2, trimethylphosphate.
• these precursor compounds can be used with deionized water, as well as with different carrier gases (argon, for example) or reactive atmospheres (partial pressure of nitrogen, oxygen or ozone, for example).
• carrier gases argon, for example
• reactive atmospheres partial pressure of nitrogen, oxygen or ozone, for example
• the solvent is inert with respect to the compounds present in the precursor composition, in particular with respect to the precursor compound of the electronic insulating and ionic conductor material.
• inert solvent is meant within the meaning of the invention a chemical compound capable of dissolving or diluting a chemical species without reacting with it.
• the method according to the invention further comprises, after step b), an additional step of deposition in at least part of the pores of the electrode, in particular of the pores of the electrode covered with the electrode. coating layer, of a solid electrolytic material as defined above.
• the solid electrolytic material is introduced into the pores of the electrode, in particular the pores of the electrode covered with the coating layer, by the infiltration of the electrolytic material in liquid form.
• the infiltration step can be carried out before the polymerization of the material, by infiltration of a composition comprising the precursor monomers of the polymer followed by a polymerization step inside the pores, or well after polymerization but before crosslinking of the polymer.
• the infiltration step can also be performed from the molten polymer electrolyte.
• the electrolytic materials of the sulphide type can be introduced into the pores of the electrode, in particular of the electrode covered with the coating layer, directly in molten form or else in the form of a precursor composition prepared by dissolving in a solvent of sulfide compound.
• the electrolytic material is chosen from sulphides
• its infiltration into the pores of the electrode, in particular into the pores of the electrode covered with the coating layer is carried out by the succession of the following steps:
• the solvent used for the preparation of the precursor composition is chosen from organic solvents, more preferably from ethanol, methanol, tetrahydrofuran (THF), hydrazine, water, acetonitrile, ethyl acetate, 1,2-dimethoxyethane and mixtures thereof.
• organic solvents more preferably from ethanol, methanol, tetrahydrofuran (THF), hydrazine, water, acetonitrile, ethyl acetate, 1,2-dimethoxyethane and mixtures thereof.
• Impregnation of the pores of the electrode in particular of the pores of the electrode covered with the coating layer, can be carried out by any known method. It can in particular be carried out by soaking the electrode in the precursor composition ("dip-coating" in English).
• Evaporation of the solvent is typically carried out under reduced pressure and with heating.
• the techniques of solvent evaporation under reduced pressure are well known to those skilled in the art who will know, depending on the solvent present in the precursor composition, to select a suitable pressure range and temperature range.
• Densification of the material is carried out by pressing, hot or cold, preferably cold.
• the pressure applied is between 20 and 1000 MPa, more preferably between 300 and 800 MPa.
• Electrode impregnation techniques are described in particular in Dong Hyeon Kim et al., Nano Lett., 2017, 17, 5, 3013-3020; S. Yubuchi et al., J. Matter. Chem. A, 2019, 7, 558-566 and S. Yubuchi et al., Journal of Power Sources, 2019, 417, 125-131.
• the invention also relates to an electrochemical element comprising a stack between two electronically conductive current collectors, said stack comprising:
• electrochemical element is understood to mean an elementary electrochemical cell consisting of the positive electrode / electrolyte / negative electrode assembly, making it possible to store the electrical energy supplied by a chemical reaction and to restore it in the form of current.
• the electrochemical element according to the invention comprises an electrode as defined above and an electrode having no coating layer as defined above.
• the electrode according to the invention is the negative electrode.
• the two electrodes are as defined above.
• microbatteries typically have an electrical charge greater than 100 mAh. They differ from micro-batteries and typically have a capacity greater than 0.1 Ah.
• the electrochemical element according to the invention is particularly suitable for lithium accumulators, such as Li-ion, primary Li (non-rechargeable) and Li-S accumulators
• the subject of the invention is also a process for manufacturing an electrochemical element as defined above.
• the method of manufacturing the electrochemical element comprises the following steps: i) providing a positive electrode and a negative electrode, at least one of said positive electrode and said negative electrode being such that defined above, and ii) forming, between said positive electrode and said negative electrode, a layer comprising a solid electrolytic composition.
• the invention also relates to an electrochemical module comprising the stack of at least two elements according to the invention, each element being electrically connected with one or more other element (s), in particular via their collectors. current.
• the present invention also relates to a battery comprising one or more modules according to the invention, and / or one or more boxes according to the invention.
• battery is understood to mean the assembly of several modules. Said assemblies can be in series and / or parallel.
• Figure 1 is a schematic representation of the different steps of the process for preparing an electrode according to the invention.
• the method according to the invention begins with the provision of an electrode (not shown) comprising a current collector (not shown) on which is deposited an electrode material 10.
• the material d The electrode 10 comprises particles of active material 12 and particles of carbonaceous electronically conductive material 14.
• step A a coating layer 16 of an electronically insulating and ionically conductive material is deposited on the surface of the electrode material 10.
• Step B then consists of a step of infiltrating a solid electrolyte composition 18 inside the pores 20 of the electrode material 10 and at the surface of the coating layer 16.
• the particles of active material 12 and the particles of carbonaceous electronic material 14 are thus covered with two successive layers 16 and 18.
• the coating layer 16 is in direct contact with the particles 12 and 14 while the solid electrolyte layer 18 is deposited on the surface. of the coating layer 16.
• Step C finally consists of a step of drying the electrolyte composition and compressing the material in order to obtain an electrode according to the invention.
• the positive electrodes according to the invention C1 to C14 are prepared according to the following protocol:
• Step 1 production of a porous electrode without solid electrolyte
• the positive electrodes are prepared according to a method analogous to that used for conventional Li-ion batteries with a liquid electrolyte.
• the conductive carbon (a carbon black or VGCF fibers with different specific surfaces varying from 15 to 200 m 2 / g) is dispersed in a solvent (N-methyl-2-pyrrolidone), to which is added a binder (PVDF - polyfluoride of vinylidene) then the active material of NMC type of composition: Li (Nio.33Mno.33Coo.33) C> 2.
• the amount of binder is 5% and those of the other constituents are shown in Table 1.
• the amount of solvent is adapted so that the mixture has a viscosity allowing uniform deposition of the ink on the aluminum current collector. After the deposit has been made, the electrode is dried at 120 ° C. for 1 h.
• Calendering of the electrode is then carried out so as to achieve a porosity of about 70%.
• a LiNbOs coating layer is then deposited on the surface of the electrode obtained at the end of step 1 by atomic layer deposition (ALD in English for “Atomic Layer Deposition”) according to a procedure adapted from those described in the publication. : B. Wang, Y. Zhao, MN Banis, Q. Sun, KR Adair, R. Li, TK Sham, X. Sun, Atomic layer deposition of lithium niobium oxides as potential solid-state electrolytes for lithium-ion batteries, ACS Appl. Check out. Interfaces, 10 (2018), pp. 1654-1661
• Successive deposition cycles are carried out on the positive electrode obtained in step 1, with lithium tert-butoxide LiO'Bu and niobium ethanolate Nb (OEt) 5 as precursors.
• the ratio between the amount of Lithium ions and the amount of Niobium ions deposited ranges from 2: 1 to 1: 4.
• the pores of the electrode are then impregnated with a sulfide electrolyte of the U3PS4 type.
• U2S and P2S5 powders are dissolved in anhydrous acetonitrile in a stoichiometric amount to achieve the U3PS4 composition with a mass concentration close to 5% by mass in the solution.
• the porous electrode obtained at the end of the 2 nd step is coated by soaking (dip-coating) in the solution.
• the electrode is then dried in a glove box and then heated under vacuum at 150 ° C. for 2 hours.
• the electrode is then compressed under a pressure of 2 t / cm 2 .
• Comparative positive electrodes C1 * to C3 * are prepared in an analogous manner, except that:
• the active material is graphite powder
• the current collector is made of copper
• - the coating layer is made of LIPON.
• the LiPON deposition is carried out by atomic layer deposition (ALD in English for “Atomic Layer Deposition”) under conditions adapted from those described in the publications:
• the comparative negative electrode C4 * is prepared in an analogous manner. However, no coating layer is deposited on the surface of the comparative C4 * electrode.
• a lithium pellet with a diameter of 6 mm and a thickness of 100 ⁇ m is placed on the electrolytic layer and compressed to approximately 50 bar.
• the assembly is then placed in a sealed electrochemical cell allowing electrical connection with the 2 electrodes, while maintaining a mechanical pressure of around 50 bar.
• the mass of the mixture in mg for producing the electrode is equal to the desired surface capacity in mAh / cm 2 multiplied by the surface of the electrode and divided by 150 mAh / g.
• Each of the cells is then charged at C / 10 to a voltage of 4.3V if the electrode under test is a positive electrode or 0V if it is a negative electrode.
• the discharge is carried out at a rate of 1C up to a voltage of 2.5 V or 1V depending on whether it is a positive or negative electrode, respectively.
• the voltage difference at 1 C related to the surface coating is measured. It corresponds to the voltage difference during the discharge at 1C at shallow depth of discharge (for example after 10min) between the treated and untreated electrode and makes it possible to measure the impact of the coating layer on the performance of the electrode. This value is expressed in V.
• the cell After discharging at 1C, the cell is then recharged at C / 10 at a temperature of 60 ° C and then maintained at 4.3V or 0.05V depending on whether it is a positive or negative electrode, respectively.
• an electrolyte decomposition current is less than 10 pA / cm 2 .
• the small voltage difference at 1C reflects the fact that the electrochemical performance of the electrode is hardly affected by the presence of the coating layer.
• the weak decomposition current demonstrates that the electrolyte is stable: it does not react with the materials of the electrodes.
• the electrolyte decomposition current is greater than 50pA / cm 2 : the electrolyte and the materials react with each other.
• the decomposition current of the electrolyte is greater than 50 pA / cm 2 .
• the presence of the LLZO coating layer does not prevent reactions between the electrolyte and the electrode materials.
• the present invention relates to the field of energy storage, and more specifically to accumulators, in particular of the lithium type.
• Rechargeable lithium-ion batteries indeed offer excellent energy and volume densities and today occupy a prominent place in the market for portable electronics, electric and hybrid vehicles and stationary energy storage systems.
• the solid sulphide electrolytes reach sufficient maturity to consider their industrial use. Their high values of ionic conductivity associated with their ductility and limited density make them serious candidates for the first generations of all-solid-state batteries that can compete with the energy densities of current Li-ion batteries with liquid electrolytes.
• US 2017/0331149 describes a solid electrolyte based on sulfide covered with an oxide phase resulting from the oxidation of the sulfur material, on the surface of the sulfur material.
• WO2014 / 201568 relates to lithium-sulfur electrochemical cells, the solid electrolyte of which comprises at least one lithium salt and a polymer but does not envisage a protective layer for the electrolyte particles.
• CN 109244547 describes a solid electrolytic separator such that the electrolyte powder is coated with an oxide layer.
• the envisioned coatings are not compatible with wide windows of stability, both at the positive electrode and the negative electrode.
• US 8,951,678 describes a solid electrolyte comprising a sulfide-based electrolyte and an electrolyte coating film based on a waterproof polymer.
• this polymer does not contain lithium salt, it cannot conduct lithium in a battery which does not contain liquid electrolyte; it is the salt of the latter that will diffuse into the polymer to make it an ionic conductor.
• the present application is aimed at electrolyte particles for use in an electrochemical element, characterized in that said particles consist of solid electrolyte particles of sulphide type coated with a layer comprising an inorganic ionic conductive material comprising a halogen. .
• the coating material is not an oxide.
• the coating layer consists exclusively of the coating material.
• the coating material may comprise several anions, it being understood that these anions are predominantly (in moles) one or more halogens.
• said coating material corresponds to formula (I):
• Y represents yttrium
• M is a metal selected from Zr, Hf, Ti, Si, B, Al, Sc, Ga, Ta, Nb, Ca, Mg;
• said coating material corresponds to the formula
• Y represents yttrium
• M 1 is a metal selected from Zr, Hf, Ti, Si, B, Al, Sc, Ga, Ta, Nb, Ca, Mg;
• u number between 0 and 0.6 (limits included)
• v number between 0.1 and 0.3 (limits included)
• w, y, z, t numbers between 0 and 0.6 (limits included)
• x number between 0 and 0.3 (limits included).
• X is Cl or Br
• X 1 and X 2 which are identical or different, are chosen from Cl or Br;
• - b is equal to approximately 0;
• - c is equal to approximately 0;
• the solid electrolyte particles can be coated on all or part of their peripheral surface. According to one embodiment, they are coated over their entire peripheral surface.
• the coating layer covers at least 50% of the specific surface of the particles, preferably at least 75%, more preferably at least 90%, still more preferably at least 95%.
• the solid electrolyte particles are of the "sulfur" type, that is to say comprising sulfur.
• the electrolyte particles can be the same or different, (ie) correspond to one or more electrolytic constituents it being understood that at least one electrolyte is sulfur.
• Said electrolytes can be mixed with other constituents, such as polymers or gels.
• these materials can be selected from sulphides of composition y (Li 2 S) - (1-y) (P2S5) (with 0 ⁇ y ⁇ 1) and their derivatives (for example with Lil, LiBr, LiCl doping, ...); sulphides of argyrodite structure; or LGPS type (Lii 0 GeP2Si2), and its derivatives.
• the electrolytic materials may also include oxysulphides, oxides (garnet, phosphate, anti-perovskite, etc.), hydrides, polymers, gels or ionic liquids which conduct lithium ions.
• the layer has a thickness less than 20 nm, in particular less than 10 nm, more preferably from 2 to 5 nm.
• the present invention also relates to a method for preparing coated solid electrolyte particles according to the invention, said method comprising depositing said layer of material on said particles.
• the application can be carried out by any method allowing the deposition of a thin layer, such as:
• sol-gel sol-gel, centrifugal coating or spin-coating, vapor deposition, atomic layer or atomic layer deposition ALD deposition, molecular layer deposition or molecular layer MLD deposition, or by controlled oxidation; and
• PVD physical vapor deposition
• the layer can be deposited by ALD or PVD, in particular by magnetron sputtering.
• LD consists of exposing the surface of the particles successively to different chemical precursors in order to obtain ultra-thin layers.
• the PVD treatment is carried out with a process allowing movement of the particles such as the fluidized bed or “barrel sputtering” (rotating drum) to allow a more homogeneous deposit on the surface of the particles.
• the deposition can in particular be carried out by applying or adapting the deposition conditions described by Fernandes et al. Surface and coatings technology 176 (2003), 103-108.
• the powders of the material to be deposited can be prepared by mechanosynthesis, from precursors in stoichiometric quantity and then ground.
• the invention also relates to an all-solid electrochemical element comprising electrolyte particles according to the invention.
• electrochemical element an elementary electrochemical cell made up of the positive electrode / electrolyte / negative electrode assembly, allowing the electrical energy supplied by a chemical reaction to be stored and returned in the form of current.
• the electrolytic compounds can be included in the electrolyte layer, but can also be partially included within the electrodes.
• An all-solid element according to the invention therefore consists of a negative electrode layer, a positive electrode layer and an electrolytic separating layer, such that the electrolyte particles according to the invention are present at within at least one of the three layers.
• electrolyte particles may be present within these three layers respectively, it being understood that electrolyte particles coated according to the invention are present, preferably within the electrolyte layer.
• the electrochemical element according to the invention is particularly suitable for lithium accumulators, such as Li-ion, primary Li (non-rechargeable) and Li-S accumulators. These materials can also be used in accumulators of the Na-ion, K-ion, Mg-ion or Ca-ion type.
• the negative electrode layer typically consists of a conductive support used as a current collector on which is deposited the negative electrode material comprising, a negative electrode active material to which can be added solid electrolyte particles and a electronically conductive material.
• a binder can also be incorporated into the mixture.
• the term “negative electrode” designates when the accumulator is in discharge, the electrode functioning as an anode and when the accumulator is in charge, the electrode functioning in cathode, the anode being defined as the electrode where takes place a. electrochemical oxidation reaction (emission of electrons), while the cathode is the seat of reduction.
• the negative electrode can be of any known type.
• the negative electrode active material is not particularly limited. It can be chosen from the following groups and their mixtures:
• M and M 'each represent at least one element selected from the group consisting of
• X represents at least one element selected from the group consisting of S, F, Cl and Br.
• the index d represents an oxygen deficiency.
• the index d can be less than or equal to 0.5.
• Said at least one titanium and niobium oxide can be chosen from TiNb 2 0, Ti 2 Nb 2 0 , TÎ2Nb20g and Ti 2 Nbi 0 C> 29 .
• lithiated titanium oxide or a titanium oxide capable of being lithiated.
• the lithiated titanium oxide is chosen from the following oxides: i) Li xa M a Ti yb M ' b C) 4- cd X c in which 0 ⁇ x £ 3; £ 1 y £ 2.5; 0 £ to 1; 0 £ b £ 1; 0 £ c £ 2 and - 2.5 £ d £ 2.5;
• M represents at least one element selected from the group consisting of Na, K, Mg, Ca, B, Mn, Fe, Co, Cr, Ni, Al, Cu, Ag, Pr, Y and La; M 'represents at least one element selected from the group consisting of B, Mo, Mn, Ce, Sn, Zr, Si, W, V, Ta, Sb, Nb, Ru, Ag, Fe, Co, Ni, Zn, Al , Cr, La, Pr, Bi, Sc, Eu, Sm, Gd, Ti, Ce, Y and Eu;
• X represents at least one element selected from the group consisting of S, F, Cl and Br;
• the index d represents an oxygen deficiency.
• the index d can be less than or equal to 0.5. ii) H x TiyC where £ 0 x £ 1; 0 £ y £ 2, and iii) a mixture of compounds i) to ii).
• lithiated titanium oxides belonging to group i) are the spinel LUTisO ⁇ , Li 2 TiC> 3, laramsdellite Li 2 Ti 3 0, LiTi 2 C> 4, Li x Ti 2 C> 4, with 0 ⁇ x ⁇ 2 and Li 2 Na 2 Ti 6 0i4.
• a preferred compound has the formula LTO LU-a M a TIS b M 'b C, for example Li 2 Ti 5 0i which still written Li / 3 Ti 5/3 04.
• the positive electrode layer typically consists of a conductive support used as a current collector on which is deposited the positive electrode material comprising, in addition to the solid electrolyte particles, a positive electrode active material and an electronically conductive material. carbon.
• a binder can also be incorporated into the mixture.
• This carbonaceous additive is distributed in the electrode so as to form an electronic percolating network between all the particles of active material and the current collector.
• positive electrode designates when the accumulator is discharging, the electrode functioning as a cathode and when the accumulator is charging, the electrode functioning as an anode.
• the positive electrode can be of any known type.
• the positive electrode active material is not particularly limited. It can be chosen from the following groups or their mixtures:
• M represents at least one element chosen from the group consisting of Na, K, Mg, Ca, B, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Y, Zr, Nb, Mo, Ru, Ag, Sn, Sb, Ta, W, Bi, La, Pr, Eu, Nd and Sm and where 0 ⁇ x ⁇ 0.5 and 0 ⁇ y ⁇ 1.
• the binder present at the positive electrode and at the negative electrode has the function of strengthening the cohesion between the particles of active materials as well as improving the adhesion of the mixture according to the invention to the current collector.
• the binder may contain one or more of the following: polyvinylidene fluoride (PVDF) and its copolymers, polytetrafluoroethylene (PTFE) and its copolymers, polyacrylonitrile (PAN), poly (methyl) - or (butyl) methacrylate, polyvinyl chloride (PVC ), poly (vinyl formai), polyester, block polyetheramides, polymers of acrylic acid, methacrylic acid, acrylamide, itaconic acid, sulfonic acid, elastomer and cellulose compounds.
• PVDF polyvinylidene fluoride
• PTFE polytetrafluoroethylene
• PAN polyacrylonitrile
• PVC poly (methyl) - or (butyl) methacrylate
• PVC
• the elastomer (s) which can be used as a binder can be chosen from styrene-butadiene (SBR), butadiene-acrylonitrile (NBR), hydrogenated butadiene-acrylonitrile (HNBR), and a mixture of several of these.
• SBR styrene-butadiene
• NBR butadiene-acrylonitrile
• HNBR hydrogenated butadiene-acrylonitrile
• the electronically conductive material is generally chosen from graphite, carbon black, acetylene black, soot, graphene, carbon nanotubes or fibers or a mixture of these.
• the term “current collector” is understood to mean an element such as a pad, plate, sheet or other, made of a conductive material, connected to the positive or negative electrode, and ensuring the conduction of the flow of electrons between the electrode and the terminals of the battery.
• the current collector is preferably a two-dimensional conductive support such as a solid or perforated strip, based on metal, for example nickel, steel, stainless steel or aluminum.
• the present invention also relates to an electrochemical module comprising the stack of at least two elements according to the invention, each element being electrically connected with one or more other element (s).
• module therefore designates here the assembly of several electrochemical elements, said assemblies being able to be in series and / or parallel.
• the invention also relates to a battery or "accumulator" comprising one or more modules according to the invention.
• battery means the assembly of one or more modules according to the invention.
• the invention preferably relates to accumulators whose capacity is greater than 100 mAh, typically 1 to 100Ah.
• FIG. 2 shows a schematic representation of the structure of an electrochemical element according to the invention.
• Said element comprises a negative electrode layer (31), a positive electrode layer (33), separated by an electrolytic layer (32).
• the negative electrode layer (31) comprises a current collector (34) on which is deposited the negative electrode material according to the invention, consisting of particles of solid electrolyte (35), particles of active material of negative electrode (36) and carbon particles (37).
• the separation layer (32) consists of solid electrolyte particles (35 ’). These particles (35 ’) can be identical to particles (35).
• the positive electrode layer (33) comprises a current collector (34 ') on which is deposited a mixture comprising particles of solid electrolyte (35 ”), conductive carbon (37'), and particles of active material. (36 ').
• the layers (31) and (33) can also comprise binders, which are not shown in Figure 2.
• the solid electrolyte particles (35), (35 ') and / or (35 ”) comprise coated particles according to the invention.
• Figure 3 shows the stacking of the solid electrolyte particles (35), (35 ') and (35 ”) within the layers (31), (32) and (33), with, in magnification, the detail of the particles (35 '), which are covered with a coating layer (38); It is understood that such a coating can be present on the particles (35 ') and / or (35 ”) as well.
• Table 4 collates the examples according to the invention.
• Table 5 collects counter-examples (CE).
• the coating for carrying out the examples is carried out by magnetron sputtering of the compound to be deposited on the electrolyte powder, the latter being placed in motion on a fluidized bed or in a rotating drum.
• Electrolyte powders are prepared by mechanosynthesis.
• the precursors used are powders of Li 2 S, P2S5, LiCI, and Lil.
• the precursors as well as the beads are introduced in a stoichiometric quantity into a sealed jar in a glove box under argon.
• the jars are then placed in a planetary mill of the Fritsch Pulverisette® P7 type.
• the mixture is ground for 24 hours at a speed of 800 revolutions / min.
• Powders of the mixture to be deposited on the surface of the electrolyte particles are prepared by the same mechanosynthesis process as above.
• the precursors used are the halides or oxides of the cations constituting the material to be deposited: either for the examples in Table 1: LiCl, LiBr, Lil, LiF, YCI 3 , YF 3 , YBr 3 , ZrCl 4 , SiCl 4 , HfCL, NaCl , MgCl2, CaCl2, Li 2 0, K 2 0, S1O2, P2O5, B 2 0 3 , Nb20 5 , Zr0 2 , T1O2.
• the stoichiometric mixture is ground under conditions similar to those of the electrolyte, ie 24 hours at 800 rpm.
• the powder of the mixture to be deposited is compressed in a pelletizer at 3 t / cm 2 in order to produce a target which will be used subsequently for carrying out the deposition by magnetron sputtering (“sputtering”).
• sputtering magnetron sputtering
• the device for producing the coating consists of placing in the sputtering chamber a chamber allowing the creation of rotational and vibrating movements.
• the electrolyte powder is placed in this chamber, the latter allowing a homogeneous coating of the compound to be coated.
• the deposition conditions are adapted from those described by Fernandes et al Surface and coatings technology 176 (2003), 103-108.
• Deposition times vary depending on the coating compounds and the desired thickness.
• the thickness can be measured by transmission microscopy. Measurement of the generation of H2S from the coated electrolyte powder in a humid atmosphere:
• the container contains ambient air at atmospheric pressure and ambient temperature in order to assess the risk associated with the release of hhS under standard conditions in which the materials might be found.
• the foregoing device contains a beaker containing acidified water whose function is to maintain humidity in the air throughout the reaction between the electrolyte powder and water in gaseous form. The level of H2S in the chamber is recorded at regular time intervals as soon as the sample is introduced and is expressed in cc of H2S formed per gram of electrolyte.
• the value indicated in Tables 1 and 2 is the hSH level measured after 30 min.
• a quantity of coated electrolyte powder of approximately 10 mg is introduced into a cell similar to a pellet mold with a diameter of 7 mm, the pistons of which are made of stainless steel and the body of insulating material which does not react chemically with the electrolyte or the materials. electrode.
• the powder is thus compressed under a pressure of 4 t / cm 2 .
• a lithium disc is then inserted between a piston and the previously obtained pellet; the whole is then compressed in the cell under a pressure of 0.1 t / cm 2 .
• the cell thus obtained is placed in a sealed enclosure ensuring that there is no trace of moisture during the test.
• the cell is heated to 60 ° C for two weeks. This treatment accelerates the possible reactions between the electrolyte and the lithium metal.
• the leakage current corresponds to the value of the current after stabilization, typically after 24 hours and is expressed per cm 2 of electrode.

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