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
  • H01M4/64—Carriers or 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
  • H01M4/64—Carriers or collectors
  • H01M4/70—Carriers or collectors characterised by shape or form
• • 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
  • H01M4/0438—Processes of manufacture in general by electrochemical processing
  • H01M4/044—Activating, forming or electrochemical attack of the supporting material
• • 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
  • H01M4/134—Electrodes based on metals, Si or alloys
• • 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
  • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
• • 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
  • H01M4/386—Silicon or alloys based on silicon
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/027—Negative electrodes
• • 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 current collector for an anode.
• the invention also relates to an accumulator and to an energy storage device comprising such a current collector.
• the invention also relates to a method of manufacturing this current collector.
• the present invention also relates to an anode for an electrochemical accumulator.
• the invention also relates to an accumulator and to an energy storage device comprising such an anode.
• the invention also relates to a method of manufacturing this anode.
• An electrochemical accumulator conventionally comprises a positive electrode, a negative electrode, an electrolyte and current collectors for each electrode.
• the assembly of a negative electrode and a current collector forms an anode while the assembly of a positive electrode and a current collector forms a cathode.
• the operating principle of such accumulators is based on the reversible storage of electrical energy into chemical energy by the implementation of two separate and coupled electrochemical reactions.
• the positive and negative electrodes are bathed in the electrolyte and are the site of electrochemical reactions, known as faradic reactions.
• the electrodes are made in particular of active materials making it possible to store and de-stock ions via oxidation and reduction reactions.
• the electrodes are made according to a composition, the composition mainly comprising one or more active material (s) (> 70% by mass), conductive particles ensuring good transport of electrons to all the active materials, and a binder which ensures the cohesion of the particles, as well as the adhesion to the current collector.
• active material s
• binder which ensures the cohesion of the particles, as well as the adhesion to the current collector.
• an electrolyte This can be liquid, in the form of a gel or else a solid.
• Lithium technologies have the best characteristics in terms of specific and volume energy densities. These technologies are therefore preferably chosen for nomadic applications, such as mobile telephony or laptops. but also for the development of new electric vehicles (EV) and stationary systems (ESS) requiring large storage capacities and long lifetimes.
• EV electric vehicles
• ESS stationary systems
• Silicon as the active material of the anode, has a storage capacity for lithium ions greater than that of graphite.
• the liquid electrolyte and lithium settle on the surface of the active material and break down to form a layer, called solid electrolyte interphase (SEI).
• SEI solid electrolyte interphase
• silicon anodes can be damaged by deformation and fractionation of the active material, caused by volume changes of up to 300%. Indeed, during cell operation, when lithium ions are intercalated, the active material of the anode expands, and when lithium ions are de-intercalated, the active material contracts. Such changes in volume can also generate spalling, or flaking, of the SEI and further decomposition of the electrolyte, accompanied by further deposition of lithium, resulting in the formation of a new SEI.
• anode current collector which provides improved properties, in particular better adhesion with the electrode and / or reduced electrical resistance between the substrate and the electrode.
• a current collector for an anode, the current collector comprising:
• interfacing layer having a thickness less than 10 micrometers, preferably less than 6 micrometers, in contact with the first face of the substrate, the interfacing layer having a roughness whose depth is between 0.5 micrometers and 10 micrometers.
• Such a collector has improved properties, whether in terms of adhesion and / or reduced electrical resistance.
• an interfacing layer provides good adhesion of the electrode to the substrate, and therefore a better electrical interface, it adds electrical resistance within it due to the limit in conductivity of its components.
• the roughness of the interfacing layer of the present collector solves this technical problem, in particular by generating better electrical percolation within the electrode and by increasing the electron exchange surface with the current collector.
• this is not a coating layer whose surface state reproduces only that of the substrate on which it is deposited, as described in document US 2013/0115510, but rather a layer with its own surface finish.
• This surface condition is controlled and adjustable, for example by virtue of the composition of the layer, in order to obtain the best electrochemical performance.
• the current collector comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:
• the interfacing layer has a second face in contact with the first face of the substrate, the second face of the interfacing layer having an area and the first face of the substrate having an area, the ratio between the area of the second face of the interfacing layer and the area of the first face of the substrate being between 0.1 and 1.
• the interfacing layer is produced by coating with a second composition, the second composition comprising a second binder material and a second conductive additive.
• the interfacing layer consists of a network comprising a plurality of elements arranged on the first face of the substrate, each element being separated from another adjacent element by a distance between 200 micrometers and 2500 micrometers, the distance separating two adjacent elements being the smallest distance between a point of an element and a point of a second element adjacent to the first element.
• the interfacing layer is produced by coating with a third composition, the third composition comprising a third conductive additive and optionally a third binder material.
• each element has a base, the base of each element being a polygon or a disc or an oval.
• the base of the elements of the interfacing layer has a degree of coverage of the first face of the substrate of between 0.1 and 0.9, preferably between 0.2 and 0.5.
• each element has a height less than or equal to 10 micrometers.
• the current collector comprises at least a first interfacing layer, the first interfacing layer having a second face in contact with the first face of the substrate, the second face of the interfacing layer having an area and the first face of the substrate having an area, the ratio between the area of the second face of the interfacing layer and the area of the first face of the substrate being between 0.1 and 1.
• the current collector comprises at least a second interfacing layer, the second interfacing layer consisting of an array comprising a plurality of elements disposed on the first face of the substrate, each element being separated from another adjacent element by a distance between 200 micrometers and 2,500 micrometers, the distance separating two adjacent elements being the smallest distance between a point of a first element and a point of a second element adjacent to the first element, the first interfacing layer and the second interfacing layer being superimposed on top of each other.
• the present description also relates to an electrochemical accumulator comprising a current collector as described above.
• This description also relates to a method of manufacturing a current collector for an anode, the method comprising:
• the interfacing layer having a thickness less than 10 micrometers, preferably less than 6 micrometers, the interfacing layer having a roughness the depth of which is between 0.5 micrometers and 10 micrometers.
• An anode for an electrochemical accumulator comprising a substrate having a first face, an electrode produced according to a first composition, the first composition comprising an intercalation material, a first binder material and a first conductive additive, the intercalation material comprising silicon.
• the electrode has one face, the first face of the substrate and the face of the electrode being opposite.
• the anode comprises at least one interfacing layer having a thickness less than 10 micrometers, preferably less than 6 micrometers, disposed between the substrate and the electrode and in contact with the first face of the substrate and the face of the electrode.
• the anode comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:
• the interfacing layer has a first face in contact with the face of the electrode, the first face of the interfacing layer having a roughness the depth of which is between 10 nanometers and 10 micrometers.
• the interfacing layer has a second face in contact with the first face of the substrate, the second face of the interfacing layer having an area and the first face of the substrate having an area, the ratio between the area of the second face of the interfacing layer and the area of the first face of the substrate being between 0.1 and 1.
• the interfacing layer is produced by coating with a second composition, the second composition comprising a second binder material and a second conductive additive.
• the interfacing layer consists of a network comprising a plurality of elements arranged on the first face of the substrate, each element being separated from another adjacent element by a distance between 200 micrometers and 2500 micrometers, the distance separating two adjacent elements being the smallest distance between a point of an element and a point of a second element adjacent to the first element.
• the interfacing layer is produced by coating with a third composition, the third composition comprising a third conductive additive and optionally a third binder material.
• each element has a base, the base of each element being a polygon or a disc or an oval.
• the base of the elements of the interfacing layer has a coverage rate of the first face of the substrate of between 0.1 and 0.9, preferably between 0.2 and 0.5.
• each element has a height less than or equal to 10 micrometers.
• the anode comprises at least a first interfacing layer, the first interfacing layer having a first face in contact with the face of the electrode, the first face of the interfacing layer having a roughness the depth of which is between 10 nanometers and 10 micrometers.
• the anode comprises at least a second interfacing layer, the second layer interface consisting of an array comprising a plurality of elements arranged on the first face of the substrate, each element being separated from another adjacent element by a distance between 200 micrometers and 2500 micrometers, the distance separating two adjacent elements being the smallest distance between a point of a first element and a point of a second element adjacent to the first element.
• the first interfacing layer and the second interfacing layer being superimposed on one another.
• the silicon content of the intercalation material is greater than or equal to 30%, preferably greater than or equal to 60% by mass.
• the intercalation material is silicon.
• the present description also relates to an electrochemical accumulator comprising an anode as described above.
• the present description also describes an energy storage device comprising at least one electrochemical accumulator as described above.
• the present description also relates to a method of manufacturing an anode for an electrochemical accumulator, the method comprising a step of providing a substrate having a first face, a step of depositing by coating on the first face of the substrate with less one interfacing layer, the interfacing layer having a thickness less than 10 micrometers, preferably less than 6 micrometers.
• the method further comprising a step of preparing a first composition comprising an intercalation material, a first binder material and a first conductive additive, the intercalation material comprising silicon, and a step of deposition by coating of the first composition on the interfacing layer to obtain an electrode having one face, the first face of the substrate and the face of the electrode being opposite, and the interfacing layer being in contact with the first face of the substrate and the face of the electrode.
• FIG. 2 a schematic side view of a section of the anode of the electrochemical accumulator comprising an interfacing layer
• FIG. 3 a schematic side view of a section of another example of an anode of the electrochemical accumulator comprising another example of an interfacing layer
• FIG. 8 a schematic side view of a section of another exemplary anode of the electrochemical accumulator comprising two interfacing layers.
• FIG. 9 a schematic side view of a section of another exemplary anode of the electrochemical accumulator comprising two interfacing layers.
• FIG. 1 An electric accumulator 10 is shown in FIG. 1.
• the accumulator 10 is intended to be connected to other electric accumulators to form an energy storage device, in particular an electric generator of the desired voltage and capacity.
• Such a generator is called an accumulator battery or more simply a battery.
• Accumulator 10 uses a reversible energy conversion technique to store energy and release it later.
• accumulator 10 is an electrochemical accumulator.
• the accumulator 10 is a lithium-ion accumulator for a lithium-ion battery.
• Accumulator 10 has an electrolyte 12, a cathode 14 and an anode 16. Accumulator 10 functions as an electrochemical accumulator through the interaction between electrolyte 12, cathode 14 and anode 16.
• the electrolyte 12 is composed of various ionic salts providing ions used for the storage reactions of charges or faradics, of carbonates and of a solvent or mixture of solvents to allow the solubilization of the ions.
• the ionic salts are chosen from lithium hexafluorophosphate (LiPFe), lithium bis (trifluoromethane sulfonyl) imide salt (LiTFSI), lithium tetrafluoroborate (LiBF), lithium bis oxalate borate (LiBOB), sodium nitrate. lithium (L1NO 3 ) and lithium difluorooxalatoborate (LiDFOB).
• the carbonates are, for example, propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC).
• PC propylene carbonate
• EC ethylene carbonate
• DMC dimethyl carbonate
• EMC ethyl methyl carbonate
• DEC diethyl carbonate
• Carbohydrates are also, in smaller proportions, fluoroethylene carbonate (FEC), vinylene carbonate (VC), methyl acetate, methyl formate, acetonitrile, tetrahydrofuran, gamma-butyrolactone, and binary or ternary mixtures, or even quaternary mixtures thereof, as well as ionic liquids.
• FEC fluoroethylene carbonate
• VC vinylene carbonate
• methyl acetate methyl formate
• acetonitrile tetrahydrofuran
• gamma-butyrolactone gamma-butyrolactone
• binary or ternary mixtures or even quaternary mixtures thereof, as well as ionic liquids.
• Cathode 14 comprises an active material.
• the active material of the cathode 14 is conventionally composed of lithium sulfur (LiS) and / or of at least one lithiated metal oxide, the lithiated metal oxide being chosen for example from lithium-cobalt oxide L1COO2 (LCO), lithium-nickel-cobalt-manganese oxide LiNiMnCoC> 2 (NMC), lithium-nickel-cobalt-aluminum oxide LiNiCoAI0 2 (NCA), lithium manganese oxide LiMnC (LMO), oxide lithium iron phosphorus LiFePC (LFP), lithium nickel manganese oxide Li (LiNiMn) C> 2, lithium manganese iron phosphate (LMFP) and lithium nickel manganese oxide LiNiMnO (LNMO) .
• LCO lithium-cobalt oxide L1COO2
• NMC lithium-nickel-cobalt-manganese oxide LiNiMnCoC> 2
• NCA lithium-nickel-cobalt-aluminum
• active material of the cathode 14 are possible, for example those suitable for sodium-ion batteries.
• the anode 16 is shown in more detail in Figure 2.
• the anode 16 has a substrate 20, an electrode 21 and an interfacing layer 22.
• the substrate 20, the electrode 21 and the interfacing layer 22 form a stack of layers in a stacking direction denoted Z, the interfacing layer 22 being disposed between the substrate 20 and the electrode 21.
• the substrate 20, the interfacing layer 22 and the electrode 21 are superimposed.
• Substrate 20 and interfacing layer 22 form an anode 16 current collector.
• Substrate 20 and interfacing layer 22 form current collector 23.
• each characteristic or embodiment relates equally to the anode 16 or the current collector 23.
• the substrate 20 has a first face 201 perpendicular to the stacking direction Z.
• the substrate 20 has a thickness e20 of between 1 and 20 micrometers (pm), preferably equal to 10 pm, the thickness e20 being measured according to the stacking direction Z.
• the value of the thickness e of a layer is measured according to the stacking direction Z.
• the substrate 20 comprises a metal sheet 35.
• the metal sheet 35 is for example made of iron, copper, aluminum, nickel, titanium or stainless steel.
• the electrode 21 is in contact with the electrolyte 12 of the accumulator 10.
• the electrode 21 has a face 212 perpendicular to the stacking direction Z.
• the face 212 of the electrode 21 is opposite the first face 201 of the substrate 20.
• the electrode 21 is disposed on the interfacing layer 22.
• the electrode 21 has a thickness e21 of between 10 ⁇ m and 150 ⁇ m.
• the electrode 21 is formed by depositing a first composition C1 on the interfacing layer 22.
• the electrode 21 is formed by coating the first composition C1 on the interfacing layer 22.
• the first composition C1 comprises an intercalation material M1, a first binder material ML1 and a first conductive additive AC1.
• the intercalation material is also referred to as the "active material”.
• the M1 intercalation material comprises at least silicon.
• the silicon content in the intercalation material M1 is greater than or equal to 30% by mass of the intercalation material M1, preferably greater than or equal to 60% by mass of the intercalation material M1, and is advantageously equal to 100 % by mass of intercalation material Ml.
• the silicon of the intercalation material M1 is in the form of a globally spherical particle having a diameter of between 5 nanometers (nm) and 500 nm, preferably between 10 nm and 200 nm. Alternatively, the silicon of the intercalation material M1 is in the form of flakes or fibers. The silicon of the intercalation material M1 can be coated with carbon. When the silicon content in the first intercalation material MI1 is strictly less than 100%, the intercalation material M1 further comprises a material chosen from mesophase microbeads, commonly designated by the English name “MesoCarbon MicroBeads”.
• MCMB artificial or natural graphites
• graphitic materials such as soft carbon (better known by its English name “soft carbon”) or hard carbon (better known by its English name “hard carbon”)
• compounds based on lithiated titanate such as mTi 5 0i 2 (also designated by the acronym LTO) and compounds based on silicon, tin or alloys.
• the first composition C1 comprises a mass content of intercalation material M1 greater than or equal to 50%, preferably greater than or equal to 60%, advantageously between 60% and 93%, relative to the mass of composition C1.
• the silicon of the electrode 21 is in the form of a dispersion of particles of pure silicon and / or silicon oxide SiO x within the material of the anode 16 (x being an integer equal to 1 or 2 ).
• the silicon and / or silicon oxide particles of electrode 21 are not covalently bonded to another chemical element, such as hydrogen for example. If the silicon has been oxidized, the silicon particles are mainly made up of pure Si and covered with SiO x .
• the mass content of an element in a composition is calculated based on the mass of the total composition.
• the choice of the first binder material ML1 varies considerably provided that the first binder material ML1 is inert with respect to the other materials of the electrode 21.
• the first binding material ML1 is a material, preferably a polymer, which makes it possible to facilitate the use of the electrodes during their manufacture.
• the first ML1 binder material comprises one or more polymers chosen from thermoplastic polymers, thermosetting polymers, elastomers and a mixture of these.
• thermoplastic polymers include, without limitation, polymers resulting from the polymerization of aliphatic or cycloaliphatic vinyl monomers, such as polyolefins (including polyethylenes or even polypropylenes), polymers resulting from the polymerization of aromatic vinyl monomers , such as polystyrenes, polymers resulting from the polymerization of acrylic and / or (meth) acrylate monomers, polyamides, polyetherketones, polyimides.
• polymers resulting from the polymerization of aliphatic or cycloaliphatic vinyl monomers such as polyolefins (including polyethylenes or even polypropylenes)
• aromatic vinyl monomers such as polystyrenes
• acrylic and / or (meth) acrylate monomers such as polystyrenes
• acrylic and / or (meth) acrylate monomers such as polyamides, polyetherketones, polyimides.
• thermosetting polymers include, without limitation, thermosetting resins (such as epoxy resins, polyester resins) optionally in admixture with polyurethanes or with polyether polyols.
• elastomeric polymers include, without limitation, natural rubbers, synthetic rubbers, styrene butadiene copolymers. (also known by the abbreviation “SBR”), ethylene-propylene copolymers (also known by the abbreviation “EPM”) and silicones.
• SBR styrene butadiene copolymers
• EPM ethylene-propylene copolymers
• silicones silicones
• the first binding material ML1 is a mixture of thermoplastic polymer (s), of thermosetting polymer (s) and / or of elastomeric polymer (s).
• first ML1 binder materials include crosslinked polymers, such as those made from polymers having carboxyl groups and crosslinking agents.
• ML1 early binding materials include cellulose derivatives.
• the first composition C1 comprises a content by mass of first binding material ML1 of less than or equal to 30%, preferably less than or equal to 20%.
• the first AC1 conductive additive has one or more types of conductive elements to improve electronic conductivity.
• Examples of conductive elements include, but are not limited to, conductive carbons, graphites, graphenes, carbon nanotubes, activated carbon fibers, unactivated carbon nanofibers, metal flakes, metal powders, metal fibers and electrically conductive polymers.
• a nanofiber is defined as a fiber having a diameter of maximum dimension between 1 nm and 200 nm and extending in a direction normal to said diameter.
• a nanotube is defined as a tube having an outer diameter of maximum dimension between 1 nm and 100 nm and extending in a direction normal to said diameter.
• the first composition C1 comprises a content by mass of the first conductive additive AC1 of less than or equal to 20%, preferably less than 10%.
• the thickness e21 of the electrode 21 varies depending on the amount of silicon included in the electrode 21.
• the electrode 21 is separated from the substrate 20 by the interfacing layer 22.
• the interfacing layer 22 has a first face 221 in contact with the face 212 of the electrode 21, and a second face 222 in contact with the first face 201 of the substrate 20.
• the first face 221 and the second face 222 of the interfacing layer 22 are perpendicular to the stacking direction Z and parallel to each other.
• the interfacing layer 22 has a thickness e22 less than or equal to 10 ⁇ m.
• the thickness e22 is greater than or equal to 10 nm. More preferably, the thickness e22 is greater than or equal to 100 nm.
• the thickness e22 is between 10 nm and 3 ⁇ m.
• the interfacing layer 22 is produced by depositing a second composition C2 on the substrate 20.
• the interfacing layer 22 is produced by coating the second composition C2 on the first face 201 of the substrate 20.
• the second composition C2 comprises a second binder material ML2 and a second conductive additive AC2.
• the second conductive additive AC2 has one or more types of conductive elements to improve electronic conductivity.
• the second conductive additive AC2 is chosen from carbon, carbon black, graphite, graphene, carbon nanotubes, activated carbon fibers, non-activated carbon nanofibers, metal flakes, metal powders , metallic fibers and electrically conductive polymers.
• the second conductive additive AC2 is chosen, without limitation, from carbon nanofibers and carbon nanotubes.
• the second composition C2 comprises a content by mass of second conductive additive AC2 of greater than or equal to 20%.
• the second composition C2 comprises a content by weight of second conductive additive AC2 of less than or equal to 70%.
• the second composition C2 comprises a content by mass of second conductive additive AC2 of between 30% and 60%.
• the choice of the second binder material ML2 is not particularly limited as long as the second binder material ML2 is inert with respect to the other materials of the second composition C2.
• the second ML2 binder material comprises one or more polymers chosen from thermoplastic polymers, thermosetting polymers, elastomers and mixtures thereof.
• thermoplastic polymers include, without limitation, polymers resulting from the polymerization of aliphatic or cycloaliphatic vinyl monomers, such as polyolefins (including polyethylenes or even polypropylenes), polymers resulting from the polymerization of aromatic vinyl monomers , such as polystyrenes, polymers resulting from the polymerization of acrylic and / or (meth) acrylate monomers, polyamides, polyetherketones, polyimides.
• polymers resulting from the polymerization of aliphatic or cycloaliphatic vinyl monomers such as polyolefins (including polyethylenes or even polypropylenes)
• aromatic vinyl monomers such as polystyrenes
• acrylic and / or (meth) acrylate monomers such as polystyrenes
• acrylic and / or (meth) acrylate monomers such as polyamides, polyetherketones, polyimides.
• thermosetting polymers include, without limitation, thermosetting resins (such as epoxy resins, polyester resins) optionally in admixture with polyurethanes or with polyether polyols.
• elastomeric polymers include, without limitation, natural rubbers, synthetic rubbers, styrene butadiene copolymers (also known by the abbreviation "SBR”), ethylene-propylene copolymers (also known by the abbreviation “ EPM ”) and silicones.
• SBR styrene butadiene copolymers
• EPM ethylene-propylene copolymers
• silicones silicones
• Suitable second ML2 binder materials include crosslinked polymers, such as those made from polymers having carboxyl groups and crosslinking agents.
• Suitable second ML2 binder materials include cellulose derivatives.
• the second composition C2 comprises a content by mass of second binding material ML2 of greater than or equal to 30%.
• the second composition C2 comprises a content by mass of second binder material ML2 of less than or equal to 80%.
• the second composition C2 comprises a content by mass of second binder material ML2 of between 40% and 70%.
• the interfacing layer 22 is characterized by the roughness of the first face 221 of the interfacing layer 22.
• the roughness of the first face 221 of the interfacing layer 22 represents the amplitude of the reliefs of the first face 221 of the interfacing layer 22.
• the amplitude of the reliefs of the first face 221 of the layer d 'interfacing 22 corresponds to the distance between the highest point and the lowest point of said reliefs, also called peak-to-valley distance according to English terminology, and denoted Rt.
• the reliefs of the first face 221 of the interfacing layer 22 can also be improperly defined as defects of the first face 221 of the interfacing layer 22.
• the amplitude of the reliefs of the first face 221 of the interfacing layer 22 has a depth of between 10 nm and 10 ⁇ m, preferably between 2 ⁇ m and 9 ⁇ m.
• the amplitude of the reliefs of the first face 221 of the interfacing layer 22 can also have a depth of between 0.5 ⁇ m and 9 ⁇ m, preferably between 0.5 ⁇ m and 8 ⁇ m, more preferably between 0.5 ⁇ m and 6 ⁇ m, advantageously between 1 ⁇ m and 6 ⁇ m.
• the reliefs of the first face 221 of the interfacing layer 22 are the result of the mixing of the constituents of the second composition C2.
• the second conductive additive AC2 and the second binder material ML2 are chosen such that the entanglement of these constituents generates reliefs in a random and relatively homogeneous manner on the total surface of the first face 221 of the interfacing layer 22.
• the mass quantities of the second conductive additive AC2 and of the second binder material ML2 make it possible to modulate the roughness of the first face 221 of the interfacing layer 22.
• the size and shape of the particles of the second conductive additive AC2 also make it possible to modulate the roughness of the first face 221 of the interfacing layer 22.
• particles in the form of flakes or fibers make it possible to generate a greater amplitude of reliefs.
• the roughness of the first face 221 of the interfacing layer 22 is modified by a surface treatment.
• the roughness of the interfacing layer 22 is for example modified by the use of a plasma torch on the surface of the first face 221 of the interfacing layer 22.
• the roughness of the first face 221 of the interfacing layer 22 is determined by measuring white light interferometry, for example using a non-contact nanometric surface topography station of the OptoSurf brand.
• the topography station makes it possible to reconstruct the first face 221 of the interfacing layer 22 in 2D and 3D and then to calculate its roughness.
• the roughness of the first face 221 of the interfacing layer 22 is defined from at least two distinct areas of the first face 221 of the interfacing layer 22.
• the roughness of the first face 221 of the interfacing layer 22 is equal to the average of at least two relief amplitude values, each relief amplitude value corresponding to a distinct zone of the first face 221 of the interfacing layer 22.
• the amplitude of reliefs of a zone distinct from the first face 221 of the interfacing layer 22 represents the distance between the highest point and the lowest point of said zone.
• the surface of each distinct zone of the first face 221 of the interfacing layer 22 measures, for example, 40,000 ⁇ m 2 . In the example proposed, the interfacing layer 22 entirely covers the surface.
• the interfacing layer 22 is perforated.
• the first face 201 of the substrate 20 is thus not entirely covered by the interfacing layer 22.
• the second face 222 of the interfacing layer 22 has an area A22.
• the first face 201 of the substrate 20 has an area A201.
• the interfacing layer 22 is characterized by an coverage rate R (i / s) of the face 201 of the substrate 20.
• the coverage rate R (i / s) corresponds to the ratio between the area A22 of the second face 222 of the interfacing layer 22 and the area A201 of the first face 201 of the substrate 20 and is calculated according to the following formula :
• the recovery rate R (i / s) is between 0.1 and 1.
• the recovery rate R (i / s) is between 0.3 and 1.
• the recovery rate R (i / s) is between 0.7 and 1.
• the coverage rate R (i / s) is strictly less than 1, preferably between 0.1 and 0.9, advantageously between 0.7 and 0.9.
• anode 16 is consistent with the operation of a prior art anode.
• the interfacing layer 22 improves the interface between the substrate 20 and the electrode 21.
• the thickness of less than 10 ⁇ m of the interfacing layer 22 advantageously makes it possible to improve the interface between the substrate 20 and the electrode 21 and to reduce the electrical resistance between the substrate 20 and the electrode 21.
• the presence of the interfacing layer 22 between the substrate 20 and the electrode 21 improves the adhesion between the different layers of the anode 16, which significantly improves its efficiency.
• the perforated appearance of the interfacing layer 22 and the roughness of the second face 222 of the interfacing layer 22 make it possible to reduce the electrical resistance between the substrate 20 and the electrode 21.
• a high resistance acts as a barrier to the transfer of electrons during the cycling of accumulator 10.
• the interfacing layer 22 therefore has a major effect on the electronic conductivity of the anode 16, because it allows a better interface between the substrate 20 and the electrode 21 and preserves a good electrical contact between the substrate 20 and the electrode. 21.
• the presence of the interfacing layer 22 also improves the conduction path.
• the electrochemical performance of the anode 16 is therefore significantly improved by the presence of the interfacing layer 22.
• the improvement of the interface resulting from the perforated appearance of the interfacing layer 22 and the roughness of the second face 222 of the interfacing layer 22 disposed between the substrate 20 and the electrode 21 also limits deterioration and the delamination of the anode 16, caused by the volume expansion of the silicon particles during the charge and discharge cycles of the accumulator 10. The retention of cycling capacity and the life of the anode 16 are thus improved .
• the interface layer 22 consists of a network 38 comprising a plurality of elements 40.
• the elements 40 are uniformly distributed over the entire surface of the first face 201 of the substrate 20.
• the number of elements 40 is denoted by n.
• each element 40 is identical.
• Each element 40 of the interfacing layer 22 is in contact with the first face 201 of the substrate 20 and with the face 212 of the electrode 21.
• Each element 40 of the interfacing layer 22 has a base 401.
• each element 40 is in contact with the first face 201 of the substrate 20.
• Each base 401 is a disk having a larger diameter with a length d1.
• the diameter d1 varies between 200 ⁇ m and 1000 ⁇ m, preferably between 500 ⁇ m and 900 ⁇ m.
• Each base 401 has a center.
• Each base 401 has an area A401.
• each base 401 is between 0.03 square millimeter and 0.8 square millimeter.
• Each element 40 is a volume generated from its base 401.
• the elements 40 are domes.
• Each element 40 of the interfacing layer 22 has a height H40 less than or equal to 10 ⁇ m.
• each element 40 of the interfacing layer 22 has a height H40 less than or equal to 6 ⁇ m. More preferably, each element 40 of the interfacing layer 22 has a height H40 greater than or equal to 10 nm. More preferably, each element 40 of the interfacing layer 22 has a height H40 greater than or equal to 0.5 ⁇ m.
• each element 40 of the interfacing layer 22 has a height H40 of between 10 nm and 3 ⁇ m.
• Such a height H40 of the elements 40 makes it possible to increase the contact surface with the electrode 21, and therefore to improve the electrical contact between the substrate 20 and the electrode 21.
• Such a height H40 of the elements 40 also makes it possible to limit the mechanical stresses linked to the volume variations of the intercalation material M1 of the electrode 21.
• the interface layer 22 is formed of n discrete elements 40 forming the network 38.
• the first face 201 of the substrate 20 is therefore not entirely covered by the plurality of elements 40.
• the interfacing layer 22 is characterized by an coverage rate R (r / s) of the first face 201 of the substrate 20.
• the coverage rate R (r / s) corresponds to the ratio between the area A22 of the interfacing layer 22 and the area A201 of the first face 201 of the substrate 20.
• the area A22 of the interfacing layer 22 is defined as the sum of the areas A401 of the base 401 of the n elements 40 of the interfacing layer 22.
• the area A22 of the interfacing layer 22 is calculated according to the following formula: where i denotes the ith area A401.
• the bases 401 are all identical and the area A22 of the interfacing layer is calculated according to the following formula:
• the recovery rate R (r / s) is calculated according to the following formula:
• the recovery rate R (r / s) is between 0.1 and 0.9.
• the coverage rate R (r / s) is between 0.2 and 0.5.
• first face 201 of the substrate 20 is not entirely covered by the interfacing layer 22 makes it possible to generate a relief on the first face 201 of the substrate 20, which makes it possible to increase the contact surface with the electrode. 21, and therefore to improve the electrical contact between the substrate 20 and the electrode 21.
• This also makes it possible to limit the mechanical stresses generated by the volume variations of the active material of the electrode 21 during the operation of the accumulator 10. Modulating the coverage rate R (r / s) also makes it possible to reduce the electrical resistance between the substrate 20 and the electrode 21 relative to the case where the coverage rate is equal to 1.
• the elements 40 of the interfacing layer 22 are produced by depositing a third composition C3 on the first face 201 of the substrate 20.
• the elements elements 40 of the interfacing layer 22 are produced by coating the third composition C3 on the first face 201 of the substrate 20.
• the third composition C3 comprises a third conductive additive AC3 and optionally a third binder material ML3.
• the third composition C3 consists of a third conductive additive AC3 and a third binder material ML3.
• the third conductive additive AC3 comprises one or more conductive elements to improve electronic conductivity.
• the third conductive additive AC3 is chosen from carbon, carbon black, graphite, graphene, carbon nanotubes, activated carbon fibers, non-activated carbon nanofibers, metal flakes, metal powders , metallic fibers and electrically conductive polymers.
• the third composition C3 comprises a content by mass of third conductive additive AC3 of greater than or equal to 20%.
• the third composition C3 comprises a content by mass of third conductive additive AC3 of less than or equal to 90%.
• the content by mass of third conductive additive AC3 included in the third composition C3 is between 40% and 70%.
• the third ML3 binder material consists of one or more polymers, chosen from thermoplastic polymers, thermosetting polymers, elastomers and mixtures thereof.
• thermoplastic polymers thermosetting polymers and elastomers are as defined above.
• the third composition C3 comprises a content by mass of third binding material ML3 of greater than or equal to 10%.
• the third composition C3 comprises a content by mass of third binding material ML3 of less than or equal to 80%.
• the content by mass of third binder material ML3 included in composition C3 is between 30% and 60%.
• n elements 40 of the interfacing layer 22 are arranged in different variants.
• the n elements 40 of the interfacing layer 22 are arranged in respective unit cells, each unit cell being identical.
• the n elements 40 of the interfacing layer are distributed randomly on the first face 201 of the substrate 20.
• the elementary mesh 50 of the interfacing layer 22 is provided by four bases 401 arranged in a square.
• the elementary mesh 50 has a side defined by a segment connecting the center of two adjacent bases 401.
• the side of the elementary mesh 50 has a length c1 of between 400 ⁇ m and 3500 ⁇ m, preferably between 600 ⁇ m and 2000 ⁇ m.
• the network 38 is a set corresponding to the periodic repetition of the elementary cell 50 in X and Y directions, the X and Y directions being normal to each other and normal to the Z direction.
• the organization of the interface layer 22 into a plurality of elements 40 arranged in a network formed of an elementary mesh makes it possible to have a homogeneous anode over its entire dimension.
• the repeatability of the pattern ensures better reproducibility of the anode and better reproducibility of electrochemical performance.
• the bases 401 of the elements 40 of the interfacing layer 22 are squares.
• Each base 401 is defined by a diagonal having a length d2.
• the length d2 varies between 200 ⁇ m and 1200 ⁇ m, preferably between 500 ⁇ m and 1000 ⁇ m.
• the elementary mesh 60 of the interfacing layer 22 is provided by five bases 401 forming a centered square.
• the elementary mesh 60 has a side defined by a segment connecting the center of two adjacent bases 401 chosen from among the four bases 401 forming the square.
• the side of the elementary cell 60 is defined by a length c2.
• the length c2 varies between 400 ⁇ m and 3700 ⁇ m, preferably between 600 ⁇ m and 2200 ⁇ m.
• the network 38 is then a set corresponding to the periodic repetition of the elementary cell 60 in X and Y directions, the X and Y directions being normal to each other and normal to the Z direction.
• the operation of the anode 16 according to the variant shown in Figure 5 is in accordance with the operation of the anode 16 as shown in Figures 3 and 4.
• the organization of the n elements 40 in staggered rows makes it possible to increase the coverage rate R (r / s), and therefore to increase the contact surface with the electrode 21.
• the fact that the bases 401 of the elements 40 are squares also makes it possible to increase the recovery rate R (r / s).
• the elementary mesh consists of an elementary mesh 70 corresponding to the elementary mesh 60 according to FIG. 5 in which the bases 401 are disks.
• Each base 401 is defined by a diameter having a length d3.
• the length d3 varies between 200 ⁇ m and 1200 ⁇ m, preferably between 500 ⁇ m and 1000 ⁇ m.
• the elementary mesh 70 has a side defined by a length c3.
• the length c3 varies between 400 ⁇ m and 3500 ⁇ m, preferably between 600 ⁇ m and 2000 ⁇ m.
• the network 38 is then a set corresponding to the periodic repetition of the elementary cell 70 in X and Y directions, the X and Y directions being normal to each other and normal to the Z direction.
• the organization of the n elements 40 in a staggered manner makes it possible to increase the recovery rate R (r / s), and therefore to increase the contact surface with the electrode 21.
• the n elements 40 of the interfacing layer 22 are randomly distributed over the first face 201 of the substrate 20.
• Two adjacent elements 40 are separated by a Dadj distance, the Dadj distance being the smallest distance between two points of the two adjacent elements 40.
• Two adjacent elements 40 form a pair of adjacent elements 40, the pair of adjacent elements 40 consisting of a first element 40 and a second element 40.
• Each element 40 of the interfacing layer 22 is included in at least one part. minus a pair of adjacent elements 40.
• the distance Dadj represents the smallest distance between a point on the base 401 of the first element 40 of the pair of adjacent elements 40 and a point on the base 401 of the second element 40 of the pair of adjacent elements 40.
• the distance Dadj of each pair of adjacent elements 40 of the interfacing layer 22 is between 200 ⁇ m and 2500 ⁇ m, preferably between 400 ⁇ m and 1000 ⁇ m.
• each element 40 of the interface layer 22 is separated from all of the elements 40 which are adjacent to it by a distance Dadj of between 200 pm and 2500 pm, preferably between 400 pm and 1000 pm.
• Each base 401 has the same shape, the shape being chosen from one of the bases 401 according to Figures 4, 5 and 6.
• the organization of the interface layer 22 into a plurality of elements 40 arranged in an array allows for a homogeneous anode over its entire dimension.
• each element 40 of the interface layer 22 is a polygon or an oval.
• the geometry of the base 401 of the elements 40 makes it possible to adjust the recovery rate R (r / s).
• Each base 401 of the elements 40 of the interfacing layer 22 is in contact with the first face 201 of the substrate 20.
• Each element 40 also has a surface 402. The surfaces 402 of the elements 40 are not in contact with the first face. 201 of substrate 20.
• the surface 402 of each element 40 has roughness.
• the roughness of the surface 402 of each element 40 represents the amplitude of the relief on the surface 402 of each element 40.
• the roughness of the surface 402 of each element 40 is determined using the same method as that described above to determine the roughness of the second face 222 of the interfacing layer 22.
• the roughness of the surface 402 of each element 40 is between 10 nm and 10 ⁇ m, preferably between 0.5 ⁇ m and 9 ⁇ m, preferably between 0.5 ⁇ m and 8 ⁇ m, more preferably between 0 , 5 pm and 6 pm, advantageously between 1 pm and 6 pm, more advantageously between 2 pm and 6 pm.
• the roughness of the surface 402 of each element 40 is modulated by the size, shape and quantity of the constituents of composition C3.
• the anode 16 comprises two interfacing layers 22.
• the two interfacing layers 22 are superimposed on top of each other in the Z stacking direction.
• the first interfacing layer 22 is in contact with the first face 201 of the substrate 20 and the second interfacing layer 22 is in contact with the face 212 of the electrode.
• the first interfacing layer 22 corresponds to the interfacing layer 22 according to Figure 2.
• the second interfacing layer 22 corresponds to the interfacing layer 22 according to Figures 3 to 6.
• the anode 16 comprises a number p of interfacing layers 22, p being an integer greater than or equal to two. Preferably, p is between 2 and 4.
• the p interfacing layers 22 of the anode 16 are superimposed on each other in the stacking direction Z.
• the p interfacing layers 22 of the anode 16 are deposited one on top of the other successively by depositing, preferably by coating, the second composition C2 or the third composition C3.
• the second composition C2 and the third composition C3 are different for each of the p interfacing layers 22.
• the presence of at least two interfacing layers 22 makes it possible to generate more relief than in the case where a single interfacing layer 22 is present, which makes it possible to increase the contact surface with the electrode. 21, and therefore to improve the electrical contact between the substrate 20 and the electrode 21.
• By modulating the compositions as well as the coverage rate of the at least two interfacing layers it is possible to shape the interfaces between the different layers. and to increase the electrochemical performance of the anode 16.
• the composition of the first interfacing layer 22 can for example improve the adhesion of the electrode 21 to the substrate 20, while the composition of the second interfacing layer 22 would significantly increase the conductivity within the anode 16.
• the interfacing layer 22 has roughness.
• the interfacing layer 22 has a face which is not in contact with the first face 201 of the substrate 20.
• the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20 corresponds to the face 221 of FIG. 2, or to all of the faces 402 of the discrete elements 40 of Figure 3.
• the roughness of the interfacing layer 22 represents the amplitude of the relief of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20.
• the roughness of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20 is determined by measuring white light interferometry, for example using a non-contact surface topography station nanometer from the OptoSurf brand.
• the topography station makes it possible to reconstruct the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20 in 2D and 3D to determine its roughness.
• the roughness of the interfacing layer 22 is defined from at least two distinct zones of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20. For each zone, the roughness of the interfacing layer 22 is defined.
• the amplitude of the reliefs Rt is determined, that is to say the distance between the highest point and the lowest point of said zone.
• the roughness of the interfacing layer 22 is equal to the average, denoted Rtm, of at least two relief amplitude values Rt, each relief amplitude value Rt corresponding to a distinct zone of the face of the layer interface 22 which is not in contact with the first face 201 of the substrate 20.
• the advantage of dividing the surface of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20 into at least two distinct zones for measuring the average of the amplitude of the reliefs is limit the uncertainty linked to a possible inhomogeneity of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20.
• each distinct zone of the face of the interfacing layer 22 which is not in contact with the first face 201 of the substrate 20 defined to determine the roughness of the interfacing layer 22 measures for example 40,000 ⁇ m 2 .
• the roughness of the interfacing layer 22 is between 10 nm and 10 ⁇ m, preferably between 0.5 ⁇ m and 9 ⁇ m, preferably between 0.5 mhi and 8 mhi, more preferably between 0.5 pm and 6 pm, advantageously between 1 pm and 6 pm, more advantageously between 2 pm and 6 pm.
• the roughness of the interfacing layer 22 makes it possible to generate better electrical percolation within the electrode 21 and to increase the electron exchange surface with the current collector 23.
• the interfacing layer 22 has an coverage rate R (ci / s) of the first face 201 of the substrate 20 which is strictly less than 1.
• R (ci / s) of the first face 201 of the substrate 20 is strictly less than 1.
• the first face 201 of the substrate 20 is not thus not entirely covered by the interfacing layer 22.
• the interfacing layer 22 has one face in contact with the first face 201 of the substrate 20.
• the face of the interfacing layer 22 in contact with the first face 201 of the substrate 20 corresponds to the face 222 of Figure 2, or to the set of bases 401 of the discrete elements 40 of Figure 3.
• the face in contact with the first face 201 of the substrate 20 has an area A22.
• the first face 201 of the substrate 20 has an area A201.
• the coverage rate R (ci / s) of the first face 201 of the substrate 20 corresponds to the ratio between the area A22 of the face in contact with the first face 201 of the substrate 20 and the area A201 of the first face 201 of the substrate 20, and is calculated according to the following formula:
• the degree of recovery R (ci / s) is preferably greater than or equal to 0.1.
• the coverage rate R (ci / s) is between 0.1 and 0.9, advantageously between 0.2 and 0.9.
• Modulating the coverage rate of the first face 201 of the substrate 20 makes it possible to reduce the electrical resistance between the substrate 20 and the electrode 21 compared to the case where the substrate 20 is entirely covered by the interfacing layer 22 (coverage rate equal to 1).
• the current collector 23 associated with the electrode 21 to form the anode 16 comprises two interfacing layers 22.
• the first and second interface layers 22 have both a roughness as defined above, and a coverage rate of the first face 201 of the substrate 20 strictly less than 1.
• the inventors believe that the fact that the electrons have at least four possible paths to go from the electrode 21 to the substrate 20 (by passing directly from the electrode 21 to the substrate 20 without passing through any interfacing layer, passing only through the first interfacing layer 22, passing only through the second interfacing layer 22 or passing through the two interfacing layers 22, as shown in Figure 9), each path having different conductivity characteristics allowing the electrons to take one or more paths in a preferential manner, the transmission of the electrons is improved.
• the first face 201 of the substrate 20 is preferably substantially smooth.
• substantially smooth is meant that the roughness of the surface of the substrate 20, measured using a profilometer, is less than or equal to 500 nm, preferably less than or equal to 200 nm, preferably less than or equal to 80 nm, more preferably less or equal to 50 nm, advantageously less than or equal to 20 nm.
• the thickness e22 of the interfacing layer 22 is preferably between 10 nm and 10 ⁇ m. If the thickness of the interfacing layer 22 is thicker than 10 ⁇ m, the interfacing layer then occupies a volume and has too great a mass to the detriment of the materials constituting the electrode, which would induce a loss in density d energy within the electrochemical cell.
• the minimum thickness of the interfacing layer 22 is controlled by the application process and / or the composition from which / from which it is obtained. For example, an interfacing layer produced by liquid coating may have a thickness greater than or equal to 100 nm.
• the thickness e22 of the interfacing layer 22 is greater than or equal to 100 nm.
• the thickness e22 of the interfacing layer 22 is between 0.5 ⁇ m and 6 ⁇ m.
• the thickness of the interfacing layer 22 corresponds to the maximum thickness of said interfacing layer 22.
• the presence of at least one interfacing layer 22 makes it possible to limit the deterioration as well as the delamination of the anode 16, caused by the volume expansion of the intercalation material of the electrode 21. This phenomenon is particularly present in silicon anodes, this active material being able to reach volume changes of 300%.
• Example 1 Measurement of the roughness of the interfacing layer as a function of its composition The roughness of three different interfacing layers was measured.
• the composition of these three interfacing layers differs in that the rate of fibers among the conductive additives is different in each of the layers, which makes it possible to assess the impact of the shape of these additives on the roughness of the layers of interfacing.
• the compositions of the three interfacing layers are as follows: Formulation A: 0% w fibers for 100% w conductive additives
• Formulation B 23% w fibers for 100% w conductive additives
• Formulation C 39% w fibers per 100% w conductive additives The remainder of the conductive additives consists of egg-shaped particles.
• the Rtm measurement corresponds to the average of the Rt measurements of each zone, the analysis surface of each interfacing layer being divided into 25 zones.
• a characterization method has been developed to assess the quality of the adhesion of the interfacing layer to the substrate. For this, a peel strength characterization is performed on a substrate coated with one or more interfacing layers through an adhesive.
• the protocol is as follows:
• Sample A interfacing layer formed from a C2 composition whose content by mass of binder material is between 60% and 65%, the content by mass of conductive additive is between 35% and 40 %, deposited on a copper foil with a recovery rate of 0.9.
• Sample B interfacing layer formed from a C3 composition whose content by mass of binder material is between 50% and 55%, the content by mass of conductive additive is between 45% and 50 %, deposited on a copper foil with a recovery rate of 0.27.
• Sample C first interfacing layer formed from a C2 composition identical to that of the EchA sample, deposited on a copper sheet and formation of a second interfacing layer formed from a composition C3 identical to the EchB sample deposited on the interfacing layer of composition C2, thus forming a superposition of interfacing layers.
• composition C2 The nature of the binder material and that of the conductive additive are the same between composition C2 and composition C3.
• the peel resistance of the interfacing layers of the different samples was characterized using the protocol detailed above.
• composition C3 It can also be assumed that a similar result would be obtained if the nature of the binder material of composition C3 was different from that of composition C2. Indeed, the choice of the binder material of composition C3 can be adapted for better compatibility with the composition of the electrode and the adhesion of this assembly to the metal sheet is ensured by composition C2. Thus, this shaping makes it possible to widen the choice of the binder material and / or of the conductive additive as well as their mass content in the composition of the interfacing layer in contact with the electrode because the latter is not not limited by its ability to adhere to the metal foil.
• the electrochemical cells are made with the following successive layers:
• the intercalation material M1 being Silicium S'tile, ML1 binding material of PAA (ThermoFisher Scientific), the conductive additive AC1 of SUPER P®-Li carbon (Imerys Graphite & Carbon )
• a lithium metal counter-electrode A lithium metal counter-electrode.
• a reference current collector (CCREF1), as a comparative example, composed of a copper sheet (Circuit Foil) with a thickness of 10 ⁇ m, without interfacing layer
• a reference current collector 2 (CCREF2), as a second comparative example, composed of a copper foil (Circuit Foil) with a thickness of 10 ⁇ m, as well as an interfacing layer with a coverage rate of 1 (100%), composed of 45% conductive additive and 55% binder material, with a thickness of 3 ⁇ m, and a roughness of 0.5 ⁇ m.
• a current collector composed of a copper sheet (Circuit Foil) with a thickness of 10 ⁇ m, as well as an interfacing layer structured in a network of plurality of elements arranged in staggered rows, of which the base of each element is a square, the coverage rate of 0.27 (i.e. 27% on the surface of the substrate), composed of 45% of conductive additive and 55% of material binder, with an element height of 3 ⁇ m.
• a current collector composed of a copper sheet (Circuit Foil) with a thickness of 10 ⁇ m, as well as an interfacing layer structured in a network of a plurality of elements, of which the base of each element is a disk, the coverage rate of 0.21 (i.e. 21% on the surface of the substrate), composed of 45% conductive additive and 55% binder material, element height of 3 ⁇ m.
• a current collector composed of a copper sheet (Circuit Foil) with a thickness of 10 ⁇ m, as well as an interfacing layer structured in a network of a plurality of elements arranged in staggered rows, the base of each element of which is a disk, the coverage rate of 0.27 (i.e. 27% on the surface of the substrate), composed of 45% of conductive additive and 55% of binder material, element height of 2 ⁇ m.
• the electrochemical performances of the cells were characterized by a VMP3 multipotentiostat (Biology).
• a training cycle between 1, 2 V and 10mV vs Li / Li + at the speed C / 20 was carried out in order to form the solid electrolyte interphase layer (SEI) on the silicon electrode and ensure that the electrode is functional.
• SEI solid electrolyte interphase layer
• EIS electrochemical impedance spectroscopy
• Electrochemical impedance spectroscopy is a useful technique for studying electrochemical and physical phenomena at the current collector / electrode / electrolyte interfaces of the electrochemical cell. It is based on the study of the transfer function of these electrochemical systems in stationary and linear regimes. To place itself in these conditions with nonlinear systems, a low amplitude disturbance is applied around the operating point assumed to be quasi stationary (system at equilibrium). In this work, impedance measurements were performed by applying a sinusoidal potential disturbance with an amplitude of 5 mV around the equilibrium voltage of the system.
• the impedance spectra obtained correspond to the different contributions within an electrochemical cell: contact resistances which may result from the assembly of the electrochemical cell and of the current collector, charge transfer resistance, diffusion Li + ions within the electrodes etc.
• contact resistances which may result from the assembly of the electrochemical cell and of the current collector
• charge transfer resistance which may result from the assembly of the electrochemical cell and of the current collector
• diffusion Li + ions within the electrodes etc.
• R EIS also called impedance

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