Current collector, an assembly that forms an anode or a cathode and a device for storing electrical energy.

Abstract

“current collector, assembly forming an anode or a cathode and electrical energy storage device” the invention relates to a current collector (22) of an electrochemical actuator, the current collector (22) being coated with an interface layer (20), the interface layer (20) being formed by coating the current collector (22) with a composition, the composition being formed by particles, at least 50% of the particles having a volume average diameter less than or equal to 10 micrometers

Description

1 / 17 “CURRENT COLLECTOR, ASSEMBLY CONSISTING OF AN ANODE OR A CATHODE AND ENERGY STORAGE DEVICE ELECTRICAL Technical Field of the Invention

[001] The present invention relates to a coated current collector. The invention also relates to an assembly and a storage device including such a current collector. Background of the Invention

[002] A conventional electrochemical accumulator comprises at least four elements: a positive electrode, a negative electrode, an electrolyte, and current collectors for each electrode. The combination of a negative electrode and a current collector forms an anode, while the combination of a positive electrode and a current collector forms a cathode.

[003] The operating principle of these accumulators is based on the reversible storage of electrical energy into chemical energy, using two separate and coupled electrochemical reactions. The positive and negative electrodes, which are immersed in the electrolyte, are the site of the electrochemical reactions, called faradic reactions. The electrodes are mainly made from active materials that enable the storage and release of ions through oxidation and reduction reactions.

[004] During discharge, the active material in the negative electrode oxidizes and releases some of the electrons that are transported through the current collector towards the external circuit and, on the other hand, cations that migrate through the electrolyte towards the positive electrode. Then, the electrons that passed through the circuit, which used their energy, and the cations, are captured by the active material in the positive electrode, which is reduced. The energy density that a battery can release depends on the potential and capacity of the electrochemical cell, which are directly connected to Petition 870260069239, dated 07 / 13 / 2026, page 12 / 54 2 / 17 System chemistry. The potential of a battery is determined by the difference between the potentials of the oxidation-reduction reactions that occur simultaneously at the positive and negative electrodes.

[005] The electrodes are made according to a composition, the composition mainly including one or more active materials (> 90% by weight), conductive particles that ensure good transport of electrons to the set of active materials and a binder that makes it possible to ensure the cohesion of the particles as well as adhesion to the substrate.

[006] The whole thing is usually manufactured in the form of a formulation comprising at least one solvent that will make it possible to coat the electrode.

[007] Next, the two positive and negative electrodes are ionically linked by an electrolyte. This can be liquid, gel, or solid.

[008] Due to the intrinsic ion migration operation of accumulators, their electrodes need materials capable of inserting or removing ions. Therefore, many developments are carried out to optimize these electrodes and obtain higher specific energy and power densities. The selection criteria are based essentially on the available capacity and operating potential – and therefore the available energy – but also on the power or safety and cost of the materials.

[009] Mass energy or specific energy is defined as the ratio between the recoverable energy at a specific degree (discharge rate C at which the battery is discharged) and the mass of the battery. Mass energy is expressed in Wh / kg.

[010] This concept is particularly useful for sizing a battery in integrated systems where mass is a predominant sizing criterion. Petition 870260069239, dated 07 / 13 / 2026, page 13 / 54 3 / 17

[011] Volume energy is the ratio between the recoverable energy at a given level and the volume of the accumulator. Volume energy is expressed in Wh / L. This concept is useful for sizing a stationary battery, since in these applications, volume is often a more decisive criterion than mass.

[012] Lithium technologies have the best characteristics in terms of mass-to-volume energy density. Therefore, these technologies are preferentially chosen for mobile applications, such as mobile telephony or laptop computers.

[013] However, for certain applications, and in particular in the automotive field, limiting the voltage of these typical batteries to voltages less than or equal to 3.5 Volts (V) is problematic. Therefore, it is desirable to use lithium-ion type batteries with a higher voltage, in particular around 4.2 Volts (V).

[014] With such a significant increase in stress, corrosion phenomena are more pronounced.

[015] To solve this problem, the US document Brazilian patent application 2012 / 0121974 proposes the combination of two elements. According to the first element, the cathode current collector is protected by a porous conductive protective coating. The porous coating comprises conductive carbon or graphite. Corrosion protection also involves a modification of the electrolytic solution, particularly with the addition of additives such as LiBOB or LiPF6.

[016] However, modifying the electrolyte is expensive, on the one hand, and, on the other hand, affects battery performance. Brief Description of the Invention

[017] There is therefore a need for a current collector for an electrode, making it possible to obtain an accumulator possessing Petition 870260069239, dated 07 / 13 / 2026, page 14 / 54 4 / 17 better performance levels and, at the same time, capable of delivering a higher voltage than the voltages delivered in the state of the art, in particular a voltage greater than 3.5 Volts.

[018] In fact, the choice of corrosive materials that allow achieving better levels of performance in terms of potential is advantageous for battery manufacturers to be able to develop their electrochemical system from an enhanced current collector and, therefore, the properties are stable over time.

[019] To this end, the present invention relates to a current collector of a device for storing electrical energy, the current collector being coated with an interface layer, the interface layer being formed by coating the current collector with a second composition (the composition being the second according to the specification name), the composition being formed by particles, at least 50% of the particles having a volume average diameter less than or equal to 10 micrometers.

[020] The expression “formed by” should be understood as “made of”, that is, in this context, the particle diameters are measured in the composition after its information and not at insertion.

[021] According to specific embodiments, the collector comprises one or more of the following features, considered alone or in combination with any technically feasible options:

[022] - The interface layer is a layer that acts as a physical barrier to the access of ions responsible for corrosion.

[023] - The interface layer is a layer that prevents oxidation of the current collector, even when the operating potential of the device for storing electrical energy is greater than or equal to the oxidation potential of the current collector material.

[024] - The current collector is adapted for a device for Petition 870260069239, dated 07 / 13 / 2026, page 15 / 54 5 / 17 storing electrical energy comprising an electrolyte comprising ionic salts selected from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiTF), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB) and a mixture thereof.

[025] - The ionic salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[026] - At least 90% of the particles have a volume average diameter less than or equal to 15 micrometers.

[027] - At least 99% of the particles have a diameter less than or equal to 10 micrometers.

[028] - The composition comprises a conductive material and a binding material.

[029] - The second composition consists of a conductive additive, a solvent and a binding material.

[030] - The conductive material comprises at least one element chosen from the list consisting of carbon, carbon black, graphite, graphene, a carbon nanotube, an activated carbon fiber and a non-activated carbon nanofiber.

[031] - The interface layer has a thickness greater than or equal to 1 micrometer.

[032] - The interface layer has a thickness less than or equal to 4 micrometers, preferably less than or equal to 2 micrometers.

[033] The present invention also describes an assembly forming an anode or cathode including an electrode and a current collector, as described above.

[034] The present invention also relates to an electrical energy storage device, electrochemical accumulator or Petition 870260069239, dated 07 / 13 / 2026, p. 16 / 54 6 / 17 supercapacitor, including an assembly as described previously. Brief Description of the Figures

[035] Other features and advantages of the invention will become apparent after reading the following description of embodiments of the invention, provided only as examples and with reference to the drawings, which are: - [Fig. 1] - Figure 1, a schematic illustration of a battery accumulator including an anode and a cathode; - [Fig. 2] - Figure 2, a schematic side-section illustration of the accumulator cathode from Figure 1; - [Fig. 3] - Figure 3, a scanning electron microscopy photograph of a coated collector according to the state of the art; and - [Fig. 4] - Figure 4, a scanning electron microscopy photograph of a coated collector used to form the cathode of Figure 2. Detailed Description of the Invention

[036] The accumulator (10) is intended to be connected to other electric accumulators in order to form an electric generator of desired voltage and capacity. This generator is called an accumulator battery or, more simply, a battery.

[037] An accumulator (10) uses a reversible energy conversion technique to store energy and retrieve it later.

[038] The accumulator (10) described using an electrochemical reaction, the accumulator (10) is an electrochemical accumulator.

[039] The accumulator (10) comprises an electrolyte (12), an anode (14) and a cathode (16).

[040] Typically, the electrolyte (12) is composed of different ionic salts that contribute ions used for charge storage or faradic reactions of carbonates and a solvent or mixture of solvents to allow the solubilization of the ions. Petition 870260069239, dated 07 / 13 / 2026, page 17 / 54 7 / 17

[041] The electrolyte (12) is composed of different ionic salts that contribute ions used for charge storage or faradic reactions of carbonates and a solvent or mixture of solvents to allow the solubilization of the ions.

[042] Preferably, the ionic salts are chosen from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiTF), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), and a mixture thereof.

[043] Carbonates are, for example, propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) or diethyl carbonate (DEC).

[044] It is also possible to find, in smaller proportions, methyl acetate or methyl formate, acetonitrile, tetrahydrofuran or gamma-butyrolactone, in binary or ternary mixtures, or even quaternary mixtures thereof, as well as ionic liquids.

[045] Typically, the anode (14) is composed of an ion insertion material, for example, in a lithium-ion accumulator, carbon, which is mainly used in the form of “MesoCarbon MicroBeads” (MCMB), graphite, whether artificial or natural, or graphitic materials, such as soft or hard carbon, or other types of negative electrode materials based on lithium titanate (Li4TiO2 or LTO), silicon, tin, or alloys.

[046] The cathode (16) is shown in more detail in Figure 2.

[047] The cathode (16) comprises an electrode (18), a current collector (22) and an interface layer (20).

[048] The current collector (22), the interface layer (20) and the electrode (18) form a stack of layers in a stacking direction indicated as (Z). Petition 870260069239, dated 07 / 13 / 2026, page 18 / 54 8 / 17

[049] The electrode (18) is in contact with the electrolyte (12).

[050] The electrode (18) is made of a first composition (C1), whose properties will now be described.

[051] The first composition (C1) comprises a first insert material (MI1), a first binder material (ML1) and a first conductive additive (AC1).

[052] The insertion material is also known as “active material”.

[053] In a lithium-ion accumulator, the active material (MI1) of the electrode (18) is conventionally composed of lithium metal oxide, for example LiCoO2 (LCO), LiNiMnCoO2 (NMC), LiNiCoAlO2 (NCA), LiMn2O4 (LMO), LiFePO4 (LFP) Li (LiNiMn)O2 or LiNiMnO (LNMO); LiS. Other examples of active electrode material (18) are possible, for example, for sodium-ion batteries, such examples are listed in the publication “Advanced Organic Electrode Materials for Rechargeable Sodium-Ion Batteries”. Zhao, Q., Lu, Y., & Chen, J. Advanced Energy Materials (2016).

[054] The choice of the first binder material (ML1) can vary considerably as long as the first binder material (ML1) is inert in relation to the other electrode materials. The first binder material (ML1) is typically a polymeric material, which facilitates the use of electrodes during their manufacture. The first binder material (ML1) typically comprises one or more polymers chosen from thermoplastic polymers, thermosetting polymers, elastomers, and mixtures thereof.

[055] Examples of thermoplastic polymers include, but are not limited to, polymers derived from the polymerization of aliphatic or cycloaliphatic vinyl monomers, such as polyolefins (including polyethylenes or polypropylenes), polymers derived from the polymerization of vinyl monomers Petition 870260069239, dated 07 / 13 / 2026, page 19 / 54 9 / 17 aromatics, such as polystyrenes, polymers derived from the polymerization of acrylic monomers and / or methacrylates, polyamides, polyether ketones, polyimides.

[056] Examples of thermosetting polymers include, but are not limited to, thermosetting resins (such as epoxy resins or polyester resins), optionally blended with polyurethanes or with polyether polyols or vice versa.

[057] Examples of elastomeric polymers include, but are not limited to, natural rubbers, synthetic rubbers, styrene-butadiene copolymers (also referred to using the abbreviation “SBR”), ethylene-propylene copolymers (also referred to using the abbreviation “EPM”), silicones.

[058] The first binder material (ML1) may be a mixture of thermoplastic polymer(s), thermosetting polymer(s) and / or elastomeric polymer(s).

[059] Other suitable first binder(s) material(s) (ML1) comprise(s) crosslinked polymers, such as those manufactured from polymers with carboxyl groups and crosslinking agents.

[060] The first conductive additive (AC1) comprises one or more types of conductive elements to improve electronic conductivity.

[061] Examples of conductive elements include, but are not limited to, conductive carbons, graphites, graphenes, carbon nanotubes, activated carbon fibers, non-activated carbon nanofibers, metal sheets, metal powders, metallic fibers and electrically conductive polymers.

[062] As an example, the thickness (e18) of electrode (18) is 50 pm.

[063] The current collector (22) is made from a material that is conductive enough to ensure electronic transport, light, thin, mechanically strong to serve as a substrate for the electrode (18).

[064] For example, the current collector (22) is a metal strip Petition 870260069239, dated 07 / 13 / 2026, page 20 / 54 10 / 17 made from iron, copper, aluminum, nickel, titanium, or stainless steel.

[065] Preferably, the current collector (22) is a metal strip made of aluminum.

[066] As an example, the thickness (e22) of the current collector (22) is 20 pm.

[067] The interface layer (20) forms an interface between the current collector (22) and the electrode (18).

[068] This, in particular, means that the interface layer (20) is a layer in contact, on the one hand, with the current collector (22) and, on the other hand, with the electrode (18).

[069] The interface layer (20) is coated on the current collector (22).

[070] The interface layer (20) has a thickness (e20) greater than or equal to 1 micrometer (pm).

[071] Preferably, the interface layer (20) has a thickness (e20) greater than or equal to 2 pm.

[072] Advantageously, the interface layer (20) has a thickness (e20) between 1 pm and 4 pm.

[073] The interface layer (20) is made according to a second composition (C2).

[074] The second composition (C2) comprises a second binder material (ML2) and a second conductive additive (AC2).

[075] Advantageously, the second composition (C2) consists of a second binder material (ML2), a second conductive additive (AC2) and a second solvent (S2).

[076] In each of the cases mentioned above, the second composition (C2) comprises a plurality of particles.

[077] These particles can have all sorts of shapes. From Petition 870260069239, dated 07 / 13 / 2026, page 21 / 54 11 / 17 preference, the particles are spherical.

[078] For each particle, a diameter is defined as the maximum distance between two points on the particle's surface.

[079] The diameter is, for example, measured by a laser particle size analysis technique.

[080] The technique for measuring particle size by laser diffraction measures the particle size distribution of particles by measuring the angular variation in the intensity of scattered light when a laser beam passes through a sample of dispersed particles. Large particles scatter light at small angles relative to the laser beam, and small particles scatter light at larger angles.

[081] Among the particles of the second composition (C2), a proportion of particles have a volume average diameter less than or equal to a threshold diameter.

[082] In each of the cases, at least 50% of the particles have a volume average diameter (called Dv50) less than or equal to 10 micrometers.

[083] The volume average diameter is a particle size distribution parameter (see, in particular, A Basic Guide to Particle Characterization, page 10, published by Malvern Instruments Limited in 2012).

[084] The volume average diameter of the particles (such as Dv50) can be measured by static light using a commercial particle size analyzer, such as the Malvern MasterSizer 3000 machine. The data are processed based on Mie scattering theory in order to calculate the particle size distribution of the particles based on a spherical equivalent volume model. More specifically, this theory, which is accurate for isotropic particles, allows us to determine, in the case of non-spherical particles, a Petition 870260069239, dated 07 / 13 / 2026, page 22 / 54 12 / 17 effective particle diameter. This theory is described, in particular, in the publication by Van de Hulst, HC, “Light Scattering by Small Particles”, chapters 9 and 10, Wiley, New York, 1957.

[085] According to a first example, the ratio is greater than or equal to 90% and the threshold diameter is less than or equal to 30 pm, preferably less than or equal to 20 pm and even more preferably less than or equal to 10 pm.

[086] Advantageously, the threshold diameter is less than or equal to 5 pm.

[087] Thus, according to this first example, at least 90% of the particles have a volume average diameter (called Dv90) less than or equal to 30 micrometers.

[088] According to a second example, the ratio is greater than or equal to 99% and the threshold diameter is less than or equal to 40 pm, preferably less than or equal to 30 pm and, even more preferably, less than or equal to 20 pm.

[089] Advantageously, the threshold diameter is less than or equal to 10 pm.

[090] Thus, according to this second example, at least 99% of the particles have a volume average diameter (called Dv99) less than or equal to 40 micrometers.

[091] According to a third example, the ratio is greater than or equal to 75% and the threshold diameter is less than or equal to 25 pm, preferably less than or equal to 15 pm and, even more preferably, less than or equal to 5 pm.

[092] Advantageously, the threshold diameter is less than or equal to 3 pm.

[093] Thus, according to this third example, at least 75% of the particles have a volume average diameter (called Dv75) less than or equal to 25 micrometers.

[094] According to a fourth example, the ratio is greater than or equal to 50% and the threshold diameter is less than or equal to 5 pm and, even more preferably, less than or equal to 3 pm. Petition 870260069239, dated 07 / 13 / 2026, p. 23 / 54 13 / 17

[095] Advantageously, the threshold diameter is less than or equal to 1 pm.

[096] Thus, according to this fourth example, at least 50% of the particles have a volume average diameter (called Dv50) less than or equal to 5 micrometers.

[097] According to a fifth example, all particles have a volume average diameter less than or equal to 40 pm, preferably less than or equal to 30 pm, and even more preferably less than or equal to 20 pm. Advantageously, the volume average diameter for a 100% proportion is less than or equal to 15 pm.

[098] In each of the examples described, at least 50% of the particles of the second composition (C2) that form the interface layer (20) have a volume average diameter less than or equal to 10 pm.

[099] The particle diameter is obtained due to the choice of binder materials (ML2), conductive additives (AC2) and solvents (S2), due to the mass of these various elements and the implementation methods, including mixing and grinding. The mixing technique consists of pre-dispersing the conductive additives in the solubilized binder materials, the conductive additives at this stage being in an agglomerated state (large particles with a diameter greater than 50 µm). The grinding technique consists of breaking the agglomerates to obtain the volume average diameter of the particles, as previously disclosed.

[0100] This corresponds to the fact that the expression “being the composition formed by particles, at least 50% of the particles having a volume average diameter less than or equal to 10 micrometers” means that the average diameter is measured in particles in the composition and excludes the measurement of the diameters of the ingredients in particle form before the composition is added when the composition formation alters the particle size.

[0101] In this context, it can thus be written in a way Petition 870260069239, dated 07 / 13 / 2026, page 24 / 54 14 / 17 equivalent that the second composition (C2) can be formed of particles or that the second composition is a composition that comprises particles.

[0102] In other words, the measurement of the average diameter in volume is here a particle size distribution of carbonated paint, that is, of the dispersion of carbon in a polymeric matrix.

[0103] The choice of the second binder material (ML2) may vary considerably, provided that the second binder material (ML2) is inert with respect to the other materials in the second composition (C2). The second binder material (ML2) comprises one or more polymers chosen from thermoplastic polymers, thermosetting polymers, elastomers and mixtures thereof.

[0104] Examples of thermoplastic polymers include, but are not limited to, polymers derived from the polymerization of aliphatic or cycloaliphatic vinyl monomers, such as polyolefins (including polyethylenes or polypropylenes), polymers derived from the polymerization of aromatic vinyl monomers, such as polystyrenes, polymers derived from the polymerization of acrylic and / or methacrylate monomers, polyamides, polyether ketones, polyimides, polyvinyl alcohols, fluorinated polymers, polyacrylonitrile.

[0105] Examples of thermosetting polymers include, but are not limited to, thermosetting resins (such as epoxy resins or polyester resins), optionally blended with polyurethanes or with polyether polyols or vice versa.

[0106] Examples of elastomeric polymers include, but are not limited to, natural rubbers, synthetic rubbers, styrene-butadiene copolymers (also referred to using the abbreviation “SBR”), ethylene-propylene copolymers (also referred to using the abbreviation “EPM”), silicones.

[0107] The second binder material (ML2) may be a mixture of thermoplastic polymer(s), thermosetting polymer(s) and / or Petition 870260069239, dated 07 / 13 / 2026, page 25 / 54 15 / 17 elastomeric polymer(s).

[0108] Other suitable second binder(s) material(s) (ML2) comprise(s) crosslinked polymers, such as those manufactured from polymers with carboxyl groups and crosslinking agents.

[0109] The second conductive additive (AC2) comprises one or more types of conductive elements to improve electronic conductivity.

[0110] Examples of conductive elements include, but are not limited to, conductive carbons, graphites, graphenes, carbon nanotubes, activated carbon fibers, non-activated carbon nanofibers, metal sheets, metal powders, metallic fibers and electrically conductive polymers.

[0111] The second solvent (S2) is chosen from water, ethanol, butanol, isopropyl alcohol (also called isopropanol), glycol ether and a mixture thereof.

[0112] The operation of the accumulator (10) is in accordance with the operation of a prior art electrochemical accumulator.

[0113] To evaluate the performance of the interface layer (20), the current collector cover with a layer according to the state of the art was compared by eye to that with an interface layer (20) according to the state of the art.

[0114] In particular, a comparison is made between a commercial composition (DAG EB-012 from Henkel Inc.) and a second composition (C2) having a volume mean diameter (Dv90) of 5 µm for 90% of the particles and a volume mean diameter (Dv90) of 10 µm for 99% of the particles.

[0115] By comparison, the commercial composition is measured to comprise particles of which 90% of the particles have a threshold diameter of 49 pm and 99% of the particles have a threshold diameter of 85 pm and 50% of the particles have a threshold diameter of 13 pm. Petition 870260069239, dated 07 / 13 / 2026, page 26 / 54 16 / 17

[0116] Figures 3 and 4 correspond to the photograph obtained by scanning electron microscopy at a magnification of 1000.

[0117] In the case of Figure 3, the interface layer obtained from the commercial compound coating shows holes, even with a thickness of 5 µm, as observed in Figure 3. It is not possible to reduce the thickness without generating an area with significant coverage deficiencies.

[0118] Even with a thickness of 5 pm, the coverage does not visually reach the coverage observed with the interface layer (20) with a thickness of 1 pm obtained from the second composition (C2) observed in Figure 4.

[0119] The collector in Figure 4 appears to be entirely covered by the interface layer (20), while the collector is visible in Figure 3, in particular at the hole (30).

[0120] These tests correspond to the depositor's unexpected observation that good collector coverage is obtained if the particle size of the particles forming the interface layer (20) is controlled.

[0121] This good quality coating allows protection of the current collector, therefore the interface layer acts as a physical barrier to the access of ions responsible for corrosion.

[0122] Further tests have shown that this coating provides good corrosion resistance, even at high potentials.

[0123] In particular, collector oxidation occurs from a potential of 3.7 V for the interface layer obtained from the commercial composition (3.7 V corresponding to the oxidation potential of aluminum, the holes in the interface layer are direct access to the electrolyte for the aluminum that oxidizes) while collector oxidation does not occur until 4.2 V for an interface layer (20), as described above.

[0124] This shows that the interface layer (20) is a layer Petition 870260069239, dated 07 / 13 / 2026, page 27 / 54 17 / 17 which prevents oxidation of the current collector, even when the operating potential of the device for storing electrical energy is greater than or equal to the oxidation potential of the current collector material.

[0125] Thus, a current collector was revealed to form an assembly, making it possible to obtain a battery with better performance levels and, at the same time, capable of supplying a higher voltage than the voltages delivered in the state of the art, in particular a voltage greater than 3.5 Volts.

[0126] The current collector can also be used for another electrical energy storage device, such as a supercapacitor. Petition 870260069239, dated 07 / 13 / 2026, page 28 / 54

Claims

1 / 3 Claims 1. CURRENT COLLECTOR (22) of a device for storing electrical energy, the current collector (22) being coated with an interface layer (20), the interface layer (20) being formed by coating the current collector (22) with a composition (C2), characterized in that the composition (C2) comprises a conductive additive (AC2), a solvent (S2) and a binder material (ML2), a conductive material (MC) comprising at least one element chosen from the list consisting of: - carbon, - carbon black, - graphite, - graphene, - a carbon nanotube, - an activated carbon fiber, and - a non-activated carbon nanofiber, the composition (C2) being formed by particles, the particles being obtained by performing a mixing technique and a grinding technique, the mixing technique consists of pre-dispersing the conductive additive (AC2) in the solubilized binder material (ML2), the conductive additive (AC2) forming agglomerates before the crushing,with a diameter greater than 50 µm, the grinding technique consisting of breaking up the agglomerates, at least 50% of the particles having a volume average diameter less than or equal to 10 micrometers, the volume average diameter being measured in the particles of the composition (C2) by static light using a granulometer and processing the data obtained by the granulometer to calculate the particle size distribution based on a spherical equivalent volume model. Petition 870260069239, dated 13 / 07 / 2026, page 29 / 54 2 / 3, 2. CURRENT COLLECTOR (22), according to claim 1, characterized in that the interface layer (20) is a layer that acts as a physical barrier to the access of ions responsible for corrosion.

3. CURRENT COLLECTOR (22), according to any one of claims 1 to 2, characterized in that the interface layer is a layer that prevents oxidation of the current collector (22) even when the operating potential of the device for storing electrical energy is greater than or equal to the oxidation potential of the material of the current collector (22).

4. CURRENT COLLECTOR (22), according to any one of claims 1 to 3, characterized in that the current collector (22) is adapted for a device for storing electrical energy comprising an electrolyte comprising ionic salts selected from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiTF), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB) and a mixture thereof.

5. CURRENT COLLECTOR (22), according to claim 4, characterized in that the ionic salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt.

6. CURRENT COLLECTOR (22), according to any one of claims 1 to 5, characterized in that at least 90% of the particles have a volume average diameter less than or equal to 15 micrometers.

7. CURRENT COLLECTOR (22), according to any one of claims 1 to 6, characterized in that at least 99% of the particles have a diameter less than or equal to 10 micrometers.

8. CURRENT COLLECTOR (22), according to any one of claims 1 to 7, characterized in that the interface layer (20) Petition 870260069239, dated 13 / 07 / 2026, page 30 / 54 3 / 3 has a thickness greater than or equal to 1 micrometer.

9. CURRENT COLLECTOR (22), according to any one of claims 1 to 7, characterized in that the interface layer (20) has a thickness less than or equal to 4 micrometers, preferably less than or equal to 2 micrometers.

10. ASSEMBLY FORMING AN ANODE (14) OR A CATHODE (16), characterized by including: - an electrode (18), and - a current collector (22), as defined in any of claims 1 to 9.

11. ELECTRICAL ENERGY STORAGE DEVICE, electrochemical accumulator (10) or supercapacitor, characterized by including an assembly, as defined in claim 10. Petition 870260069239, dated 07 / 13 / 2026, page 31 / 54

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