Method of manufacturing an electrode precursor of an electrochemical cell

Abstract

A method of manufacturing an electrode precursor (P) of an electrochemical cell comprises the steps of: - providing a powdered solid substance (S) comprising at least one electrode active material; 5 - feeding a current collector metal foil (2) to an inkjet printing station (3) along a transport direction (T); - inkjet printing a hardenable liquid substance (L) on said metal foil (2) to form a print pattern on the metal foil (2); - applying the powdered solid substance (S) on the hardenable liquid substance 0 (L) printed on the metal foil (2); and - hardening the hardenable liquid substance (L) so as to form on the metal foil (2) a layer of electrode active material comprising the electrode active material.

Description

[0001] Method of manufacturing an electrode precursor of an electrochemical cell

[0002] DESCRIPTION

[0003] Field of the invention

[0004] The present invention relates to a method of manufacturing an electrode precursor of an electrochemical cell, for example for use in an energy storage device such as a rechargeable battery.

[0005] Related art

[0006] A first type of electrochemical cell comprises stacks of positive and negative electrode precursors, arranged alternately one above the other, with a separation layer of dielectric material interposed, generally indicated in the technical jargon of the sector by the term “separator”.

[0007] Such electrochemical cells are usually made by stacking a positive electrode precursor on a separator sheet, stacking a further separator sheet on the positive electrode precursor, and stacking a negative electrode precursor on the further separator sheet to obtain a first stacking group. This operation is repeated by stacking as many stacking groups on above the other as necessary to obtain the desired electrical characteristics of the electrolytic cell.

[0008] A second type of electrochemical cell, referred to in the jargon as a “jelly roll” or “Swiss roll”, comprises electrode precursors, between which a ribbon-like separator is interposed, wherein the electrode precursors form a stacking assembly that is wound to form a cylindrical or quasi-cylindrical electrochemical cell.

[0009] In both cases, by adding an electrolyte to the stacking group, ions can migrate between anode and cathode transforming the electrode precursors into electrodes and the electrochemical cell into a battery.

[0010] Electrode precursors are substantially made by depositing a layer of active material for electrodes on one surface or on both surfaces of a current collector metal foil. By choosing a suitable combination of active material for electrodes and of material of the current collector metal foil, it is possible to obtain electrode precursors intended for making positive electrodes and electrode precursors intended for making negative electrodes. In the Applicant’s experience, positive and negative electrode precursors can be manufactured by means of two so-called wet or dry production technologies.

[0011] In the first case, a dispersion (slurry) comprising an electrode active material, at least one solvent and at least one binder is formed and applied to at least one surface of a current collector metal foil to form a layer that is dried to remove the solvent and then calendered to even out the thickness.

[0012] However, in the context of this wet production technology, the application of the active material as a dispersion on the current collector metal foil can cause certain drawbacks resulting from the drying process during which the solvent of the dispersion is evaporated.

[0013] The removal of the solvent is a relatively slow and energy-intensive operation, which adds to production time and costs.

[0014] In some cases, the solvent can also be toxic, so evaporation of large quantities of it triggers undesirable environmental problems.

[0015] Finally, if the drying process is too fast, bubble formation and poor contact between the current collector metal foil and the active material may occur.

[0016] In so-called dry production technology, on the other hand, an essentially solvent- free mixture is formed, comprising an electrode active material, at least one binder and possible additives, which is then applied to at least one surface of a current collector metal foil to form a layer that is subsequently consolidated e.g. by calendering.

[0017] Generally, “dry” production techniques that have been proposed in the art include high shear mixing of a binder that can be fi bri Hated, the use of disposable binders to be removed at the time of electrode precursor processing, dry powder spraying, electrostatic spray deposition, cold plasma deposition, sputtering deposition and powder printing. In some cases, a fibrillation promoter is incorporated into the binder and the resulting formulation is subjected to high shear mixing to fibrillate the binder, thus generating a mesh-like structure that can better hold materials together and support the active material.

[0018] Although “dry” production techniques make it possible to reduce or eliminate some of the problems posed by the addition and / or removal of (often harmful) solvents, they are not without their drawbacks. For example, current “dry” manufacturing techniques do not only use the electrode active material, but also many other ingredients such as fibrillation promoters, conductive additives and binders. Since many of these components are not involved in the electrochemical reactions that generate electricity, they may adversely affect certain performance characteristics (e.g. capacity and energy density) of the device that includes the electrochemical cell, as they effectively reduce the amount of active material that can be contained in a given volume.

[0019] Summary of the invention

[0020] In the Applicant’s experience, there is a growing need for a method of manufacturing an electrode precursor of an electrochemical cell that is simple to perform, energy-efficient and as environmentally friendly as possible.

[0021] The Applicant has perceived that this requirement can be fulfilled by manufacturing the electrode precursor by applying by inkjet printing limited quantities of a hardenable liquid substance to a current collector metal foil and applying to this hardenable liquid substance a powdered solid substance comprising at least one electrode active material.

[0022] The present invention thus relates, in a first aspect thereof, to a method of manufacturing an electrode precursor of an electrochemical cell according to claim 1 .

[0023] Preferably, the electrode precursor comprises a current collector metal foil and a layer of electrode active material on at least one surface of said metal foil.

[0024] Preferably, a powdered solid substance comprising at least one electrode active material is provided.

[0025] Preferably, it is provided to feed a current collector metal foil to an inkjet printing station along a transport direction.

[0026] Preferably, it is intended to inkjet print a hardenable liquid substance to form on said metal foil a print pattern.

[0027] Preferably, it is provided to apply said powdered solid substance on the hardenable liquid substance printed on the metal foil.

[0028] Preferably, it is provided to harden the hardenable liquid substance so as to form a layer of electrode active material comprising said electrode active material.

[0029] The Applicant has found that the formation of a layer of electrode active material by inkjet printing of a hardenable liquid substance advantageously allows the use of a very low quantity of solvent compared to the known wet production technology, achieving several important advantages.

[0030] Firstly, a drastic reduction in the energy is required to remove the solvent itself.

[0031] Secondly, a reduction in production time and, finally, a strong reduction in environmental impact if organic solvents are used.

[0032] At the same time, the formation of a layer of electrode active material by inkjet printing of a hardenable liquid substance advantageously allows the use of a very low quantity of binder compared to both wet and dry production technology, with an advantageous increase in the amount of active material that can be contained in a given volume of the layer of active material obtained.

[0033] In this way, optimal performance characteristics (e.g. capacity and energy density) of the electrochemical cell and the device incorporating it, e.g. a rechargeable battery, can be advantageously achieved.

[0034] The Applicant has also found that the formation of a layer of electrode active material by inkjet printing of a hardenable liquid substance advantageously allows for the precise application of sufficient dosed quantities of active material on the current collector metal foil to establish a proper electrical connection, while at the same time limiting any wastage of this material.

[0035] The Applicant has also found that the formation of a layer of electrode active material by inkjet printing of a hardenable liquid substance advantageously allows a print pattern of any selectable geometry to be formed on the current collector metal foil.

[0036] Thus, for example, the print pattern can leave areas of the metal foil uncovered by the electrode active material, so that a wide variety of application requirements can be met in a very flexible manner.

[0037] The Applicant also found that the formation of a layer of electrode active material by inkjet printing of a hardenable liquid substance advantageously allows one or more overlapping layers of electrode active material, each with its own composition and printing pattern, possibly different between layers, to be formed on the current collector metal foil. In this way, it is advantageously possible to further extend the possibility of meeting the most diverse application requirements in a very flexible manner. By way of example, as an alternative to making battery electrodes, this method can be used for the deposition of decorative patterns on metal plates.

[0038] Detailed description of embodiments of the invention

[0039] In the context of the present description and in subsequent claims, “print pattern” means any graphic element that can be obtained by means of an inkjet printer. In the context of the present disclosure, a “print pattern” may, for example, be a geometric, regular or irregular figure and may uniformly or non-uniformly cover the surface of the metal foil on which the hardenable liquid substance is printed.

[0040] Within the context of the present description and following claims, all the numerical magnitudes indicating quantities, parameters, percentages, and so on are to be considered preceded in every circumstance by the term “about” unless indicated otherwise. Furthermore, all ranges of numerical quantities are to be understood as including extremes, unless otherwise indicated, and include all possible combinations of maximum and minimum numerical values and all the possible intermediate ranges, in addition to those specifically indicated below.

[0041] The present invention can be presented in one or more of its aspects or one or more of the preferred characteristics reported below, which can be combined with one another as preferred according to the application requirements.

[0042] Preferably, said current collector metal foil is a metal foil made of copper or aluminium.

[0043] Preferably, the current collector metal foil is a copper metal foil in the case of the manufacture of an anode electrode precursor.

[0044] Preferably, the current collector metal foil is an aluminium foil in the case of the manufacture of a cathode electrode precursor.

[0045] In preferred embodiments, the current collector metal foil can be a continuous metal foil, e.g. a foil unwound from a collection coil.

[0046] In alternative preferred embodiments, the current collector metal foil can be a piece of metal foil. In this case, a current collector metal foil is fed to an inkjet printing station and then pieces of foil are fed spaced apart along the transport direction to the printing station.

[0047] Continuous metal foil or sections of metal foil can be handled by any suitable handling system, e.g. including a conveyor belt.

[0048] Preferably, preparing said powdered solid substance comprises storing at least one electrode active material in a suitable storage container.

[0049] In some embodiments, the hardenable liquid substance may comprise at least one solvent.

[0050] Preferably, the solvent is selected from any one of water, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), cirene™, toluene, xylene, or mixtures thereof if compatible.

[0051] In preferred embodiments, the hardenable liquid substance comprises at least one binder.

[0052] In preferred embodiments, the binder may be a water-soluble binder, preferably selected from any one of polyvinyl alcohol (PVA), polyethylene oxide (PEO) polyvinylpyrrolidone (PVP), styrene butadiene rubber (SBR), carboxymethylcellulose (CMC), sodium alginate, styrene butadiene rubber (SBR), polyacrylic acid (PAA), polyurethane (PU), or mixtures thereof where compatible.

[0053] In alternative preferred embodiments, the binder may be a non-water-soluble binder, preferably polyvinylidene fluoride (PVDF).

[0054] In preferred embodiments, the binder comprises at least one polymerisation catalyst, more preferably a UV catalyst.

[0055] Preferably, the electrode active material is an anode active material.

[0056] Preferably, the anode active material is selected from any one of graphite, soft carbon, hard carbon, N-doped carbon, silicon, silicon oxide, lithium titanate, Li4Ti50i2 (LTO), titanium dioxide, TiC>2, or mixtures thereof if compatible.

[0057] Preferably, the electrode active material is a cathode active material.

[0058] Preferably, the active cathode material is selected from any one of lithium and cobalt oxide, LiCC (LCO), lithium nickel manganese and cobalt oxide (NMC), lithium cobalt and aluminium oxide (NCA), lithium iron phosphate LiFePC (LFP), lithium manganese dioxide LiMnC , or mixtures thereof if compatible.

[0059] In preferred embodiments, the powdered solid substance and / or the hardenable liquid substance may comprise at least one conductive additive.

[0060] In preferred embodiments, the conductive additive can be selected from any one of carbon black (CB), conductive graphite (CG), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), graphene, vapour grown carbon fibres (VGCFs), or mixtures thereof if compatible.

[0061] In preferred embodiments, preparing the powdered solid substance includes mixing it with at least one electrode active material and / or with at least one conductive additive preferably before storing the powdered solid substance.

[0062] Preferably, mixing said at least one electrode active material with at least one conductive additive is carried out dry.

[0063] Preferably, such mixing can be carried out by means of any suitable mixing apparatus, such as a rotor mixer with a shaft equipped with blades that rotates within an outer casing, e.g. cylindrical.

[0064] In preferred embodiments, the hardenable liquid substance comprises as % by weight of its total weight:

[0065] - 2 to 100% by weight, preferably 5 to 50% by weight, of at least one binder,

[0066] - 0 to 98% by weight, preferably 0.1 % to 50% by weight, more preferably 2% to 50% by weight of at least one solvent,

[0067] - 0% to 10% by weight, preferably 0.1 % to 5% by weight, more preferably 0.5% to 5% by weight of at least one additive.

[0068] Preferably, said at least one additive is selected from among one or more rheology modifiers, such as a fluidifying agent preferably polyvinyl alcohol, surfactants, suspending agents, antifoaming agents, colourants, co-solvents, such as ethylene glycol, wetting agents, dispersing agents, buffers, antibacterial agents.

[0069] In preferred embodiments, the powdered solid substance comprises as % by weight of its total weight: - 80% to 100% by weight, preferably 85% to 98% by weight, more preferably 90% to 96% by weight of at least one electrode active material,

[0070] - 0% to 10% by weight, preferably 0.5% to 5% by weight, more preferably 1 % to 5% by weight of at least one conductive additive,

[0071] - 0% to 10% by weight, preferably 0.5% to 5% by weight, more preferably 1 % to 5% by weight of at least one solid additive.

[0072] Preferably, said at least one solid additive comprises at least one processability aid and / or at least one filler.

[0073] In the context of this description and subsequent claims, the term “processability aid” is used to refer to an additive that aids the processability of the powdered solid substance including the electrode active material. The term is general and includes any agent that assists in making flowable the dry components of the powdered solid substance.

[0074] Preferably, the hardenable liquid substance has a suitable viscosity to make it printable by an inkjet printer.

[0075] Preferably, the hardenable liquid substance has a viscosity comprised between 3 and 150 mPa«s, more preferably between 5 and 100 mPa«s, when measured at 25°C using the Anton Paar MCR 302 model viscometer.

[0076] Preferably, inkjet printing the hardenable liquid substance on the metal foil comprises feeding said hardenable liquid substance to an inkjet printer comprising at least one printhead assembly.

[0077] In preferred embodiments, each printhead of the at least one printhead assembly comprises a plurality of dispensing nozzles of the hardenable liquid substance.

[0078] Preferably, inkjet printing the hardenable liquid substance onto the metal foil comprises applying an amount of hardenable liquid substance comprised between 20 g / m2and 500 g / m2, more preferably between 30 g / m2and 350 g / m2.

[0079] Preferably, applying the powdered solid substance onto the hardenable liquid substance printed on the metal foil comprises dispensing the powdered solid substance onto the liquid substance using at least one dispensing device for powdered materials. A dispensing device that finds preferred use within the scope of the present invention is illustrated in international patent application WO 2020 / 183353 A1 incorporated herein by reference.

[0080] Preferably, applying the powdered solid substance to the hardenable liquid substance printed on the metal foil comprises applying an amount of powdered solid substance comprised between 15 g / m2and 600 g / m2, more preferably between 20 g / m2and 400 g / m2.

[0081] In preferred embodiments, the manufacturing method described herein may further comprise removing excess powdered solid substance that has not come into contact with the hardenable liquid substance.

[0082] In preferred embodiments, the manufacturing method described herein may further comprise at least partially hardening the hardenable liquid substance before applying the powdered solid substance to the hardenable liquid substance printed on the metal foil.

[0083] In preferred embodiments, hardening the hardenable liquid substance comprises removing said at least one solvent by heating the hardenable liquid substance.

[0084] In preferred embodiments, hardening the hardenable liquid substance may comprise polymerising said at least one binder.

[0085] Preferably, the polymerisation of said at least one binder can be carried out by any suitable technique for the purpose, such as by heating, irradiation by infrared radiation, irradiation by UV radiation, irradiation by a UV laser or by electron beam heating, of the hardenable liquid substance.

[0086] In preferred embodiments, the manufacturing method described herein may further comprise calendering the layer of electrode active material formed on the metal foil.

[0087] In preferred embodiments, the thickness of the layer of electrode active material formed on said metal foil is comprised between 50 microns and 250 microns, preferably between 100 microns and 250 microns, more preferably between 100 microns and 150 microns for a cathode active material and between 50 microns and 150 microns, more preferably between 50 microns and 100 microns, for an anode active material.

[0088] Brief of the Further characteristics and advantages of the present invention will become clearer from the following detailed description of some preferred embodiments thereof, with reference to the accompanying drawing and provided by way of indicative and non-limiting example.

[0089] In the drawings:

[0090] - Fig. 1 shows an illustrative schematic illustration of a plant for implementing preferred embodiments of a method according to the invention for manufacturing an electrode precursor of an electrochemical cell.

[0091] With reference to this figure, a plant configured to implement preferred embodiments of a method according to the invention is collectively referred to as 1.

[0092] In the preferred embodiment shown in Fig. 1 , a current collector metal foil 2 is provided, e.g. a copper foil if an anode is to be manufactured and an aluminium foil if a cathode is to be manufactured.

[0093] In the preferred embodiment shown in Fig. 1 , the metal foil 2 is a continuous foil appropriately unwound from a collection reel (not shown) and fed to an inkjet printing station 3 along a transport direction T from right to left in Fig. 1 .

[0094] The metal foil 2 is appropriately moved along the transport direction T by suitable handling means, e.g. by means of one or more conveyor belts, conventional per se and not shown in Figure 1 .

[0095] In alternative, not illustrated, preferred embodiments, the method may involve forming, e.g. by shearing or laser cutting, pieces of metal foil and arranging the pieces spaced apart on the conveyor belt(s) along the transport direction T.

[0096] In the inkjet printing station 3, a hardenable liquid substance L is printed on an upper surface of the metal foil 2 according to a predetermined print pattern as illustrated above in this document.

[0097] Preferably, the inkjet printing station 3 comprises at least one set of printheads, each preferably comprising a plurality of nozzles for dispensing the hardenable liquid substance L.

[0098] The hardenable liquid substance L can be any hardenable liquid substance as described herein. In the preferred embodiment shown in Fig. 1 , the hardenable liquid substance L can be appropriately stored in a respective storage container 4 in liquid communication with the inkjet printing station 3.

[0099] In preferred embodiments, not illustrated, a plurality of inkjet printing stations 3 arranged in succession along the transport direction T can be provided for overlapping print patterns, e.g. with different hardenable liquid substances L.

[0100] In the preferred embodiment shown in Fig. 1 , a powdered solid substance S comprising at least one electrode active material, for example, is prepared and suitably stored in a respective storage container 5.

[0101] In preferred embodiments, the powdered solid substance S may comprise at least one conductive additive as described herein.

[0102] Within the scope of these preferred embodiments and as schematically illustrated in Fig. 1 , the powdered solid substance S can be prepared by dry mixing the electrode active material with said at least one conductive additive in a suitable mixing device 6 as described herein.

[0103] In the preferred embodiments of the method illustrated in Fig. 1 , the metal foil 2 with the above-mentioned print pattern is transported to a dispensing station 7 of the powdered solid substance S.

[0104] In the preferred embodiments of the method illustrated in Fig. 1 , the method involves transporting the powdered solid substance S from the respective storage container 5 to the dispensing station 7 via suitable conduits not illustrated in detail.

[0105] Preferably, the dispensing station 7 comprises at least one dispensing device for powdered materials, for example, a dispensing device of the type illustrated in the above-mentioned international patent application WO 2020 / 183353 A1 .

[0106] According to the method of the invention, the powdered solid substance S adheres to the hardenable liquid substance L and can be at least partially absorbed and / or dispersed therein.

[0107] The result is a component of liquid and powder layered on the metal foil 2 that can be subjected to hardening.

[0108] In the preferred embodiments of the method illustrated in Fig. 1 , the method may comprise removing the excess powdered solid substance S that is not in contact with the hardenable liquid substance L and is therefore in a free-flowing condition.

[0109] This removal step can be carried out in a suction station 8 provided with at least one suction device capable of removing the excess powdered solid S, which can, for example, be suitably recycled to the powdered solid S storage container 5.

[0110] In preferred embodiments, not illustrated, it is possible to provide for a plurality of pairs of inkjet printing stations 3 / dispensing stations 7 arranged in succession along the transport direction T so as to obtain overlapping layers, e.g. with different hardenable liquid substances L and powdered solid substances S, by means of each pair of inkjet printing stations 3 / dispensing stations 7 and in a manner similar to that described above.

[0111] If necessary, it is also possible to remove the excess powdered solid S in additional suction stations 8 downstream of the dispensing station 7 of each pair of inkjet printing stations 3 / dispensing stations 7.

[0112] Next, the method according to this preferred embodiment of the invention comprises moving the metal foil 2 with the above-mentioned liquid and powder component applied to it to a curing station 9 in which the hardenable liquid substance L is hardened to form a layer of electrode active material.

[0113] This step of hardening the hardenable liquid substance L can be carried out as described above in this document.

[0114] The step of hardening the hardenable liquid substance L allows a layer of electrode active material, either for anode or cathode, to be formed on a surface, in this case the upper surface, of the metal foil 2.

[0115] In the preferred embodiments of the method illustrated in Fig. 1 , the method may comprise cooling the resulting coated metal foil 2 in a cooling station 10.

[0116] In the preferred embodiments of the method illustrated in Fig. 1 , the method finally comprises calendering the layer of electrode active material formed on the metal foil 2 so as to obtain an electrode precursor P preferably having a thickness of the electrode active material layer formed on the metal foil 2 comprised between 100 microns and 250 microns.

[0117] Calendering of the layer of electrode active material can be performed in a calendering apparatus 1 1 e.g. equipped with a pair of counter-rotating rollers 12, In the preferred embodiments of the method illustrated in Fig. 1 , the calendered metal foil 2 coated with the layer of electrode active material constitutes an essentially continuous electrode precursor P of an electrochemical cell. The electrode precursor P of this preferred embodiment can then be stored in a coil, not illustrated in the figure, prior to subsequent electrochemical cell manufacturing.

[0118] In further preferred embodiments, not illustrated, the method of the invention may further comprise at least partially hardening the hardenable liquid substance L before applying the powdered solid substance S to the hardenable liquid substance L printed on the metal foil 2.

[0119] In this case, a pre-hardening station, not shown, can be provided in the plant 1 upstream of the dispensing station 7 of the powdered solid substance S similar to the hardening station 9 described above. Naturally, those skilled in the art may make further modifications and variants to the above-described invention with the purpose of meeting specific and contingent application needs, variants and modifications in any case falling within the scope of protection as defined by the successive claims.

Claims

CLAIMS1 . Method of manufacturing an electrode precursor (P) of an electrochemical cell, said electrode precursor comprising a current collector metal foil (2) and a layer of electrode active material on at least one surface of said metal foil (2), wherein the method comprises:- providing a powdered solid substance (S) comprising at least one electrode active material;- feeding a current collector metal foil (2) to an inkjet printing station (3) along a transport direction (T);- inkjet printing a hardenable liquid substance (L) on said metal foil (2) to form a print pattern on said metal foil (2);- applying said powdered solid substance (S) on the hardenable liquid substance (L) printed on the metal foil (2); and- hardening the hardenable liquid substance (L) so as to form on the metal foil (2) a layer of electrode active material comprising said electrode active material.

2. Method according to claim 1 , wherein said current collector metal foil (2) is a metal foil of copper or aluminium.

3. Method according to any one of the preceding claims, wherein said current collector metal foil (2) is a continuous metal foil or a piece of metal foil.

4. Method according to any one of the preceding claims, wherein said hardenable liquid substance (L) comprises at least one solvent, said solvent being preferably selected from any one of water, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), cirene™, toluene, xylene, or mixtures thereof if compatible.

5. Method according to any one of the preceding claims, wherein said hardenable liquid substance (L) comprises at least one binder, said binder being preferably a water-soluble binder, preferably selected from any one of polyvinyl alcohol (PVA), polyethylene oxide (PEO) polyvinylpyrrolidone (PVP), styrene butadiene rubber (SBR), carboxymethylcellulose (CMC), sodium alginate, styrene butadiene rubber (SBR), polyacrylic acid (PAA), polyurethane (PU), or mixturesthereof where compatible, or a non-water-soluble binder, preferably polyvinylidene fluoride (PVDF).

6. Method according to any one of the preceding claims, wherein said electrode active material is an anode active material selected from any one of graphite, soft carbon, hard carbon, N-doped carbon, silicon, silicon oxide, lithium titanate, Li4TisOi2 (LTO), titanium dioxide, TiC , or mixtures thereof if compatible, and / or the electrode active material is a cathode active material selected from any one of lithium and cobalt oxide, LiCO2 (LCO), lithium nickel manganese and cobalt oxide (NMC), lithium cobalt and aluminium oxide (NCA), lithium iron phosphate LiFePC (LFP), lithium manganese dioxide LiMnC , or mixtures thereof if compatible.

7. Method according to any one of the preceding claims, wherein said powdered solid substance (S) and / or said hardenable liquid substance (L) comprises at least one conductive additive, said conductive additive being preferably selected from any one of carbon black (CB), conductive graphite (CG), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), graphene, vapour grown carbon fibres (VGCFs), or mixtures thereof if compatible.

8. Method according to any one of the preceding claims, wherein providing said powdered solid substance (S) comprises mixing, preferably dry mixing, said at least one electrode active material with at least one conductive additive.

9. Method according to any one of the preceding claims, wherein inkjet printing said hardenable liquid substance (L) on said metal foil (2) comprises feeding said hardenable liquid substance (L) to an inkjet printer comprising at least one printhead assembly.

10. Method according to claim 9, wherein each printhead of the at least one printhead assembly comprises a plurality of dispensing nozzles of said hardenable liquid substance (L).11 . Method according to any one of the preceding claims, wherein inkjet printing said hardenable liquid substance (L) on said metal foil (2) comprises applying on said metal foil (2) an amount of hardenable liquid substance (L) between 20 g / m2and 500 g / m2, preferably between 30 g / m2and 350 g / m2.

12. Method according to any one of the preceding claims, wherein applying saidpowdered solid substance (S) on the hardenable liquid substance (L) printed on the metal foil (2) comprises dispensing the powdered solid substance (S) on the hardenable liquid substance (L) by means of at least one dispensing device of powdered material.

13. Method according to any one of the preceding claims, wherein applying said hardenable powdered solid substance (S) on the hardenable liquid substance (L) printed on the hardenable metal foil (2) comprises applying on said hardenable liquid substance (L) an amount of hardenable powdered solid substance (S) between 15 g / m2and 600 g / m2, preferably between 20 g / m2and 400 g / m2.

14. Method according to any one of the preceding claims, further comprising removing the hardenable powdered solid substance (S) in excess that has not come into contact with the hardenable liquid substance (L).

15. Method according to any one of the preceding claims, further comprising at least partially hardening said hardenable liquid substance (L) prior to applying said powdered solid substance (S) on the hardenable liquid substance (L) printed on the metal foil (2).

16. Method according to any one of the preceding claims, wherein hardening the hardenable liquid substance (L) comprises removing said at least one solvent by heating the hardenable liquid substance (L).

17. Method according to any one of the preceding claims, wherein hardening the hardenable liquid substance (L) comprises polymerising said at least one binder by heating, irradiation by infrared rays, irradiation by UV rays, irradiation by a UV laser or by electron beam heating, of the hardenable liquid substance (L).

18. Method according to any one of the preceding claims, further comprising calendering the layer of electrode active material formed on said metal foil (2).

19. Method according to any one of the preceding claims, wherein the thickness of the layer of electrode active material formed on said metal foil (2) is between 50 microns and 250 microns, preferably between 100 microns and 250 microns, more preferably between 100 microns and 150 microns, for a cathode active material and between 50 microns and 150 microns, more preferably between 50 microns and 100 microns, for an anode active material.

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