TW202510381A - Method for producing a porous electrode, and battery containing such an electrode - Google Patents

Abstract

The present invention relates to a porous electrode that can be used in electrical energy storage or production devices, such as a lithium-ion battery. This porous electrode is a porous layer comprising at least one electrode active material P and an oxide electronic conductor material.

Description

Method for manufacturing porous electrode and battery containing the same

Invention Field

The invention relates to an energy storage or production device. More specifically, the invention relates to an electrode that can be used in an energy storage or production device, such as a capacitor, a photovoltaic cell or an ion insertion battery, especially a lithium-ion battery, a sodium-ion battery and a potassium-ion battery. The invention is applicable to negative electrodes and positive electrodes. The invention relates to a porous electrode that can be impregnated with an ion-conducting phase, such as a solid electrolyte or a liquid electrolyte without a liquid phase.

The present invention also relates to a method for preparing the porous electrode and the electrode obtained thereby, the method using nanoparticle aggregates or agglomerates of electrode materials and at least one oxide electronic conductor material precursor. The present invention also relates to a method for manufacturing an energy storage or production device, in particular to a method for manufacturing a lithium ion battery comprising at least one of these electrodes, and the battery obtained thereby.

Invention Background

Among the various commercially available electrochemical storage technologies, lithium-ion batteries have the best energy density. There are various architectures and chemical compositions of the electrodes that can be used to make these batteries. Methods for making lithium-ion batteries are presented in many articles and patents; a review is given in the publication " Advances in lithium-ion Batteries " (W. van Schalkwijk and B. Scrosati, eds.) (Kluever Academic/Plenum Publishers), published in 2002.

There is a growing demand for rechargeable batteries of extremely small size that can be incorporated into electronic circuits that are used in many areas, such as secure transaction cards, electronic tags, implantable medical devices, and various micromechanical systems.

There is also a growing demand for high-capacity rechargeable batteries, in particular for powering transport devices (e-bikes, scooters, e-motorcycles, e-cars, e-commercial vehicles) and for storing electrical energy, for example for power generated by intermittent generators (wind turbines, photovoltaic panels) or for stabilizing power grids with highly fluctuating supply and demand.

There is also a growing demand for medium-sized rechargeable batteries for use in a variety of autonomous and portable devices (e.g., mobile phones, portable computers, portable power tools, and intermittently used kitchen appliances).

In all these applications, the possibility of rapid recharging of the battery is a particularly desirable feature. Similarly, these batteries must not present the risk of thermal runaway. Finally, they need to be able to operate over a wide temperature range.

According to the prior art, electrodes for lithium-ion batteries can be manufactured by coating techniques, in particular by coating. These methods make it possible to deposit on the surface of a substrate an ink consisting of particles of the active material in powder form; the average size of the particles constituting this powder is generally between 5 μm and 15 μm in diameter.

These deposition techniques, in particular by coating, make it possible to produce layers with a thickness between about 20 µm and about 400 µm. The power and energy of the battery can be adjusted by adjusting the thickness and porosity of the layers, the size of the active particles constituting the battery and by the presence of various components within the layers, such as binders or electronic conductor materials. In order to manufacture a microbattery, it is necessary that the layers constituting the microbattery have a small thickness.

In addition to the problems associated with the formulation of the ink in order to obtain a high-performance electrode at a low manufacturing cost, it must also be remembered that the ratio between the energy density and the power density of the electrode can be adjusted according to the size of the active material particles and indirectly by the specific surface area of the electrode layer and its thickness. J. Newman (" Optimization of Porosity and Thickness of a Battery Electrode by Means of A Reaction-Zone Model ", J. Electrochem. Soc., 142 (1), pp. 97-101 (1995)) showed the corresponding effects of the thickness of the electrode and its porosity on its discharge mechanism (power) and energy density.

Binder-free mesoporous electrode layers for lithium-ion batteries can be deposited by electrophoresis; this is known from WO 2019/215 407 (I-TEN). They can be impregnated with liquid electrolytes, but their resistivity remains quite high.

In order to increase the low electronic conductivity of electrodes, especially when such electrodes have a high thickness or are made of electrode active materials with low electronic conductivity, a certain amount of electronic conductive material (such as carbon black) is usually added to the electrode active material particles. Ideally, the electronic conductive particles should be available at any point on the surface of the particles of the electrode active material so that they can be inserted/removed simultaneously over the entire surface of the electrode active particles, thereby maximizing the current density and minimizing stress and local heating caused by uneven electrical transport. In practice, it is extremely difficult to control the configuration of carbon black within the electrode. Moreover, with the increasing use of smaller and smaller active material particles, these problems become more prevalent. The non-uniform distribution of carbon black in the electrode causes a higher polarization of the electrode, which leads to an increase in the series resistance of the battery containing such an electrode. The higher the current density, the more pronounced these local charge state imbalances will be. These imbalances therefore lead to cycling performance losses, safety risks and power limitations of the battery cells. The same applies when the electrode has a non-uniform porosity (i.e. size distribution); this non-uniformity contributes to making the wetting of the electrode pores more difficult.

In this context and in order to reduce the resistivity of the electrode, the applicant has developed a mesoporous electrode comprising a mesoporous layer of at least one electrode active material, the at least one electrode active material having a carbon coating on and in the pores of this mesoporous layer; this is known from WO 2021/220 174 (I-TEN). The presence of this carbon electronic conductor coating on the electrode reduces its resistivity, but does not significantly increase its voltage, temperature and electrochemical stability. In addition, the production of carbon electronic conductor coatings on electrodes is expensive and difficult to implement.

As the demand for rechargeable batteries of extremely small size continues to increase, electrodes must meet increasingly stringent specifications. Electrodes must have high chemical and electrochemical stability, robustness, and corrosion resistance so that batteries containing the electrodes have high cycle performance, storage stability, temperature stability, and long-term reliability, and have both high energy density and high power density. The present invention seeks to overcome at least some of the above-mentioned shortcomings of the prior art.

More specifically, the problem that the present invention seeks to solve is to provide a method for manufacturing a porous electrode with high, uniform electronic conductivity and controlled pore density, which method is simple, safe, fast, easy to implement and low cost.

The present invention also aims to provide a safe porous electrode having high electronic conductivity, a stable mechanical structure, good thermal stability (especially at high temperatures) and a long service life, and this can be achieved regardless of the thickness of the electrode.

Another object of the present invention is to provide an electrode for a battery that can operate at high temperatures without reliability problems and without the risk of fire.

Another object of the present invention is to provide a porous electrode which can be easily wetted and impregnated by an ionic liquid or a polymer in addition to the above-mentioned characteristics.

Another object of the present invention is to provide a method for manufacturing an energy storage or production device, such as a capacitor, a supercapacitor, a hybrid supercapacitor, a photovoltaic cell, a photochemical cell, or a battery, in particular a lithium-ion battery, a sodium-ion battery or even a potassium-ion battery, comprising a porous electrode according to the present invention.

Yet another object of the present invention is to provide an energy storage or production device, such as a battery, in particular a lithium-ion battery and a microbattery, a capacitor, a supercapacitor, a hybrid supercapacitor (such as a lithium-ion hybrid supercapacitor (hereinafter referred to as LiC), a sodium-ion hybrid supercapacitor (hereinafter referred to as SIHC), a potassium-ion hybrid supercapacitor (hereinafter referred to as PIHC)), which can store high energy density, recover the energy (especially in a capacitor or supercapacitor) with extremely high power density, withstand high temperatures, have an extremely good cycle life and increased safety.

Summary of the Invention Objectives of the Invention

In order to improve the performance of electrodes that can be used for energy storage or production devices, in particular conventional lithium-ion batteries, in particular by reducing the resistivity of the electrode while significantly increasing the voltage, temperature and electrochemical stability of the electrode, the inventors of the present case sought an alternative to the carbon electronic conductor coating presented in application WO 2021/220 174 (I-TEN).

According to the invention, this problem is solved by an electrode for lithium-ion, sodium-ion or potassium-ion batteries, which is completely ceramic, porous, contains no organic binder and has a porosity of between 25% and 60% by volume. The electrode according to the invention comprises a porous, preferably mesoporous layer of at least one electrode active material and an oxide electronic conductor material, the porosity of the layer being between 25% and 60% by volume. Advantageously, the electrode according to the present invention comprises a region of electrode active material P, which is at least partially covered by a coating of an oxide electronic conductor material throughout the entire internal volume of the electrode and on the surface. Preferably, the electrode according to the present invention comprises a region of electrode active material P, which is covered by a coating of an oxide electronic conductor material throughout the entire internal volume of the electrode and on the surface.

This completely solid porous (preferably mesoporous) layer without organic components is obtained from agglomerates and/or aggregates of primary nanoparticles of at least one electrode active material and at least one oxide electronic conductor material precursor. The size of the primary particles constituting these agglomerates and/or aggregates is on the order of nanometers or tens of nanometers, and the agglomerates and/or aggregates contain at least four primary particles.

In a first embodiment, the substrate may be a substrate capable of acting as a current collector, or in a second embodiment, may be a temporary intermediate substrate, which will be explained in more detail below.

The fact of using agglomerates of tens or even hundreds of nanometers in diameter, instead of non-agglomerated primary particles each having a size of the order of nanometers or tens of nanometers, enables the thickness of the deposit to be increased. However, the agglomerates must remain small to be able to form a continuous mesoporous film during the thermal treatment of the layer. If two large agglomerates are present, this will impair their sintering and the formation of two different porosities will be seen in the layer: the porosity between the agglomerates and the porosity inside the agglomerates.

After sintering, a porous, preferably mesoporous layer or plate is obtained, without carbon black or organic binders, in which all the primary nanoparticles are welded together (by the necking phenomenon known elsewhere) so as to form a continuous mesoporous network structure, which is characterized by a unimodal porosity. The porous, preferably mesoporous layer thus obtained is completely solid and ceramic. During cycling, there is no longer a risk of losing electrical contact between the active material particles, which improves the cycling performance of the battery. Moreover, after sintering, the porous, preferably mesoporous layer adheres perfectly to the metal substrate on which it is deposited or transferred (in the case of an initial deposition on an intermediate substrate).

The heat treatment is performed at a high temperature to sinter the nanoparticles together, so that the electrode can be perfectly dried and any traces of water or solvents or other organic additives (stabilizers, binders) absorbed at the surface of the active material particles can be removed. The high-temperature heat treatment (sintering) can be preceded by a low-temperature heat treatment (debonding) to dry the placed or deposited electrode and remove traces of water or solvents or other organic additives (stabilizers, binders) absorbed at the surface of the active material particles; the debonding can be performed in an oxidizing atmosphere.

It is possible to adjust the porosity of the final electrode depending on the sintering time and temperature. The porosity can be adjusted in the range between 25% and 60% depending on the energy density required.

In any case, the power density of the electrode thus obtained remains extremely high due to the porosity, preferably due to the mesoporosity. Moreover, independently of the size of the mesopores in the active material (it should be understood that after sintering, the concept of nanoparticles no longer applies to the material which now has a three-dimensional structure with a network of channels and mesopores), the dynamic balance of the cell remains perfect, which helps to maximize the power density and the service life of the battery cell.

The electrode according to the invention has a high specific surface area, which reduces the ionic resistance of the electrode. However, in order for this electrode to deliver maximum power, it still needs to have an excellent electronic conductivity to avoid resistance losses in the battery. The greater the thickness of the electrode, the more critical this improvement in the electronic conductivity of the battery will be. In addition, this electronic conductivity must be completely uniform throughout the electrode to avoid having more resistive local areas, which can lead to the formation of hot spots during power operation of the battery.

According to the basic characteristics of the present invention, the electrode according to the present invention comprises at least one electrode active material and an oxide electronic conductor material, preferably comprising an area of the electrode active material P at least partially covered by a coating of the oxide electronic conductor material in the entire internal volume of the electrode and at the surface, preferably comprising an area of the electrode active material P covered by a coating of the electronic conductor material in a perfectly distributed manner in the entire internal volume of the electrode and at the surface.

The coating according to the invention is advantageously of an oxide electronic conductor material of _SnO2 , ZnO doped with aluminum (ZnO:Al, preferably with a Zn:Al molar ratio between 1:0.015 and 1: _0.05 ), _MoO3 , _SrMoO3 , _In2O3 , _Ga2O3 or _indium tin oxide.

The thickness of the oxide electronic conductor material coating in the entire inner volume of the electrode is advantageously less than 10 nm, preferably less than 7 nm, preferably less than 5 nm, more preferably between 5 nm and 3 nm and still more preferably less than 3 nm. This oxide electronic conductor material can be produced from at least one precursor of the oxide electronic conductor material, in particular from at least one liquid precursor of the oxide electronic conductor material.

This thickness is measured by any suitable technique, in particular by transmission electron microscopy.

More specifically, as explained above, the method according to the present invention must include a step of forming a layer from agglomerated nanoparticles of electrode material (active material) and at least one oxide electronic conductor material precursor, so that the nanoparticles are naturally "welded" together so as to produce a porous, rigid, three-dimensional structure in the absence of organic binders after consolidation (such as annealing); this porous, preferably mesoporous layer is perfectly suitable for applying surface treatment by gas or liquid means or by immersion deep into the open porous structure of the layer.

The first object of the invention is a method for manufacturing a porous electrode, in particular for use in electrical energy storage or production devices (such as batteries), the electrode being a porous layer deposited on a substrate comprising at least one electrode active material P and an oxide electronic conductor material, the electrode being binder-free, having a porosity by volume of between 25% and 60%, preferably between 25% and 50%, and pores having an average diameter of less than 100 nm, the manufacturing method being characterized by comprising: (a) Providing a substrate, at least one oxide electronic conductor material precursor and a colloidal suspension or a paste, the colloidal suspension or paste comprising aggregates or agglomerates of primary nanoparticles of at least one electrode active material P, the primary median diameter _D50 of the primary nanoparticles being between 2 nm and 400 nm, preferably between 2 nm and 100 nm, and more preferably between 2 nm and 60 nm, the aggregates or agglomerates having a median diameter _D50 between 50 nm and 900 nm, and preferably between 100 nm and 800 nm, it should be understood that the substrate can be a substrate capable of serving as a current collector, or an intermediate substrate, (b) The precursor of the one or more oxide electronic conductor materials provided in step (a) is mixed with the colloidal suspension or the paste of aggregates or agglomerates of primary nanoparticles of at least one electrode active material P to form a mixture, (c) forming a layer from the mixture obtained at the end of step (b) by a method selected from the group consisting of: electrophoresis; a lamination method; extrusion; a printing method, preferably inkjet printing or flexographic printing; a coating method, preferably doctor blade coating, roll coating, curtain coating, dip coating or slit coating. (d) drying the layer obtained in step (c) so as to obtain a dried layer, and if appropriate separating the dried layer from its intermediate substrate after the drying step (d), (e) converting the one or more oxide electronic conductor material precursors into oxide electronic conductor materials so that the dried layer contains the oxide electronic conductor materials, (f) consolidating the layer by thermal treatment and/or mechanical treatment, preferably by sintering, so as to obtain a porous, preferably mesoporous electrode, it should be understood that steps (e) and (f) can be carried out during the same thermal treatment.

The method according to the invention may comprise a heat treatment of the dried layer, preferably in an oxidizing atmosphere, in step (e), in step (f) or between step (e) and step (f). Advantageously, after step (f), the pores of the porous electrode are impregnated with an electrolyte. Depending on the desired type of battery, the electrolyte may comprise a lithium salt, a potassium salt or a sodium salt. The electrolyte is preferably a phase carrying lithium ions, sodium ions or potassium ions selected from the group consisting of: ○    an electrolyte consisting of at least one aprotic solvent and at least one lithium, sodium or potassium salt; ○    an electrolyte consisting of at least one ionic liquid and at least one lithium, sodium or potassium salt; ○    a mixture of at least one aprotic solvent and at least one ionic liquid and at least one lithium, sodium or potassium salt; ○    an ionic liquid polymer; ○    a polymer of an ionic conductor prepared by adding at least one lithium, sodium or potassium salt; and ○   An ion conductor polymer is prepared by adding a liquid electrolyte into the polymer phase or in the porous structure of the porous electrode, or impregnated with an ion conductor polymer, the ion conductor polymer is preferably selected from polyethylene oxide (PEO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(propylene carbonate) (PPC), poly(ethylene carbonate) (PEC), poly(vinyl carbonate) (PVC), polyvinylidene fluoride (PVDF), polypropylene glycol (PPG), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polydimethylsiloxane (PDMS), poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC).

The phase carrying lithium ions may comprise a mixture of several ionic liquids. Advantageously, the ionic liquid may be a combination of cations of the type 1-ethyl-3-methylimidazolium (also known as EMI+) and/or n-propyl-n-methylpyrrolidinium (also known as _PYR13 ⁺ ) and/or N-butyl-n-methylpyrrolidinium (also known as _PYR14 ⁺ ), and anions of the type bis(trifluoromethanesulfonyl)imide ( ^TFSI- ) and/or bis(fluorosulfonyl)imide ( ^FSI- ). To form an electrolyte, a lithium salt such as LiTFSI may be dissolved in an ionic liquid acting as a solvent or in a solvent such as γ-butyrolactone. γ-Butyrolactone prevents the ionic liquid from crystallizing, thereby providing it with a larger operating temperature range, especially at low temperatures. The phase carrying sodium or potassium ions may comprise a mixture of several ionic liquids. The ionic liquid may be as described above. To form the electrolyte, a sodium salt such as NaTFSI may be used instead of LiTFSI in a sodium ion battery, or a potassium salt such as KTFSI may be used instead of LiTFSI in a potassium ion battery. The phase carrying lithium, sodium or potassium ions may comprise an ionic liquid polymer, such as poly(1-vinyl-3-alkyl-imidazolium) or poly(1-vinyl-N-alkyl-pyrrolidinium).

In step (c), the layer may be formed on one or both surfaces of the substrate.

Advantageously, when the substrate is an intermediate substrate, the layer of the intermediate substrate is separated in step (d) after drying the layer to form a porous plate, in particular after consolidation.

Advantageously, when the substrate is an intermediate substrate, after (f), a conductive sheet is provided, the conductive sheet being covered with a conductive adhesive film on at least one face and on two faces thereof, respectively, and then at least one porous plate is bonded to one face of the conductive sheet, preferably to each face, to obtain a plate or porous layer, preferably a mesoporous layer, capable of serving as a current collector on the substrate. In the present application, the terms "porous layer" and "porous plate" are interchangeable.

Advantageously, step (b) is carried out by contacting the colloidal suspension or paste of aggregates or agglomerates of primary nanoparticles comprising at least one electrode active material P provided in step (a) with a liquid phase containing at least one precursor of the oxide electronic conductor material, and during step (e) the conversion of the one or more oxide electronic conductor material precursors into the oxide electronic conductor material is carried out by heat treatment such as calcination, preferably in air or an oxidizing atmosphere.

Advantageously, the one or more oxide electronic conductor material precursors are selected from organic salts containing one or more metal elements, which are capable of forming oxide electronic conductors after heat treatment such as calcination, and the conversion into electronic conductor materials is a heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere.

Such organic salts are preferably selected from: -     an alkyd salt of at least one metal element, which is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, -     a nitrate salt of at least one metal element, which is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, -     an oxalate salt of at least one metal element, which is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, and -    An acetate of at least one metal element, which is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, and/or preferably the metal element is selected from tin, zinc, indium, gallium, molybdenum or a mixture of two or three or four or five of these elements.

The metal element may contain at least one dopant element.

Advantageously, the porous layer obtained at the end of step (f) has a specific surface area between ¹⁰ and 500 m ² /g and/or a thickness between 2 and 400 µm, preferably between 2 and 300 µm, more preferably between 3 and 200 µm.

Advantageously, when the substrate is a substrate capable of acting as a current collector, the porous electrode obtained at the end of step (f) has a specific surface area between 10 m ² /g and 500 m ² /g; and/or the porous electrode has a thickness between 2 µm and 20 µm.

Advantageously, when the substrate is an intermediate substrate, the porous electrode obtained at the end of step (f) has a specific surface area between 10 m ² /g and 500 m ² /g and/or a thickness between 25 µm and 500 µm, preferably between 50 µm and 400 µm.

Advantageously, when the colloidal suspension or the paste provided in step (a) contains organic additives, such as ligands, stabilizers, binders or residual organic solvents, the dried layer or the porous plate obtained at the end of step (d) is subjected to a heat treatment, preferably in an oxidizing atmosphere. It should be understood that the heat treatment and steps (e) and/or (f) can be carried out during the same heat treatment step.

Advantageously, the electrode active material P is selected from the group consisting of (A): ○ oxides LiMn ₂ O ₄ ; Li _1+x Mn _2-x O ₄ , wherein 0 < x <0.15; LiCoO ₂ ; LiNiO ₂ ; LiMn _1.5 Ni _0.5 O ₄ ; LiMn _1.5 Ni _0.5-x X _x O ₄ , wherein X is selected from Al, Fe, Cr, Co, Rh, Nd, other rare earths such as Sc, Y, Lu, La, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and wherein 0 < x <0.1; LiMn _2-x M _x O ₄ , wherein M = Er, Dy, Gd, Tb, Yb, Al, Y, Ni, Co, Ti, Sn, As, Mg, or a mixture of these compounds, and wherein 0 < x <0.4; LiFeO ₂ ; LiMn _1/3 Ni _1/3 Co _1/3 O ₂ ; LiNi _0.8 Co _0.15 Al _0.05 O ₂ ; LiAl _x Mn _2-x O ₄ , wherein 0 ≤ x <0.15; LiNi _1/x Co _1/y Mn _1/z O ₂ , wherein x+y+z =10; ○ Li _x M _y O ₂ , wherein 0.6≤y≤0.85; 0≤x+y≤2; and M is selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Sn and Sb, or a mixture of these elements; Li _1.20 Nb _0.20 Mn _0.60 O ₂ ; ○ Li _1+x Nb _y Me _z A _p O ₂ , wherein Me is at least one transition metal selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, and wherein 0.6＜x＜1; 0＜y＜0.5; 0.25≤z＜1; wherein A ≠ Me and A ≠ Nb, and 0≤p≤0.2; ○ Li _x Nb _ya Na _a M _zb P _b O _2-c F _c , wherein 1.2＜x≤1.75; 0≤y＜0.55; 0.1＜z＜1; 0≤a＜0.5; 0≤b＜1; 0≤c＜0.8; and wherein M, N and P are each at least one element selected from the group consisting of Ti, Ta, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, Ce and Sb; ○ Li _1.25 Nb _0.25 Mn _0.50 O ₂ ; Li _1.3 Nb _0.3 Mn _0.40 O ₂ ; Li _1.3 Nb _0.3 Fe _0.40 O ₂ ; Li _1.3 Nb _0.43 Ni _0.27 O ₂ ; Li _1.3 Nb _0.43 Co _0.27 O ₂ ; Li _1.4 Nb _0.2 Mn _0.53 O ₂ ; ○ Li _x Ni _0.2 Mn _0.6 O _y , wherein 0.00≤x≤1.52; 1.07≤y＜2.4; Li _1.2 Ni _0.2 Mn _0.6 O ₂ ; ○ LiNi _x Co _y Mn _1−x−y O ₂ , wherein 0 ≤ x and y ≤ 0.5; LiNi _x Ce _z Co _y Mn _1−x−y O ₂ , wherein 0 ≤ x and y ≤ 0.5 and 0 ≤ z; ○ Phosphates LiFePO ₄ ; LiMnPO ₄ ; LiCoPO ₄ ; LiNiPO ₄ ; Li ₃ V ₂ (PO ₄ ) ₃ ; Li ₂ MPO ₄ F, wherein M = Fe, Co, Ni or a mixture of these different elements; LiMPO ₄ F, wherein M = V, Fe, T or a mixture of these different elements; phosphates of formula LiMM'PO ₄ , wherein M and M' (M ≠ M') are selected from Fe, Mn, Ni, Co, V, such as LiFe _x Co _1-x PO ₄ , and wherein 0 ＜ x ＜ 1; ○ Fe _0.9 Co _0.1 OF; FeF ₃ ; LiMSO ₄ F, wherein M = Fe, Co, Ni, Mn, Zn, Mg; ○ titanium oxysulfide (TiO _y S _z , wherein z=2-y and 0.3≤y≤1); tungsten oxysulfide (WO _y S _z , wherein 0.6＜y＜3 and 0.1＜z＜2); CuS; CuS ₂ ; Li _x V ₂ O ₅ , wherein 0 ＜ x ≤ 2; Li _x V ₃ O ₈ , wherein 0 ＜ x ≤ 1.7; Li _{x TiS2} , wherein 0 < x ≤ 1; titanium oxysulfide _and lithium _{LixTiOySz ,} wherein z = 2-y, 0.3≤y≤1 and 0 < x ≤1; _LixWOySz , _wherein z = 2-y, 0.3≤y≤1 and 0 < _x ≤1; _LixCuS , wherein 0 < x ≤1; _LixCuS2 , wherein 0 _< x ≤1; or selected from the group consisting of (B): - transition metal oxides: ○ _{NaxMO2 +z} , wherein M is selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ _{NaxMu /2} M' _v/2 O _2+z , wherein u + v = 2, and M, M' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ Na _x M _u/3 M' _v/3 M'' _w/3 O _2+z , wherein u + v + w = 3, and M, M', M'' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ Na _x Mn _y Ni _z Fe _0.1 Mg _0.1 O ₂ , wherein 0.67 ≤ x ≤ 1.0; 0.5 ≤ y ≤ 0.7 and 0.1 ≤ z ≤ 0.3; - Prussian blue and/or Prussian blue analogs, said Prussian blue analogs being denoted as PBA: ○ Na _x M ¹ [M ² '(CN) ₆ ] _y .nH ₂ O, M ¹ being a transition metal or a transition metal alloy, M ² ' being a transition metal, said transition metal and said transition metal alloy being selected from Fe, Ni, Co and Mn, wherein 0 ≤ x ≤ 2; y ≤ 1 and 0 ≤ n ≤ 12; - Polyanionic compounds: ○ Na _x M ₂ (XO ₄ ) ₃ , wherein 0 < x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W, such as Na ₃ V ₂ (PO ₄ ) ₃ ; ○ Na _x M ₃ (XO ₄ ) ₂ (X ₂ O ₇ ), where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M (X ₂ O ₇ ), where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ (XO ₄ ) ₂ F ₃ , where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ (XO ₄ ) ₂ F _3-y O _y , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and 0.07 ≤ y ≤ 0.12 and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ O ₂ (XO ₄ ) ₂ F, wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x MXO ₄ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; or selected from the group consisting of: - transition metal oxides: ○ K _x MO _2+z , wherein M is selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x M _u/2 M' _v/2 O _2+z , wherein u + v = 2, and M, M' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x M _u/3 M' _v/3 M'' _w/3 O _2+z , wherein u + v + w = 3, and M, M', M'' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 <x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x Mn _y Ni _z Fe _0.1 Mg _0.1 O ₂ , wherein 0.67 ≤ x ≤ 1.0; 0.5 ≤ y ≤ 0.7 and 0.1 ≤ z ≤ 0.3; - Prussian blue and/or Prussian blue analogs, wherein the Prussian blue analogs are represented by PBA: ○ K _x M ¹ [M ² '(CN) ₆ ] _y .nH ₂ O, M ¹ is a transition metal or a transition metal alloy, M ² ' is a transition metal, the transition metal and the transition metal alloy are selected from Fe, Ni, Co and Mn, wherein 0 ≤ x ≤ 2; y ≤ 1 and 0 ≤ n ≤ 12; - polyanionic compounds: ○ K _x M ₂ (XO ₄ ) ₃ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W, such as Na ₃ V ₂ (PO ₄ ) ₃ ; ○ K _x M ₃ (XO ₄ ) ₂ (X ₂ O ₇ ), wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M(X ₂ O ₇ ), wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M ₂ (XO ₄ ) ₂ F ₃ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M ₂ (XO ₄ ) ₂ F _3-y O _y , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and 0.07 ≤ y ≤ 0.12 and X = P, S, As, Si, Mo or W; ○ K _x M ₂ O ₂ (XO ₄ ) ₂ F , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x MXO ₄ , where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W.

Advantageously, the above-mentioned electrode active material P is used to manufacture a cathode.

Advantageously, the electrode active material P is selected from the group consisting of: ○ Li ₄ Ti ₅ O ₁₂ ; Li ₄ Ti _5-x M _x O ₁₂ , wherein M = V, Zr, Hf, Nb, Ta, and 0 ≤ x ≤ 0.25; ○ Niobium oxide and mixed oxides of niobium with titanium, germanium, niobium or tungsten, and is preferably selected from the group consisting of: ○ Nb ₂ O _5±δ , Nb ₁₂ WO _33±δ , Nb ₁₄ W ₃ O _44±δ , Nb ₁₈ W ₁₆ O _93±δ , Nb ₁₆ W ₅ O _55±δ , wherein 0 ≤ δ ≤ 2; LiNbO ₃ , ○ TiNb ₂ O _7±δ ; Li _w TiNb ₂ O ₇ , wherein w ≥ 0; Ti _1-x M ¹ _x Nb _2-y M ² _y O _7±δ or Li _w Ti _1-x M ¹ _x Nb _2-y M ² _y O _7±δ , wherein M ¹ and M ² are each at least one element selected from the group consisting of Nb, V, Ta, Fe, Co, Ti, Bi, Sb, As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, Pb, Al, Zr, Si, Sr, K, Cs and Sn, M ¹ and M ² can be the same as or different from each other, and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and 0 ≤ δ ≤ 0.3; ○ La _x Ti _1-2x Nb _2+x O ₇ , wherein 0＜x＜0.5; ○ M _x Ti _1-2x Nb _2+x O _7±δ ○ wherein M is an element having an oxidation number of +III, more specifically, M is at least one element selected from the group consisting of Fe, Ga, Mo, Al, B, and wherein 0＜x≤0.20 and -0.3≤ δ ≤0.3; Ga _0.10 Ti _0.80 Nb _2.10 O ₇ ; Fe _0.10 Ti _0.80 Nb _2.10 O ₇ ; ○ M _x Ti _2-2x Nb _10+x O _29±δ ○ wherein M is an element having an oxidation number of +III, more specifically, M is at least one element selected from the group consisting of Fe, Ga, Mo, Al, B, and wherein 0＜x≤0.40 and -0.3≤ δ ≤0.3; ○ Ti _1-x M ¹ _x Nb _2-y M ² _y O _7-z M ³ _z or Li _w Ti _1-x M ¹ _x Nb _2-y M ² _y O _7-z M ³ _z , wherein ○ M ¹ and M ² are each at least one element selected from the group consisting of Nb, V, Ta, Fe, Co, Ti, Bi, Sb, As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, Pb, Al, Zr, Si, Sr, K, Cs and Sn, ○ M ¹ and M ² can be the same as or different from each other, ○ M ³ is at least one halogen, ○ and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; ○ TiNb ₂ O _7-z M ³ _z or Li _w TiNb ₂ O _7-z M ³ _z , wherein M ³ is at least one halogen, preferably selected from F, Cl, Br, I or a mixture of these halogens, wherein 0 ≤ z ≤ 0.3 and 0 < w ≤ 0.5; ○ Ti _1-x Ge _x Nb _2-y M ¹ _y O _7±z ; Li _w Ti _1-x Ge _x Nb _2-y M ¹ _y O _7±z ; Ti _1-x Ce _x Nb _2-y M ¹ _y O _7±z ; Li _w Ti _1-x Ce _x Nb _2-y M ¹ _y O _7±z , wherein ○ M ¹ is at least one element selected from the group consisting of Nb, V, Ta, Fe, Co, Ti, Bi, Sb, As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, Pb, Al, Zr, Si, Sr, K, Cs and Sn; ○ 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; ○ Ti _{1- x} Ge _x Nb 2 _{- y} ^{M 1 y} _{O 7 - z M} ² _z ^; _{Li w Ti 1 -} ^x _Ge O _7-z M ² _z ; Li _w Ti _1-x Ce _x Nb _2-y M ¹ _y O _7-z M ² _z , where ○ M ¹ and M ² are each at least one element selected from the group consisting of Nb, V, Ta, Fe, Co, Ti, Bi, Sb, As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, Pb, Al, Zr, Si, Sr, K, Cs, Ce and Sn, ○ ^M1 and ^M2 can be the same or different from each other, ○ and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; ○ TiO ₂ ; TiO _x N _y , wherein x＜2 and 0＜y＜0.2; ○ LiSiTON, a nitride oxide mainly composed of tin and silicon, and more specifically, the formulation SiSn _0.87 O _1.20 N _1.72 and its lithiated forms; ○ MO _x N _y -type nitrides and oxynitrides, wherein M is at least one element selected from Ge, Si, Sn, Zn, Co, Ni, Cu, Fe or a mixture of one or more of these elements, and wherein x ≥ 0 and y ≥ 0.3; ○ Li _3-X M _x N, wherein M is at least one element selected from Cu, Ni, Co or a mixture of one or more of these elements, and 0 ≤ x ≤ 1; ○ Li _3-X M _x N, wherein M is cobalt (Co) and 0 ≤ x ≤ 0.5; Li _3-X M _x N, wherein M is nickel (Ni) and 0 ≤ x ≤ 0.6; Li _3-X M _x N, wherein M is copper (Cu) and 0 ≤ x ≤ 0.3; ○ Lithium iron phosphate (with the typical formula LiFePO ₄ ); ○ Si _a Sn _b O _y N with the typical formula _z , wherein a＞0, b＞0, a+b≤2, 0＜ _y≤4 , 0＜ _z≤3 , also known as SiTON, and in particular _{SiSn0.87O1.2N1.72} ; and _oxynitride carbides having the typical formula _SiaSnbCcOyNz , wherein a＞0, b＞0, a+b≤2, 0＜ _c ＜ ₁₀ , 0＜y＜24, 0＜z＜17; _○ Nitrides of _{the SixNy} type, in particular wherein x=3 and y=4; _SnxNy , in particular wherein x=3 and _y = ₄ ; _ZnxNy , in particular wherein x=3 and y=2; Li3 _{- xMx} N, wherein for M=Co, 0≤x≤0.5, for M=Ni, 0≤x≤0.6, for M=Cu, 0≤x≤0.3; Si _3-x M _x N ₄ , wherein M=Co or Fe and 0≤x≤3; ○ oxides SnO ₂ , SnO, Li ₂ SnO ₃ , SnSiO ₃ , Li _x SiO _y , wherein x≥0 and 2＞y＞0; Li ₄ Ti ₅ O ₁₂ , TiNb ₂ O ₇ , Co ₃ O ₄ , SnB _0.6 P _0.4 O _2.9 and TiO ₂ , ○ Si, Sn, SiO ₂ , SnO ₂ , SiN, SnN and mixtures thereof, ○ composite oxides TiNb ₂ O ₇ , which contains between 0% and 10% carbon by mass, the carbon being preferably selected from graphene and carbon nanotubes; or selected from the group consisting of (E): - alloys based on Si, Ge, Sn, Sb, Bi or P and alloys of various compounds thereof, - MXene, which is a class of two-dimensional materials, whose stoichiometry is of the Mn _{+ 1XnTx} type, wherein M is a transition metal, preferably selected from Sc, Ti, _V , Cr, Y, Zr, Nb, Mo, Hf, Ta, W, and X is selected from C and/or N, and T is a surface termination selected from F, Cl, I, Br, O, S, Se, Te, OH, _NH2 , 1 ≤ n ≤ ₄ , - conversion anode materials, such as: _{○ G2Ti3O7} , G ₄ Ti ₅ O ₁₂ , GTi ₂ (PO ₄ ) ₃ type oxides, where G is Na or K; ○ Oxides, sulfides, selenides and phosphides of the following elements and their alloys: Si, Ge, Sn, Sb, Bi.

Advantageously, the above-mentioned electrode active material P is used to manufacture an anode.

Another object of the present invention is a porous electrode, in particular for use in electrical energy storage or production devices, characterized in that the porous electrode comprises at least one electrode active material P and an oxide electronic conductor material, wherein the porous electrode does not contain a binder, wherein the porous electrode has a porosity by volume of between 25% and 60%, preferably between 25% and 50%.

Another object of the invention is a porous electrode obtainable by a method according to the invention. Another object of the invention is a porous electrode obtainable by a method according to the invention, characterized in that the porous electrode comprises at least one electrode active material P and an oxide electronic conductor material, wherein the porous electrode is free of binder, and wherein the porous electrode has a porosity by volume of between 25% and 60%, preferably between 25% and 50%.

Another object of the present invention is a method for manufacturing an energy storage or production device, which is preferably selected from the group consisting of: capacitors; supercapacitors; hybrid supercapacitors, such as lithium-ion hybrid supercapacitors, sodium-ion hybrid supercapacitors, and potassium-ion hybrid supercapacitors; photovoltaic cells; photochemical cells; and batteries, such as lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries, which implements the method for manufacturing a porous electrode according to the present invention or uses a porous electrode according to the present invention. Another object of the present invention is a method for manufacturing an energy storage or production device (such as a battery, a capacitor, a supercapacitor, a hybrid supercapacitor (such as a lithium-ion hybrid supercapacitor, a sodium-ion hybrid supercapacitor, a potassium-ion hybrid supercapacitor), a photochemical cell, a photovoltaic cell), and in particular a method for manufacturing a lithium-ion, sodium-ion or potassium-ion battery, which implements the method for manufacturing a porous electrode according to the present invention.

Advantageously, when the electric energy storage or production device is a lithium-ion hybrid supercapacitor or a lithium-ion battery, the cathode manufacturing method uses an electrode active material P selected from group (A), or the anode manufacturing method uses an electrode active material P selected from group (D).

Advantageously, when the energy storage or production device is a sodium ion hybrid supercapacitor or a sodium ion battery, the cathode manufacturing method uses an electrode active material P selected from group (B), or the anode manufacturing method uses an electrode active material P selected from group (E) (where appropriate, G is Na).

Advantageously, when the energy storage or production device is a potassium ion hybrid supercapacitor or a potassium ion battery, the cathode manufacturing method uses an electrode active material P selected from group (C), or the anode manufacturing method uses an electrode active material P selected from group (E) (where appropriate, G is K).

Advantageously, in a method for manufacturing a lithium-ion battery, a method for manufacturing a porous electrode is implemented so as to manufacture a cathode using an electrode active material P selected from group (A), or a method for manufacturing an anode is implemented using an electrode active material P selected from group (D).

In particular, this method is very suitable for manufacturing batteries, and in general, batteries according to the invention can be designed and dimensioned as surface mount components (a technique for surface mount technology, which is usually abbreviated to "SMT") so as to be compatible with methods for manufacturing microelectronic devices, in particular with robotic methods for populating electronic boards, which are referred to under the term "pick and place". Advantageously, the porous electrode is impregnated with an electrolyte, preferably with a phase carrying lithium, sodium or potassium ions selected from the group consisting of: ○    an electrolyte consisting of at least one aprotic solvent and at least one lithium, sodium or potassium salt; ○    an electrolyte consisting of at least one ionic liquid and at least one lithium, sodium or potassium salt; ○    a mixture of at least one aprotic solvent and at least one ionic liquid and at least one lithium, sodium or potassium salt; ○    an ionic liquid polymer; ○   A polymer of an ion conductor made by adding at least one lithium, sodium or potassium salt; and ○    A polymer of an ion conductor made by adding a liquid electrolyte in the polymer phase or in a porous structure, or impregnated with an ion conductor polymer, the ion conductor polymer is preferably selected from polyethylene oxide (PEO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(propylene carbonate) (PPC), poly(ethylene carbonate) (PEC), poly(vinyl carbonate) (PVC), polyvinylidene fluoride (PVDF), polypropylene glycol (PPG), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polydimethylsiloxane (PDMS), poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC).

Another object of the invention is an electrical energy storage or production device obtainable by the method according to the invention, preferably a battery, preferably a lithium-ion, sodium-ion or potassium-ion battery obtainable by the method according to the invention.

Advantageously, the electrical energy storage or production device according to the invention is a capacitor; a supercapacitor; a hybrid supercapacitor, such as a lithium-ion hybrid supercapacitor, a sodium-ion hybrid supercapacitor, a potassium-ion hybrid supercapacitor; a photovoltaic cell; a photochemical cell; or a battery, such as a lithium-ion battery, a sodium-ion battery or a potassium-ion battery.

Advantageously, when the electrical energy storage or production device is a lithium-ion hybrid supercapacitor or a lithium-ion battery, an electrode active material P selected from group (A) is used for the cathode active material and/or an electrode active material P selected from group (D) is used for the anode active material.

Advantageously, when the electrical energy storage or production device is a sodium ion hybrid supercapacitor or a sodium ion battery, an electrode active material P selected from group (B) is used for the cathode active material and/or an electrode active material P selected from group (E) is used for the anode active material (where appropriate, G is Na).

Advantageously, when the electrical energy storage or production device is a potassium ion hybrid supercapacitor or a potassium ion battery, an electrode active material P selected from group (C) is used for the cathode active material and/or an electrode active material P selected from group (E) is used for the anode active material (where appropriate, G is K).

The method according to the invention is particularly suitable for producing porous electrodes with a thickness greater than 1 µm or even greater than 3 µm, while ensuring a low series resistance of the battery.

Another object of the invention is an electrical energy storage or production device, such as a battery, a capacitor, a supercapacitor, a photovoltaic cell or a photochemical cell, which comprises a porous electrode according to the invention or a porous electrode obtainable by a method according to the invention.

Detailed description of preferred embodiments 1. Definitions

The present invention relates to a porous electrode, the accessible surface of which (ie, the outer surface of the electrode) and the accessible inner pores of the electrode are covered by an oxide electronic conductor material. The term "oxide electronic conductor" includes oxide electronic conductors and oxide electronic semiconductors.

In the context of this document, the size of a particle is defined by its largest dimension. The term "nanoparticle" shall mean any particle or object having nanometer dimensions, at least one of whose dimensions is less than or equal to 400 nm.

The term "ionic liquid" shall mean any liquid salt capable of transporting electricity, which is distinguished from molten salts by having a melting temperature below 100°C. Some of these salts remain liquid at ambient temperature and do not solidify even at extremely low temperatures. Such salts are called "ambient temperature ionic liquids".

The term "electrolyte" shall mean any substance which has ionic conductivity due to the presence of mobile ions; it may be a solid without a liquid phase, or a liquid. Such ions are preferably Li+, Na+ or K+. Liquid electrolytes may be in the form of gels. In order to galvanically separate the electrodes, the electrolyte is electronically insulating.

The term "mesoporous" material shall mean any solid having within its structure pores called "mesopores" having an intermediate size between micropores (less than 2 nm in width) and macropores (greater than 50 nm in width), i.e. a size between 2 nm and 50 nm. This terminology corresponds to the terminology adopted by IUPAC (International Union for Pure and Applied Chemistry), which is provided for reference by those skilled in the art. Thus, the term "nanopore" is not used in this text, even though mesopores as defined above have nanometer dimensions in the sense of the definition of nanoparticles, it is understood that pores of a size smaller than that of mesopores are referred to as "micropores" by those skilled in the art.

An introduction to the concept of porosity (and the terms just explained above) is given in the article by F. Rouquerol et al., "Texture des materials pulvérulents ou poreux" (Texture of powdery or porous materials), published in "Techniques de l'Ingénieur" (Techniques for the Engineer), Treaty, Analyse et Caractérisation (Analysis and Characterisation), brochure page 1050; this article also describes the techniques used to characterize the porosity, in particular the BET method.

In the meaning of the present invention, the term "porous layer" means a layer having pores. The term "mesoporous layer" means a layer having mesopores. In such layers, the pores and mesopores make a significant contribution to the total porous volume; the expression "the porosity of the porous/mesoporous layer is greater than X% (by volume)" used in this specification shows this situation.

According to the IUPAC definition, the term "aggregate" means a weakly cohesive assembly of primary particles. In this case, these primary particles, preferably nanoparticles, are particles having a diameter that can be measured by transmission electron microscopy. Aggregates of aggregated primary nanoparticles can be broken up (i.e. reduced to primary nanoparticles) in a suspension in a liquid phase, usually under the action of ultrasound, using techniques known to those skilled in the art.

According to the IUPAC definition, the term "agglomerate" means a strongly cohesive assembly of primary particles or aggregates. 2. Preparation of nanoparticle suspensions

The porous electrode according to the present invention is formed from a colloidal suspension or paste of clusters and/or agglomerates of nanoparticles.

In another preferred embodiment of the present invention, nanoparticles are directly prepared in primary size by precipitation, Pechini synthesis, spray pyrolysis, hydrothermal or solvent thermal synthesis. Hydrothermal or solvent thermal synthesis can be used to obtain nanoparticles (NANOPARTICLE), preferably nanoparticles with a very narrow size distribution, called "monodisperse nanoparticles". The size of these non-aggregated or non-agglomerated nanopowders/nanoparticles is called primary size. It is typically between 2 nm and 400 nm, preferably between 2 nm and 100 nm and more preferably between 2 nm and 60 nm, and advantageously between 10 nm and 50 nm, preferably between 10 nm and 30 nm; this promotes the formation of an interconnected electronically and ionically conducting mesoporous network by a "neck" phenomenon during subsequent method steps.

Additives such as binders may also be added to the suspension of nanoparticles (clusters and/or agglomerates of nanoparticles, it being understood that such clusters are also in the form of nanoparticles) in order to promote the production of a deposit or green sheet, especially a thick deposit without cracks.

A layer of at least one oxide electronic conductor material precursor is formed on these preferably monodisperse aggregates and/or agglomerates of primary nanoparticles of at least one electrode active material P by any suitable means.

3. A mixture comprising at least one oxide electronic conductor material precursor and a colloidal suspension or paste, wherein the colloidal suspension or paste comprises aggregates and/or agglomerates of primary particles of at least one electrode active material P - a layer of at least one oxide electronic conductor material precursor is formed on the aggregates and/or agglomerates of primary nanoparticles of at least one electrode active material P.

Highly advantageously, the oxide electronic conductor material layer can be obtained in various ways and by any suitable means, in particular by contacting a colloidal suspension, a paste of aggregates or agglomerates of primary nanoparticles of at least one electrode active material P with a liquid phase containing at least one oxide electronic conductor material precursor after converting the one or more electronic conductor material precursors into the electronic conductor material.

More generally, using the techniques indicated herein for producing a coating of at least one oxide electronic conductor material precursor, only the accessible surfaces of aggregates or agglomerates of primary nanoparticles of at least one electrode active material P are covered.

The formation of a layer of at least one precursor of an oxide electronic conductor material on the aggregates and/or agglomerates of the suspension or paste is advantageously carried out in the presence of a complexing agent, such as polyvinylpyrrolidone (PVP), to promote complexation of the one or more precursors at the surface of the aggregates/agglomerates.

The method is simple, rapid and easy to implement. Advantageously, the one or more precursors of the electronic conductor material are selected from organic salts containing one or more metal elements, which are capable of forming oxide electronic conductors after heat treatment such as calcination (preferably carried out in air or in an oxidizing atmosphere). The oxide electronic conductor may optionally contain at least one dopant element. These metal elements, preferably metal cations, may advantageously be tin, zinc, indium, gallium, molybdenum or a mixture of two or three or four or five of these elements.

The organic salt is preferably selected from: -     an alkyd salt of at least one metal element, which is capable of forming an oxide electronic conductor after a heat treatment such as calcination preferably in air or in an oxidizing atmosphere, -     a nitrate salt of at least one metal element, which is capable of forming an oxide electronic conductor after a heat treatment such as calcination preferably in air or in an oxidizing atmosphere, -     an oxalate salt of at least one metal element, which is capable of forming an oxide electronic conductor after a heat treatment such as calcination preferably in air or in an oxidizing atmosphere, and -    An acetate of at least one metal element capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere.

In order to obtain a layer of an electron conductor material, preferably an oxide electron conductor material, from an alkyd, nitrate, oxalate or acetate on aggregates or agglomerates of primary nanoparticles of at least one electrode active material P, a colloidal suspension or paste containing the aggregates or agglomerates of the nanoparticles can be contacted with a solution rich in a precursor of the desired electron conductor material.

It is a mixture of this colloidal suspension or paste (containing aggregates or agglomerates of primary nanoparticles of electrode active material P) and at least one oxide electronic conductor material precursor, which is then used to manufacture the porous dry layer and electrode according to the present invention. The mixture of this colloidal suspension or paste (containing aggregates or agglomerates of primary nanoparticles of electrode active material P) and at least one oxide electronic conductor material precursor is hereinafter referred to as "the mixture according to the present invention". Advantageously, the mixture according to the present invention is in the form of a colloidal suspension or paste (ink). 4. Manufacture of porous layer

The method for making an electrode according to the present invention involves coating a mixture comprising one or more oxide electronic conductor material precursors and a colloidal suspension or paste (comprising aggregates or agglomerates of primary nanoparticles of at least one electrode active material P) on a substrate to form a layer, followed by drying the layer to obtain a porous layer. The sequence comprising coating the mixture on a substrate to form a layer and drying it can be repeated several times to increase the thickness of the porous layer. The final thickness of the porous layer is advantageously less than or equal to 5 mm, preferably between about 1 μm and about 500 μm. The thickness of this porous layer is advantageously less than 500 μm, preferably between about 2 μm and about 400 μm, more preferably between 2 μm and 300 μm, still more preferably between 3 μm and 200 μm. Typically, the mixture according to the invention in the form of a colloidal suspension or paste is deposited on the substrate by any suitable technique, and in particular by electrophoresis, extrusion, lamination (or "robocasting"), inkjet printing, painting, flexographic printing, by a coating method, preferably using a blade (known by the terms "doctor blade" or "tape casting"), by roll coating, curtain coating, through slit extrusion or by immersion coating.

In order to make the mixture according to the present invention have a viscosity suitable for the coating technology commonly used to manufacture electrodes and also be deposited on a substrate, it is preferable to use the mixture according to the present invention in the form of a colloidal suspension or paste with a solid content of less than 30% by mass.

According to the findings of the present applicant, in case the average diameter of the aggregates or agglomerates of the nanoparticles is between 50 nm and 900 nm, preferably between 100 nm and 800 nm (more preferably between 100 nm and 400 nm), during the subsequent method steps, a mesoporous layer with an average diameter of the mesopores between 2 nm and 100 nm is obtained.

According to the present invention, the porous layer can be deposited by an inkjet printing method or by a coating method, and in particular by immersion coating, roll coating, curtain coating, slit coating or by doctor blade coating, and this is deposited from the mixture according to the present invention in the form of a relatively concentrated suspension, the suspension containing at least one oxide electronic conductor material precursor and nanoparticle aggregates or agglomerates of the active material P.

The porous electrode layer can also be deposited by electrophoresis, but then the mixture according to the invention is advantageously used in the form of a less concentrated suspension comprising at least one precursor of an oxide electron conductor material and nanoparticle agglomerates of the active material P.

The method of depositing the mixture according to the invention by electrophoresis, extrusion, layering, dip coating, inkjet, roll coating, curtain coating, doctor blade or slot coating is simple, safe, easy to implement and industrialize, and makes it possible to obtain a uniform final porous layer. Electrophoretic deposition makes it possible to deposit layers uniformly on large surfaces at high deposition rates. Compared with electrophoretic deposition techniques, coating techniques, especially those mentioned above, can simplify the management of the bath liquid, because the suspension is not exhausted during the deposition. Deposition by inkjet printing enables localized deposition.

Thicker porous layers, preferably with a thickness of between 50 and 400 μm, can be produced in a single step by roll coating, curtain coating, slot coating or by doctor blade coating (ie by means of a blade) or else by extrusion.

The technology used to deposit the mixture according to the invention in the form of a colloidal suspension or paste (ink) and the performance of the deposition method must be compatible with the viscosity of the colloidal suspension or paste (ink) used, and vice versa.

The substrate is advantageously an intermediate substrate or a substrate that can serve as a current collector. 4.1 Substrate that can serve as a current collector

In a first embodiment, the substrate is a substrate capable of acting as a current collector and which is advantageously compatible with the heat treatment used in the method according to the invention. The substrate can advantageously be a metal substrate or a substrate made of electron-conducting carbon, in particular mainly graphite, graphene and/or carbon nanotubes. The substrate on which the mixture according to the invention is deposited in the form of a colloidal suspension or a paste (ink) ensures the current collector function of the electrode. The mixture according to the invention in the form of a colloidal suspension or a paste (ink) can be deposited on one or both faces of the substrate, in particular by the deposition techniques indicated above.

The current collector in an electrochemical device using an electrode according to the invention may be a substrate that is stable within the potential operating range of the electrochemical device. Inside a battery using an electrode according to the invention, the current collector must be a substrate that is stable within a potential range relative to the potential of lithium, preferably between 2.5 V and 5 V for the cathode, and between 0 V and 2.5 V for the anode. Advantageously, a metal substrate is selected, such as a metal strip (i.e., a laminated metal sheet). The substrate may be made, in particular, of tungsten, molybdenum, chromium, titanium, tungsten, zirconium, niobium, stainless steel, or an alloy of two or more of these materials. Such metal substrates are quite expensive and can significantly increase the cost of the battery. Tungsten, molybdenum, chromium, titanium, tantalum, zirconium, niobium, stainless steel and their alloys are particularly resistant to high temperature heat treatment; they are therefore particularly suitable as electrode substrates that can be sintered. The reason for using these heat-resistant substrates is that deposits, preferably thin deposits, can be sintered directly on the substrate.

It is also possible to coat this substrate capable of acting as a current collector with a conductive or semiconductive oxide before depositing the mixture according to the invention in the form of a colloidal suspension or paste (ink), which makes it possible in particular to protect less expensive substrates, such as copper, nickel, aluminum and carbon, in particular in the form of graphite. These less expensive substrates can therefore be used as electrode substrates, in particular due to their cost. They may involve conductive carbon sheets (usually graphite), metal sheets or metallized non-metal sheets (that is, covered with a metal layer). The substrate is preferably chosen from strips made of copper, nickel, molybdenum, tungsten, tantalum, chromium, niobium, zirconium, titanium and alloy strips containing at least one of these elements. Stainless steel can also be used. These substrates have the advantage of being stable over a wide range of potential and resistant to heat treatment.

Copper, nickel, molybdenum and their alloys are preferably used as anode substrates. Carbon-based substrates (especially in the form of graphite) based on nickel-chromium alloys, stainless steel, chromium, titanium, aluminum, tungsten, molybdenum, tantalum, zirconium, niobium or alloys containing at least one of these elements are preferably used as collector substrates for cathodes. Such anode and/or cathode substrates may be covered or uncovered by an electrochemically inert conductive layer. Such layers may be produced by depositing nitrides, carbides, graphite, gold, palladium and/or platinum.

The mixture according to the invention in the form of a colloidal suspension or paste (ink) can be deposited on one or both faces of a substrate capable of acting as a current collector. The layer deposited on this substrate is then dried in order to obtain a porous layer comprising the electrode active material P and at least one precursor of the active electronic conductor material.

Then, one or more oxide electronic conductor material precursors are converted into oxide electronic conductor materials on this porous dry layer initially deposited on one or both surfaces of the substrate capable of serving as a current collector. 4.2 Intermediate substrate

According to a second embodiment, the mixture according to the invention is not deposited in the form of a colloidal suspension or paste (comprising the electrode active material P and at least one precursor of the active material electronic conductor (ink)) on a substrate capable of acting as a current collector, but is deposited on an intermediate substrate which is usually used in a temporary manner.

In this embodiment, the mixture according to the invention in the form of a colloidal suspension or paste (ink) is deposited on the face of an intermediate substrate, so that the layers obtained from this intermediate substrate can subsequently be easily separated.

Specifically, it is possible to deposit a relatively thick layer from a mixture according to the present invention (comprising aggregates and/or agglomerates of nanoparticles of at least one oxide electron conductor material precursor and electrode active material P) in the form of a suspension or paste, preferably from a concentrated suspension comprising aggregates and/or agglomerates of nanoparticles of at least one oxide electron conductor material precursor and electrode active material P (i.e., having lower fluidity and preferably in the form of a paste), and the relatively thick layer is referred to as a "green sheet". These thick layers can be deposited by any suitable means, in particular by an inkjet printing method, by extrusion, lamination, spraying, flexographic printing, coating methods, preferably doctor blade coating, roll coating, curtain coating, by slot extrusion or by dipping.

The method of depositing the nanoparticles by immersion coating, by inkjet printing, by roll coating, curtain coating, slot coating, by extrusion, lamination, spraying, flexographic printing or doctor blade coating is a simple, safe, easy to implement and industrialized method that enables a uniform deposit to be obtained. Inkjet printing allows the mixture according to the invention to be deposited in a localized manner in the same way as doctor blade deposition under a mask. Thick layers can be applied in a single step by roll coating, curtain coating, slot coating, dip coating, extrusion, lamination or doctor blade coating techniques.

The intermediate substrate may be a flexible substrate, which may be a polymer sheet, such as polyethylene terephthalate, abbreviated PET. In this second embodiment, the deposition step is advantageously carried out on one face of the intermediate substrate in order to facilitate the subsequent separation of the layer from its substrate. In this second embodiment, the layer is separated from its substrate after drying and before any high temperature thermal treatment. The thickness of the layer after drying is advantageously less than or equal to 5 mm, advantageously between about 1 μm and about 600 μm. The thickness of the layer after drying is advantageously less than 500 μm, preferably between about 3 μm and about 400 μm, more preferably between 3 μm and 300 μm.

In this second embodiment, the method for manufacturing electrodes for electrochemical devices such as batteries uses an intermediate substrate preferably made of a polymer such as PET and produces a strip called "green strip". After drying, this green strip is then separated from its substrate; it is then formed into a self-supporting plate or sheet (herein below, the term "plate" is used regardless of its thickness).

Then, one or more oxide electronic conductor material precursors are converted into oxide electronic conductor materials on such self-supporting porous plates or sheets. 5. One or more oxide electronic conductor material precursors present in the porous dry layer are converted into oxide electronic conductor materials

A self-supporting porous dry layer or porous plate comprising an electrode active material P and at least one active material electronic conductor precursor is heat treated at a temperature sufficient to convert one or more oxide electronic conductor material precursors discussed into an oxide electronic conductor material, and the heat treatment is preferably carried out in air or in an oxidizing atmosphere. Thus, a region of electrode active material P is formed, which is at least partially covered in a perfectly distributed manner throughout the entire internal volume of the electrode and at the surface with a coating of an electronic conductor material, preferably a coating of an oxide electronic conductor material, more preferably SnO ₂ , ZnO doped with aluminum (ZnO:Al, preferably with a Zn:Al molar ratio between 1:0.015 and 1:0.05), In ₂ O ₃ , Ga ₂ O ₃ , MoO ₃ and SrMoO ₃ , including a mixture of two of these oxides (such as corresponding to indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ), a mixture of three of these oxides, a mixture of four of these oxides, a mixture of five of these oxides, or a mixture of six of these oxides.

The heat treatment, which is preferably carried out in an oxidizing atmosphere, can eliminate organic components, i.e., debond. Depending on the nature of the electrode active material P used and the temperature used to convert one or more of the oxide electronic conductor material precursors discussed into oxide electronic conductor materials, the heat treatment can also make it possible to consolidate the layer or porous plate, as will be explained in detail in the following chapters.

Regarding the prior art and in particular the porous electrode comprising a carbon coating on and inside the pores of the electrode as described in application WO 2021/220174, the electrode is at least partially covered with a coating of an oxide electronic conductor material in a perfectly distributed manner throughout the entire internal volume of the electrode and at the surface. The presence of areas of electrode active material P preferably covered with a coating of an oxide electronic conductor material enables the electrode to have better electrochemical performance at high temperatures and significantly increases the stability of the electrode. The fact of using this single three-dimensional structure, preferably containing regions of electrode active material P throughout the entire internal volume of the electrode and at least partially covered by a coating of oxide electronic conductor material at the surface, makes the final electrode have better performance. More specifically, the presence of regions of electrode active material P that are at least partially covered with a coating of oxide electronic conductor material throughout the entire interior volume of the electrode and at the surface, preferably covered with a coating of oxide electronic conductor material, can improve the final properties of the electrode, in particular the voltage stability of the electrode and its temperature stability, and improve the electrochemical stability of the electrode, especially when it is in contact with a liquid electrolyte, so as to reduce the polarization resistance of the electrode, and this is true even when the electrode is thicker. When the electrode is thick and/or the active material resistance of the porous layer is too large, it is particularly advantageous to use electronic conductor materials in the form of oxides in the electrode volume, especially of the type _In2O3 , _SnO2 , _ZnO doped with aluminum (ZnO:Al, preferably with a Zn:Al molar ratio between 1:0.015 and 1:0.05), _Ga2O3 , _MoO3 , _SrMoO3 , or one or more of these _oxides or mixtures of these doped oxides.

The electrode according to the present invention is porous, preferably mesoporous, and its large specific surface area is advantageous. The increase in the specific surface area of the electrode doubles the exchange surface area and thus doubles the power of the battery, but it also accelerates parasitic reactions. The presence of these electronic conductor coatings in the form of oxides in the volume of the electrode will enable these parasitic reactions to be blocked.

Furthermore, due to the fact of the extremely large specific surface area, the effect of these electron conductor coatings in the form of oxides on the electron conductivity of the electrode will be more significant than in the case of conventional electrodes with a smaller specific surface area, and this is true even if the deposited conductor coating has a lower thickness. These oxide electron conductor coatings disposed in the electrode volume of the porous layer give the electrode an extremely good electron conductivity, especially when the porous layer is formed from an electrode active material that is poorly electronically conductive. This oxide electronic conductor material layer can improve the conductivity of the electrode while limiting the dissolution of the electrode, thereby making it possible to increase the power of the battery; this result is more realistic because the thickness of the oxide electronic conductor material coating layer in the area with the electrode active material P is relatively low.

This is basically a single structure of a porous electrode manufactured according to the method of the present invention, which includes areas of electrode active material P covered with an oxide electronic conductor material coating throughout the entire internal volume of the electrode and at the surface, which makes it possible to improve the final properties of the electrode, and in particular makes it possible to obtain a thick electrode without increasing the internal resistance of the electrode.

The thickness of the coating of the oxide electronic conductor material throughout the entire internal volume of the electrode (the area where the electrode active material P is coated) is generally less than 10 nm, preferably less than 7 nm, more preferably less than 5 nm, even more preferably between 5 nm and 3 nm and even more preferably less than 3 nm. The coating of the oxide electronic conductor material throughout the entire internal volume of the electrode advantageously has an optimal thickness; this coating must be thick enough to improve electronic conduction, and thin enough not to hinder ion conduction inside the electrode, and ultimately not to reduce the performance of the energy storage or production device such as a battery. In addition, due to the large specific surface area of the electrode, this coating enables the electrode to have good electronic conduction.

Advantageously, the electronic conductor material may be an oxide electronic conductor material, preferably chosen from: - tin oxide (SnO ₂ ); zinc oxide doped with aluminum (ZnO:Al), preferably with a Zn:Al molar ratio between 1:0.015 and 1:0.05; indium oxide (In ₂ O ₃ ); gallium oxide (Ga ₂ O ₃ ); molybdenum oxide (MoO ₃ ); molybdenum strontium oxide (SrMoO ₃ ); a mixture of two of these oxides, such as indium tin oxide corresponding to a mixture of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ); a mixture of three of these oxides; a mixture of four of these oxides; a mixture of five of these oxides or a mixture of six of these oxides, - A doped oxide mainly composed of zinc oxide, preferably doped with gallium (Ga) and/or aluminum (Al) and/or boron (B) and/or curium (Be) and/or chromium (Cr) and/or niobium (Ce) and/or titanium (Ti) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Indium oxide-based doped oxide, preferably doped with tin (Sn) and/or gallium (Ga) and/or chromium (Cr) and/or cadmium (Ce) and/or titanium (Ti) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Tin oxide doped, preferably doped with arsenic (As) and/or fluorine (F) and/or nitrogen (N) and/or niobium (Nb) and/or phosphorus (P) and/or antimony (Sb) and/or aluminum (Al) and/or titanium (Ti), and/or gallium (Ga) and/or chromium (Cr) and/or niobium (Ce) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Molybdenum oxide-based doped oxide, preferably doped with lithium (Li) and/or sodium (Na) and/or potassium (K) and/or curium (Be) and/or magnesium (Mg) and/or calcium (Ca) and/or sintered carbide (Sc) and/or titanium (Ti) and/or vanadium (V) and/or chromium (Cr) and/or manganese (Mn) and/or iron (Fe) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or Zinc (Zn) and/or Gallium (Ga) and/or Germanium (Ge) and/or Arsenic (As) and/or Rb and/or Cs and/or Yttrium (Y) and/or Zirconium (Zr) and/or Sr and/or Nb and/or Tritium (T) and/or Rh and/or Ir and/or Platinum (Pt) and/or Gold (Au) and/or Mercury (Hg) and/or Lead (Pb) and/or Bismuth (Bi).

6. Consolidating the porous layer comprising the electrode active material P and the oxide electronic conductor material to obtain a porous, preferably mesoporous electrode.

The porous layer or the self-supporting porous plate can then be subjected to a heat treatment, preferably in an oxidizing atmosphere, if necessary, to eliminate organic components. The porous layer or the self-supporting porous plate can then be consolidated. This consolidation can be carried out by pressing and/or heat treatment, i.e. by heat treatment (heating), by heat treatment before mechanical treatment and optionally by thermomechanical treatment (usually thermocompression). In a very advantageous embodiment of the invention, this treatment causes, on the one hand, partial aggregation of the primary nanoparticles into aggregates or agglomerates and, on the other hand, partial aggregation between adjacent aggregates or agglomerates due to the presence of a coating of oxide electronic conductor material; this phenomenon is called "neck" or "neck formation". It is characterized by partial agglomeration of two particles that are in contact, which particles remain separated but are connected by (confined) necks. Lithium ions and electrons can move within such necks and can diffuse from one particle to another without encountering grain boundaries. The nanoparticles are welded together to ensure the conduction of electrons from one particle to another. Adjacent aggregates or agglomerates are welded together by the presence of an oxide electron conductor coating to ensure the conduction of electrons from one aggregate or agglomerate to another. The electron conduction is carried out by two different means, in particular by nanoparticles of electrode active material P welded together (1), and by adjacent aggregates or agglomerates welded together by oxide electron conductor material (2); this is schematically shown in Figure 1.

Thus, in the absence of an organic binder, a rigid mesoporous film is formed from primary nanoparticles (1) of an electrode active material P and an oxide electronic conductor material (2), thereby forming a three-dimensional network structure with high ion mobility and electronic conductivity; this network structure comprises interconnected pores, preferably mesopores. The porous, preferably mesoporous layer thus obtained is perfectly suitable for the depth of the open porous structure of the layer by impregnation of the pores of the electrode with an ion conductor material.

The temperature required to obtain the "necking" depends on the material; the duration of the treatment depends on the temperature, taking into account the diffuse nature of the phenomenon causing the necking. This process can be called sintering; depending on its duration and the temperature, a more or less pronounced agglomeration (necking) is obtained, which has an impact on the porosity. It is thus possible to obtain electrodes with the desired porous or mesoporous ceramic structure with controlled porosity, while maintaining perfectly uniform channel dimensions. During this thermomechanical or thermal treatment, the electrode layer will be freed from all organic components and residues (such as the liquid phase of the suspension of nanoparticles, binders and optional surfactant products): it becomes an inorganic (ceramic) layer.

The thickness of these porous electrodes or plates centered in this way is advantageously less than or equal to 5 mm, preferably between about 1 μm and about 500 μm. The thickness of the porous plates after sintering is advantageously between 2 μm and 400 μm, preferably between 2 μm and 300 μm, more preferably between 3 μm and 200 μm.

According to the second embodiment and in order to obtain a porous electrode disposed on a substrate capable of acting as a current collector, a conductive sheet is also provided, which is covered on at least one of its surfaces, preferably on both of its surfaces, with a thin layer of conductive adhesive (loaded with graphite) or a sol-gel deposit filled with conductive particles. These thin layers preferably have a thickness of less than 1 μm. This conductive sheet can be a metal strip or a graphite sheet.

When the conductive layer is a metal, it is preferably a laminated layer, that is to say a laminated layer obtained by lamination. Lamination may optionally be followed by a final annealing, which may be a (complete or partial) softening annealing or for recrystallization, according to metallurgical terminology. It is also possible to use a layer obtained by electrolytic deposition, for example an electrodeposited copper layer or an electrodeposited nickel layer.

This conductive sheet is then placed on a board or inserted between two previously obtained boards after consolidation (i.e. sintering). The assembly is then advantageously pressed so that the intermediate conductive adhesive layer promotes the adhesion of the board to the substrate and forms a board/substrate or board/substrate/board assembly in order to obtain a rigid one-piece subassembly.

One of the advantages of the second embodiment is that it makes it possible to use less expensive substrates, such as aluminum, copper or graphite strips. More specifically, these strips cannot withstand the heat treatment used to consolidate the deposited layer; the fact of bonding the strips to the plate after its heat treatment also makes it possible to avoid its oxidation.

The resulting board/substrate or board/substrate/sub-board assembly can be used to manufacture electrochemical devices such as batteries.

Optionally, according to the porous electrode of the invention, the preferably self-supporting porous plate can be impregnated with an ion-conducting phase, i.e. a phase comprising at least one ion-conducting material, such as an ion-conducting polymer or an ion-liquid polymer. This ion-conducting material can also have electron conductivity. The ion-conducting material can be of different types. It can be liquid, in the form of a gel, and also solid. Impregnation with a solid ion conductor is advantageously carried out by using the ion conductor in the molten state or dissolved in a solvent that will subsequently evaporate. The ion-conductive phase may include or be an ion-conductive polymer, preferably selected from polyethylene oxide (PEO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(propylene carbonate) (PPC), poly(ethylene carbonate) (PEC), poly(vinyl carbonate) (PVC), polyvinylidene fluoride (PVDF), polypropylene glycol (PPG), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polydimethylsiloxane (PDMS), poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC).

The presence of the ion-conducting polymer in the pores of the porous electrode, preferably in the pores of the self-supporting porous plate, gives it better mechanical rigidity. The use of the porous electrode according to the invention impregnated with the ion-conducting polymer in energy storage or production devices such as batteries can increase its service life.

Optionally, a layer may be deposited on top of the porous electrode according to the invention, which layer is electrically insulating and has good ionic conductivity; its thickness is typically of the order of 0.5 nm to 20 nm, preferably less than 5 nm and still more preferably less than 2 nm.

The ion-conducting and electronically insulating layer may be inorganic or organic in nature. More specifically, inorganic layers that may be used include, for example, oxide, phosphate or borate conductors of lithium ions, and organic layers that may be used include polymers (e.g., PEO optionally containing a lithium salt, or tetrafluoroethylene sulfonate copolymers such as Nafion™, CAS No. 31175-20-9). The ion-conducting and electronically insulating layer must be stable in contact with the electrode on which it is deposited. Lithium ion borate conductors are preferably used on the cathode.

This ion-conducting and electronically insulating layer makes it possible to limit the dissolution of ions from the electrode and to limit their migration into the electrolyte, it being understood that in electrodes made of LiMn ₂ O ₄ , manganese is at risk of dissolving in certain liquid electrolytes, especially at high temperatures.

When the electrode according to the invention is covered with an ion-conducting layer, the ion-conducting layer primarily ensures the protective function as described above (especially avoiding dissolution of the electrode).

In summary, according to the present invention, the presence of an area of electrode active material P at least partially covered with an oxide electronic conductor material coating in the entire internal volume of the electrode and at the surface of the porous electrode, preferably covered with an oxide electronic conductor material coating, at least allows an increase in electronic conductivity, and depending on the nature of the oxide electronic conductor material, can advantageously protect the electrode from dissolution in the electrolyte at high temperatures. Either of these two effects is obtained only by a single arrangement of the oxide electronic conductor material according to the present invention in the entire internal volume of the electrode and at the surface, or this specific arrangement of the oxide electronic conductor material in the entire internal volume of the electrode according to the present invention is not sufficient to obtain these two effects, in which case it is possible to deposit, for example, an ion-conducting and electronically insulating layer on and inside the pores of the electrode according to the present invention in order to obtain additional protection at high temperatures.

According to the first and second embodiments, a porous electrode according to the invention is obtained, which is arranged on a metal substrate serving as an electron collector or on either side of a metal substrate serving as an electron collector. The electrode/substrate/electrode subassembly thus obtained by the first or second embodiment can be used to manufacture electrochemical devices, such as batteries, and in particular microbatteries. Assembly by thermal welding can also be carried out by stacking and hot pressing the structure of electrochemical devices (such as batteries and in particular microbatteries); in this case, a multi-layer stack is assembled, which comprises a first anode according to the invention, its metal substrate, a second anode according to the invention, a solid electrolyte layer or an electrolytic separator, a first cathode according to the invention, its metal substrate, a second cathode according to the invention, a new solid electrolyte layer or a new electrolytic separator, and so on.

This electrode/substrate/electrode subassembly can be used to manufacture electrochemical devices, such as batteries (and in particular microbatteries). Regardless of the embodiment of the electrode/substrate/electrode subassembly, an electrolyte membrane or electrolyte separator is then deposited on the latter. The necessary cuts are then made to produce a battery with multiple basic units, and the subassemblies are then stacked (usually "head to tail") and hot pressed to weld the anode and cathode of the solid electrolyte together.

Alternatively, the necessary cutting for manufacturing a battery with multiple basic units can be carried out before the electrolyte membrane or electrolyte separator is deposited on each anode/substrate/anode and cathode/substrate/cathode subassembly. The anode/substrate/anode subassembly and/or cathode/substrate/cathode subassembly are then covered with the electrolyte membrane or electrolyte separator, and the subassemblies are then stacked and hot-pressed so that the anodes and cathodes are welded together at the electrolyte membrane or electrolyte separator, and if necessary, the stack obtained is impregnated with an electrolyte, preferably a phase carrying lithium, sodium or potassium ions.

In the two alternatives just proposed, soldering by hot pressing can be performed at relatively low temperatures, especially when the electrode according to the invention is impregnated with an ion-conducting material, which can be an ion-conducting polymer or an ion-liquid polymer. For this reason, oxidation of the metal layer of the substrate is not observed. Examples Example 1: Fabrication of a mesoporous cathode based on LiMn ₂ O ₄ according to the invention

The aqueous suspension of _{LiMn2O4 nanoparticles} was prepared by hydrothermal synthesis according to the method described in the article entitled " A new one pot hydrothermal synthesis and electrochemical characterisation of Li1 ₊ xMn2 _{- yO4} spinel structured compounds " by Liddle et al., Energy & Environmental Science (2010) Vol. 3, pp. 1339-1346:

14.85 g of LiOH.H ₂ O are dissolved in 500 mL of water. To this solution are added 43.1 g of KMnO ₄ and this liquid phase is poured into an autoclave. Under stirring, 28 ml of isobutyraldehyde and water are added until a total volume of 3.54 L is obtained. The autoclave is then heated to 180° C. and kept at this temperature for 6 hours. After slow cooling, a black precipitate is obtained in the form of a suspension in the solvent. This precipitate is subjected to a series of centrifugation steps: it is dispersed again in water until an aggregate suspension is obtained with a conductivity of about 300 µS/cm and a zeta potential of -30 mV. The aggregates obtained are formed by aggregated primary particles with a size of 10 to 20 nm. The aggregates obtained had a spherical shape and an average diameter of about 150 nm; they were characterized by x-ray diffraction and electron microscopy.

1 g of polyvinylpyrrolidone (PVP) with a molar mass of 55,000 g/mol was added to 50 mL of distilled water at 40°C, and then 3 g of tin acetate was added to the PVP aqueous solution.

_{The LiMn2O4} suspension was reconcentrated by centrifugation and redispersing the centrifuged mass in the necessary volume of water to obtain a 16 wt% paste. This volume of PVP and aqueous tin acetate solution (corresponding to a ratio of tin _acetate to _LiMn2O4 of 10 wt%) and the necessary amount of water were then added to the _LiMn2O4 suspension of nanoparticle aggregates to obtain a final suspension _of aggregates with a solid content of 10%.

The ink thus obtained was applied to a stainless steel (316L) strip with a thickness of 5 µm. The obtained layer was dried in a temperature-controlled oven. The thickness of the obtained layer was about 6 µm.

This layer is then heat treated in air at 600°C for 5 hours in order to convert tin acetate (precursor of oxide electronic conductor material) into SnO ₂ , i.e., oxide electronic conductor material, on the one hand, to remove reaction byproducts, and on the other hand, to weld primary nanoparticles together and adjacent aggregates together through the presence of the formed oxide electronic conductor material SnO ₂ , so as to improve adhesion to the substrate and optimize the recrystallization of LiMn ₂ O _4. The open porosity of the porous layer thus obtained is about 45% by volume, and the size of its mesopores is between 10 nm and 20 nm.

Example 2: Fabrication of a Li ₄ Ti ₅ O ₁₂ -based mesoporous anode according to the present invention

Preparation of a suspension of Li ₄ Ti ₅ O ₁₂ nanoparticles by sugar thermal synthesis: 190 mL of 1,4-butanediol was poured into a beaker and 4.25 g of lithium acetate was added under stirring. The solution was kept without stirring until the acetate was completely dissolved. 16.9 g of titanium butoxide was then taken under an inert atmosphere and introduced into the acetate solution. The solution was then stirred for several minutes and then transferred to an autoclave pre-filled with an additional 60 mL of butanediol. The autoclave was then closed and purged with nitrogen for at least 10 minutes. The autoclave was then heated to 300°C at a rate of 3°C/min and kept at this temperature for 2 hours under stirring. Finally, allow to cool, stirring constantly.

A white precipitate is obtained as a suspension in a solvent. This precipitate is subjected to a series of centrifugation steps: redispersion in ethanol is performed to obtain a pure colloidal suspension with low ionic conductivity. It contains aggregates of about 150 nm formed from primary particles of 10 nm. The zeta potential is of the order of -45 mV. The product is characterized by x-ray diffraction and electron microscopy.

1 g of polyvinylpyrrolidone (PVP) with a molecular weight of 55,000 g/mol was added to 50 mL of ethanol at 40°C, and then 3 g of tin acetate was added to the PVP solution.

Then, a volume of this PVP and tin acetate solution (corresponding to a ratio of 10 mass % of tin acetate relative to Li ₄ Ti ₅ O ₁₂ ) is added to the suspension of Li ₄ Ti ₅ O ₁₂ nanoparticle aggregates. The ethanol is evaporated until the solid content of the aggregate suspension is 10%. The ink thus obtained is coated on a stainless steel (316L) strip with a thickness of 5 µm. The obtained layer is dried in a temperature and humidity controlled oven to avoid the formation of cracks during drying. The deposition and drying of the ink are then repeated to obtain a layer with a thickness of about 4 µm. This layer is then heat treated at 600°C in air for 5 hours. This heat treatment can convert tin acetate (an oxide electronic conductor material precursor) into _SnO2 , that is, into an oxide electronic conductor material to eliminate reaction byproducts, thereby forming a porous layer comprising _{Li4Ti5O12 nanoparticle} aggregates covered _with a uniform _SnO2 coating, and consolidating the layer, that is, welding the primary nanoparticles together and the adjacent aggregates together through the presence of the formed oxide electronic conductor material _SnO2 , so as to improve the adhesion to the substrate _of the _{Li4Ti5O12 nanoparticle} aggregates covered with the _SnO2 coating, and optimize the _{recrystallization} of _{Li4Ti5O12 .}

Example 3: Manufacturing a battery using the porous cathode and porous anode according to the present invention a. Manufacturing Li ₃ PO ₄ nanoparticle suspension

Two solutions were prepared. 11.44 g CH ₃ COOLi, 2H ₂ O was dissolved in 112 ml water, and then 56 ml water was added under vigorous stirring to obtain solution A. 4.0584 g H ₃ PO ₄ was diluted in 105.6 ml water, and then 45.6 ml ethanol was added to this solution to obtain a second solution, hereinafter referred to as solution B.

Solution B was then added to solution A under vigorous stirring. The resulting solution, which was completely clear after the bubbles formed during mixing disappeared, was added to 1.2 liters of acetone under the action of an Ultraturrax™ homogenizer to homogenize the medium. A white precipitate was then observed in the form of a suspension in the liquid phase.

The reaction medium is homogenized for 5 minutes and then kept under magnetic stirring for 10 minutes. It is allowed to decant for 1 to 2 hours. The supernatant is discarded and the remaining suspension is then centrifuged at 6000 rpm for 10 minutes. Subsequently, 300 ml of water are added to restore the precipitate to a suspension (using a sonotrode probe, magnetic stirring). Under vigorous stirring, 125 ml of a 100 g/l sodium tripolyphosphate solution are added to the colloidal suspension thus obtained. The suspension then becomes more stable. The suspension is then sonicated using a sonotrode probe. The suspension is then centrifuged at 8000 rpm for 15 minutes. The precipitate was then redispersed in 150 ml of water. The resulting suspension was then centrifuged again at 8000 rpm for 15 minutes, and the resulting pellet was redispersed in 12 mL of water.

Thus, aggregates of about 100 nm formed by 10 nm Li ₃ PO ₄ primary particles were obtained in a suspension in water.

b. Fabricating a porous inorganic layer from the suspension of Li ₃ PO ₄ nanoparticles previously described in part a) on the previously formed anode and cathode layers.

A porous thin layer of Li ₃ PO ₄ is then deposited by coating the previously obtained suspension of Li ₃ PO ₄ nanoparticles on the surface of the previously formed anode and cathode to obtain a layer with a thickness of about 3 µm. This layer is then dried at 120°C in air in order to remove any traces of organic residues and then calcined at 350°C in air for one hour. c. Fabrication of electrochemical cells

After depositing 3 µm porous Li ₃ PO ₄ on each of the previously formed electrodes (see Examples 1 and 2), the two subsystems were stacked so that the Li ₃ PO ₄ films were in contact. The stack was then hot pressed under vacuum.

To do this, the stack is placed under a pressure of 1.5 MPa and subsequently dried under vacuum at 10 to 3 bar for 30 minutes. The plates of the press are then heated to 450°C at a rate of 4°C/s. The stack is then hot-pressed at 45 MPa for 1 minute at 450°C, followed by cooling of the system to ambient temperature.

Once assembled, a rigid multi-layer system is obtained, formed by one or more assembled battery cells.

The assembly was then immersed in an electrolyte solution containing 0.7 M LiTFSI in PYR14TFSI. The electrolyte entered the pores by capillary action. The system was kept immersed for 1 minute, after which the surface of the battery stack was dried by a _N2 blade.

1: Primary nanoparticles of electrode active material P 2: Oxide electronic conductor material

FIG. 1 schematically shows nanoparticles (1) of an electrode active material P and an oxide electronic conductor material (2).

(without)

Claims (20)

A method for manufacturing a porous electrode, the porous electrode is particularly used in an electric energy storage or production device, the electrode is a porous layer comprising at least one electrode active material P and an oxide electronic conductor material, the electrode does not contain a binder, has a porosity of between 25% and 60%, preferably between 25% and 50% by volume, and pores with an average diameter of less than 100 nm, the manufacturing method is characterized by comprising: (a) providing a substrate, at least one oxide electronic conductor material precursor and a colloidal suspension or a paste, the colloidal suspension or the paste comprising aggregates or agglomerates of primary nanoparticles of at least one electrode active material P, the primary median diameter _D50 of the primary nanoparticles being within 2 nm and 400 nm, preferably between 2 nm and 100 nm, and more preferably between 2 nm and 60 nm, said aggregates or agglomerates having a median diameter _D50 between 50 nm and 900 nm, and preferably between 100 nm and 800 nm, it should be understood that said substrate may be a substrate capable of serving as a current collector, or an intermediate substrate, (b) mixing said one or more precursors of oxide electronic conductor material provided in step (a) with said colloidal suspension or said paste of aggregates or agglomerates of primary nanoparticles of at least one electrode active material P to form a mixture, (c) forming a layer from the mixture obtained at the end of step (b) by a method selected from the group consisting of: electrophoresis; a lamination method; extrusion; a printing method, preferably inkjet printing or flexographic printing; a coating method, preferably doctor blade coating, roll coating, curtain coating, dip coating or slit coating; (d) drying the layer obtained in step (c) so as to obtain a dry layer, where appropriate, separating the dry layer from its intermediate substrate after the drying step (d), (e) converting the one or more oxide electronic conductor material precursors into oxide electronic conductor materials so that the dried layer comprises the oxide electronic conductor materials, (f) consolidating the layer by thermal and/or mechanical treatment, preferably by sintering, so as to obtain a porous, preferably mesoporous electrode, it being understood that steps (e) and (f) may be performed during the same heat treatment. A method for manufacturing a porous electrode as claimed in claim 1, wherein step (b) is carried out by contacting the colloidal suspension or paste of aggregates or agglomerates of primary nanoparticles of at least one electrode active material P provided in step (a) with a liquid phase containing at least one precursor of the oxide electronic conductor material, and wherein during step (e) the conversion of the one or more oxide electronic conductor material precursors into oxide electronic conductor materials is carried out by heat treatment such as calcination, preferably in air or an oxidizing atmosphere. A method for manufacturing a porous electrode as claimed in claim 1 or 2, wherein after step (f), the pores of the porous electrode are impregnated with an electrolyte, preferably with a phase carrying lithium ions, sodium ions or potassium ions selected from the group consisting of: -     an electrolyte consisting of at least one aprotic solvent and at least one lithium, sodium or potassium salt; -     an electrolyte consisting of at least one ionic liquid and at least one lithium, sodium or potassium salt; -     a mixture of at least one aprotic solvent, at least one ionic liquid and at least one lithium, sodium or potassium salt; -     an ionic liquid polymer; -     A polymer of an ion conductor made by adding at least one lithium, sodium or potassium salt; and -     A polymer of an ion conductor made by adding a liquid electrolyte in the polymer phase or in the porous structure of the porous electrode, or impregnated with an ion conductor polymer, the ion conductor polymer is preferably selected from polyethylene oxide (PEO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(propylene carbonate) (PPC), poly(ethylene carbonate) (PEC), poly(vinyl carbonate) (PVC), polyvinylidene fluoride (PVDF), polypropylene glycol (PPG), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polydimethylsiloxane (PDMS), poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC). A method for manufacturing a porous electrode as claimed in any one of claims 1 to 3, wherein the one or more oxide electronic conductor material precursors are selected from organic salts containing one or more metal elements, which can form oxide electronic conductors after heat treatment such as calcination, and wherein the conversion to the electronic conductor material is a heat treatment, such as calcination, preferably in air or in an oxidizing atmosphere, and these organic salts are preferably selected from: -     an alkoxide of at least one metal element, which can form an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, -    a mononitrate of at least one metal element, which nitrate is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, -     an oxalate of at least one metal element, which oxalate is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, and -     an acetate of at least one metal element, which acetate is capable of forming an oxide electronic conductor after heat treatment such as calcination, preferably in air or in an oxidizing atmosphere, -    And/or wherein the metal element is preferably selected from tin, zinc, indium, gallium, molybdenum or a mixture of two, three, four or five of these elements. A method for producing a porous electrode according to any one of claims 1 to 4, wherein the oxide electronic conductor material is selected from: - tin oxide (SnO ₂ ); zinc oxide doped with aluminum (ZnO:Al), preferably having a Zn:Al molar ratio between 1:0.015 and 1:0.05; indium oxide (In ₂ O ₃ ); gallium oxide (Ga ₂ O ₃ ); molybdenum oxide (MoO ₃ ); molybdenum strontium oxide (SrMoO ₃ ); a mixture of two of these oxides, such as corresponding to indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) ; a mixture of three of these oxides; a mixture of four of these oxides; a mixture of five of these oxides or a mixture of six of these oxides, - a doped oxide mainly composed of zinc oxide, preferably doped with gallium (Ga) and/or aluminum (Al) and/or boron (B) and/or curium (Be) and/or chromium (Cr) and/or niobium (Ce) and/or titanium (Ti) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Indium oxide-based doped oxide, preferably doped with tin (Sn) and/or gallium (Ga) and/or chromium (Cr) and/or cadmium (Ce) and/or titanium (Ti) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Tin oxide doped, preferably doped with arsenic (As) and/or fluorine (F) and/or nitrogen (N) and/or niobium (Nb) and/or phosphorus (P) and/or antimony (Sb) and/or aluminum (Al) and/or titanium (Ti) and/or gallium (Ga) and/or chromium (Cr) and/or niobium (Ce) and/or indium (In) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or manganese (Mn) and/or germanium (Ge) and/or molybdenum (Mo), - Molybdenum oxide-based doped oxide, preferably doped with lithium (Li) and/or sodium (Na) and/or potassium (K) and/or curium (Be) and/or magnesium (Mg) and/or calcium (Ca) and/or sintered carbide (Sc) and/or titanium (Ti) and/or vanadium (V) and/or chromium (Cr) and/or manganese (Mn) and/or iron (Fe) and/or cobalt (Co) and/or nickel (Ni) and/or copper (Cu) and/or Zinc (Zn) and/or Gallium (Ga) and/or Germanium (Ge) and/or Arsenic (As) and/or Rb and/or Cs and/or Yttrium (Y) and/or Zirconium (Zr) and/or Sr and/or Nb and/or Tritium (T) and/or Rh and/or Ir and/or Platinum (Pt) and/or Gold (Au) and/or Mercury (Hg) and/or Lead (Pb) and/or Bismuth (Bi). A method for producing a porous electrode as claimed in any one of claims 1 to 5, wherein the porous electrode obtained at the end of step (f) has a specific surface area between 10 ^m2 /g and 500 ^m2 /g, and/or a thickness between 2 µm and 400 µm, preferably between 2 µm and 300 µm, and more preferably between 3 µm and 200 µm. A method for manufacturing a porous electrode as claimed in any one of claims 1 to 5, wherein the porous electrode obtained at the end of step (f) has a specific surface area between 10 ^m2 /g and 500 ^m2 /g; and/or when the substrate is a substrate capable of serving as a current collector, the porous electrode has a thickness between 2 µm and 20 µm, and/or when the substrate is an intermediate substrate, the porous electrode has a thickness between 25 µm and 500 µm, preferably between 50 µm and 400 µm. A method for manufacturing a porous electrode as claimed in any one of claims 1 to 5, wherein when the substrate is an intermediate substrate, after drying the layer, the layer is separated from the intermediate substrate in step (d) to form a porous plate. A method for manufacturing a porous electrode as claimed in any one of claims 1 to 8, wherein: the colloidal suspension or the paste provided in step (a) contains organic additives, such as ligands, stabilizers, binders or residual organic solvents, and the dried layer obtained at the end of step d) as in any one of claims 1 to 7 or the porous plate as in claim 8 is subjected to a heat treatment, and the heat treatment is preferably carried out in an oxidizing atmosphere. It should be understood that the heat treatment and steps (e) and/or (f) can be carried out during the same heat treatment step. A method for manufacturing a porous electrode as claimed in any one of claims 1 to 9, wherein the electrode active material P is selected from the group consisting of (A): - _{oxides LiMn2O4} ; Li1 _{+xMn2 -xO4 ,} wherein 0＜x＜0.15; LiCoO2; _LiNiO2 ; _{LiMn1.5Ni0.5O4 ; LiMn1.5Ni0.5-xXXO4 , wherein X} is selected from Al, _Fe , Cr, Co, Rh, Nd, other rare earths such as Sc, Y, _Lu , La, Ce, Pr, Pm, Sm, Eu, Gd, _Tb , Dy, Ho, Er, Tm, Yb, and wherein 0＜x＜0.1 _; LiMn2 _{- xMxO4} , wherein M= Er, Dy, Gd, Tb, Yb, Al, Y, Ni, Co, Ti, Sn, As, Mg, or a mixture of these compounds, and wherein 0 < x <0.4; LiFeO ₂ ; LiMn _1/3 Ni _1/3 Co _1/3 O ₂ ; LiNi _0.8 Co _0.15 Al _0.05 O ₂ ; LiAl _x Mn _2-x O ₄ , wherein 0 ≤ x <0.15; LiNi _1/x Co _1/y Mn _1/z O ₂ , wherein x+y+z =10; - Li _x M _y O ₂ , wherein 0.6≤y≤0.85; 0≤x+y≤2; and M is selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Sn and Sb, or a mixture of these elements; Li _{1.20 Nb0.20Mn0.60O2} ; _- Li1 _{+xNbyMezApO2 ,} wherein Me is at least one transition metal selected from the _group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, _Nb , _Mo , _Tc , Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, and wherein 0.6<x<1;0<y<0.5;0.25≤z<1; wherein A≠ _Me and A _{≠ Nb} , and 0≤p≤0.2; _{- LixNbyaNaMzbPbO2 - cFc} , wherein 1.2＜x≤1.75; 0≤y＜0.55; 0.1＜z＜1; 0≤a＜0.5; 0≤b＜1; 0≤c＜0.8; and wherein M, N and P are each at least one element selected from the group consisting of Ti, Ta, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, Ce and Sb; - Li _1.25 Nb _0.25 Mn _0.50 O ₂ ; Li _1.3 Nb _0.3 Mn _0.40 O ₂ ; Li _1.3 Nb _0.3 Fe _0.40 O ₂ ; Li _1.3 Nb _0.43 Ni _0.27 O ₂ ; Li _1.3 Nb _0.43 Co _0.27 O ₂ ; Li _1.4 Nb _0.2 Mn _0.53 O ₂ ; - Li _x Ni _0.2 Mn _0.6 O _y , wherein 0.00≤x≤1.52; 1.07≤y＜2.4; Li _1.2 Ni _0.2 Mn _0.6 O ₂ ; - LiNi _x Co _y Mn _1−x−y O ₂ , wherein 0 ≤ x and y ≤ 0.5; LiNi _x Ce _z Co _y Mn _1−x−y O ₂ , wherein 0 ≤ x and y ≤ 0.5 and 0 ≤ z; - phosphates LiFePO ₄ ; LiMnPO ₄ ; LiCoPO ₄ ; LiNiPO ₄ ; Li ₃ V ₂ (PO ₄ ) ₃ ; Li ₂ MPO ₄ F, wherein M = Fe, Co, Ni or a mixture of these different elements; LiMPO ₄ F, wherein M = V, Fe, T or a mixture of these different elements; phosphates of formula LiMM'PO ₄ , wherein M and M' (M ≠ M') are selected from Fe, Mn, Ni, Co, V, such as LiFe _x Co _1-x PO ₄ , and wherein 0 ＜ x ＜ 1; - Fe _0.9 Co _0.1 OF; FeF ₃ ; LiMSO ₄ F, wherein M = Fe, Co, Ni, Mn, Zn, Mg; - titanium oxysulfide (TiO _y S _z , wherein z=2-y and 0.3≤y≤1); tungsten oxysulfide (WO _y S _z , wherein 0.6＜y＜3 and 0.1＜z＜2); CuS; CuS ₂ ; Li _x V ₂ O ₅ , wherein 0 ＜ x ≤ 2; Li _x V ₃ O ₈ , wherein 0 ＜ x ≤ 1.7; Li _x TiS ₂ , wherein 0 < x ≤ 1; titanium and lithium oxysulfides Li _x TiO _y S _z , wherein z = 2-y, 0.3 ≤ y ≤ 1 and 0 < x ≤ 1; Li _x WO _y S _z , wherein z = 2-y, 0.3 ≤ y ≤ 1 and 0 < x ≤ 1; Li _x CuS , wherein 0 < x ≤ 1; Li _x CuS ₂ , wherein 0 < x ≤ 1; or selected from the group consisting of (B): - transition metal oxides: ○ Na _x MO _2+z , wherein M is selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ Na _{x Mu/2} M' _v/2 O _2+z , wherein u + v = 2, and M, M' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ Na _x M _u/3 M' _v/3 M'' _w/3 O _2+z , wherein u + v + w = 3, and M, M', M'' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ Na _x Mn _y Ni _z Fe _0.1 Mg _0.1 O ₂ , wherein 0.67 ≤ x ≤ 1.0; 0.5 ≤ y ≤ 0.7 and 0.1 ≤ z ≤ 0.3; - Prussian blue and/or Prussian blue analogs, said Prussian blue analogs being represented by the abbreviation PBA: ○ Na _x M ¹ [M ² ' (CN) ₆ ] _y .nH ₂ O, M ¹ being a transition metal or a transition metal alloy, M ² ' being a transition metal, said transition metal and said transition metal alloy being selected from Fe, Ni, Co and Mn, wherein 0 ≤ x ≤ 2; y ≤ 1 and 0 ≤ n ≤ 12; - polyanionic compounds: ○ Na _x M ₂ (XO ₄ ) ₃ , wherein 0 < x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W, such as Na ₃ V ₂ (PO ₄ ) ₃ ; ○ Na _x M ₃ (XO ₄ ) ₂ (X ₂ O ₇ ), where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M (X ₂ O ₇ ), where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ (XO ₄ ) ₂ F ₃ , where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ (XO ₄ ) ₂ F _3-y O _y , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and 0.07 ≤ y ≤ 0.12 and X = P, S, As, Si, Mo or W; ○ Na _x M ₂ O ₂ (XO ₄ ) ₂ F, wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ Na _x MXO ₄ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; or selected from the group consisting of (C): - transition metal oxides: ○ K _x MO _2+z , wherein M is selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x M _u/2 M' _v/2 O _2+z , wherein u + v = 2, and M, M' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z ≤ 0.3 and 0 < x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x M _u/3 M' _v/3 M'' _w/3 O _2+z , wherein u + v + w = 3, and M, M', M'' are selected from Mg, Ca, Li, Mn, Ni, Co, Cr, Sc, Te, wherein z≤ 0.3 and 0 <x ≤ 1, preferably 0 < x < 0.44 or 0.44 ≤ x ≤ 0.67 or 0.67 < x ≤ 1; ○ K _x Mn _y Ni _z Fe _0.1 Mg _0.1 O ₂ , wherein 0.67 ≤ x ≤ 1.0; 0.5 ≤ y ≤ 0.7 and 0.1 ≤ z ≤ 0.3; - Prussian blue and/or Prussian blue analogs, wherein the Prussian blue analogs are represented by the abbreviation PBA: ○ K _x M ¹ [M ² '(CN) ₆ ] _y .nH ₂ O, M ¹ is a transition metal or a transition metal alloy, M ² ' is a transition metal, the transition metal and the transition metal alloy are selected from Fe, Ni, Co and Mn, wherein 0 ≤ x ≤ 2; y ≤ 1 and 0 ≤ n ≤ 12; - polyanionic compounds: ○ K _x M ₂ (XO ₄ ) ₃ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W, such as Na ₃ V ₂ (PO ₄ ) ₃ ; ○ K _x M ₃ (XO ₄ ) ₂ (X ₂ O ₇ ), wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M(X ₂ O ₇ ), wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M ₂ (XO ₄ ) ₂ F ₃ , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x M ₂ (XO ₄ ) ₂ F _3-y O _y , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and 0.07 ≤ y ≤ 0.12 and X = P, S, As, Si, Mo or W; ○ K _x M ₂ O ₂ (XO ₄ ) ₂ F , wherein 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W; ○ K _x MXO ₄ , where 0 ＜ x ≤ 4, M = V, Fe, Cr, Mn, Co, Ni or Sc, and X = P, S, As, Si, Mo or W. A method for manufacturing a porous electrode as claimed in any one of claims 1 to 9, wherein the electrode active material P is selected from the group consisting of: ● Li ₄ Ti ₅ O ₁₂ ; Li ₄ Ti _5-x M _x O ₁₂ , wherein M = V, Zr, Hf, Nb, Ta, and 0 ≤ x ≤ 0.25; ● Niobium oxide and mixed oxides of niobium and titanium, germanium, niobium or tungsten, and is preferably selected from the group consisting of: Nb ₂ O _5±δ , Nb ₁₂ WO _33±δ , Nb ₁₄ W ₃ O _44±δ , Nb ₁₈ W ₁₆ O _93±δ , Nb ₁₆ W ₅ O _55±δ , where 0 ≤ δ ≤ 2; LiNbO ₃ , TiNb ₂ O _7±δ ; Li _w TiNb ₂ O ₇ , wherein w ≥ 0; Ti _1-x M ¹ _x Nb _2-y M ² _y O _7±δ or Li _w Ti _1-x M ¹ _x Nb _2-y M ² _y O _7±δ , wherein M ¹ and M ² are each at least one element selected from the group consisting of Nb, V, Ta, Fe, Co, Ti, Bi, Sb, As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, Pb, Al, Zr, Si, Sr, K, Cs and Sn, M ¹ and M ² can be the same as or different from each other, and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and 0 ≤ δ ≤ 0.3; _{LaxTi1-2xNb2 +xO7 ,} where 0＜x＜0.5 _; M _x Ti _1-2x Nb _2+x O _7±δ , wherein M is an element having an oxidation number of +III, more specifically, M is at least one element selected from the group consisting of Fe, Ga, Mo, Al, B, and wherein 0＜x≤0.20 and -0.3≤δ≤0.3; Ga _0.10 Ti _0.80 Nb _2.10 O ₇ ; Fe _0.10 Ti _0.80 Nb _2.10 O ₇ ; _{MxTi2-2xNb10 +xO29 ±δ} , wherein M is an element having an oxidation number of +III, more specifically, M is at least one element selected from the group consisting of Fe, Ga, Mo, Al, B, and wherein 0＜x≤0.40 _and -0.3≤δ≤0.3; Ti1 _- ^xM1xNb2 _-yM2yO7-zM3z ^or _{LiwTi1 -} ^xM1xNb2 _{- yM2yO7 -} ^zM3z , wherein - M1 _and ^M2 are each at least one element selected _from the group consisting of Nb, V _, Ta, Fe _{, Co} , Ti, ^Bi , ^Sb , As, P, Cr, Mo, W, B, Na, Mg, Ca, Ba, _Pb , Al, Zr, Si, Sr, K, Cs and ^Sn , - ^M1 and ^M2 can be the same as or different from each other, - ^M3 is at least one halogen, - and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; TiNb ₂ O _7-z M ³ _z or Li _w TiNb ₂ O _7-z M ³ _z , wherein M ³ is at least one halogen, preferably selected from F, Cl, Br, I or a mixture of these halogens, wherein 0 ≤ z ≤ 0.3 and 0 ≤ w ≤ 5; Ti1 _{- xGexNb2 -} ^yM1yO7 _±z ; _LiwTi1 -xGexNb2-yM1yO7± _z ;Ti1 _{- xCexNb2 -} ^yM1yO7 _±z ;LiwTi1 _{- xCexNb2 -} ^yM1yO7 _±z , wherein _{- M1 is at} least one element selected from the group consisting of _Nb , V, Ta, Fe, Co, _Ti , _Bi , _Sb , As, P, _Cr , ^Mo , W, B, Na, Mg, Ca, Ba, _Pb , Al, Zr, Si, Sr, K, Cs and Sn; - ⁰ ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; Ti1 _{- xGexNb2 -} ^yM1yO7 _- ^zM2z _; LiwTi1-xGexNb2-yM1yO7-zM2z; _{Ti1 -xCexNb2-yM1yO7-zM2z; LiwTi1-xCexNb2-yM1yO7-zM2z, wherein - M1 and} ^M2 _are ^each _{at least one} ^element _selected ^from _the group consisting of Nb _{, V} , Ta, Fe _{, Co} , Ti _{, Bi ,} ^Sb , _As , P _, ^Cr , _Mo , W, ^B , _Na , Mg, Ca, _Ba , Pb, Al, Zr, Si, Sr, K, Cs, Ce ^and Sn, - ^M1 and ^M2 can be the same as or different from each other, - and wherein 0 ≤ w ≤ 5 and 0 ≤ x ≤ 1 and 0 ≤ y ≤ 2 and z ≤ 0.3; ● TiO ₂ ; TiO _x N _y , wherein x＜2 and 0＜y＜0.2; ● LiSiTON, a nitride oxide mainly composed of tin and silicon, and more specifically, the formulation SiSn _0.87 O _1.20 N _1.72 and its lithiated forms; ● Nitrides and nitride oxides of the MO _x N _y type, wherein M is at least one element selected from Ge, Si, Sn, Zn, Co, Ni, Cu, Fe or a mixture of one or more of these elements, and wherein x≥0 and y≥0.3; ● Li _3-X M _x N, wherein M is at least one element selected from Cu, Ni, Co or a mixture of one or more of these elements, and 0 ≤ x ≤ 1; ● Li _3-X M _x N, wherein M is cobalt (Co) and 0 ≤ x ≤ 0.5; Li _3-X M _x N, wherein M is nickel (Ni) and 0 ≤ x ≤ 0.6; Li _3-X M _x N, wherein M is copper (Cu) and 0 ≤ x ≤ 0.3; ● Lithium iron phosphate having the typical formula LiFePO ₄ ; ● Mixed oxynitrides of silicon and tin having the typical formula Si _a Sn _b O _y N _z , wherein a＞0, b＞0, a+b≤2, 0＜y≤4, 0＜z≤3, also known as SiTON, and specifically SiSn _0.87 O _1.2 N _1.72 ; and oxynitride carbides having the typical formula Si _a Sn _b C _c O _y N _z , wherein a＞0, b＞0, a+b≤2, 0＜c＜10, 0＜y＜24, 0＜z＜17; ● Si _x N _y -type nitrides, particularly wherein x=3 and y=4; _SnxNy , particularly wherein x=3 and y=4; _ZnxNy , particularly wherein x=3 and _y =2; _{Li3-xMxN , wherein} for M=Co, 0≤x≤0.5, for M=Ni, 0≤x≤0.6, _for M=Cu, 0≤x≤0.3; Si3 _{- xMxN4 ,} wherein M=Co _or Fe _and 0≤x≤3; ● _{oxides SnO2} , SnO, _{Li2SnO3 , SnSiO3} , _LixSiOy , wherein _x≥0 and ₂ ＞y＞0; _Li4Ti5O12 , _TiNb2O7 , _Co3O4 , _{SnB0.6P0.4O2.9} and _{TiO2 ,} ● Si, Sn, SiO ₂ , SnO ₂ , SiN, SnN and mixtures thereof, ● a complex oxide TiNb ₂ O ₇ containing between 0% and 10% by mass of carbon, the carbon being preferably selected from graphene and carbon nanotubes, or selected from the group consisting of (E): - alloys mainly based on Si, Ge, Sn, Sb, Bi or P and alloys of these compounds, - MXene, which is a class of two-dimensional materials with a stoichiometry of the M _n+1 X _n T _x type, wherein M is a transition metal, preferably selected from Sc, Ti, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, and X is selected from C and/or N, and T is a surface termination selected from F, Cl, I, Br, O, S, Se, Te, OH, NH ₂ , 1 ≤ n ≤ 4, - conversion anode materials, such as: ○ oxides of the type G ₂ Ti ₃ O ₇ , G ₄ Ti ₅ O ₁₂ , GTi ₂ (PO ₄ ) ₃ , where G is Na or K; ○ oxides, sulfides, selenides and phosphides of the following elements and their alloys: Si, Ge, Sn, Sb, Bi. A porous electrode, which can be obtained by the method of any one of claims 1 to 11. A method for manufacturing an electric energy storage or production device, which uses the method for manufacturing a porous electrode as described in any one of claims 1 to 11 or uses the porous electrode as described in claim 12. A method as claimed in claim 13, wherein the electrical energy storage or generation device is selected from the group consisting of: capacitors; supercapacitors; hybrid supercapacitors, such as lithium-ion hybrid supercapacitors, sodium-ion hybrid supercapacitors, and potassium-ion hybrid supercapacitors; photovoltaic cells; photochemical cells; and batteries, such as lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries. A method as claimed in claim 14, wherein the device is a lithium ion battery, and the method for manufacturing a porous electrode as claimed in claim 10 is implemented so as to manufacture a cathode using the electrode active material P selected from group (A), or the method as claimed in claim 11 is implemented so as to manufacture an anode using the electrode active material P selected from group (D). A method as claimed in claim 14, wherein the device is a sodium ion battery, and the method for manufacturing a porous electrode as claimed in claim 10 is implemented so as to manufacture a cathode using the electrode active material P selected from group (B), or the method as claimed in claim 11 is implemented so as to manufacture an anode using the electrode active material P selected from group (E). A method as claimed in claim 14, wherein the device is a potassium ion battery, and the method for manufacturing a porous electrode as claimed in claim 10 is implemented so as to manufacture a cathode using the electrode active material P selected from group (C), or the method as claimed in claim 11 is implemented so as to manufacture an anode using the electrode active material P selected from group (E). A method as claimed in any one of claims 13 to 17, wherein the device is a lithium ion, sodium ion or potassium ion battery, and the porous electrode is impregnated with an electrolyte, preferably with a phase carrying lithium ions, sodium ions or potassium ions selected from the group consisting of: -     an electrolyte consisting of at least one aprotic solvent and at least one lithium, sodium or potassium salt; -     an electrolyte consisting of at least one ionic liquid and at least one lithium, sodium or potassium salt; -     a mixture of at least one aprotic solvent, at least one ionic liquid and at least one lithium, sodium or potassium salt; -    An ionic liquid polymer; -     a polymer that is an ionic conductor made by adding at least one lithium, sodium or potassium salt; and -     a polymer that is an ionic conductor made by adding a liquid electrolyte in the polymer phase or in the porous structure, or impregnated with an ionic conductor polymer, the ionic conductor polymer is preferably selected from polyethylene oxide (PEO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), poly(propylene carbonate) (PPC), poly(ethylene carbonate) (PEC), poly(vinyl carbonate) (PVC), polyvinylidene fluoride (PVDF), polypropylene glycol (PPG), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polydimethylsiloxane (PDMS), poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC). An electrical energy storage or production device, which can be obtained by the method of any one of claims 13 to 18. An energy storage or production device as claimed in claim 19, wherein the energy storage or production device is a capacitor; a supercapacitor; a hybrid supercapacitor, such as a lithium-ion hybrid supercapacitor, a sodium-ion hybrid supercapacitor, or a potassium-ion hybrid supercapacitor; a photovoltaic cell; a photochemical cell; or a battery, such as a lithium-ion battery, a sodium-ion battery, or a potassium-ion battery.