METHOD FOR MANUFACTURED A POROUS ELECTRODE, AND A BATTERY CONTAINING SUCH AN ELECTRODE

Abstract

The present invention relates to a porous electrode usable in electrochemical devices, such as a lithium-ion battery. This porous electrode comprises a porous layer of at least one active electrode material P deposited on a substrate, and a coating of electronically conductive oxide material present on and within the pores of said porous layer of at least one active electrode material P.

Description

Title of the invention: METHOD FOR MANUFACTURING A POROUS ELECTRODE, AND BATTERY CONTAINING SUCH AN ELECTRODE Technical field of the invention

[0001] The invention relates to the field of electrochemistry, and more particularly to thin-film electrochemical devices. It relates more precisely to electrodes usable in electrochemical devices such as capacitors, lithium ion batteries, mini-batteries or lithium ion batteries having a capacity greater than 1 mA h. The invention applies to negative electrodes and positive electrodes. It relates to porous electrodes which can be impregnated with a solid electrolyte without a liquid phase or with a liquid electrolyte.

[0002] The invention also relates to a method for preparing such a porous electrode which uses nanoparticles of an electrode material, and the electrodes thus obtained. The invention also relates to a method for manufacturing a lithium ion battery comprising at least one of these electrodes, and the batteries thus obtained, preferably lithium ion batteries having a capacity greater than 1 mA h State of the art

[0003] Lithium ion batteries have the best energy density among the various electrochemical storage technologies available on the market. There are different electrode architectures and chemical compositions for producing these batteries. The manufacturing processes for lithium ion batteries are presented in numerous articles and patents; an overview is given in the book "Advances in Lithium-Ion Batteries" (ed. W. van Schalkwijk and B. Scrosati), published in 2002 (Kluever Academie / Plénum Publishers).

[0004] According to the state of the art, the electrodes of lithium ion batteries can be manufactured using 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 active materials in the form of powder; the particles constituting this powder have an average particle size which is typically between 5 μm and 15 μm in diameter.

[0005] These deposition techniques, in particular by coating, make it possible to produce layers with a thickness of between approximately 50 μm and approximately 400 μm. The power and energy of the battery can be modulated by adapting the thickness and the porosity of the layers, the size of the active particles which constitute them and by the presence of various constituents within the layer such as binders or even electronically conductive materials.

[0006] In addition to the problems related to the formulation of inks to obtain a high-performance electrode at low manufacturing cost, it must be kept in mind that the ratio between the energy density and the power density of the electrodes can be adjusted according to the particle size of active materials, and indirectly to the porosity of the electrode layers and their thickness. The article by J. Newman (“Optimization of Porosity and Thickness of a Battery Electrode by Means of a Reaction-Zone Model”, J. Electrochem. Soc., 142 (1), p. 97-101 (1995)) demonstrates the respective effects of the thicknesses of the electrodes and their porosity on their discharge regime (power) and energy density.

[0007] Binder-free mesoporous electrode layers for lithium ion batteries can be deposited by electrophoresis; this is known from WO 2019 / 215 407 (LTEN). They can be impregnated with a liquid electrolyte, but their electrical resistivity remains quite high.

[0008] To increase the low electronic conductivity of the electrodes, especially when these electrodes are of great thickness or made from electrode active materials with low electronic conductivity, a certain amount of electronic conductive material, such as carbon black, is generally added to the electrode active material particles. Ideally, the electronic conductor particles should be available at any point on the surface of the electrode active material particle in order to allow simultaneous insertion / deinsertion over the entire surface of the electrode active particles, thus maximizing the current density and minimizing local stress and heating due to inhomogeneous electrical transport.

[0009] In practice, it is very difficult to control the arrangement of the carbon black within the electrodes. Moreover, with the increasing use of smaller and smaller active material particles, these problems are even more preponderant. A non-uniform distribution of the carbon black in the electrode induces a much higher polarization of the electrode, which leads to an increase in the series resistance of the battery comprising such an electrode. These imbalances of local charge states will be all the more pronounced as the current density is high. These imbalances consequently induce a loss of cycling performance, a safety risk and a limitation of the power of the battery cell. The same is true when the electrodes have an inhomogeneous porosity, namely distributed in size; this inhomogeneity contributes to making the wetting of the pores of the electrodes more difficult.

[0010] In this context and in order to reduce the electrical resistivity of mesoporous electrodes, the applicant has developed a mesoporous electrode comprising a mesoporous layer of at least one active electrode material having on and inside the pores of this mesoporous layer, a carbon coating; this is known from WO 2021 / 220 174 (I-TEN). The presence of this carbon electronically conductive coating on the electrode makes it possible to reduce its electrical resistivity but does not make it possible to significantly increase its voltage and temperature resistance and its electrochemical stability. In addition, the production of a carbon electronically conductive coating on the electrode is expensive and difficult to implement.

[0011] As there is a growing need for very small rechargeable batteries, the electrodes must meet increasingly stringent specifications. They must have high chemical and electrochemical stability, strength and corrosion resistance so as to give the batteries comprising them high cycling performance, storage stability, temperature stability and long-term reliability. The present invention seeks to remedy at least in part the drawbacks of the prior art mentioned above.

[0012] More specifically, the problem that the present invention seeks to solve is to provide a method for manufacturing porous electrodes having high, homogeneous electronic conductivity and controlled pore density which is simple, safe, fast, easy to implement and inexpensive.

[0013] The present invention also aims to provide safe porous electrodes having high electronic conductivity, a stable mechanical structure, good thermal stability, especially at high temperature, a long service life, regardless of the thickness of the electrode,

[0014] Another object of the invention is to provide electrodes for batteries capable of operating at high temperature without reliability problems and without risk of fire.

[0015] Another object of the invention is to provide porous electrodes which, in addition to the preceding characteristics, can easily be wetted and impregnated with an ionic liquid.

[0016] Another aim of the invention is to provide a method for manufacturing an electrochemical device such as a battery, a capacitor, a supercapacitor comprising a porous electrode according to the invention.

[0017] Yet another aim of the invention is to propose electrochemical devices such as batteries, in particular lithium ion batteries, capacitors, supercapacitors capable of storing high energy densities, of restoring this energy with very high power densities (in particular in capacitors or supercapacitors), of resisting high temperatures which have an excellent cycling life as well as increased safety.

[0018] Objects of the invention

[0019] In order to increase the performance of electrodes usable in conventional lithium ion batteries, in particular by reducing their electrical resistivity while significantly increasing their voltage and temperature resistance and their electrochemical stability, the inventors sought to find an alternative to the carbon electronic conductive coating presented in application WO 2021 / 220 174 (I-TEN).

[0020] According to the invention, the problem is solved by an electrode for a lithium ion battery which is totally ceramic, mesoporous and free of organic binders, the porosity of which is between 25% and 50%, the size of the channels and pores of which is homogeneous in order to ensure perfect dynamic balancing of the cell. The electrode according to the invention comprises a porous layer, preferably mesoporous, of at least one active electrode material the porosity of which is between 25% and 50%, the size of the channels and pores of which is homogeneous in order to ensure perfect dynamic balancing of the cell, and having on and inside the pores of the porous layer, a coating of an electronically conductive oxide material.

[0021] This porous, preferably mesoporous, entirely solid layer, without organic components, is obtained by the deposition, on a substrate, of agglomerates and / or aggregates of nanoparticles of active electrode materials. The sizes of the primary particles constituting these agglomerates and / or aggregates are of the order of a nanometer or tens of nanometers, and the agglomerates and / or aggregates contain at least four primary particles.

[0022] Said substrate may be, in a first embodiment, a substrate capable of acting as an electric current collector, or be, in a second embodiment, an intermediate, temporary substrate which will be explained in more detail below.

[0023] Using agglomerates of a few tens or even hundreds of nanometers in diameter rather than primary, non-agglomerated particles, each with a size of the order of a nanometer or tens of nanometers, makes it possible to increase the deposit thicknesses. The agglomerates must have a size of less than 300 nm. Sintering agglomerates of a size greater than 500 nm would not make it possible to obtain a continuous mesoporous film. In this case, two different porosity sizes are observed in the deposit, namely a porosity between agglomerates and a porosity inside the agglomerates.

[0024] Indeed, it is observed that during the drying of nanoparticle deposits on a substrate capable of acting as an electric current collector, cracks appear in the layer. It is noted that the appearance of these cracks depends essentially on the size of the particles, the compactness of the deposit and its thickness. This cracking limit thickness is defined by the following relationship:

[0025] hmax= 0.41 [(GM0rcpR3) / 2y]

[0026] where hmax denotes the critical thickness, G the shear modulus of the nanoparticles, M the coordination number, 0rcp the volume fraction of nanoparticles, R the radius of the particles and y the interfacial tension between the solvent and the air.

[0027] It follows that the use of mesoporous agglomerates, consisting of primary nanoparticles at least ten times smaller than the size of the agglomerate, makes it possible to considerably increase the cracking limit thickness of the layers. In the same way, it is possible to add a few percent of a solvent with a lower surface tension (such as isopropyl alcohol (abbreviated IPA)) in water or ethanol in order to improve the wettability and adhesion of the deposit, and to reduce the risk of cracking. In order to increase the deposit thicknesses while limiting or even eliminating the appearance of cracks, it is possible to add binders, dispersants. These additives and organic solvents can be removed by a heat treatment in air, such as by debinding, during a sintering treatment or during a heat treatment carried out prior to the sintering treatment.

[0028] Furthermore, for the same size of primary particles when these particles are produced by hydrothermal synthesis, it is possible during their synthesis by precipitation to modify the size of the agglomerates by modulating the quantity of binders (for example polyvinyl pyrrolidone, abbreviated PVP) in the synthesis reactor. Thus, it is possible to produce an ink containing agglomerates that are very dispersed in size or have two complementary size populations, so as to maximize the compactness of the agglomerate deposition. Unlike the sintering of non-agglomerated nanoparticles, the sintering conditions between agglomerates of different sizes will not be modified. It is the primary nanoparticles, which constitute the agglomerates, which will weld together. These primary nanoparticles have identical sizes regardless of the size of the agglomerate.The size distribution of the agglomerates will improve the compactness of the deposits and multiply the contact points between nanoparticles, but will not modify the consolidation temperature.

[0029] However, the agglomerates must remain small in order to be able to form a continuous mesoporous film during the heat treatment of the layer. If the agglomerates are too large, this hinders their sintering and the formation of two distinct porosities is observed in the layer: a porosity between agglomerates and a porosity inside the agglomerates.

[0030] After sintering, a porous, preferably mesoporous, layer or plate is obtained, without carbon black or organic binders, in which all the nanoparticles are welded together (by the necking phenomenon, known elsewhere) to form a continuous mesoporous network characterized by unimodal porosity. The porous, preferably mesoporous, layer thus obtained is entirely solid and ceramic. There is no longer any risk of loss of electrical contact between the particles of materials active during cycling, which is likely to improve the cycling performance of the battery. Furthermore, after sintering, the porous layer, preferably mesoporous, is perfectly adherent to the metal substrate on which it was deposited or transferred (in the case of an initial deposit made on an intermediate substrate).

[0031] The heat treatments carried out at high temperature to sinter the nanoparticles together make it possible to dry the electrode perfectly and to eliminate all traces of water or solvents or other organic additives (stabilizers, binders) adsorbed on the surface of the particles of active material. The high-temperature heat treatment (sintering) may be preceded by a lower-temperature heat treatment (debinding) to dry the electrode placed or deposited and to eliminate traces of water or solvents or other organic additives (stabilizers, binders) adsorbed on the surface of the particles of active material; this debinding may be carried out in an oxidizing atmosphere.

[0032] Depending on the sintering times and temperatures, it is possible to adjust the porosity of the final electrode. Depending on the energy density requirements, the latter can be adjusted in a range between 25% and 50% porosity.

[0033] In all cases, the power density of the electrodes thus obtained remains extremely high due to the mesoporosity. Furthermore, regardless of the size of the mesopores in the active material (knowing that after sintering the notion of nanoparticle no longer applies to the material which then has a three-dimensional structure with a network of channels and mesopores), the dynamic balancing of the cell remains perfect, which contributes to maximizing the power densities and lifetimes of the battery cell.

[0034] The electrode according to the invention has a high specific surface area, which reduces the ionic resistance of the electrode. However, for this electrode to deliver maximum power, it is still necessary for it to have very good electronic conductivity to avoid ohmic losses in the battery. This improvement in the electronic conductivity of the cell will be all the more critical as the thickness of the electrode increases. Furthermore, this electronic conductivity must be perfectly homogeneous throughout the electrode in order to avoid having locally more electrically resistive zones which could lead to the formation of a hot spot during the power operation of the battery.

[0035] According to an essential characteristic of the present invention, a coating of an electronically conductive oxide material is produced on and inside the pores of the porous layer. This electronically conductive oxide material may be deposited from a precursor of said electronically conductive oxide material, in particular from a liquid precursor of said electronically conductive oxide material.

[0036] Indeed, as explained above, the method according to the invention, which necessarily involves a step of depositing agglomerated nanoparticles of electrode material (active material), causes the nanoparticles to "weld" naturally together to generate, after consolidation such as annealing, a porous, rigid, three-dimensional structure, without organic binder; this porous layer, preferably mesoporous, is perfectly well suited to the application of a surface treatment, by gaseous or liquid means, which enters the depth of the open porous structure of the layer.

[0037] A first subject of the invention is a method for manufacturing a porous electrode, in particular for electrochemical devices, such as a battery, in particular a lithium ion battery having a capacity greater than 1 mA h, said electrode comprising a porous layer of at least one active electrode material P deposited on a substrate, and a layer of an electronically conductive oxide material present on and inside the pores of said porous layer, said electrode being free of binder, having a porosity of between 20% and 60% by volume, preferably between 25% and 50%, and pores with an average diameter of less than 50 nm, said manufacturing method being characterized in that:

[0038] (a) a substrate and a colloidal suspension or paste comprising are provided aggregates or agglomerates of monodisperse primary nanoparticles, of at least one active electrode material P, with an average primary diameter D50 of between 2 nm and 150 nm, preferably between 2 nm and 100 nm, and more preferably between 2 nm and 60 nm, said aggregates or agglomerates having an average diameter D50 of between 50 nm and 300 nm, and preferably between 100 nm and 200 nm, knowing that said substrate may be a substrate capable of acting as an electric current collector, or be an intermediate substrate,

[0039] (b) depositing on at least one face of said substrate a layer from said colloidal suspension or paste supplied in step (a), by a process selected from the group consisting of: electrophoresis, extrusion, a printing process, preferably inkjet printing or flexographic printing, a coating process, preferably doctor blade, roller, curtain, dip-shrink, or through a slot-shaped die,

[0040] (c) drying said layer obtained in step (b), where appropriate, before or after having separated said layer from its intermediate substrate, then, optionally, said dried layer is heat-treated, preferably in an oxidizing atmosphere; then said layer is consolidated, by heat and / or mechanical treatment, preferably by sintering, to obtain a porous, preferably mesoporous, layer,

[0041] (d) forming, on and inside the pores of said porous layer, a layer of a electronically conductive oxide material so as to form a porous layer coated with a layer of an electronically conductive oxide material,

[0042] (e) optionally, pores of said porous layer are formed on and inside coated with a layer of an electronically conductive oxide material obtained in step (d), an ionically conductive and electronically insulating layer.

[0043] In step (b) the deposition can be done on one or both sides of the substrate.

[0044] Advantageously, when said substrate is an intermediate substrate, said layer is separated in step (c) from said intermediate substrate, to form, in particular after consolidation, a porous plate. This separation step can be carried out before or after drying the layer obtained in step b).

[0045] Advantageously, when said substrate is an intermediate substrate, after step c) and before step d), an electrically conductive sheet is provided, covered on at least one face, respectively on both of its faces, with a thin layer of conductive adhesive or a thin layer of nanoparticles of at least one active electrode material P, then at least one porous plate is bonded to one face, preferably to each of the faces, of the electrically conductive sheet, so as to obtain a porous plate or layer, preferably mesoporous on a substrate capable of acting as a current collector. In the present application, the terms "porous layer" and "porous plate" are interchangeable.

[0046] Advantageously, in step (d), a layer of a precursor of an electronically conductive oxide material is deposited during a step (dl) on and inside the pores of said porous layer, and during a step (d2), the transformation of the precursor of an electronically conductive oxide material, deposited during step (dl) on said porous layer, into an electronically conductive material is carried out, so that said porous layer has on and inside the pores, a layer of said electronically conductive oxide material.

[0047] Advantageously, step (d1) is carried out by immersing the porous layer in a liquid phase comprising a precursor of said electronically conductive oxide material, and said transformation of the precursor of an electronically conductive oxide material into an electronically conductive material, during step (d2), is carried out by heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere.

[0048] Advantageously, said precursor of the electronically conductive oxide material is chosen from organic salts containing one or more metallic elements capable, after heat treatment such as calcination, of forming an electronically conductive oxide, and said transformation into an electronically conductive material is a heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere.

[0049] These organic salts are preferably chosen from:

[0050] - an alcoholate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, to form an electronically conductive oxide,

[0051] - an oxalate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, to form an electronically conductive oxide, and

[0052] - an acetate of at least one metallic element capable, after heat treatment such that a calcination, preferably carried out in air or in an oxidizing atmosphere, forms an electronically conductive oxide,

[0053] and / or preferably, the metallic element is chosen from tin, zinc, indium, gallium, or a mixture of two or three or four of these elements.

[0054] Advantageously, said porous layer obtained at the end of step (c) has a specific surface area of ​​between 10 m2 / g and 500 m2 / g and / or a thickness of between 4 μm and 400 μm.

[0055] Advantageously, when said colloidal suspension or paste supplied in step (a) comprises organic additives, such as ligands, stabilizers, binders or residual organic solvents, said layer dried in step c) or said porous plate is heat treated, preferably under an oxidizing atmosphere.

[0056] Advantageously, said active electrode material P is selected from the group formed by:

[0057] • the oxides LiMn2O4, Lii+xMn2 XO4 with 0< x < 0.15, LiCoO2, LiNiO2, LiMnM Ni0>5O4, LiMnij5Nioj5-xXx04 where 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 where 0 < x < 0.1, LiMn2 xMxO4 with M = Er, Dy, Gd, Tb, Yb, Al, Y, Ni, Co, Ti, Sn, As, Mg or a mixture of these compounds and where 0 < x < 0.4, LiFeO2, LiMni / 3Nii / 3Coi / 302 jLiNio.8Coo.i5Alo.o502jLiAlxMn2_x04withO< x < 0.15, LiNii / xCoi / yMni / zO2 with x+y+z =10; • LixMy02 where 0.6 <y<0.85; 0<x+y<2; et M est choisi parmi Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Sn, and Sb ou un mélange de ces éléments ; Lii.2oNbo.2oMn0.6o02 ; • Lii+xNbyMezApO2 where Me is at least one transition metal chosen from: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Te, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Rf, Db, Sg, Bh, Hs and Mt, and where 0.6 <x<l; 0<y<0.5; 0.25<z<l; avec A Me et A Nb, et 0<p<0.2 ; • LixNby_aNaMz_bPbO2_cFc where 1.2 <x<1.75; 0<y<0.55; 0.1<z<l; 0<a<0.5; 0<b<l; 0<c<0.8; et où M, N, et P sont chacun au moins un des éléments choisi dans le groupe constitué par Ti, Ta, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, et Sb ; • Li1.25Nbo.25Mno.50O2; Li1.3Nbo.3Mno.40O2; Li1.3Nbo.3Feo.40O2; Li1.3Nbo.43Nio.27O2; Li1.3Nb0.43Co0.27O2; Li14Nbo.2Mno.53O2; • LixNi0.2Mn0.6Oy where 0.00 <x<1.52; 1.07<y<2.4 ; Li1.2Nio.2Mno.6O2 ; • LiNixCoyMni_x_yO2 where 0 < x and y < 0.5; LiNixCezCoyMni x yO2 where 0 < x and y < 0.5 and 0 < z; • the phosphates LiFePO4, LiMnPO4, LiCoPO4, LiNiPO4, Li3V2(PO4)3> Li2MPO4 F with M = Fe, Co, Ni or a mixture of these different elements, LiMPO4F with M = V, Fe, T or a mixture of these different elements; the phosphates of formula LiMM'P04, with M and M' (M M') selected from Fe, Mn, Ni, Co, V such as LiFexCol xPO4et where 0 < x < 1; • Fe0ç)Co01OF ; LiMSO4F with M = Fe, Co, Ni, Mn, Zn, Mg ; • all lithiated forms of the following chalcogenides: V2O5, V3O8, TiS2, titanium oxysulfides (TiOySz with z=2-y and 0.3 <y<l), les oxysulfures de tungstène (WOySz avec 0.6<y<3 et 0.1<z<2), CuS, CuS2, de préférence LixV2 O5 avec 0 < x < 2, LixV3O8 avec 0 < x < 1,7, LixTiS2 avec 0 < x < 1, les oxysulfures de titane et de lithium LixTiOySz avec z=2-y, 0,3<y<l et 0 < x < 1, Li xWOySzavec z=2-y, 0,3<y<l et 0 < x < 1, LixCuS avec 0 < x < 1, LixCuS2 avec 0 < x < 1.

[0058] Advantageously, said aforementioned active P electrode material is used to manufacture a cathode.

[0059] Advantageously, said active electrode material P is selected from the group formed by:

[0060] • Li4Ti5O12, Li4Ti5 XMXO12 with M = V, Zr, Hf, Nb, Ta and 0 < x < 0.25; • niobium oxides and mixed oxides of niobium with titanium, germanium, cerium or tungsten, and preferably in the group formed by: • Nb2O5±ô, Nb18W16O93±ô, Nbi6W5O55±ô with 0 <x<let0<ô<2, LiNbO3, • TiM^CL+s, LiwTiNb2O7 with w>0, Tii xM'xNb2 yM2yO7±ô or LiwTii xM'xNb2 yM 2yO7±ô in which 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 being the same or different from each other, and in which 0 <w<5et0<x< 1 et 0 < y < 2 et 0 < ô < 0,3 ; • LaxTii 2xNb2+xO7 where 0 <x<0.5 ; • MxTii_2xNb2+xO7±ô • in which M is an element whose oxidation state is +III, more particularly M is at least one of the elements chosen from the group consisting of Fe, Ga, Mo, Al, B, and where 0 <x<0.20 et -0.3<ô <0.3 ; Ga0.ioTio.8oNb2.io07 ; Feo.ioTio.8oNb 2.10O7 ; • MxTi2_2xNbio+x029±ô • in which M is an element whose oxidation state is +III, more particularly M is at least one of the elements chosen from the group consisting of Fe, Ga, Mo, Al, B, and where 0 <x<0.40 et -0.3< ô <0.3 ; • Tii_xM1xNb2_yM2yO7_zM3z or LiwTibxM1xNb2_yM2yO7_zM3zin which • 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 may be identical or different from each other, • M3 is at least one halogen, • and in which 0 <w<5et0<x< let0<y<2etz< 0,3 ; • TiNb2O7 zM3z or LiwTiNb2O7 zM3z in which M3 is at least one halogen, preferably chosen from F, Cl, Br, I or a mixture thereof, and 0 < z < 0.3; • TiixGexNb^yM'yO^, LiwTibxGexNb2_yM ^07+,, Tii^Ce^b^M'yO^, LiwTii xCexNb^yM'yO^z in which • 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<5et0<x<let0<y<2etz< 0,3 ; • Ti1_xGexNb2_yM1yO7_zM2z, LiwTi, sGcsNb2 yM'yO- ZM2Z, Ti1_xCexNb2_yM1 yO7 zM2z, LCTii xCexNb^yM'yO^M^ in which • 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 may be identical or different from each other, • and in which 0 <w<5et0<x<let0<y<2etz< 0,3 ; • TiO2; TiOxNy with x<2 and 0 <y<0,2 ;

[0061] • LiSiTON, oxynitrides based on tin and silicon, and more particularly the formulation SiSno,870i>2oNi,72 and their lithiated forms; • nitrides and oxynitrides of the MOxNy type where M is at least one element chosen from Ge, Si, Sn, Zn or a mixture of one or more of these elements, and where x>=0 and y >=0.3; • Li3_xMxN with M is at least one element chosen from Cu, Ni, Co or a mixture of one or more of these elements;

[0062] • Li3 xMxN with M being cobalt (Co) and 0 < x < 0.5; Li3 xMxN with M being nickel (Ni) and 0 < x < 0.6; Li3 xMxN with M being copper (Cu) and 0 < x <0.3.

[0063] Advantageously, said aforementioned active electrode material P is used to manufacture an anode.

[0064] Another subject of the invention is a porous electrode capable of being obtained by the method according to the invention, characterized in that the porous electrode comprises a porous layer of at least one active electrode material P deposited on a substrate, and a layer of an electronically conductive oxide material arranged on and inside the pores of said porous layer, in that it is free of binder, in that it has a porosity of between 20% and 60% by volume, preferably between 25% and 50%, and pores with an average diameter of less than 50 nm.

[0065] Another subject of the invention is a method of manufacturing an electrochemical device, such as a battery, a capacitor, a supercapacitor, a photovoltaic cell, implementing the method of manufacturing a porous electrode according to the invention or implementing a porous electrode according to the invention.

[0066] Another subject of the invention is a method of manufacturing a battery, preferably a lithium ion battery, preferably a lithium ion battery having a capacity greater than 1 mA h, implementing the method of manufacturing a porous electrode according to the invention or implementing a porous electrode according to the invention.

[0067] Advantageously, said porous electrode is impregnated with an electrolyte, preferably a lithium ion-carrying phase selected from the group formed by:

[0068] • an electrolyte composed of at least one aprotic solvent and at least one lithium salt; • an electrolyte composed of at least one ionic liquid and at least one lithium salt; • a mixture of at least one aprotic solvent and at least one ionic liquid and at least one lithium salt; • a polymer made ionically conductive by the addition of at least one lithium salt; and • a polymer made ionically conductive by the addition of a liquid electrolyte, either in the polymer phase or in the mesoporous structure.

[0069] Another object of the invention is a battery, preferably a lithium ion battery lithium, preferably a lithium ion battery having a capacity greater than 1 mA h capable of being obtained by the method according to the invention.

[0070] Generally speaking, the battery according to the invention may be a mini-battery, the capacity of which is greater than 1 mA h and up to approximately 1 mA h or a battery the capacity of which is greater than 1 mA h. Indeed, the method according to the invention lends itself particularly well to the production of layers with a thickness greater than 1 μm or even greater than 5 μm, while ensuring a low series resistance of the battery.

[0071] Another subject of the invention is an electrochemical device, such as a battery, a capacitor, a supercapacitor, a photovoltaic cell, comprising a porous electrode according to the invention or capable of being obtained by the method according to the invention.

[0072] Detailed description of the invention

[0073] 1. Definitions

[0074] The present invention relates to a porous electrode whose accessible surface, i.e. the external surface of the electrode as well as the interior of the accessible pores of the electrode, is coated with an electronically conductive oxide material. The term "electronically conductive oxide" includes electronically conductive oxides and electronically semiconductive oxides.

[0075] For the purposes of this document, the size of a particle is defined by its largest dimension. The term "nanoparticle" means any particle or object of nanometric size having at least one of its dimensions less than or equal to 100 nm.

[0076] By "ionic liquid" is meant any liquid salt, capable of transporting electricity, differing from all molten salts by a melting temperature below 100°C. Some of these salts remain liquid at room temperature and do not solidify, even at very low temperatures. Such salts are called "ionic liquids at room temperature".

[0077] By “mesoporous” materials is meant any solid which has within its structure pores called “mesopores” having an intermediate size between that of micropores (width less than 2 nm) and that of macropores (width greater than 50 nm), namely a size between 2 nm and 50 nm. This terminology corresponds to that adopted by IUP AC (International Union for Pure and Applied Chemistry), which is a reference for those skilled in the art. The term “nanopore” is therefore not used here, even if the mesopores as defined above have nanometric dimensions within the meaning of the definition of nanoparticles, knowing that pores of a size smaller than that of mesopores are called “micropores” by those skilled in the art.

[0078] A presentation of the concepts of porosity (and the terminology just set out above) is given in the article “Texture of powdery or porous materials” by F. Rouquerol et al., published in the collection “Techniques de l'Ingénieur”, treatise Analysis and Characterization, booklet P 1050; this article also describes the techniques for characterizing porosity, in particular the BET method.

[0079] For the purposes of the present invention, the term "porous layer" means a layer which has pores. The term "mesoporous layer" means a layer which has mesopores. In these layers, the pores and mesopores contribute significantly to the total pore volume; this fact is translated by the expression "Porous / mesoporous layer with porosity greater than X% by volume" used in the present description.

[0080] The term "aggregate" means, according to the IUPAC definitions, a loosely bound assembly of primary particles. In this case, these primary particles are nanoparticles having a diameter which can be determined by transmission electron microscopy. An aggregate of aggregated primary nanoparticles can normally be destroyed (i.e. reduced to primary nanoparticles) in suspension in a liquid phase under the effect of ultrasound, according to a technique known to those skilled in the art.

[0081] The term "agglomerate" means, according to the IUPAC definitions, a strongly bound assembly of primary particles or aggregates.

[0082] 2. Preparation of nanoparticle suspensions

[0083] The porous electrodes according to the invention are produced from a colloidal suspension of clusters and / or agglomerates of nanoparticles or a paste.

[0084] In an even more preferred embodiment of the invention, the nanoparticles are prepared directly at their primary size by precipitation, Pechini synthesis, hydrothermal or solvothermal synthesis; this technique makes it possible to obtain nanoparticles with a very narrow size distribution, called “monodisperse nanoparticles”. The size of these non-aggregated or non-agglomerated nanopowders / nanoparticles is called the primary size. It is typically between 2 nm and 150 nm. It is advantageously between 10 nm and 50 nm, preferably between 10 nm and 30 nm; this promotes, during subsequent process steps, the formation of an interconnected mesoporous network with electronic and ionic conduction, thanks to the “necking” phenomenon.

[0085] Binders can also be added to the suspension of nanoparticles (clusters and / or agglomerates of nanoparticles, knowing that these clusters are also in the form of nanoparticles) to facilitate the production of deposits or green strips, in particular thick deposits without cracks.

[0086] It is a colloidal suspension or paste comprising aggregates or ag nanoparticle glomerates which is then used for the fabrication of a dried porous layer of an active P electrode material.

[0087] 3. Production of a porous layer

[0088] The method for manufacturing an electrode according to the invention comprises the application of such a colloidal suspension or a paste comprising aggregates or agglomerates of monodisperse primary nanoparticles of at least one active electrode material P, on a substrate to form a layer, then the drying of said layer in order to obtain a porous layer. This sequence comprising the application of this colloidal suspension or paste on a substrate to form a layer and its drying can be repeated several times in order to increase the thickness of the porous layer. The final thickness of this porous layer is advantageously less than or equal to 5 mm, preferably between approximately 1 μm and approximately 500 μm. The thickness of this porous layer is advantageously less than 300 μm, preferably between approximately 5 μm and approximately 300 μm, preferentially between 5 μm and 150 μm.Generally speaking, the colloidal suspension or paste is deposited on a substrate, by any suitable technique, and in particular by electrophoresis, by extrusion, by the ink-jet printing process hereinafter "ink-jet", by spraying, by flexographic printing, by a coating process, preferably by doctor blade (technique known in English as "doctor blade" or "tape casting"), by roll coating, by curtain coating, by extrusion through a slot-die, or by dip-coating.

[0089] In order for the colloidal suspension or paste (ink) to have a viscosity suitable for the coating techniques usually used for electrode manufacturing, and thus to be able to be deposited on a substrate, it is advantageous to use a colloidal suspension or paste having a dry extract of less than 30% by mass.

[0090] According to the applicant's findings, with an average diameter of the aggregates or agglomerates of nanoparticles of between 80 nm and 300 nm (preferably between 100 nm and 200 nm), a mesoporous layer having an average diameter of the mesopores of between 2 nm and 50 nm is obtained during the subsequent process steps.

[0091] According to the invention, the porous layer of at least one active electrode material P can be deposited by the inkjet printing process (called “ink-jet” in English) or by a coating process, and in particular by the coating process by dipping (called “dip-coating” in English), by roller coating (called “roll coating” in English), by curtain coating (called “curtain coating” in English), by coating through a slot-die (called “slot-die” in English), or by scraping (called “doctor blade” in English), and this from a fairly concentrated suspension comprising aggregates or agglomerates of nanoparticles of the material active P.

[0092] The porous electrode layer can also be deposited by electrophoresis, but then a less concentrated suspension containing agglomerates of nanoparticles of the active material P is advantageously used.

[0093] The processes for depositing aggregates or agglomerates of nanoparticles by electrophoretic means, by extrusion, by the dip coating process, by inkjet, by roller coating, by curtain coating, by coating through a slot-shaped die or by scraping are simple, safe, easy to implement, to industrialize and allowing to obtain a homogeneous final porous layer. Electrophoretic deposition allows to deposit layers uniformly on large surfaces with high deposition speeds. The coating techniques, in particular those mentioned above, allow to simplify the management of the baths compared to electrophoretic deposition techniques because the suspension does not become depleted in particles during deposition. Deposition by inkjet printing allows to make localized deposits.

[0094] Thick-film porous layers can be produced in a single step by roller coating, curtain coating, slot die coating, or scraping (i.e., with a doctor blade).

[0095] The technique for depositing the colloidal suspension or paste (ink), and the conduct of the deposition process must be compatible with the viscosity of the colloidal suspension or paste (ink) used, and vice versa.

[0096] The substrate is advantageously an intermediate substrate or a substrate which can serve as a current collector.

[0097] 3.1. Substrate capable of acting as a current collector

[0098] In a first embodiment, said substrate is a substrate capable of acting as an electric current collector. The substrate may advantageously be a metal substrate or an electronically conductive carbon substrate, in particular based on graphite, graphene and / or carbon nanotubes. Said substrate on which the colloidal suspension or paste (ink) is deposited ensures the current collector function for the electrode. The colloidal suspension or paste (ink) may be deposited on one or both sides of the substrate, in particular by the deposition techniques indicated above.

[0099] The current collector within the electrochemical devices employing electrodes according to the invention may be a stable substrate in the operating potential range of the electrochemical device. Within the batteries employing electrodes according to the invention, the current collector must be a stable substrate in a potential range, preferably between 2.5 V and 5 V for the cathode and between 0 V and 2.5 V for the anode, relative to the lithium potential. In a manner advantageous, a metal substrate is chosen, for example a metal strip (i.e. a rolled metal sheet). The substrate can be made of tungsten, molybdenum, chromium, titanium, tantalum, 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 treatments; they are therefore particularly well suited as a sintered electrode substrate.

[0100] It is also possible to coat this substrate capable of acting as an electric current collector, with a conductive or semiconductive oxide before the deposition of the colloidal suspension or paste (ink), which makes it possible in particular to protect less noble substrates such as copper, nickel, aluminum and carbon, in particular in the form of graphite. These less noble substrates can thus be used as an electrode substrate. It can be a conductive carbon sheet (typically graphite), a metal sheet, or a metallized non-metal sheet (i.e. coated with a layer of metal). The substrate is preferably chosen from copper, nickel, molybdenum, tungsten, tantalum, chromium, niobium, zirconium, titanium sheets, and alloy sheets comprising at least one of these elements. Stainless steel can also be used.These substrates have the advantage of being stable over a wide potential range and resistant to heat treatments.

[0101] Copper, nickel, molybdenum and their alloys are preferably used as an anodic substrate. Carbon-based substrates, in particular in the form of graphite, based on nickel-chromium alloys, stainless steels, chromium, titanium, aluminum, tungsten, molybdenum, tantalum, zirconium, niobium or alloys containing at least one of these elements are preferably used as an electric current collector substrate for cathodes. These anodic and / or cathodic substrates may or may not be coated with an electrochemically conductive and inert layer. Such layers may be produced by deposition of nitrides, carbides, graphites, gold, palladium and / or platinum.

[0102] The colloidal suspension or paste (ink) can be deposited on one or both sides of the substrate capable of acting as a current collector. The layer deposited on this substrate is then dried so as to obtain a porous layer of an active P-electrode material.

[0103] This porous layer of an active electrode material P thus dried is then consolidated. This consolidation can be carried out by pressing and / or heat treatment, i.e. by heat treatment (heating), by heat treatment preceded by mechanical treatment, and possibly by heat treatment mechanical, typically thermocompression. In a very advantageous embodiment of the invention, this treatment leads to a partial coalescence of the primary nanoparticles in the aggregates, or agglomerates, and between neighboring aggregates or agglomerates; this phenomenon is called "necking" or "neck formation". It is characterized by the partial coalescence of two particles in contact, which remain separated but connected by a (narrowed) neck. Lithium ions and electrons are mobile within these 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. Thus, a continuous, rigid mesoporous film is formed from the primary nanoparticles, without organic binder, forming a three-dimensional network with high ionic mobility and electronic conduction; this network comprises interconnected pores, preferably mesopores.This porous layer, preferably mesoporous, thus obtained is perfectly well suited to the application of a surface treatment, by gas or liquid means, which enters the depth of the open porous structure of the layer.

[0104] The temperature required to obtain "necking" depends on the material; given the diffusive nature of the phenomenon that leads to necking, the duration of the treatment depends on the temperature. This process can be called sintering; depending on its duration and temperature, a more or less pronounced coalescence (necking) is obtained, which has an impact on the porosity. It is thus possible to obtain an electrode with a desired porous or mesoporous ceramic structure of controlled porosity while maintaining a perfectly homogeneous channel size. During this thermomechanical or thermal treatment, the electrode layer will be freed from any organic constituent and residue (such as the liquid phase of the suspension of nanoparticles, binders and possible surfactants): it becomes an inorganic (ceramic) layer.

[0105] According to an essential characteristic of the present invention, a coating of an electronically conductive oxide material is produced on and inside the pores of said porous layer, i.e. on the accessible surface of said porous layer, as will be explained later in paragraph 3.3.

[0106] 3.2. Intermediate substrate

[0107] According to a second embodiment, the colloidal suspension or paste (ink) is not deposited on a substrate capable of acting as an electric current collector, but on an intermediate substrate, which is typically used temporarily.

[0108] In this embodiment, the colloidal suspension or paste (ink) is deposited on one face of the intermediate substrate, so as to be able to subsequently easily detach the layer obtained from this intermediate substrate.

[0109] In particular, it is possible to deposit, from a suspension of nanoparticles and / or ag glomerates of nanoparticles of active electrode material P, preferably from a concentrated suspension containing nanoparticles of active electrode material P (i.e. less fluid, preferably pasty), fairly thick layers (called "green sheets" in English). These thick layers can be deposited by any suitable means, in particular by the inkjet printing process, by spraying, by flexographic printing, by a coating process, preferably by doctor blade, by roller coating, by curtain coating, by extrusion through a slot-shaped die, or by dipping.

[0110] The nanoparticle deposition processes, by the dip coating process, by the inkjet printing process, by roller coating, by curtain coating, by extrusion through a slot-shaped die, by spraying, by flexographic printing or by doctor-blade coating are simple, safe, easy to implement, to industrialize and allowing to obtain a homogeneous deposition. Inkjet printing allows to deposit the colloidal suspension or paste (ink) in a localized manner, in the same way as the doctor-blade depositions under mask. Thick layers can be obtained in a single step by the techniques of roller coating, curtain coating, slot-die, by dip or by doctor-blade.

[0111] Said intermediate substrate may be a flexible substrate, which may be a polymer sheet, for example polyethylene terephthalate, abbreviated PET. In this second embodiment, the deposition step is advantageously carried out on one face of said intermediate substrate in order to facilitate the subsequent separation of the layer from its substrate. In this second embodiment, the layer may be separated from its substrate before or after drying, preferably after drying and before any heat treatment. The thickness of the layer after drying is advantageously less than or equal to 5 mm, advantageously between approximately 1 μm and approximately 500 μm. The thickness of the layer after drying, i.e. of the non-sintered electrode, is advantageously less than 300 μm, preferably between approximately 5 μm and approximately 300 μm, preferentially between 5 μm and 150 μm.

[0112] In said second embodiment, the method for manufacturing an electrode for an electrochemical device such as a battery uses an intermediate polymer substrate (such as PET) and results in a strip called a “green strip”. This green strip is then separated from its substrate; it then forms self-supporting plates or sheets (the term “plate” is used hereinafter, regardless of its thickness).

[0113] These self-supporting porous plates or sheets are then dried. After drying, these self-supporting porous plates or sheets can then be heat-treated, preferably in an oxidizing atmosphere, if necessary, in order to remove the organic constituents. These self-supporting porous plates or sheets are then consolidated, as explained above in paragraph 3.1.

[0114] These plates thus sintered have a thickness advantageously less than or equal to 5 mm, preferably between approximately 1 μm and approximately 500 μm. The thickness of the porous plate after sintering is advantageously less than 300 μm, preferably between approximately 5 μm and approximately 300 μm, preferentially between 5 μm and 150 μm.

[0115] According to the second embodiment and in order to obtain a porous electrode arranged on a substrate capable of acting as a current collector, an electrically conductive sheet is also provided, covered on at least one of its faces, preferably on both of its faces, with an intermediate thin layer of nanoparticles of the active electrode material P, preferably identical to those constituting the plate, or covered on at least one of its faces, preferably on both of its faces with a thin layer of conductive glue (loaded with graphite) or a sol-gel type deposit loaded with conductive particles. Said thin layers preferably have a thickness of less than 1 μm. This electrically conductive sheet may be a metal strip or a graphite sheet.

[0116] When said electrically conductive sheet is metallic, it is preferably a rolled sheet, i.e. obtained by rolling. The rolling may optionally be followed by a final annealing, which may be a softening annealing (total or partial) or a recrystallization annealing, according to the terminology of metallurgy. It is also possible to use an electrochemically deposited sheet, for example an electrodeposited copper sheet or an electrodeposited nickel sheet.

[0117] This electrically conductive sheet is then placed on a plate or inserted between two plates obtained previously after drying and possibly heat treatment (i.e. sintering). The assembly is then heat-pressed so that said intermediate thin layer of nanoparticles is transformed by sintering and consolidates the plate / substrate or plate / substrate / plate assembly to obtain a rigid and single-piece subassembly. During this sintering, the bond between the plate and the intermediate layer is established by diffusion of atoms; this phenomenon is known by the English term “diffusion bonding”. This assembly is done with two plates, preferably made from the same nanoparticles of the active electrode material P, and the metal sheet placed between these two plates.

[0118] One of the advantages of the second embodiment is that it allows the use of inexpensive substrates such as aluminum foils, copper foils or graphite foils. Indeed, these foils do not resist the heat treatments for consolidating the deposited layers; gluing them to the plates after their heat treatment also prevents their oxidation.

[0119] This assembly by “diffusion bonding” can be carried out separately as has just been described, and the plate / substrate or plate / substrate / plate subassemblies thus obtained, once coated with a layer of an electronically conductive oxide material, can be used in the manufacture of an electrochemical device such as a battery.

[0120] 3.3. Production of a coating or layer of an electrically conductive oxide material electronics on and inside the porous layer or porous plate

[0121] According to an essential characteristic of the present invention, after drying and consolidation, a coating of electronically conductive oxide is produced on and inside the pores of these porous layers, porous plates or self-supporting porous sheets (hereinafter referred to indifferently as porous layers or porous plates), i.e. on the accessible surface of these porous layers or porous plates, so that they can be used as porous electrodes, in particular in electrochemical devices such as in batteries or capacitors.

[0122] Using an electronically conductive coating in the form of an oxide instead of a carbon coating provides, among other things, better performance to the final electrode. Indeed, the presence of this electronically conductive oxide layer on and inside the pores of the porous layer or plate, in particular because the electronically conductive coating is in the form of an oxide, makes it possible to improve the final properties of the electrode, in particular to improve the voltage resistance of the electrode, its temperature resistance, to improve the electrochemical stability of the electrode, in particular when it is in contact with a liquid electrolyte, to reduce the polarization resistance of the electrode, even when the electrode is thick.It is essentially the synergistic combination of a porous layer or plate made from an active electrode material, and an electronically conductive coating in the form of oxide placed on and inside the pores of said porous layer or plate which makes it possible to improve the final properties of the electrode, in particular to obtain thick electrodes without increasing the internal resistance of the electrode.

[0123] Very advantageously, the layer of electronically conductive oxide material can be obtained in different ways, in particular by the ALD (Atomic Layer Deposition) technique or by immersion in a liquid phase comprising a precursor of the electronically conductive oxide material followed by the transformation of said precursor of an electronically conductive material into an electronically conductive material, in particular by heat treatment. More generally, with the techniques for producing the coating of an electronically conductive oxide material indicated here, only the free surfaces of the pores are covered, in particular the accessible surfaces of the porous layer or plate and those of the substrate. The “welding” zone between the porous layer and the substrate is not covered by the electronically conductive oxide material. The techniques indicated here make it possible to obtain a constant thickness of said layer of an electronically conductive oxide material within the porous, preferably mesoporous, layer or plate. Its thickness is typically between 0.5 nm and 10 nm, preferably less than 2 nm.

[0124] ALD deposition techniques are particularly well suited to covering, layer by layer, by a cyclic process, rigid surfaces having a high roughness in a completely sealed and conformal manner. They make it possible to produce conformal (totally covering) layers of very thin thickness, free from defects, such as holes (so-called "pinhole-free" layers). However, before carrying out any deposition by the atomic layer deposition (ALD) technique, it is necessary to first eliminate, on the surface of the porous layer, any trace of organic compounds. Since ALD deposition is typically carried out at a temperature between 100°C and 300°C, residual organic matter, such as organic binders, would risk, in this temperature range, decomposing and polluting the ALD deposition reactor. Furthermore, the growth of the layer deposited by ALD is influenced by the nature of the substrate.A layer deposited by ALD on a substrate presenting different zones of different chemical natures will have inhomogeneous growth, which can cause a loss of integrity.

[0125] A layer of an electronically conductive material can be formed, very advantageously, by immersion in a liquid phase comprising a precursor of said electronically conductive material followed by the transformation of said precursor of an electronically conductive material into an electronically conductive material by heat treatment. This method is simple, rapid, easy to implement and is less expensive than the ALD atomic layer deposition technique. Advantageously, said precursor of the electronically conductive material is chosen from organic salts containing one or more metallic elements capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, of forming an electronically conductive oxide. These metallic elements, preferably these metallic cations, can advantageously be chosen from tin, zinc, indium, gallium, or a mixture of two or three or four of these elements.The organic salts are preferably chosen from an alcoholate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, of forming an electronically conductive oxide, an oxalate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, of forming an electronically conductive oxide and an acetate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, of forming an electronically conductive oxide.

[0126] Advantageously, said electronically conductive material may be an electronically conductive oxide material, preferably chosen from:

[0127] - tin oxide (SnO2), zinc oxide (ZnO), indium oxide (In2O3), oxide of gallium (Ga2O3), a mixture of two of these oxides such as indium-tin oxide corresponding to a mixture of indium oxide (In2O3) and tin oxide (SnO2), a mixture of three of these oxides or a mixture of four of these oxides,

[0128] - doped oxides based on zinc oxide, the doping preferably being gallium (Ga) and / or aluminium (Al) and / or boron (B) and / or beryllium (Be), and / or chromium (Cr) and / or cerium (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),

[0129] - doped oxides based on indium oxide, the doping preferably being tin (Sn), and / or gallium (Ga) and / or chromium (Cr) and / or cerium (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),

[0130] - doped tin oxides, the doping preferably being arsenic (As) and / or fluorinated (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 cerium (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).

[0131] To obtain a layer of an electronically conductive material, preferably an electronically conductive oxide material, from an alcoholate, an oxalate or an acetate, the porous layer can be immersed in a rich solution of the precursor of the desired electronically conductive material. Then the electrode is dried and subjected to a heat treatment, preferably in air or in an oxidizing atmosphere, at a temperature sufficient to transform the precursor of the electronically conductive material of interest into an electronically conductive material. Thus, a coating of the electronically conductive material is formed, preferably a coating of an electronically conductive oxide material, more preferably SnO2, ZnO, In2O3, Ga2 O3, or indium-tin oxide, over the entire internal surface of the electrode, perfectly distributed.

[0132] The presence of an electronically conductive coating in the form of an oxide instead of a carbonaceous coating on and inside the pores of the porous layer gives the electrode better electrochemical performance at high temperature, and makes it possible to significantly increase the stability of the electrode. Using an electronically conductive coating in the form of an oxide instead of a carbonaceous coating gives, among other things, better performance to the final electrode. Indeed, the presence of this electronically conductive oxide layer on and inside the pores of the porous layer or plate, in particular because the electronically conductive coating is in oxide form, makes it possible to improve the final properties of the electrode, in particular to improve the voltage resistance of the electrode, its temperature resistance, to improve the electrochemical stability of the electrode, in particular when it will be in contact with a liquid electrolyte, to reduce the polarization resistance of the electrode, even when the electrode is thick. It is particularly advantageous to use an electronically conductive coating in oxide form, in particular of the In2O3, SnO2, ZnO, Ga2O3 type or a mixture of one or more of these oxides, on and inside the pores of the porous layer of an active electrode material, when the electrode is thick, and / or when the active materials of the porous layer are too resistive.

[0133] The electrode according to the invention is porous, preferably mesoporous, and its specific surface area is large. Increasing the specific surface area of ​​the electrode multiplies the exchange surfaces, and consequently, the power of the battery, but it also accelerates parasitic reactions. The presence of these electronically conductive coatings in oxide form on and inside the pores of the porous layer will make it possible to block these parasitic reactions.

[0134] Furthermore, due to the very large specific surface area, the effect of these electronically conductive coatings in oxide form on the electronic conductivity of the electrode will be much more pronounced than in the case of a conventional electrode, where the specific surface area is less, even if the deposited conductive coatings have a small thickness. These electronically conductive oxide coatings, deposited on and inside the pores of the porous layer, give the electrode excellent electronic conductivity, particularly when the porous layer is made from an active electrode material that is not very electronically conductive.This layer of electronically conductive oxide material improves the electrical conductivity of the electrode while limiting the dissolution of the electrode and also increases the power of the battery; this is all the more true when the coating layer of electronically conductive oxide material has a small thickness.

[0135] It is essentially the synergistic combination of a porous layer or plate made from an active electrode material, and an electronically conductive coating in the form of oxide arranged on and inside the pores of said porous layer or plate which makes it possible to improve the final properties of the electrode, in particular to obtain thick electrodes without increasing the internal resistance of the electrode.

[0136] Furthermore, the electronically conductive coating in the form of oxide on and inside the pores of a porous layer is easier and less expensive to produce than a carbon coating. Indeed, in the case of coatings made of an electronically conductive material electronic in oxide form, the transformation of the precursor of the electronic conductive material into an electronic conductive coating does not need to be carried out under an inert atmosphere unlike the carbon coating.

[0137] This coating of an electronically conductive oxide material typically has a thickness of less than 10 nm, preferably less than 5 nm and more preferably less than 2 nm.

[0138] This coating gives the electrode good electronic conduction, regardless of its thickness. Using an electronically conductive coating in oxide form instead of a carbon coating gives, in particular, better performance to the final electrode. It is noted that the formation of this coating of an electronically conductive oxide material is possible after sintering because the electrode is entirely solid, without organic residues, and resists the thermal cycles imposed by the different heat treatments.

[0139] Optionally, a layer which is electronically insulating and which has good ionic conductivity can be deposited above this layer of an electronically conductive oxide material; its thickness is typically of the order of 0.5 nm to 20 nm, preferably less than 5 nm, and even more preferably less than 2 nm.

[0140] Said ionically conductive and electronically insulating layer may be of inorganic or organic nature. More particularly, among the inorganic layers, for example, an oxide, a phosphate or a borate conducting lithium ions may be used, and among the organic layers, polymers may be used (for example, PEO possibly containing lithium salts, or a sulfonated tetrafluoroethylene copolymer such as Nafion™, CAS No. 31175-20-9).

[0141] This ionic conductive and electronic insulating layer makes it possible to limit the dissolution of ions from the electrode and their migration towards the electrolyte, knowing that in LiMn2O4 electrodes manganese risks dissolving in certain liquid electrolytes, particularly at high temperature.

[0142] When the layer of electronically conductive oxide material is covered with an ionically conductive layer, it is the latter which will mainly provide the protective functions, as described above (in particular preventing dissolution of the electrode).

[0143] To summarize, with these coatings deposited on and inside the pores of the porous electrode layer, we seek to obtain two effects: the increase in electronic conductivity and protection against dissolution in the electrolyte at high temperature. Either these two effects are obtained with only the layer of electronically conductive oxide material, or a single coating is not sufficient to obtain both effects in which case two layers can be deposited, for example, a first layer of an electronically conductive oxide material according to the invention to obtain electronic conduction and a second layer, ionically conductive and electronically insulating; to obtain additional protection at high temperature.

[0144] According to the first and second embodiments, a porous electrode according to the invention is obtained, arranged on a metal substrate serving as an electronic current collector or located on either side of a metal substrate serving as an electronic current collector. The electrode / substrate / electrode subassemblies thus obtained, by the first or second embodiment, can be used in the manufacture of an electrochemical device such as a battery.Diffusion bonding assembly can also be achieved by stacking and heat-pressing the entire structure of the electrochemical device such as a battery; in this case, a multi-layer stack is assembled comprising a first anode according to the invention, its metal substrate, a second anode according to the invention, a solid electrolyte layer, a first cathode according to the invention, its metal substrate, a second cathode according to the invention, a new solid electrolyte layer, and so on.

[0145] This electrode / substrate / electrode subassembly can be used to manufacture electrochemical devices such as batteries. Whatever the embodiment of the electrode / substrate / electrode subassembly, the electrolyte film is then deposited on the latter. The necessary cuts are then made to produce a battery with several elementary cells, then the subassemblies are stacked (typically in "head to tail" mode) and thermocompression is carried out to weld the anodes and cathodes together at the level of the solid electrolyte.

[0146] Alternatively, the cuts necessary to produce a battery with several elementary cells can be made, before the deposition of an electrolyte film, on each anode / substrate / anode and cathode / substrate / cathode subassembly. Then the anode / substrate / anode subassemblies and / or the cathode / substrate / cathode subassemblies are coated with an electrolyte film, then the subassemblies are stacked (typically in “head to tail” mode) and thermocompression is carried out to weld the anodes and the cathodes together at the level of the electrolyte film.

[0147] In the two variants just presented, the thermocompression welding is carried out at a relatively low temperature, which is possible thanks to the very small size of the nanoparticles. As a result, no oxidation of the metal layers of the substrate is observed. Examples

[0148] Example 1: Production of a mesoporous cathode based on LiMn2O4 according to the invention

[0149] A suspension of LiMn2O4 nanoparticles was prepared by hydrothermal synthesis according to the method described in the article by Liddle et al. entitled "A new onepot hydrothermal synthesis and electrochemical characterization of Lii+sMn2 O4 spinel structured compounds", Energy & Environmental Science (2010) vol.3, page 1339-1346:

[0150] 14.85 g of LiOH,H2O were dissolved in 500 ml of water. To this solution was added 43.1g of KMnO4 and poured this liquid phase into an autoclave. With stirring, 28 ml of isobutyraldehyde and water were added until a total volume of 3.54 l was reached. The autoclave was then heated to 180°C and maintained at this temperature for 6 hours. After slow cooling, a black precipitate suspended in the solvent was obtained. This precipitate was subjected to a succession of centrifugation - redispersion steps in water, until an aggregated suspension with a conductivity of about 300 pS / cm and a zeta potential of -30mV was obtained. The aggregates obtained consisted of primary aggregated 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.

[0151] Approximately 10 to 15% by mass of polyvinylpyrrolidone (PVP) at 360,000 g / mol was then added to the aqueous suspension of aggregates. The water was evaporated until the suspension of aggregates had a solids content of 10%. The ink thus obtained was applied to a stainless steel strip (316L) with a thickness of 5 μm. The resulting layer was dried in a temperature and humidity controlled oven to prevent the formation of cracks upon drying. The ink deposition and drying were repeated to obtain a layer approximately 10 μm thick.

[0152] This layer was consolidated at 600 °C for 1 h in air in order to weld the primary nanoparticles together, improve adhesion to the substrate and perfect the recrystallization of the LiMn2O4. The porous layer thus obtained has an open porosity of approximately 45% by volume with pores of a size between 10 nm and 20 nm.

[0153] A thin layer of ZnO was then produced on and inside the pores of the mesoporous cathode based on LiMn2O4, in an ALD reactor of type P300B (supplier: Picosun), under an argon pressure of 2 mbar at 180°C. Argon (Ar) was used here both as a carrier gas and for purging. Before each deposition a drying time of 3 hours was applied. The precursors used were water and diethylzinc. A deposition cycle consisted of the following steps: Injection of diethylzinc, purging of the chamber with Ar, injection of water, purging of the chamber with Ar.

[0154] This cycle is repeated to achieve a coating thickness of 1.5 nm. After these different cycles, the product was dried under vacuum at 120°C for 12 hours to eliminate the surface reagent residues and thus obtain a mesoporous cathode based on LiMn2O4 having a 1.5 nm ZnO coating over its entire accessible surface.

[0155] Example 2: Production of a mesoporous anode based on Li4Ti50i2

[0156] A suspension of Li4Ti50i2 nanoparticles was prepared by glycothermal synthesis: 190 ml of 1,4-butanediol was poured into a beaker, and 4.25 g of lithium acetate was added with stirring. The solution was kept stirring until the acetate was completely dissolved. 16.9 g of titanium butoxide was taken under an inert atmosphere and introduced into the acetate solution. The solution was then stirred for a few minutes before being transferred to an autoclave previously 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 maintained at this temperature for 2 hours, with stirring. At the end, it was allowed to cool, still with stirring.

[0157] A white precipitate was obtained in suspension in the solvent. This precipitate was subjected to a succession of centrifugation - redispersion steps in ethanol to obtain a pure colloidal suspension, with low ionic conductivity. It comprised aggregates of approximately 150 nm made up of primary particles of 10 nm. The zeta potential was of the order of -45 mV. The product was characterized by X-ray diffraction and electron microscopy.

[0158] These aggregates were deposited by electrophoresis on stainless steel strips with a thickness of 5 μm, in an aqueous medium, by applying pulsed currents of 0.6 A peak and 0.2 A average; the applied voltage was of the order of 3 to 5 V for 500 s. A deposit of approximately 4 μm thickness was thus obtained. It was consolidated by RTA annealing at 40% power for 1 s under nitrogen in order to weld the nanoparticles together, improve adhesion to the substrate and perfect the recrystallization of the Li4Ti50i2.

[0159] A thin layer of SnO2 was then produced on and inside the pores of the mesoporous anode based on Li4Ti50i2.

[0160] 1 g of polyvinyl pyrrolidone (abbreviated PVP) with a weight-average molecular weight of 55,000 g / mol was added to 50 mL of distilled water at 40°C, and then 3 g of tin oxalate SnC2O4 was added to this aqueous PVP solution. The mesoporous anode based on Li4Ti5O[2] was then immersed in this solution so that the tin oxalate could be deposited on and inside the pores of the mesoporous anode based on Li4Ti50i2. The electrode was then dried and subjected to a heat treatment, preferably under nitrogen, at 600°C for 5 hours in order to form a homogeneous coating of SnO2 2 nm thick, over the entire accessible surface of the electrode, i.e. on and inside the pores of the anode, in a perfectly distributed manner.

[0161] Example 3: Manufacture of a battery using a porous cathode according to the invention and a porous anode according to the invention

[0162] a. Production of a suspension of Li3PO4 nanoparticles

[0163] Two solutions were prepared. 11.44 g of CH3COOLi, 2H2O were dissolved in 112 ml of water, then 56 ml of water were added with vigorous stirring to the medium in order to obtain a solution A. 4.0584 g of H3PO4 were diluted in 105.6 ml of water, then 45.6 ml of ethanol were added to this solution in order to obtain a second solution hereinafter called solution B.

[0164] Solution B was then added, with vigorous stirring, to solution A. The solution obtained, perfectly clear after the disappearance of the bubbles formed during mixing, was added to 1.2 liters of acetone under the action of an Ultraturrax™ type homogenizer in order to homogenize the medium. A white precipitation suspended in the liquid phase was immediately observed.

[0165] The reaction medium was homogenized for 5 minutes and then kept for 10 minutes under magnetic stirring. It was left to settle for 1 to 2 hours. The supernatant was discarded and the remaining suspension was centrifuged for 10 minutes at 6000 rpm. Then 300 ml of water was added to resuspend the precipitate (using a sonotrode, magnetic stirring). With vigorous stirring, 125 ml of a 100 g / l sodium tripolyphosphate solution was added to the colloidal suspension thus obtained. The suspension thus became more stable. The suspension was then sonicated using a sonotrode. The suspension was then centrifuged for 15 minutes at 8000 rpm. The pellet was then redispersed in 150 ml of water. Then the suspension obtained was centrifuged again for 15 minutes at 8000 rpm and the pellets obtained were redispersed in 300 ml of ethanol in order to obtain a suspension suitable for electrophoretic deposition.

[0166] Agglomerates of approximately 100 nm consisting of primary Li3PO4 particles of 10 nm were thus obtained in suspension in ethanol.

[0167] b. Production on the anode and cathode layers previously developed of a porous inorganic layer from the suspension of Li3PO4 nanoparticles previously described in part a)

[0168] Thin porous layers of Li3PO4 were then deposited by electrophoresis on the surface of the anode and cathode previously prepared by applying an electric field of 20V / cm to the suspension of Li3PO4 nanoparticles previously obtained, for 90 seconds to obtain a layer with a thickness of approximately 1.5 μm. This layer was air-dried at 120°C in order to remove any trace of organic residues, and then it was calcined at 350°C for one hour in air.

[0169] c. Production of an electrochemical cell

[0170] After depositing 1.5 pm of porous Li3PO4 on each of the pre- previously developed (see examples 1 & 2), the two subsystems were stacked so that the Li3PO4 films were in contact. This stack was then hot-pressed under vacuum.

[0171] To do this, the stack was placed under a pressure of 1.5 MPa and then dried under vacuum for 30 minutes at 103 bar. The press plates were then heated to 450 °C at a speed of 4 °C / second. At 450 °C, the stack was then thermo-compressed under a pressure of 45 MPa for 1 minute, and then the system was cooled to room temperature.

[0172] Once the assembly was completed, a rigid, multi-layer system consisting of one or more assembled battery cells was obtained.

[0173] This assembly was then impregnated in an electrolytic solution comprising PYR14TFSI and LiTFSI at 0.7 M. The ionic liquid instantly enters the porosities by capillarity. The system was kept immersed for 1 minute, then the surface of the cell stack was dried by a blade of N2.

Claims

1. Claims Method for manufacturing a porous electrode, in particular for electrochemical devices, said electrode comprising a porous layer of at least one active electrode material P deposited on a substrate, and a layer of an electronically conductive oxide material present on and inside the pores of said porous layer, said electrode being free of binder, having a porosity of between 20% and 60% by volume, preferably between 25% and 50%, and pores with an average diameter of less than 50 nm, said manufacturing method being characterized in that: (a) a substrate and a colloidal suspension or a paste comprising aggregates or agglomerates of monodisperse primary nanoparticles, of at least one active electrode material P, with an average primary diameter D50 of between 2 nm and 150 nm, preferably between 2 nm and 100 nm, and more preferably between 2 nm and 60 nm, are provided, said aggregates or agglomerates having an average diameter D50 of between 50 nm and 300 nm, and preferably between 100 nm and 200 nm, knowing that said substrate can be a substrate capable of acting as an electric current collector, or be an intermediate substrate, (b) depositing on at least one face of said substrate a layer from said colloidal suspension or paste supplied in step (a), by a method selected from the group formed by: electrophoresis, extrusion, a printing method, preferably inkjet printing or flexographic printing, a coating method, preferably by doctor blade, roller, curtain, dip-shrink, or through a slot-shaped die, (c) said layer obtained in step (b) is dried, where appropriate, before or after separating said layer from its intermediate substrate, then, optionally, said dried layer is heat-treated, preferably in an oxidizing atmosphere; then said layer is consolidated, by heat and / or mechanical treatment, preferably by sintering, to obtain a porous, preferably mesoporous, layer, (d) forming, on and inside the pores of said porous layer, a layer of an electronically conductive oxide material so as to form a porous layer coated with a layer of an electronically conductive oxide material, (e) optionally, an ionic conductive and electronic insulating layer is formed on and inside the pores of said porous layer coated with a layer of an electronically conductive oxide material obtained in step (d).

2. Method for manufacturing a porous electrode according to claim 1, characterized in that in step (d), a layer of a precursor of an electronically conductive oxide material is deposited during a step (dl), on and inside the pores of said porous layer, and during a step (d2), the transformation of the precursor of an electronically conductive oxide material, deposited during step (dl) on said porous layer, into an electronically conductive material, is carried out, so that said porous layer has on and inside the pores, a layer of said electronically conductive oxide material.

3. A method of manufacturing a porous electrode according to claim 2, characterized in that step (dl) is carried out by immersing the porous layer in a liquid phase comprising a precursor of said electronically conductive oxide material, and in that said transformation of the precursor of an electronically conductive oxide material into an electronically conductive material during step (d2) is carried out by heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere.

4. A method of manufacturing a porous electrode according to claim 3, characterized in that said precursor of the electronically conductive oxide material is chosen from organic salts containing one or more metallic elements capable, after heat treatment such as calcination, of forming an electronically conductive oxide, and in that said transformation into an electronically conductive material is a heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, these organic salts being, preferably, chosen from - an alcoholate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere, of forming an electronically conductive oxide, - an oxalate of at least one metallic element capable, after heat treatment such as calcination, preferably carried out in air or in an oxidizing atmosphere,to form an electronically conductive oxide, and - an acetate of at least one metallic element capable, after treatment, thermal process such as calcination, preferably carried out in air or in an oxidizing atmosphere, to form an electronically conductive oxide, and / or in that, preferably, the metallic element is chosen from tin, zinc, indium, gallium, or a mixture of two or three or four of these elements.

5. A method of manufacturing a porous electrode according to any one of claims 1 to 4, characterized in that said electronically conductive oxide material is chosen from: - tin oxide (SnO2), zinc oxide (ZnO), indium oxide (In2O3), gallium oxide (Ga2O3), a mixture of two of these oxides such as indium-tin oxide corresponding to a mixture of indium oxide (In2O3) and tin oxide (SnO2), a mixture of three of these oxides or a mixture of four of these oxides, - doped oxides based on zinc oxide, the doping preferably being gallium (Ga) and / or aluminum (Al) and / or boron (B) and / or beryllium (Be), and / or chromium (Cr) and / or cerium (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), - doped oxides based on indium oxide, the doping preferably being tin (Sn),and / or gallium (Ga) and / or chromium (Cr) and / or cerium (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), - doped tin oxides, the doping preferably being 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 cerium (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).,

6. Method for manufacturing a porous electrode according to any one of claims 1 to 5, characterized in that said porous layer obtained at the end of step (c) has a specific surface area of ​​between 10 m2 / g and 500 m2 / g and / or a thickness of between 4 pm and 400 pm.

7. A method of manufacturing a porous electrode according to any one of claims 1 to 6, characterized in that when said substrate is an intermediate substrate, said layer is separated in step (c) before or after its drying from said intermediate substrate, to form a plate porous.

8. A method of manufacturing a porous electrode, characterized in that when said colloidal suspension or paste supplied in step (a) comprises organic additives, such as ligands, stabilizers, binders or residual organic solvents, said layer dried in step c) according to any one of claims 1 to 6, or said porous plate according to claim 7, is heat treated, preferably in an oxidizing atmosphere.

9. A method of manufacturing a porous electrode according to any one of claims 1 to 8, wherein said electrode active material P is selected from the group formed by: • the oxides LiMn2O4, Li[+xMn2 XO4 with 0 < x < 0.15, LiCoO2, LiNiO2, LiMnij5Nio>504, LiMni sNio.s-xX^where 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 where 0 < x < 0.1, LiMn2xMxO4 with M = Er, Dy, Gd, Tb, Yb, Al, Y, Ni, Co, Ti, Sn, As, Mg or a mixture of these compounds and or 0 < x < 0.4, LiFeO2, LiMni^NiiflCoiflO^LiNio gCoo isAloosO 2> LiAlxMn2xO4 with 0 < x < 0.15, LiNii / xCoi / yMni / zO2 with x+y+z =10; • LixMy02 where 0.6 <y<0.85; 0<x+y<2; et M est choisi parmi Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Sn, and Sb ou un mélange de ces éléments ; Lii.20Nbo.2oMn0.6o02 ; • Lii+xNbyMezApO2 where Me is at least one transition metal chosen from: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Te, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Rf, Db, Sg, Bh, Hs and Mt, and where 0.6 <x<l; 0<y<0.5; 0.25<z<l; avec A Me et A Nb, et 0<p<0.2 ; • LixNby aNaMzbPbO2_cFc où 1.2<x<1.75; 0<y<0.55; 0.1<z<l; 0<a<0.5; 0<b<l; 0<c<0.8; et où M, N, et P sont chacun au moins un des éléments choisi dans le groupe constitué par Ti, Ta, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh, et Sb ; • Li125Nbo.25Mno.5o02 ; Li1.3Nbo.3Mno.4o02 ; Li1.3Nbo.3Feo.4o02 ; Li13 Nb0.43Nio.2702 ; Li1.3Nb043Co0.37O3 ; Li14Nbo.3Mno.53O3 ; • LixNio.2Mn0.6Oy où 0.00<x<1.52; 1.07<y<2.4 ; Lii.2Nio.2Mn0.60 2 ;. LiNixCoyMni_x_yO2 where 0 < x and y < 0.5; LiNixCezCoyMni x yO2 where 0 < x and y < 0.5 and 0 < z; the phosphates LiFePO4, LiMnPO4, LiCoPO4, LiNiPO4, Li3V2 (PO4)3> Li2MPO4F with M = Fe, Co, Ni or a mixture of these different elements, LiMPO4F with M = V, Fe, T or a mixture of these different elements; the phosphates of formula LiMM'P04, with M and M' (M M') selected from Fe, Mn, Ni, Co, V such as LiFexCoi xPO4et where 0 < x < 1; FeogCûo iOF ; LiMSO4F with M = Fe, Co, Ni, Mn, Zn, Mg ; all lithiated forms of the following chalcogenides: V2O5, V 3O8, TiS2, titanium oxysulfides (TiOySz with z=2-y and 0.3 <y<l), les oxysulfures de tungstène (WOySz avec 0.6<y<3 et 0. l<z<2), CuS, CuS2, de préférence LixV2O5 avec 0 < x < 2, LixV3O8 avec 0 < x < 1,7, LixTiS2 avec 0 < x < 1, les oxysulfures de titane et de lithium LixTiOySz avec z=2-y, 0,3<y<l et 0 < x < 1, LixWOySzavec z=2-y, 0,3<y<l et 0 < x < 1, Lix CuS avec 0 < x < 1, LixCuS2avec 0 < x < 1.

10. A method of manufacturing a porous electrode according to any one of claims 1 to 8, wherein said electrode active material P is selected from the group consisting of: • Li4Ti50i2, Li4Ti5 xMxO[2 with M = V, Zr, Hf, Nb, Ta and 0 < x < 0.25; • niobium oxides and mixed oxides of niobium with titanium, germanium, cerium or tungsten, and preferably in the group formed by: • Nb2O5±s, Nbi8Wi6O93±ô, Nbi6W5O55±ô with 0 <x<let0<ô< 2, LiNbO3, • TiNb2O7±ô, LiwTiNb2O7 with w>0, Tii xM'xNb2 yM2yO7±ô or Li wTii^M'xNb^yM^O?^ in which 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 being the same or different from each other, and in which 0 < w < 5 and 0 < x < let0 <y<2et0<ô< 0,3 ; LaxTii 2xNb2+xO7 where 0 <x<0.5 ; MxT i ! _2xNb2+xO7±s • in which M is an element whose oxidation state is +III, more particularly M is at least one of the elements chosen from the group consisting of Fe, Ga, Mo, Al, B, and where 0 <x<0.20 et -0.3< ô <0.3 ; Ga0.ioTio.8oNb2.ioO 7 ; Fe0.10Ti0.80Nb2.10O7 ; • MxTi2_2xNbio+x029±ô • in which M is an element whose oxidation state is +III, more particularly M is at least one of the elements chosen from the group consisting of Fe, Ga, Mo, Al, B, and where 0 <x<0.40 et -0.3< ô <0.3 ; Tii_xM1xNb2_yM2yO7_zM3z or LiwTii_xM1xNb2_yM2yO7_zM3zin which 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 being able to be the same or different from each other, M3 is at least one halogen, and in which 0 <w<5et0<x< let0<y<2etz< 0,3 ; TiNb2O7 ZM3Z ou LiwTiNb2O7 ZM3Z dans lesquels M3 est au moins un halogène, de préférence choisi parmi F, Cl, Br, I ou un mélange de ceux-ci, et 0 < z < 0,3 ; • TiixGexNb^yM'yO^, LCTi^GeJWyM'yO^, Tii xCe xNb2.yM1yO7±z, LiwTii_xCexNb2_yM1yO7±zin which • M1 is at least one element chosen 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<5et0<x<let0<y<2etz< 0.3; • Ti1_xGexNb2_yM1yO7_zM2z, LiwTi, sGcsNb2yM'yO- ZM2Z, Ti1_xCexNb2_yM*yO7.zM2Z, LiwTi, sCcsNb2 yM 'yO7 ZM2Z, in which • 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 may be identical or different from each other, • and in which 0 <w<5et0<x<let0< y < 2 et z < 0,3 ; • TiO2 ; TiOxNy avec x<2 et 0<y<0,2 ; • LiSiTON, les oxynitrures à base d’étain et de silicium, et plus particulièrement la formulation SiSno,870i,2oNi,72 et leurs formes lithiées ; • les nitrures et oxynitrures de type MOxNy où M est au moins un élément choisi parmi Ge, Si, Sn, Zn ou un mélange d’un ou plusieurs de ces éléments, et où x> =0 and y >=0.3; • Li3 xMxN with M being at least one element selected from Cu, Ni, Co or a mixture of one or more of these elements; • Li3 xMxN with M being cobalt (Co) and 0 < x < 0.5; Li3_xMx N with M being nickel (Ni) and 0 < x < 0.6; Li3 xMxN with M being copper (Cu) and 0 < x < 0.

3.

11. Porous electrode obtainable by the method according to any one of claims 1 to 10, characterized in that the porous electrode comprises a porous layer of at least one active electrode material P deposited on a substrate, and a layer of an electronically conductive oxide material arranged on and inside the pores of said porous layer, in that it is free of binder, in that it has a porosity of between 20% and 60% by volume, preferably between 25% and 50%, and pores with an average diameter of less than 50 nm.

12. A method of manufacturing a lithium ion battery having a capacity greater than 1 mA h, implementing the method of manufacturing a porous electrode according to one of claims 1 to 10, or implementing a porous electrode according to claim 11.

13. A method of manufacturing a battery according to claim 12, wherein the method of manufacturing a porous electrode according to claim 9 is used to manufacture a cathode or implementing the method according to claim 10 for manufacturing an anode.

14. A method of manufacturing a battery according to any one of claims 12 to 13, wherein said porous electrode is impregnated with an electrolyte, preferably a lithium ion-carrying phase selected from the group consisting of: • an electrolyte composed of at least one aprotic solvent and at least one lithium salt; • an electrolyte composed of at least one ionic liquid and at least one lithium salt; • a mixture of at least one aprotic solvent and at least one ionic liquid and at least one lithium salt; • a polymer made ionically conductive by the addition of at least one lithium salt; and • a polymer made ionically conductive by the addition of a liquid electrolyte, either in the polymer phase or in the mesoporous structure.

15. A lithium ion battery having a capacity greater than 1 mA h obtainable by the method according to any one of claims 12 to 14.