Process for preparing a particulate composite material for an organic electrode

Abstract

Method for preparing a particulate composite material for an organic electrode. The present invention relates to a method for preparing a particulate, electroactive, and electronically conductive composite material, comprising at least the steps of: (i) having a formulation of at least one redox organic material, in a swollen or solubilized state in a solvent medium in which is dispersed at least one electronically conductive nanostructured material, in particular at least one carbon-based nanostructured material; (ii) removing the solvent(s) from the solvent medium; and (iii) grinding the solid material obtained at the end of step (ii) into a powder to form said particulate composite material. It also relates to a particulate composite material obtained by this method, as well as its use as an active electrode material.

Description

Title of the invention: Method for preparing a particulate composite material for an organic electrode technical field

[0001] The present invention relates to the field of electrochemical energy storage, in particular to batteries with organic electrode materials. It aims more particularly at the preparation of particulate composite materials, based on electronically conductive nanostructured material(s), in particular nanostructured carbon material(s), and redox organic material(s), and their implementation as active materials for organic electrodes in electrochemical systems, in particular in lithium batteries. Previous technique

[0002] Lithium batteries are increasingly used as autonomous power sources, particularly in portable devices, where they are gradually replacing nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries. This trend is due to the continuous improvement in the performance of lithium batteries, giving them significantly higher energy densities than those offered by NiCd and NiMH batteries. Lithium batteries have numerous applications, notably in new information and communication technologies (ICT), medical devices, electric vehicles, energy storage for photovoltaic cells, etc.

[0003] These lithium electrochemical generators conventionally operate on the principle of insertion or disinsertion (or intercalation-disintercalation) of lithium on at least one electrode. In particular, in a lithium-ion battery, the Li+ cations thus move back and forth between the positive and negative electrodes, respectively, with each charge and discharge of the battery. The active material of the positive electrode is capable of releasing lithium ions during charging and incorporating lithium ions during discharge.

[0004] Generally, the active electrode compounds used in commercial batteries are, for the positive electrode, lamellar compounds such as LiCoO2, LiNiO2 and mixed Li(Ni, Co, Mn, Al)O2, spinel structure oxides with compositions close to LiMn2O4 or of the lithium phosphate type, such as LiM1PO4 with M1 being chosen from Fe, Mn, Co and mixtures thereof. The negative electrode is generally carbon (graphite, coke, etc.) or possibly the spinel Li4Ti50i2 or a metal forming an alloy with lithium (Sn, Si, etc.).

[0005] To respond more specifically to the new electronics markets portable, hybrid and electric car or photovoltaic solar, the constraints of cost, production volume and power performance require the search for new active electrode materials.

[0006] In this perspective, organic compounds (molecules and polymers) have already been developed as active electrode materials, for example for lithium batteries, for their ability to capture lithium reversibly by releasing or capturing one or more electrons.

[0007] The most commonly used polymers are, for example, polyanilines, polypyrroles, polythiophenes, conducting compounds containing at least one heterocycle with a nitrogen atom, or polymers having on their main or pendant chain a component bearing a disulfide bridge or various redox functions (carbonyls, amines, radicals, (thio)ethers, etc.). By way of example, document JP 2008-192452 describes the use, as active electrode materials, of conducting polymers formed from monomers having five-membered heteroaromatic rings, in particular polythiophenes bearing TEMPO radicals or derivatives.

[0008] However, the use of redox molecules or electroactive polymers as battery electrode materials presents two major drawbacks. On the one hand, the solubility of organic compounds in battery electrolytes leads to a rapid loss of capacity during repeated charge / discharge cycles.

[0009] On the other hand, the electrically insulating nature of organic compounds generally necessitates the combined use of significant quantities of conventional electronic additives, particularly carbon, typically on the order of 40 to 60 wt%, to enable the extraction of electrons from the active material. Unfortunately, the addition of such quantities of electronic conductors comes at the expense of the mass or volume energy density of the electrode, making any industrial application extremely expensive.

[0010] To limit the problem of dissolution of the organic active material, several strategies have already been proposed, for example, the use of organic compounds in complex insoluble polymeric forms, the introduction of ionic functions, grafting onto supports, etc., to render the active material insolubilized, as reported for example by Liang et al. [1]. Unfortunately, the fabrication of electrodes with high surface capacitance from these organic materials requires the use of prohibitively high carbon content.

[0011] There is therefore a need to develop new active materials to overcome the aforementioned drawbacks and to access organic electrode formulations with a reduced carbon content, while leading to high performance, in particular high surface capacitance.

[0012] For example, Iwasa et al. [2] proposed to produce composite organic positive electrodes based on a crosslinked poly(2,2,6,6-tetramethylpiperidinyl-N-oxy-4-yl methacrylate) (PTMA) gel and carbon nanofibers (VGCF), by mechanically mixing a crosslinked PTMA gel, swollen in N-methyl-2-pyrolidinone (NMP), with carbon nanofibers. The dispersion of the PTMA / VGCF composite in NMP is then directly used to form an ink when mixed with an aqueous solution of sodium carboxymethylcellulose (CMC) and PTFE powder. Description of the invention

[0013] The present invention proposes a new method for preparing a composite based on redox organic material(s) and electronically conductive nanostructured materials, in particular nanostructured carbons, such as carbon nanotubes or nanoparticles, which can be used as an active electrode material.

[0014] More particularly, the invention relates, according to a first aspect, to a process for preparing a particulate, electro-active and electronically conductive composite material, comprising at least the steps of: (i) have a formulation of at least one redox organic material, in the swollen or solubilized state in a solvent medium in which is dispersed at least one electronically conductive nanostructured material, in particular at least one carbon nanostructured material; (ii) remove the solvent(s) from the solvent medium; and (iii) grind the solid material obtained at the end of step (ii) into a powder to form said particulate composite material.

[0015] According to a particular embodiment, the process of the invention is implemented from a formulation of at least one redox organic material, in particular polymeric, in the swollen state in a solvent medium in which is dispersed at least one carbon nanostructured material.

[0016] The inventors have found that it is possible to access, via such a process, a particulate composite material which is particularly advantageous as an active material for organic electrodes, in particular for secondary lithium batteries.

[0017] The invention further relates to a particulate composite material obtained by the process according to the invention as defined above.

[0018] A particulate composite material according to the invention advantageously combines a nanostructured, electronically conductive matrix, in particular a nanostructured carbon matrix, and a redox organic material, preferably polymeric, electro active. Advantageously, the proportion of electronically conductive nanostructured material(s), in particular of carbon type, in a particulate composite material according to the invention, is less than or equal to 30% by mass, in particular between 25 and 0.5% by mass, and especially between 20 and 5% by mass, relative to the total mass of said composite material.

[0019] In particular, the said electronically conductive nanostructured material(s), in particular carbon-based, and the said redox organic material(s) are present in a mass ratio of electronically conductive nanostructured material(s) / redox organic material(s) between 0.005 and 1, in particular between 0.01 and 0.5, in particular between 0.05 and 0.3, more particularly between 0.1 and 0.25.

[0020] The particulate composite material, in other words in the form of a powder, thus obtained according to the invention proves to be particularly advantageous as an active material for an organic electrode.

[0021] Thus, the invention also relates, according to another of its aspects, to the use of a particulate composite material obtained by the process of the invention, as an active electrode material.

[0022] It also relates to an electrode comprising, as an active material, at least one particulate composite material obtained by the process of the invention.

[0023] It also relates to a method for preparing such an electrode comprising at least the following steps: (a) preparation of a dispersion comprising, in an aqueous or organic medium, at least one particulate composite material according to the invention, and optionally one or more electronically conductive and / or binder additive(s); (b) deposition of the dispersion thus prepared onto the surface of a current collector, for example, of the aluminium strip type; and (c) evaporation of said aqueous or organic medium to form an electrode film.

[0024] The formulation of the ink used to prepare an electrode according to the invention is more particularly adjusted so as to avoid the dissolution of the particulate composite material according to the invention.

[0025] According to a particular embodiment, the particulate composite material is formulated using an aqueous process.

[0026] The implementation of a particulate composite material according to the invention as an active electrode material proves advantageous in several respects.

[0027] First, the particulate composite material according to the invention makes it possible to obtain electrode formulations with good performance, in particular high surface capacitances, advantageously exceeding 1 mAh.cm², without requiring the combined use of significant quantities of electronically conductive additives, in particular carbon-based additives. Thus, The use of a composite material according to the invention makes it possible to reduce the amount of additional electronic conductors.

[0028] Thus, the electrode comprising a particulate composite material according to the invention may comprise less than 20% by mass, in particular less than 10% by mass and more particularly less than 5% by mass of additional electronic conductive additives, in particular additional carbon additives.

[0029] Advantageously, the total proportion of carbon materials in an organic electrode according to the invention does not exceed 40% by mass, in particular is less than or equal to 30% by mass and more particularly less than or equal to 25% by mass, in particular less than or equal to 20% by mass.

[0030] Also, as illustrated in the examples that follow, an organic electrode implementing a particulate composite material according to the invention makes it possible to access an electrochemical system, such as a lithium battery, advantageously exhibiting excellent electrochemical performance, in particular in terms of cycling stability and resistance to high charge / discharge rates.

[0031] Advantageously, an electrochemical system according to the invention exhibits a high specific capacity, whether in slow cycling regime (for example, C / 10) or in fast regime (for example, up to 5C, or even 10C, or even 20C).

[0032] The invention further relates, according to another aspect, to an electrochemical system comprising at least one electrode according to the invention. Such an electrochemical system is more particularly an organic battery, in particular a cation-ion battery, notably a lithium-ion, sodium-ion, potassium-ion, or magnesium-ion battery, a dual-ion battery in which both cations and anions are involved in the electrochemical redox reaction (metallic or non-metallic anode), or an anion-ion battery.

[0033] Other characteristics, variants and advantages of the composite materials according to the invention, their preparation and implementation, will become clearer from the description, examples and figures which follow, given by way of illustration and not limitation of the invention.

[0034] In the following text, the expressions "between ... and ...", "ranging from ... to ..." and "varying from ... to ..." are equivalent and are meant to mean that the limits are included, unless otherwise stated. Brief description of the drawings

[0035] [Fig. 1] shows the potential evolution curves (in V vs Lr7Li°) as a function of the specific capacity (in mAh / g) during the 6th to 10th charge-discharge cycles at a C regime for a battery such as that prepared in Example 3, implementing a conventional electrode based on PTMA (30 / 50 / 20).

[0036] [Fig.2] shows the potential evolution curves (in V vs Li+ / Li°) as a function of the specific capacity (in mAh / g) during the 6th to 10th charge-discharge cycles at a C regime for a battery such as prepared in example 3, implementing an electrode based on the PTMA / NTC particulate composite material according to the invention.

[0037] [Fig.3] shows the evolution of the specific capacity (in mAh / g) as a function of the number of cycles, at increasing regimes (5 cycles at C / 10, C, 2C, 5C, 10C and 20C), for the batteries prepared in example 3, respectively implementing a conventional electrode based on PTMA (30 / 50 / 20) and an electrode based on the PTMA / NTC particulate composite material according to the invention.

[0038] [Fig.4] shows the curves of evolution of the potential (in V vs Lr7Li°) as a function of the specific capacity (in mAh / g) during the 1st to 5th charge-discharge cycles at a C / 10 regime for a battery such as prepared in example 6, implementing a conventional PVR-based electrode (40 / 20 / 20 / 20).

[0039] [Fig.5] shows the curves of evolution of the potential (in V vs Lr7Li°) as a function of the specific capacity (in mAh / g) during the 1st to 5th charge-discharge cycles at a C / 10 regime for a battery such as prepared in example 6, implementing an electrode based on the particulate composite material PVR / KB600 according to the invention. Detailed description

[0040] Preparation of the particulate, electro-active and electronically conductive composite material

[0041] Step (i): Intimate mixing in dispersion of the redox organic material(s) and the electronically conductive nanostructured material(s)

[0042] As mentioned previously, step (i) of the process of the invention consists of having a formulation of at least one redox organic material in a swollen or solubilized state in a solvent medium in which is dispersed at least one electronically conductive nanostructured material, in particular a nanostructured carbon material. Redox organic material

[0043] By material, also called compound, redox “organic”, we classically mean a compound, in particular of molecular, oligomeric or polymeric nature, of carbon chemistry, comprising carbon and hydrogen atoms, and one or more heteroatoms chosen from oxygen, nitrogen, sulfur, phosphorus, these atoms and heteroatoms being linked only by covalent bonds, this compound being able to be in the form of a salt, for example a metallic salt.

[0044] The organic compound or material is described as "redox" because it is susceptible to exist in an oxidized form and in a reduced form, the redox couple can be characterized by an equilibrium potential.

[0045] The organic redox material can be chosen from among the organic compounds (molecules, oligomers or polymers) known as organic electrode materials, in particular from among the organic compounds exhibiting insufficient performance in terms of electronic conductivity.

[0046] Such redox organic materials are described in the literature, for example in documents [1] and [5]. These compounds generally comprise one or more redox motifs, and can be selected from conjugated polymers, compounds with stable radicals, more particularly nitroxide (NO•) functions, (thio)ether compounds, compounds comprising one or more aromatic or heterocyclic amine groups, compounds comprising one or more disulfide groups, azo compounds, compounds comprising one or more carboxylate groups, compounds comprising one or more carbonyl groups and mixtures thereof.

[0047] More specifically, the redox organic compounds used according to the invention can be chosen from:

[0048] - compounds, for example polymers, comprising one or more groups possessing at least one nitroxide function (NO•), preferably oligomers or polymers grafted by groups possessing at least one nitroxide function, for example TEMPO groups;

[0049] - compounds, preferably oligomers or polymers, comprising one or more carbonyl groups, in particular conjugated carbonyl groups, in particular quinone compounds. These can include, for example, polymeric compounds, such as polyanthraquinone, or molecular compounds, such as lithium dihydroxyterephthalate.

[0050] - polyimides;

[0051] - compounds, in particular molecular, oligomeric or polymeric, comprising a or several carboxylate groups, such as lithia carboxylate groups. This may include, more specifically, molecular compounds, for example dilithium terephthalate, lithia naphthalene carboxylate, lithia perylene carboxylate; or oligomers or polymers functionalized by carboxylate groups, such as polythiophene terephthalate.

[0052] - compounds, preferably oligomers or polymers, comprising one or more aromatic or heterocyclic amine groups. This may specifically involve molecular compounds, for example diamine terephthalate salts, or oligomers or polymers, for example poly- viologens or polytriphenylamines.

[0053] - azo compounds, such as azobenzene 4,4-dicarboxylate of lithium;

[0054] - (thio)ether compounds, in other words compounds having one or more thio (-S-) and / or ether (-O-) functions. Examples include thianthrene, phenothiazine, polythianthrene, and polyphenothiazine.

[0055] - compounds, preferably oligomers or polymers, comprising one or more disulfide groups (-SS-). Examples include tetrathionaphthalene or poly(2,5-dimercapto-l,3,4-thiadiazole).

[0056] The process of the invention can implement a single redox organic material, or a mixture of at least two redox organic materials, in particular chosen from the compounds described above.

[0057] It is understood that the said redox organic compound(s) implemented according to the invention have a structure capable of being deployed, solubilized or "swollen" by insertion of the solvent medium, so as to allow insertion of the nanostructured carbon material(s).

[0058] Preferably, the redox organic compound is in the form of an oligomer or polymer, in particular in the form of a polymer, especially having redox groups or motifs such as listed above.

[0059] In particular, the redox organic material, preferably in oligomeric or polymeric form, advantageously has a molecular mass by weight between 500 g / mol and 10.106 g / mol, in particular between 1000 and 1.106 g / mol.

[0060] The redox organic compound is thus advantageously chosen from among the known organic oligomers or polymers as electrode materials.

[0061] The term “polymer” is understood to refer to both homopolymers and copolymers.

[0062] Advantageously, the organic redox material is in the form of a cross-linked polymer.

[0063] By “crosslinked polymer”, we mean, in the sense of the invention, polymers resulting from the use, during polymerization, of a crosslinking or branching agent, that is to say, having several polymerizable functions, preferably bi- or tri-functionalized.

[0064] The organic redox material can thus be an organic redox oligomer or polymer, preferably a cross-linked polymer, of which at least one of the repeating motifs carries one or more redox groups, in particular chosen from the organic redox compounds listed above.

[0065] These redox organic materials can be prepared according to conventional methods tionals, known to the man of the trade.

[0066] According to a particular embodiment, the redox organic material can be chosen from oligomers or polymers, preferably cross-linked, bearing side groups having at least one nitroxide function.

[0067] This may include, for example, polymers having a linear skeleton, for example chosen from poly(meth)acrylates, polythiophenes, polyfluorenes, polycarbozoles, polyanilines, polyphenylenes, polyisothionaphthenes, polyacetylenes, polyphenylene-vinylenes, and bearing at least one lateral group having at least one nitroxide function.

[0068] The group bearing a nitroxide function (NO) can be, for example, a 2,2,6,6-tetramethyl-piperidinyl-N-oxy (TEMPO) group.

[0069] Such grafted polymers are described for example in document WO 2015 / 140249.

[0070] By way of example, we can cite poly(2,2,6,6-tetramethyl-piperidinyloxyl-4-yl methacrylate), noted PTMA, preferably crosslinked, for example PTMA crosslinked by 2-(methacryloyloxy)ethyl methacrylate.

[0071] According to another particular embodiment, the redox organic material can still be chosen from polyviologens, preferably cross-linked polyviologens.

[0072] Polyviologens are more particularly formed of monomers comprising a viologenic motif, in oxidized form, of the following formulas (la) or (Ib):

[0073] [Chem.l] (Rio N® ^—4 H™* x ..... /

[0074] [Chem.2] (R)n' *—N \—4 © N—*

[0075] in which: the R groups, identical or different, represent a hydrogen atom, a linear alkyl in C2 to C50 where appropriate substituted by at least one carboxylic, carboxylate, sulfonic, sulfonate, phosphonic, phosphonate, amine function, at least one halogen atom, at least one hydroxy or aldehyde group or even interrupted by a ketone motif; n and n are independently of each other equal to 0 or to an integer between 1 and 50; and the radicals X, identical or different and preferably identical, are respectively an organic anion chosen from [N(SO2CF3)2] (=TFSI ), [N(SO2F)2] (=FSI ), 4,5-dicyano-2-(trifluoromethyl)imidazole (=TDI), RCOO, HCOO, or inorganic such as PF6, BF4, C1O4, F , Cl, Br , I, NO3 and HSO4.

[0076] The redox organic material can thus be a polyviologenic material of the following formula (II):

[0077] [Chem.3] in its oxidized forms, in particular radical cation or reduced, and in which: - the identical or different Ai and A2 motifs, independently of each other, represent a covalent bond or an alkyl chain in C1 to C50, where applicable substituted by at least one carboxylic, carboxylate, sulfonic, sulfonate, phosphonic, phosphonate, amine function, at least one halogen atom, at least one hydroxyl or aldehyde group, or even interrupted by a ketone radical or a motif of formula - Ar(A3) - with Ar being a trivalent or tetravalent C6 to C1 arylene motif, preferably a C6H3 phenylene, and A3 a C20 to C1 alkyl chain covalently bonded to the Ar motif and to a viologenic derivative of formula (II) and - R, n, n' and X are such as defined in formula (la) or (Ib) and a is an integer ranging from 1 to 10 million.

[0078] According to a particular embodiment, the redox organic material can thus be a cross-linked polyviologenic material, in particular of the following general formula (IV):

[0079] [Chem.4] in its oxidized or reduced forms and in which R, n, n', a and X if present, have the same meanings as before.

[0080] Polyviologens of formula (IV) in particular are suitable for the invention which R=H ; n=n'=l ; and a is an integer greater than 5 and less than 100. The radicals X can notably represent PF6 anions.

[0081] Polyviologens suitable for the invention as an active electrode material can be prepared electrochemically as described in the article by Sano et al. [3] or chemically as described in the article by Yao et al. [4].

[0082] Polymeric compounds comprising at least one repeating unit comprising one or more rings, one of which is a ring comprising a disulfide group, may be cited as examples of compounds comprising one or more disulfide groups. Such compounds may, for example, comprise at least one repeating unit conforming to one of the following formulas:

[0083] [Chem.5] W

[0084] Polyanthraquinones are a particularly good example of compounds comprising one or more carbonyl groups. Such polymers may, for example, comprise at least one repeating motif conforming to one of the following formulas:

[0085] [Chem.6]

[0086] According to a preferred embodiment, the redox organic material is a redox organic polymer, preferably crosslinked, selected from polymers bearing side groups having at least one nitroxide function, such as 2,2,6,6-tetramethyl-piperidinyl-N-oxy (TEMPO) groups and compounds comprising one or more aromatic or heterocyclic amine groups, in particular polyviologens, notably as defined above.

[0087] The solvent medium used in step (i) is formed of one or more solvents which swell or solubilize the said redox organic material(s), in particular the said redox organic polymer(s), preferably crosslinked.

[0088] A solvent used in the formulation in step (i) of the process of the invention is both a solvent which swells or solubilizes the redox organic material(s) and which allows good dispersion of said electronically conductive nanostructured material(s), in particular of said nanostructured carbon material(s).

[0089] Preferably, the formulation implemented in step (i) of the process of the invention comprises at least one redox organic material of oligomeric or polymeric nature, in particular of the crosslinked polymer type, in the swollen state in a solvent medium.

[0090] By solvent which “swells” the redox organic material, we mean a solvent which inserts itself into the redox organic material and which unfolds its structure to allow the insertion into the redox organic material of the electronically conductive nanostructured material, preferably carbon material, dispersed in said solvent.

[0091] A person skilled in the art is able to choose the appropriate solvent(s) to meet the two aforementioned requirements.

[0092] In particular, the solvent medium in step (i) of swelling or solubilization of organic redox materials, in particular of organic redox polymers, may be formed of one or more organic solvent(s), and more particularly chosen from among chlorinated solvents such as dichloromethane, dichlorobenzene and chloroform; acetonitrile; aromatic solvents such as benzene, toluene and xylene; dimethylformamide; cresol; ethers, in particular tetrahydrofuran, and mixtures thereof, in particular binary and ternary mixtures.

[0093] Preferably, the swelling or solubilizing solvents are chosen from dichloromethane, acetonitrile, dimethylformamide, chloroform and mixtures thereof, in particular from dichloromethane and acetonitrile.

[0094] By way of example, polyviologenic materials, preferably cross-linked, can be swollen in acetonitrile. Polymeric materials bearing side groups having at least one nitroxide function, in particular of the poly(2,2,6,6-tetramethyl-piperidinyloxyl-4-yl methacrylate) type, preferably cross-linked, can for example be swollen in dichloromethane.

[0095] The proportions of redox organic material(s) and solvent medium are adjusted so as to obtain solubilization or sufficient swelling of said redox organic material(s).

[0096] According to a particular embodiment, the said organic redox material(s) is / are implemented in the solvent medium at a rate of 10 to 100 g / L, in particular 20 to 50 g / L of solvent medium.

[0097] Preferably, the formulation in step (i) of the process of the invention of said redox organic material(s), in particular of polymeric nature, advantageously crosslinked, in the swollen state in the solvent medium, is in a viscous form, in particular in the form of a gel.

[0098] Material(x) nanostructured(fs) conductive(fs) electronic(fs)

[0099] The solvent medium comprises at least one electronically conductive nanostructured material in dispersion.

[0100] By "nanostructured material", it is understood that said material is formed of particles having a dimension less than or equal to 500 nm, preferably less than or equal to 300 nm, in particular less than or equal to 200 nm, notably less than or equal to 100 nm. In the remainder of this text, the particles of said electronically conductive nanostructured material(s) dispersed according to the invention will be referred to more simply as "nano-objects".

[0101] Advantageously, the nano-objects forming the electronically conductive nanostructured materials can be of various morphologies, for example chosen from nanotubes, nanowires, nanofibers, nanorods, nanoparticles and mixtures thereof.

[0102] Electronically conductive nanostructured materials can be more particularly selected from carbon nanostructured materials, metallic nanostructured materials, and mixtures thereof.

[0103] Preferably, the process of the invention uses at least one nanostructured carbon material.

[0104] The nanostructured carbon material(s) may comprise different types of carbon. In particular, the nanostructured carbon material may be selected from carbon nanotubes, carbon nanowires, carbon nanofibers, carbon nanoparticles, carbon nanocrystals, graphene or a graphene derivative selected from graphene oxides or reduced graphene oxides, carbon black and mixtures thereof.

[0105] Preferably, the nanostructured carbon material comprises, in particular is formed, of carbon nano-objects selected from carbon black nanoparticles, carbon nanotubes, and mixtures thereof.

[0106] Carbon nanotubes can be single-walled carbon nanotubes (known by the abbreviation SWNT for "single-walled nanotubes" in Anglo-Saxon terminology) or multi-walled (known by the abbreviation MWNT for "multi-walled nanotubes" in Anglo-Saxon terminology).

[0107] Carbon nanotubes can have an average length ranging from 1 pm to 10 pm, and an average diameter ranging from 5 nm to 50 nm.

[0108] Carbon black can have an average particle size between 30 nm and 100 nm, in particular between 50 nm and 70 nm and more particularly between 55 nm and 65 nm.

[0109] Alternatively, or in combination with one or more carbon nanostructured materials, the process of the invention may implement one or more electronically conductive nanostructured materials selected from metallic nanostructured materials.

[0110] These may include, for example, nanostructured materials made of aluminum, copper, nickel, silver, gold, platinum, titanium, palladium, zinc, or alloys thereof. Preferably, the metallic nanostructured material is selected from copper, aluminum, nickel, or silver. Metallic nano-objects, particularly those made of aluminum or copper, may be more specifically selected from nanowires or nanoparticles.

[0111] The size of nano-objects can be evaluated by scanning electron microscopy.

[0112] In the case of particles of spherical or globally spherical shape, the average particle size refers to the diameter of the particle.

[0113] The electronically conductive nanostructured material(s) may be commercially available or prepared by methods known to those skilled in the art.

[0114] According to a particular embodiment, the formulation in step (i) comprises a mixture of at least one nanostructured carbon material and at least one metallic nanostructured material, in particular such as described above.

[0115] According to a particular embodiment, the electronically conductive nanostructured material or materials dispersed in the formulation in step (i) are carbon materials.

[0116] Advantageously, the concentration of electronically conductive nanostructured material(s), in particular of nanostructured carbon material(s), in the solvent medium of step (i) of the process of the invention is between 1 g / L and 50 g / L, in particular between 1 and 20 g / L.

[0117] According to a particular embodiment, the said redox organic material(s), in particular polymeric, and the said electronically conductive nanostructured material(s) are implemented in a mass ratio of redox organic material(s) / electronically conductive nanostructured material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1, notably between 4 / 1 and 5 / 1.

[0118] In particular, in the case of the implementation of carbon nanostructured material(s), the said redox organic material(s), in particular polymeric, and the said nanostructured carbon material(s) can be implemented in a mass ratio of redox organic material(s) / nanostructured carbon material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1, notably between 4 / 1 and 5 / 1.

[0119] According to a particular embodiment, the process of the invention is implemented from a formulation of at least one redox organic polymer, in particular as described above, advantageously crosslinked, in the swollen or solubilized state in an organic solvent medium in which is dispersed at least one electronically conductive nanostructured material, in particular as defined above and more particularly a nanostructured carbon material.

[0120] A person skilled in the art is able to implement the operating conditions necessary to obtain the swelling or solubilization of the redox organic material, in particular of the crosslinked redox organic polymer, by the solvent medium in which the electronically conductive nanostructured material is dispersed, and a good insertion of said nanostructured material within the swollen or solubilized redox organic material.

[0121] Thus, according to a particularly preferred embodiment, the electronically conductive nanostructured material, in particular carbon-based, is dispersed in one or more solvents suitable for swelling or solubilizing the redox organic material, and then the redox organic material, preferably the redox organic polymer, advantageously crosslinked, is introduced into said dispersion of said electronically conductive nanostructured material.

[0122] According to another embodiment, the redox organic material, preferably a redox organic polymer, advantageously crosslinked, is introduced into a solvent medium suitable for its swelling, and then the electronically conductive nanostructured material, in particular carbon-based, is added before swelling of the redox organic material.

[0123] The suspension or solution of said redox organic material in the solvent medium in which the electronically conductive nanostructured material is dispersed, can be agitated, for example by magnetic, mechanical, vibratory agitation, grinding or shaking, in particular for a period of 0.5 hours to 48 hours, in particular from 2 hours to 24 hours.

[0124] The addition of the nanostructured material, particularly carbonaceous material, to the swelling or solubilizing solvent(s) of the redox organic material thus makes it possible, after the swelling or solubilization of said redox organic material, to obtain an intimate mixture of the two materials within the formulation of step (i). Step (ii): removal of the solvent medium

[0125] In a step (ii), the solvent(s) of the solvent medium of the formulation of step (i) are removed.

[0126] Preferably, the solvent(s) are removed by evaporation, in particular by heating the formulation (drying).

[0127] It is understood that the temperatures used to remove the solvent(s) must not degrade the chemical structure of the redox organic material(s), in particular the crosslinked redox organic polymer(s) used according to the invention.

[0128] Typically, drying is carried out at a temperature ranging from 20 to 250 °C, in particular from 30 to 200 °C, especially from 50 to 150 °C and more particularly from 60 to 80 °C. The drying time can be between 1 hour and 24 hours, in particular between 4 hours and 10 hours.

[0129] After the removal of the solvent(s), a solid composite material is obtained, comprising, or even being formed, of an electronically conductive matrix (or three-dimensional network), in particular carbonaceous and / or metallic, in particular carbonaceous, coated with a redox organic film, formed of said redox organic material(s), preferably polymeric, and advantageously crosslinked.

[0130] The electronically conductive matrix is ​​formed by the agglomeration of said electronically conductive nanostructured material(s).

[0131] According to a particular embodiment, it may be a carbon matrix formed by the agglomeration of said nanostructured carbon material(s), for example by carbon nanotubes or carbon black.

[0132] It advantageously has a high specific surface area, in particular varying from 10 to 2000 m2 / g and preferably from 50 to 500 m2 / g.

[0133] Advantageously, the solid composite material obtained at the end of step (ii) of the process of the invention may comprise said redox organic material(s) and said electronically conductive nanostructured material(s), in a mass ratio of redox organic material(s) / electronically conductive nanostructured material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more specifically between 4 / 1 and 8 / 1, especially between 4 / 1 and 5 / 1.

[0134] According to a particular embodiment, in the case of the implementation of carbon nanostructured material(s), the solid composite material, obtained at the end of step (ii) of the process of the invention, may comprise said redox organic material(s) and said carbon nanostructured material(s), in a mass ratio of redox organic material(s) / carbon nanostructured material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1, notably between 4 / 1 and 5 / 1.

[0135] Step (iii): Composite material in powder form

[0136] The process of the invention includes a step of grinding said solid composite material obtained at the end of the aforementioned step in the form of a powder.

[0137] The grinding step can be a dry or wet grinding step.

[0138] In the case of wet grinding, in other words in the presence of a or several solvents, the nature of said solvent(s) is chosen so that the redox organic material is insoluble in said grinding solvent(s).

[0139] Without wanting to be bound by theory, this grinding step makes it possible to expose part of the electronically conductive matrix, in particular carbonaceous, in order to be able to have current resumptions on the surface of the particles of the powder thus formed.

[0140] Moreover, this step advantageously allows the particle size to be adapted for easier implementation during the formulation of the ink for the preparation of the electrode.

[0141] The grinding can be carried out manually using a mortar and pestle. Preferably, it is carried out mechanically, in a mechanical mill, for example a ball mill or a planetary mill.

[0142] After grinding, a composite material is obtained in the form of a powder, also called "particulate composite material".

[0143] Thus, the invention also relates to a particulate composite material obtained by the process as defined above.

[0144] The particulate composite material comprises particles formed from an electronically conductive nanostructured matrix, in particular carbonaceous, partially coated with the redox organic material, in particular with a redox organic polymeric film, preferably crosslinked.

[0145] The particulate composite material according to the invention advantageously has a specific surface area between 10 m2 / g and 2000 m2 / g, in particular between 50 m2 / g and 500 m2 / g.

[0146] Advantageously, the particulate composite material according to the invention comprises, or is formed from, redox organic material(s) and electronically conductive nanostructured material(s), in a mass ratio of organic material(s) redox / nanostructured electronically conductive material(s), between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1, especially between 4 / 1 and 5 / 1.

[0147] According to a particular embodiment, the particulate composite material according to the invention comprises, or is formed of, redox organic material(s) and carbon nanostructured material(s), in a mass ratio of redox organic material(s) / carbon nanostructured material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1, especially between 4 / 1 and 5 / 1. Use as an active electrode material

[0148] As mentioned previously, the particulate composite material according to the invention can advantageously be used as an active material for an organic electrode.

[0149] For the purposes of this invention, "active electrode material or compound" means a material (or compound) for the insertion / disinsertion of a Cn+ cation in which n is 1 or 2 (Li+, Na+, K+, Ca2+, or Mg2+) or an Am anion in which m is 1 or 2 (PF6, BF4, C1O4, (CF3SO2)2N, (FSO2)2N) from an electrode of an electrochemical generator. More particularly, the active material (or compound) of the positive electrode is capable of releasing Cn+ or Am ions during charging and incorporating Cn+ or Am ions during discharging of the electrochemical generator. Conversely, the active material (compound) of the negative electrode is capable of incorporating Cn+ or Am ions at the time of charging and releasing Cn+ or Am ions at the time of discharge of the electrochemical generator.

[0150] Thus, the invention also relates to the use of a particulate composite material according to the invention or as obtained by the process of the invention, as an active electrode material.

[0151] The invention also relates to an electrode comprising, as an active material, at least one particulate composite material according to the invention.

[0152] Preferably, the particulate composite material(s), implemented as the active electrode material according to the invention, advantageously represents more than 60% by mass of the total mass of the electrode, in particular from 70% to 99% by mass, and more particularly from 80% to 96% by mass of the total mass of the electrode.

[0153] The said particulate composite material(s) according to the invention can be implemented, in a conventional manner, in conjunction with one or more binder(s), in particular one or more polymeric binders.

[0154] Such binders may be selected from fluorinated binders, in particular from polytetrafluoroethylene, polyvinylidene fluoride, carboxymethylcellulose and its derivatives, polysaccharides, polyacrylates, latex, especially styrene-type latex butadiene.

[0155] Preferably, the binder used is carboxymethylcellulose.

[0156] According to a particular embodiment, the particulate composite material(s) according to the invention, and the binder(s), can be implemented, in a mass ratio of particulate composite material(s) / binder(s) between 4 / 1 and 99 / 1, in particular between 85 / 15 and 98 / 2 and more particularly between 90 / 10 and 98 / 2, and more particularly between 95 / 5 and 96 / 4.

[0157] The said particulate composite material(s) according to the invention can be implemented, in a conventional manner, in conjunction with one or more electronically conductive additive(s).

[0158] Said electronically conductive additive(s) may be selected from carbon fibers, carbon black, carbon nanotubes, graphene, graphite, and metallic particles, such as metallic nanowires or nanoparticles.

[0159] The metallic particles may be, for example, aluminium, copper, nickel, silver, gold, platinum, titanium, palladium, zinc or alloys thereof.

[0160] Preferably, the electronically conductive additives are chosen from carbon-based additives, such as carbon nanofibers and carbon black.

[0161] Advantageously, as mentioned previously, the implementation of a particulate composite material according to the invention as an active electrode material makes it possible to significantly reduce the amount of electronically conductive additives within the electrode.

[0162] Thus, advantageously, the said electronic conducting additive(s), in particular carbon-based, can be implemented at the level of the composition of the organic electrode, at a rate of less than 20% by mass, in particular from 1 to 10% by mass, relative to the total mass of the electrode.

[0163] According to a particular embodiment, the particular composite material(s) according to the invention, and the electronically conductive additive(s) can be implemented in a weight ratio of particular composite material(s) / electronically conductive additive(s) between 4 / 1 and 99 / 1, in particular between 9 / 1 and 97 / 3.

[0164] The electrode based on said particulate composite material(s) according to the invention may thus comprise, in addition to said composite material(s), one or more electronically conductive additive(s) and / or one or more binder(s), in particular as described above.

[0165] According to a particular embodiment, an organic electrode according to the invention can thus comprise, or even be formed from: - from 60 to 99% by mass, in particular from 80 to 99% by mass, notably from 90 to 95% mass of one or more particulate composite material(s) prepared according to the invention; - from 0.5 to 20% by mass, in particular from 1 to 10% by mass and preferably from 1 to 5% by mass, of one or more electronically conductive additive(s), in particular of the carbon-based type; and - from 0.5 to 20% by mass, in particular from 1 to 10% by mass and preferably from 1 to 5% by mass, of one or more binders, in particular carboxymethylcellulose; the percentages being expressed in relation to the total mass of the electrode (excluding current collector).

[0166] According to another preferred embodiment, an organic electrode according to the invention comprises less than 40% by mass, in particular less than 30% by mass, notably less than 25% by mass, and more particularly less than 20% by mass, of electronically conductive carbon(s). The proportion of electronically conductive carbon in the electrode refers both to the content of nanostructured carbon material(s) present in the particulate composite material prepared according to the invention, and to the carbon in said electronically conductive additive(s) possibly used in conjunction with the particulate composite material according to the invention.

[0167] The electrode, comprising as an electrochemically active material a composite material according to the invention, can be a positive electrode or a negative electrode.

[0168] In a conventional manner, the electrode is in contact with a current collector.

[0169] For example, copper, aluminum, nickel, carbon felt or stainless steel can be used as a current collector for a positive electrode; and copper, or steel, processed into a cut sheet, foam metal or laminated sheet plate, for example, can be used as a current collector for a negative electrode. Preparation of the organic electrode

[0170] For the preparation of the electrode, the particulate composite material according to the invention is advantageously formulated with one or more aqueous or organic solvents in which the said redox organic material(s) forming the composite material are insoluble (they are then referred to as "non-solvents") and do not swell.

[0171] Thus, an organic electrode based on a particulate composite material according to the invention can be prepared via at least the following steps: (a) preparation of a dispersion, commonly called "ink", comprising, in an aqueous or organic medium, at least one particulate composite material according to the invention, and optionally one or more electronically conductive and / or binder additive(s); (b) deposition of the dispersion thus prepared onto the surface of a current collector, for example, of the aluminium strip type; and (c) evaporation of the aqueous or organic medium to form an electrode film.

[0172] In particular, the particulate composite material according to the invention is implemented in step (a) of the process of the invention in an aqueous medium, preferably in water.

[0173] Thus, the invention also relates to an ink useful for the preparation of an organic electrode, comprising, in an aqueous or organic medium, in particular aqueous, at least one particulate composite material according to the invention, and optionally one or more electronically conductive and / or binder additive(s).

[0174] The ink deposition, in step (b) of the process of the invention, can be carried out by coating, by a printing technique, by extrusion or by lamination. A person skilled in the art is able to adjust the conditions for implementing these different techniques.

[0175] The evaporation of the aqueous solvent(s) in step (c) can be carried out by drying, for example in an oven, at a temperature between 20 and 150°C, in particular between 60 and 80°C, for a period of between 1 and 15 hours. Electrochemical system

[0176] The invention also relates to an electrochemical system comprising at least one organic electrode comprising a particulate composite material obtained according to the invention.

[0177] The electrochemical system in which the electrode according to the invention is implemented can be in particular a rechargeable electrochemical accumulator, in particular a lithium accumulator or battery.

[0178] Preferably, this rechargeable electrochemical accumulator comprises, in addition to the positive or negative organic electrode as defined above comprising a composite material according to the invention, a negative or positive electrode not comprising a composite material according to the invention, and an electrolyte.

[0179] Advantageously, an electrode according to the invention can be implemented in a battery in cation-ion configuration, in particular a lithium-ion, sodium-ion, potassium-ion, magnesium-ion battery; a battery in "dual-ion" configuration, in which both cations and anions are involved in the redox reaction; or even an anion-ion battery.

[0180] This may be a lithium-ion, lithium-polymer, lithium-sulfur, lithium-air or supercapacitor battery, and preferably a lithium-ion battery.

[0181] The rest of the battery can be formed using conventional methods.

[0182] Generally, batteries have an architecture with two electrodes (a positive electrode and a negative electrode), both coated on an electrically conductive current collector, arranged on either side of a se Organic or inorganic cell. The two most commonly used assembly techniques for this architecture are winding (winding the different components in a cylindrical or prismatic geometry) and stacking (layering the different elements). Of course, other assembly techniques for forming a battery are possible, such as printing techniques.

[0183] The invention will now be described by means of the following figures and examples, given of course by way of illustration and not limitation of the invention. Examples

[0184] Example 1: Synthesis of the redox organic polymer of the type polyf2.2.6.6-tetramethyl-piperidenvloxvl-4-vl methacrylate) crosslinked (PTMA)

[0185] First, 10 g of 2,2,6,6-tetramethyl-4-piperidyl methacrylate are polymerized at 60°C in the presence of a crosslinking agent (~1 wt% ethylene glycol dimethacrylate) in 60 mL of tetrahydrofuran (THF) using azobisisobutyronitrile (AIBN, 0.15 wt%) as a catalyst. The resulting gel is dried and then introduced into 500 mL of dichloromethane (CH2C12) before being oxidized with 3-chloroperbenzoic acid (mCPBA, 2 equivalents). After neutralization with a sodium carbonate solution and washing with water, the solvent is evaporated, leading to the formation of a polymer (denoted PTMA) in the form of a red solid, which is ground and washed in a Soxhlet-type device with 200 mL of dimethyl carbonate.

[0186] [Chem.7]

[0187] Example 2: Preparation of the electronically conductive particulate composite material PTMA / NTC

[0188] 4 g of PTMA, synthesized according to example 1, are introduced into 150 mL of CH2C12 to which 1 g of carbon nanotubes (CNTs) is added. The suspension is stirred for 2 hours and then dried at 60 °C in an oven to remove the solvent. The resulting solid is then ground in an agate bowl containing three large 20 mm diameter beads for 2 hours at 400 rpm. A black powder is obtained.

[0189] Example 3: Formulation and implementation of an electrode based on the PTMA / NTC composite material according to the invention

[0190] Electrode preparation

[0191] An aqueous formulation comprising 90% by mass of the PTMA / NTC composite material (prepared in Example 2), 5% by mass of Super P® carbon black and 5% by mass of carboxymethylcellulose (CMC) is prepared and coated onto an aluminum strip.

[0192] After drying at 55°C overnight, electrodes are cut and dried under vacuum for 48 hours.

[0193] For comparison, a conventional PTMA (30 / 50 / 20) based electrode is prepared.

[0194] An organic formulation comprising 30% by mass of PTMA (prepared in Example 1), 50% by mass of carbon nanoparticles (Ketjen Black EC600J) and 20% by mass of polyvinyl difluoride (PVdF) in N-methylpyrrolidinone (NMP) is prepared and coated onto an aluminum foil.

[0195] After drying at 55°C overnight, electrodes are cut and dried under vacuum for 48 hours. Evaluation of electrochemical performance

[0196] In order to determine the electrochemical performance of the electrode material according to the invention, the electrodes prepared as described above are implemented in "button cell" type accumulators, with a metallic lithium negative electrode, a Celgard® type stretched polyolefin separator, and an electrolyte consisting of a mixture of carbonate and a lithium salt (ethylene carbonate / dimethyl carbonate 1 / 1 + LiPF6(lM)).

[0197] Electrochemical tests are carried out in galvanostatic cycling at a C regime.

[0198] Figures 1 and 2 represent the potential evolution curves as a function of specific capacity, during the 6th to 10th charge-discharge cycles at a C regime, for batteries implementing respectively a conventional electrode based on PTMA and an electrode according to the invention based on the electronically conductive particulate composite material.

[0199] A strong polarization (difference between the charging and discharging potentials) is observed in the case of conventional electrodes ([Fig.1]), which is not the case for electrodes prepared according to the invention ([Fig.2]).

[0200] Very low surface capacitances, on the order of 0.1 mAh.cm2, are obtained for the conventional PTMA-based electrode, while the electrode based on the electronically conductive particulate composite material has a surface capacitance greater than 1 mAh.cm2.

[0201] Fig. 3 represents the evolution of the specific capacity (in mAh / g) as a function of the number of cycles, at increasing regimes (C / 10, C, 2C, 5C, 10C, 20C).

[0202] The specific capacity, for the battery implementing an electrode based on the

[0203]

[0204]

[0205]

[0206]

[0207] electronic conductive particulate composite material according to the invention, remains high, even for high regimes (5C, 10C, 20C). On the other hand, the specific capacity, for the battery using a conventional electrode, remains stable for the C / 10 to 2C cycling regimes, but becomes zero for higher cycling regimes. Example 4: Synthesis of the crosslinked polyvinyl-derived (PVR) type organic redox polymer [Chem. 8] First, a linear polyviologen (PV) is prepared by condensing 5 g of 4,4'-bipyridine with 6.93 g (1 equivalent) of 1,4-dibromobutane at 150°C in 30 mL of dimethylformamide (DMF). The precipitate is filtered, washed with ethyl acetate, and then dried at 80°C. The polymer is then dissolved in water to which 11.5 equivalents of ammonium hexafluorophosphate (NH4PF6) are added. The resulting precipitate is filtered and washed with water before being dried under vacuum. [Chem.9]

[0208] [Chem. 10] 6 g of linear polymer are then redissolved in 25 mL of DMF to which 1.3 g of 1,3,5-tribromomethylbenzene is added, and then heated to 160°C. The suspension is then filtered, washed with ethyl acetate, and dried at 80°C. The polymer (PVR) is then dispersed in water to which 11.5 equivalents of NH4PF6 are added. The resulting precipitate is filtered and washed with water before being dried under vacuum.

[0209] Example 5: Preparation of the electronically conductive particulate composite material PVR / KB600 80 / 20

[0210] 0.8 g of PVR, synthesized according to example 4, is dissolved in 25 mL of acetonitrile to which 0.2 g of Ketjen Black EC600-J carbon black is added. The suspension is stirred for 2 hours and then dried at 60°C in an oven to remove the solvent. The resulting solid is then ground in an agate bowl containing three large 25 mm diameter balls for 1 hour at 300 rpm. A black powder is obtained.

[0211] Example 6: Formulation and implementation of a material-based electrode PVR / KB600 80 / 20 particulate composite according to the invention. Electrode preparation.

[0212] An aqueous formulation comprising 90% by mass of the PVR / NTC composite material (prepared in Example 5); 5% by mass of vapor-grown carbon fiber (VGCF); and 5% by mass of CMC is prepared and coated onto an aluminum foil. After drying at 55°C overnight, electrodes are cut and dried under vacuum for 48 hours.

[0213] For comparison, a conventional PVR-based electrode (40 / 20 / 20 / 20) is prepared.

[0214] An organic formulation comprising 40% by mass of PVR (prepared in Example 4), 20% by mass of Super C65 carbon black, 20% by mass of VGCF, and 20% by mass of PVdF is prepared and coated onto an aluminum foil. After drying at 55°C overnight, electrodes are cut and dried under vacuum for 48 hours. Evaluation of electrochemical performance

[0215] In order to determine the electrochemical performance of the electrode material according to the invention, the electrodes prepared as described above are implemented in "button cell" type accumulators, with a metallic lithium negative electrode, a Celgard® type stretched polyolefin separator, and an electrolyte consisting of a mixture of carbonate and a lithium salt (ethylene carbonate / dimethyl carbonate 1 / 1 + LiPF6(lM)).

[0216] Electrochemical tests are carried out in galvanostatic cycling at a C / 10 regime.

[0217] Figures 3 and 4 represent the potential evolution curves as a function of specific capacity, during the 1st to 5th charge-discharge cycle at a C / 10 regime, for batteries respectively implementing a conventional PVR-based electrode and an electrode according to the invention based on the particulate composite material electronic driver.

[0218] The potential evolution curves are comparable in both cases, while the first battery uses a conventional electrode containing 40% mass of carbon, while the second battery uses an electrode according to the invention comprising a carbon content of less than 25% mass.

[0219] Very low surface capacities, strictly less than 0.1 mAh.cm2, are obtained with a battery implementing the conventional PVR-based electrode, while the implementation of an electrode based on the electronically conductive particulate composite material leads to surface capacities greater than 1 mAh.cm2. List of documents cited

[0220] [1] Liang et al., Adv. Energy Mater., 2012, 2, 742-769;

[0221] [2] Iwasa et al., J. of the Electrochemical Society, 164(4), A884-A888 (2017);

[0222] [3] Sano et al., ACS Appl. Interfaces, 2013, 5, 1355-1361;

[0223] [4] Yao et al., Scientific Reports, 5,10962, 2015; DOI: 10.1038 / srep 10962;

[0224] [5] Gutel et al., chap. 4, Li-ion Batteries, From the present to the future, EDP Sciences, 2020.

Claims

Demands

1. A method for preparing a particulate, electroactive, and electronically conductive composite material, comprising at least the steps of: (i) having a formulation of at least one redox organic material, in the swollen or solubilized state in a solvent medium in which is dispersed at least one electronically conductive nanostructured material; said redox organic material being molecular, oligomeric, or polymeric in nature and selected from conjugated polymers, compounds exhibiting stable radicals, more particularly nitroxide (NO•) functions, (thio)ether compounds, compounds comprising one or more aromatic or heterocyclic amine groups, compounds comprising one or more disulfide groups, azo compounds, and mixtures thereof; (ii) removing the solvent(s) from the solvent medium of the formulation of step (i) by evaporation;and (iii) grind the solid material obtained at the end of step (ii) into a powder to form said particulate composite material.

2. A process according to claim 1, wherein said redox organic material is a redox organic polymer, preferably crosslinked, selected from polymers bearing side groups having at least one nitroxide function, such as 2,2,6,6-tetramethyl-piperidinyl-N-oxy (TEMPO) groups and compounds comprising one or more aromatic or heterocyclic amine groups such as polyviologens.

3. A process according to any one of the preceding claims, wherein the solvent medium in step (i) is formed of one or more organic solvent(s), in particular selected from chlorinated solvents such as dichloromethane, dichlorobenzene and chloroform; acetonitrile; aromatic solvents such as benzene, toluene and xylene; dimethylformamide; cresol; ethers, in particular tetrahydrofuran, and mixtures thereof.

4. A method according to any one of the preceding claims, wherein said electronically conductive nanostructured material is selected from nanostructured carbon materials; nanostructured metallic materials, in particular aluminium, copper, nickel, silver, gold, platinum, titanium, palladium, zinc or alloys of these; and their mixtures, in particular said electronically conductive nanostructured material is a nanostructured carbon material.

5. A method according to the preceding claim, wherein the carbon nanostructured material is selected from carbon nanotubes, carbon nanowires, carbon nanofibers, carbon nanoparticles, carbon nanocrystals, graphene or a graphene derivative selected from graphene oxides or reduced graphene oxides, carbon black and mixtures thereof.

6. A method according to any one of the preceding claims, wherein the redox organic material(s), in particular polymeric, and the electronically conductive nanostructured material(s) are implemented in a mass ratio of redox organic material(s) / electronically conductive nanostructured material(s) of between 1 / 1 and 20 / 1, in particular between 2 / 1 and 10 / 1 and more particularly between 4 / 1 and 8 / 1.

7. A method according to any one of the preceding claims, wherein the solvent(s) are removed by heating the formulation to a temperature ranging from 20 to 250 °C, in particular from 30 to 200 °C, in particular from 50 to 150 °C and more particularly from 60 to 80 °C

8. V-. Electrode comprising, as active material, at least one particulate composite material obtained by the process defined according to any one of claims 1 to 7, wherein said particulate composite material(s) represents(s) more than 60% to 99% by mass of the total mass of the electrode, and has(s) a specific surface area between 10 m2 / g and 2000 m2 / g.

9. Electrode according to the preceding claim, further comprising one or more electronically conductive additive(s) and / or one or more binder(s).

10. Electrode according to claim 8 or 9, wherein said particulate composite material(s) represents from 70% to 99% by mass, and more particularly from 80% to 96% by mass of the total mass of the electrode.

11. Electrode according to claim 9 or 10, wherein said electronic conductive additive(s), in particular carbon-based, are implemented at the level of the composition of the organic electrode, at a rate of less than 20% by mass, in particular from 1 to 10% by mass, relative to the total mass of the electrode.

12. A method for preparing an electrode as defined according to any one of claims 8 to 11, comprising at least the following steps: (a) preparing a dispersion comprising, in an aqueous or organic medium, at least one particulate composite material obtained by the method defined according to any one of claims 1 to 7, and optionally one or more electronically conductive and / or binder additive(s); (b) deposition of the dispersion thus prepared on the surface of a current collector, for example, of the aluminum foil type; and (c) evaporation of the aqueous or organic medium to form an electrode film.

13. Electrochemical system comprising at least one electrode as defined according to any one of claims 8 to 11.

14. Electrochemical system according to the preceding claim, characterized in that it is a rechargeable electrochemical accumulator, in particular a lithium accumulator or battery.

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