EP2271423A2 - Carbon-based materials derived from latex - Google Patents

Abstract

Organic gels of resorcinol-formaldehyde type, carbon-based materials of adjusted porosity derived therefrom by pyrolysis. Such materials may be used, in particular, for the production of electrodes.

Description

 CARBON MATERIALS FROM LATEX

The subject of the invention is new organic gels of the resorcinol-formaldehyde type (RP gels) as well as carbonaceous materials of adjusted porosity deriving by pyrolysis. Such materials can be used in particular for the production of electrodes.

WO 2007/024241 discloses a method of manufacturing a porous carbonaceous material. According to this process, a mixture of a carbon precursor such as a resorcinol for example and a block polymer is formed to form a structured material. The carbon precursor is then crosslinked with formaldehyde and then the whole is pyrolyzed. A carbonaceous material having an organized nanostructure whose pores have a uniform size which can vary from 4 to 100 nm is obtained.

However, this process is implemented in organic medium, which poses pollution problems, this synthesis is complicated due to problems of miscibility between the components, it is expensive and low yield. Finally, the products obtained are not entirely satisfactory.

The document Chem. Mater. 2002, 14, 1665-1670 describes the production of mesoporous carbon materials. The process uses polystyrene microspheres in admixture with an aqueous suspension of resorcinol / formaldehyde resin. The polystyrene latex induces the formation of pores of sizes ranging from 50 to 100 nm, resulting in a low full capacity.

Document FR-I 097 512 describes a process for the manufacture of sponges based on latex and resorcinol / formaldehyde resin. The latex and the resin are mixed with various additives and then the mixture is gelled and vulcanized.

FR-0 961 294 relates to a process for reinforcing latex mixtures. The latex is mixed with a resin and then gelled and dried.

J. Accession, 1984, vol. 16, p. 179-216 relates to latex adhesive compositions and resorcinol / formaldehyde mixture. This is a study of the structure of these materials and their basic properties.

Journal of Non-crystalline Solids, 353 (2007), 2893-2899 discloses a carbonaceous material prepared from a resorcinol / formaldehyde resin and a PMMA latex. At first a gel is formed, which is dried and then pyrolyzed. The latex makes it possible to induce a mesoporous structure in the carbonaceous material. The presence of a graphitic structure is mentioned, but the X-ray spectrum does not detect such a structure. US-4,873,218 discloses low density RF type xerogels and their pyrolysis resulting in carbon foams also of low density.

These xerogels are intended for use as phonic and / or thermal insulators, in applications in high energy physics, catalysis or to produce ion exchange resins.

These materials are prepared by a process comprising mixing the reactants and polymerizing them using a basic catalyst in an aqueous medium, solvent exchange with an organic solvent and drying in a supercritical CO ₂ medium. Such a process has a very high cost and is not adaptable to the industrial scale especially because it assumes the use of very large amounts of organic solvents.

In addition, the materials obtained after pyrolysis have a very high porosity (and therefore a low density) which results in unsatisfactory conductive properties. Various improvements of this process and of these materials have been proposed:

• Convective drying, which generates xerogels of RF (C. Lin and A. Ritter, Carbon 35 (1997) 1271), followed by pyrolysis leads to carbon xerogels which are particularly interesting because, on the one hand, convective drying has the advantage of being simple and inexpensive, and secondly, the materials retain very good structural and textural characteristics that allow them to be used in powder form (C. Lin et al., J. Electrochem Soc., 146 (1999) 3639) or as monoliths (N. Job et al, Carbon 43 (2005) 2481).

• The variation of certain synthesis parameters (pH, reagent content ...) or post-synthesis (physical or chemical activations) makes it possible to adjust and control the final structural, textural and mechanical properties (specific surface, porous volume, density, ...) carbon xerogels (EJ Zanto et al., Ind. Eng Chem Res 41 (2002) 3151).

Certain additives (inorganic salts) have been used in the formulation of the precursor gels in order to possibly modify the surface composition of the final porous carbons (N. Job et al, Carbon 42 (2004) 3217).

• WO 01/19904 describes a mesoporous carbon material prepared by polymerization of a resorcinol / formaldehyde system in the presence of a surfactant and treatment of the gel obtained by pyrolysis. The applications concerned are the production of supercapacitive electrodes and chromatography resins. However, the specific capacity of the materials described in the prior art can be further improved.

The specific capacity measured in the documents of the prior art (in particular WO 01/19904) is calculated with respect to the dry mass of the material. This method of calculation is nevertheless not satisfactory because it is not representative of the performance of the material when it is used as an electrode.

A better match between the quantitative numerical evaluation and the reality of the performances can be obtained by the evaluation of the solid mass capacity of the material, which takes into account the pore volume of this material. One of the objectives that is achieved by the invention is to obtain materials derived from an RF type gel after a pyrolysis step, these materials having a solid capacity greater than that of the materials of the prior art. And it has also sought to obtain carbonaceous materials with a graphitic structure. Amorphous carbon has a low conductivity. In the fabrication of capacitance electrodes, the amorphous carbon usually has to be mixed with graphitic carbon or metal particles to increase its conductivity. The advantage of having a partially graphitized structure is therefore to reduce the resistivity of the monolithic carbon obtained by a simple process that does not require mixing.

These materials, their methods of preparation and their uses, are described below.

This objective has been achieved in particular by controlling the porosity to obtain carbonaceous materials whose porosity is different from that of the materials of the prior art.

Porous materials are characterized by the pore size they comprise.

Materials whose pore diameters are less than 2 nm are called microporous. Those with pore diameters between 2 and 50 nm are called mesoporous. Finally, materials whose pores have a diameter greater than 50 nm are called macroporous. The method described in WO 01/19904 leads to essentially mesoporous carbon materials, the choice of this type of pores supposedly making it possible to optimize the mass capacity of the material.

The present invention is based on the observation that a carbonaceous material having a controlled porosity comprising a network of pores, a part of which is mesoporous and whose overall pore volume is reduced, makes it possible to improve the performance of these materials with respect to the prior art when they are used in particular as electrodes. In addition, a large part of the carbonaceous materials of the prior art has a limited mechanical strength that does not allow their machining. To produce electrodes from such materials it is first necessary to reduce them to a powder which is then compressed in admixture with a binder, most often a fluorinated polymer. Since the binder is a non-conductive material, the mass capacity of such electrodes is limited and less than that of the carbonaceous material itself if it were in the form of a monolith.

It has therefore been sought to develop a material which has both a density, and therefore a high mechanical strength, and also a high solid mass capacity. The invention particularly relates to a machinable monolithic carbon material.

In addition, products and processes have been sought which are economical and easy to implement, which can be applied on an industrial scale.

The subject of the invention is polymer gels of controlled porosity, their method of preparation, their use for producing monolithic carbonaceous materials having a high mechanical strength, a high solid mass capacity and therefore a high conductivity. It relates to the electrodes obtained from these carbonaceous materials.

The invention firstly relates to a gel of at least one hydrophilic polymer and at least one latex, the polymer and the latex being co-crosslinked.

Gel means the mixture of a colloidal material and a liquid, which is formed spontaneously or under the action of a catalyst by flocculation and coagulation of a colloidal solution.

The subject of the invention is also a xerogel of at least one hydrophilic polymer and at least one latex, the polymer and the latex being co-crosslinked.

By xerogel is meant a gel whose volatile solvent is gone to give a harder structure and reduced volume.

By hydrophilic polymer is meant either a water-soluble polymer or a water-dispersible polymer. By water-soluble polymer is meant a polymer which can be solubilized in water without addition of additives (surfactants in particular).

A water-dispersible polymer is a polymer capable of forming a dispersion when it is mixed with water.

The water-soluble or water-dispersible nature of a polymer may vary depending on various parameters such as the temperature and the pH of the water.

Among the polymers that can be used in the present invention, mention may be made of the following systems: hydroquinone / resorcinol / formaldehyde, phloroglucinol / resorcinol / formaldehyde, catechol / resorcinol / formaldehyde, chloride of polyvinyl, phenol / formaldehyde, polyamino phenol / benzaldehyde, epoxy phenol / formaldehyde, phenol / benzaldehyde, oxidized polystyrene, polyfurfuryl alcohol, polyvinyl alcohol, polyacrylonitrile, polyvinylidene chloride, cellulose, polybutylene, cellulose acetate, melamine / formaldehyde, polyvinyl acetate , ethyl cellulose, epoxy resins, acrylonitrile / styrene, polystyrene, polyamide, polyisobutylene, polyethylene, polymethyl methacrylate and divinylbenzene / styrene.

Preferably, the polymers used in the invention are polymers of the polyhydroxybenzene / formaldehyde type, that is to say polymers resulting from the polycondensation of at least one monomer of the polyhydroxybenzene type and at least one monomer formaldehyde. of.

This polymerization reaction may involve more than two distinct monomers, the additional monomers being of the polyhydroxybenzene type or not.

The polyhydroxybenzenes that can be used for carrying out the invention are preferably di- or tri-hydroxybenzenes, and advantageously resorcinol (1,3-dihydroxybenzene) or the mixture of resorcinol with another compound chosen from catechol and hydroquinone. , phloroglucinol.

The polymer system, preferably a resorcinol / formaldehyde system, is mixed with a latex.

By latex is meant an aqueous dispersion of an elastomer. Advantageously, according to the invention, a latex with a pH of between 3 and 7.5, advantageously between 5.5 and 7.5, is used.

Preferably, the latex is a nitrogenous latex, that is to say a latex carrying nitrogen functions such as nitrile, azo, amine or amide functional groups.

Advantageously, the nitrogenous latex is characterized by a quantity of nitrogenous monomers which represents between 2 and 90 mol% relative to all the monomers of the latex. These quantities are evaluated on the active ingredient, excluding the water in which the latex is dispersed.

According to the invention, the latex may be a mixture of at least two latexes, a nitrogen latex and a non-nitrogen latex. Advantageously, the nitrogen latex represents from 5 to 100% by weight of the mass of latex.

Among the latices that can be used in the invention, mention may be made of: nitrile rubbers, copolymers of acrylonitrile and butadiene (NBR), copolymers of hydrogenated acrylonitrile and butadiene (HNBR), copolymers of styrene and acrylonitrile ( SAN), terpolymers of acrylonitrile, butadiene and styrene (ABS), terpolymers of styrene, acrylonitrile and styrene (SAS), polyurethane elastomers. These polymers may be in the form of latex or possibly suspension of particles or fibers. They may be partially pre-crosslinked or not and may be in the form of micro-gels. Such products are commercially available under the following references: NIPOL®, LIPOLAN®, PERBUNAN-N®. Hydrogenated NBR (HNBR), Carbox NBR (XNBR) and HXNBR are manufactured by Polymer Latex, Lanxess, Sumitomo and Nippon Zeon. Styrene acrylonitrile (SAN) latices are described in Colloid and

Polymer Science (1975) Vol 253 pp 538-54, SAN Butadiene Styrene core-shell latexes are described in US 6753382.

Other compounds which have a high level of pyrolysis residues such as carbohydrate-based polymers (cellulose, hemicellulose, rayon, polysaccharides) can be added to this gel or xerogel composition.

PolyAcrylonitriles (in the form of suspensions or fibers) or polyimides of amic acid (Torlon ® AiIO sold by Solvay in solution)

In the gel or xerogel of the invention the components are present in the following amounts: The molar ratio of polyhydroxybenzene, designated R, and which is preferably resorcinol, and formaldehyde, designated F, is 0.4 <R / F <0.6, preferably 0.45 <R / F <0.55. Advantageously R / F ≈ 0.5.

The mass ratio of the latex particles (M _L ) to the sum of all the constituents M _L + M _R + Mp, with M _R = mass of polyhydroxybenzene (preferably resorcinol), Mp = mass of formaldehyde, is within the limits following: preferably this ratio is between 1 and 40%, even more preferably between 1 and 30% and advantageously between 2 and 15%, so as to promote the increase in density of the product and therefore its mechanical strength. In this calculation, the mass of the particles of latex M _L is evaluated out of solvent. The mass of the latex particles is calculated by deducting the mass of water from the total mass of the latex dispersion.

The invention further relates to a method for producing a xerogel of at least one hydrophilic polymer and at least one co-crosslinked latex as described above, this method comprising the steps of:

(i) mixing in aqueous solution the monomers used in the composition of the hydrophilic polymer;

(ii) introduction of the latex and mixing;

(iii) adding a basic aqueous solution so as to adjust the pH to a value between 5.5 and 7.5;

(iv) gelation, preferably by heating;

(v) drying. The mixture of the monomers in step (i) is made in the proportions indicated above. The total amount of water (including the water of the latex and optional additives) is chosen to have a mass ratio M _R / M _W ≤ 1.4 with M _R the weight of the polyhydroxybenzene monomers (preferably resorcinol) and Mw the body of water. Optionally it is possible to replace part of the water with a water-miscible solvent such as: methanol, ethanol, isopropanol, acetone, acetonitrile, dimethylformamide, dimethylsulfoxide, dioxane, tetrahydrofuran, hexamethylphosphotriamide. The amount of organic solvent is advantageously less than 20% by weight relative to the total mass of solvent. In conjunction with the introduction of the latex or before step (iii) it is possible to add to the mixture one or more additives which may be chosen from: metal particles, surfactants, mineral or organic fillers, aerogels, viscosifying agents.

Among the metal particles, mention may be made of lithium salts and boron salts.

Among the surfactants, it is possible to choose a cationic, nonionic or anionic surfactant, such as, for example, a quaternary ammonium, an alkyl sulphate or an alkyl sulphonate, or a poly (ethylene oxide).

Among the aerogels, mention may be made of the products described in US Pat. No. 5,508,341, which are in the form of microspheres, or those described in US Pat. No. 4,873,218, which is introduced in the form of a powder.

Among the inorganic or organic fillers, mention may be made of: carbon black, carbon nanotubes, particles of aluminum, nickel, palladium, platinum, hollow glass beads, silica particles coated with metal. Among the viscosifiers, mention may be made of polyethylene glycols.

The basic aqueous solution is advantageously a solution of a mineral base, such as a carbonate. For example, an IM solution of Na ₂ CO _{3 can be used} .

The passage of the pH to a value between 5.5 and 7.5, accompanied or followed by heating, causes the formation of a gel. The heating is preferably at constant volume, preferably under pressure, for example by passing in an oven in a closed container. On an industrial scale, heating can be done under controlled pressure. The duration of the heating is advantageously 24 to 72 hours and the temperature is between 70 and 90 ° C.

The gel thus obtained is then dried. Different drying modes can be envisaged: either by heating under a gas flow so as to promote evaporation (convective drying), or by lyophilization or drying in a supercritical CO ₂ medium.

Preferably one chooses to apply a convective drying which is the least expensive. A xerogel of hydrophilic polymer and latex, preferably a resorcinol-formaldehyde xerogel (RF) / latex, is then obtained.

The process of the invention, unlike the methods of the prior art, makes it possible to obtain xerogels of high density, especially with a density greater than or equal to 1.5.

A xerogel of the invention is distinguished from xerogels of the prior art by the presence of nitrogen functions when the latex is itself carrying nitrogen functions.

Such a material has the appearance of a gel, it is used as an acoustic or thermal insulating material. Another subject of the invention is a carbon material that can be obtained by pyrolysis of the xerogel of the invention.

The carbonaceous material of the invention is a carbon monolith comprising graphite.

Graphite is an allotropic form of carbon characterized by layers of atoms in a hexagonal arrangement.

Advantageously, the carbonaceous material of the invention comprises 0.1 to 20%, preferably 0.5 to 10% by weight of graphite relative to the total mass of the material.

The presence of graphite can be observed by X-ray analysis and in particular, the presence of the following peaks in the X-ray diffraction spectrum measured on a theta-theta configuration diffractometer equipped with a copper anticathode and expressed in Bragg angle terms 2 theta:

Angle 2-theta 26.2 (*) 54.4 (*) 56.1 (**)

** values ± 0.5 ° * value ± 1 °

The carbon spectra obtained have peaks offset from pure graphite. The spectra may also have peaks at 61 °, 75 °, 79 ° and 81.5 ° and these are + - 1 ° values.

The amplitude of the peaks varies in proportion to the amount of graphite present and it is sufficient that the three peaks corresponding to angles less than 60 ° are present to characterize the presence of graphite.

The material of the invention is further characterized by a density of between 0.5 and 1.5, preferably between 0.7 and 1.2. The carbonaceous material of the invention is distinguished from the carbonaceous materials of the prior art by the presence of a network of pores of which at least 10% is mesoporous, preferably more than 20%, and a total pore volume: 0.4 -1 cm ³ / g, preferably

0.5-1 cmVg (measured by BET method or dry impregnation), total BET surface of less than 1000m / g, outer surface of the sample less than 300m / g.

By carbon monolith is meant a material of a single block consisting essentially of carbon atoms.

The material of the invention is characterized by a solid mass capacity greater than or equal to 75 F / g, measured in a molar aqueous solution of H ₂ SO ₄ . The solid mass capacity is the mass capacity of the material measured on the electrolyte filled material. It is measured after immersion of the material in an electrolyte solution. It varies according to the electrolyte used, and in particular it is a function of the density of the electrolyte.

The subject of the invention is also a process for producing a carbonaceous material of the invention, this process comprising a step of heating a xerogel as described above at a temperature of between 700 and 1050 ° C. for duration between 5 and 8 hours.

Advantageously, this heating is operated under a nitrogen atmosphere. This results in a carbonization of all the components of the xerogel. The material undergoes a volume reduction and is in the form of a monolith of high mechanical strength, which allows its machining, in particular to produce electrodes. Such electrodes which do not comprise binder material are, for an equal volume, of capacity greater than that of the electrodes obtained from a powder.

According to a variant of the invention, this carbonaceous material can, if desired, be reduced to powder and used in all usual applications of electroconductive carbons, and especially as a filler in plastics for the production of electroconductive parts. Examples include automobile body parts which must be painted by electrostatic painting.

Another object of the invention is the use of a carbon material as described above to produce electrodes.

EXPERIMENTAL PART I- Synthesis Protocol

1- Preparation of xerogel

The organic gels result from the polycondensation of resorcinol with formaldehyde in the presence of latex particles.

The resorcinol / formaldehyde (R / F) mole ratio and the resorcinol / water (R / W) mass ratio were set at 0.5 and 0.4, respectively. The formaldehyde used is in the form of an aqueous solution (stabilized in the presence of 10 to 15% of methanol), the quantity of water it contains is taken into account in the total volume of water present in the formulation, therefore in the ratio R / W. Resorcinol (10,204 g, supplied by the company Acros, quality 98%) is first dissolved in distilled water. The aqueous formaldehyde solution (Riedel de Haën, in 36.5% solution) is then added: 14.944 g.

The content of latex particles added (Latex Perbunan® RN-2890) to the system is defined by the ratio:

This calculated mass represents the mass of latex particles, and not the overall mass of latex solution. The following three latex contents were tested: 5, 10 and 25%.

The pH is then adjusted to pH 5.5 or 6.5 by adding a few drops of a solution of sodium carbonate (5M and / or IM).

The final mixture is placed in test tubes, which are then sealed and placed in an oven at 90 ° C for 1 day. The gels obtained are washed by immersing them in distilled water for 2 hours, so as to remove the traces of reagents still present. They are then placed in a tubular oven for 6 hours at 85 ° C., and under nitrogen

(10 L / min) for a duration that can vary from 1 day to 7 days.

2- Preparation of the carbonaceous material

The dried gels (xerogels of RF + latex) are subjected to pyrolysis at 800 ° C. under a nitrogen flow of 10 L / min. Each product is characterized by its latex content and its gelation pH.

H- Measurement of energy capacities and densities

The capacities of the carbonaceous materials of the invention have been characterized within an electrochemical device with three electrodes, in particular by chronopotentiometry (1 A / g in an aqueous medium and 0.5 A / g in an organic medium). Their capacity was measured and produced a charge-discharge curve for each of these materials in an aqueous electrolyte and in a non-aqueous electrolyte. The charge and discharge curves were obtained by applying a constant current pulse and following the voltage response over time, using a VersaStat (EG & G) potentiometer with a computer interface (IBM). The EG & G Model 270 software was used for wave function application and data acquisition. The capacity has been measured in farads (F) and the resistance of the cell in ohms from the charge / discharge curve using conventional procedures and the equation: C = ItZ (V ₁ -V ₂ ).

The aqueous electrolyte is a solution of 1M H ₂ SO ₄ , while the organic electrolyte is a solution of sodium perchlorate in acetonitrile: NaClO ₄ 2M + ACN.

The working electrode consists of a platinum grid in which is placed the monolithic carbon to be analyzed (mass and surface known). The counter electrode used is platinum, the reference electrode is a saturated calomel electrode in an aqueous medium, and an electrode with potential limits in an organic medium. The energy densities were measured according to the protocol described in JR Miller and AF Burke "Electric vehicle capacitor test procedure manual" 1994 DOE / ID 1049, p.21-25.

IH- Performance Comparison

We distinguish the specific capacity measured with respect to the dry mass of carbon, which simply gives an idea of the performances, and the specific capacity estimated with respect to the real mass involved, namely the mass of carbon impregnated with electrolyte (capacities actual or actual).

1 - Capacity in aqueous and organic media

The estimated capacity relative to the dry mass of carbon, then compared to the mass filled with sulfuric acid IM, for the carbon from the RF + Latex 5% system (pH 6.5) is compared with that of the carbon from the RF equivalent equivalent (same ratio R / F and R / W and even pH but no latex). The results are summarized in Table 1.

The two carbons have an identical R / W ratio, but their capacitive properties are different, the latex plays on the textural properties that govern the capacitive behavior.

Table 1: Actual and specific capacities with respect to the porous volume of dry carbon. Measured by immersion of the carbon electrode in H ₂ SO ₄ IM. There is an increase in the density and volume capacity of the carbon xerogel initially containing latex.

Once filled with electrolyte, the RF + Latex system (5%) is more interesting because of its smaller pore volume which reduces the amount of useful electrolyte.

In Table 2 are presented the results of the characteristics in organic medium.

Table 2: Actual and specific capacities with respect to the porous volume of dry carbon. Measured by immersion of the carbon electrode in ACN + 2M NaClO ₄ .

In this second example, the capacity of the carbon derived from the RF + Latex system with respect to the pore volume is improved compared with that of its counterpart without latex. The carbon from the RF + Latex system is therefore much more efficient.

2- Evolutions of the textural and capacitive properties (H ₂ SO ₄ IM) according to the initial content of latex in the gels

The same protocol is followed as in I, by varying the amount of latex: 0% (RF system); 5% (RF-L0.05 system); 10% (RF-LO system, 1) and the gelation pH.

The results are shown in Tables 3 and 4. a- Materials made at pH 6.5

Table 3: Evolution of capacities according to the initial latex content at pH 6.5. b- Materials made at pH 5.5

Table 4: Evolution of the volume capacities (calculated with respect to the mass of dry carbon) as a function of the initial latex content at pH 5.5.

In the two preceding tables, it can be seen that the density always increases with the initial content of latex and the same for the volume capacity. The presence of the latex causes a reduction of a part of the "dead" porous volume (where no role is played by the electrolyte in the electrochemical processes), in parallel with obtaining good capacitive performances: there is therefore a optimization of supercapacitive properties per unit of pore volume

IV Measurement of the Mesoporous Volume and the BET Surface: The specific surface and the pore size distribution were analyzed by nitrogen adsorption on a Micromeritics Gemini apparatus and by mercury porosimetry on a Micromeritics Autopore II 9220 apparatus.

These measurements are made on materials made at pH 6.5

Table 5: Specific surface area and mesoporous volume of different carbons

V- RX diffractograms of the different xerogels of carbons A RX PW 1830 Panalytical apparatus is used

- Detector type: linear

- Operating voltage and intensity: 135 W 45 kv, 30 mA

- RX source type: Cu

An additional carbonaceous material is prepared from a high nitrile content latex with 5% Synthomer 6617 latex (40% ACN) prepared at pH 6.5.

Figures:

- Figure IA: X-ray diffractogram of carbon from the RF system prepared at pH = 5.5. - Figure IB: X-ray diffractogram of carbon from the system

RF-latex (25%) prepared at pH = 5.5.

- Figure 2 A: X-ray diffractogram of carbon from the RF system prepared at pH = 6.5.

- Figure 2B: X-ray diffractogram of the carbon from the RF-latex system (5%) prepared at pH = 6.5.

- Figure 2C: X-ray diffractogram of carbon from the system

RF-latex (10%) prepared at pH = 6.5.

FIG. 2D: X-ray diffractogram of the carbon derived from the Latex RF system (5%) prepared at pH 6.5 with a latex with a high nitrile group content (40% ACN Synthomer 6617)

Carbon xerogels from conventional RF gels are fully amorphous carbons (Figures 1A and 2A). We can observe on diffractograms IB, 2B and 2C that the initial presence of latex generates graphitic zones within the carbons, there is indeed appearance of characteristic lines on the spectra. These are the carbon residues from the latex particles that are organized in the form of sheets. VI - Comparative example:

A xerogel and a carbon material are prepared according to the same protocol as above, replacing the latex with a styrenic latex. A - Preparation of the xerogel:

The gel is derived from the polycondensation of resorcinol with formaldehyde in the presence of latex particles.

The resorcinol / formaldehyde molar ratio (RJF) and the resorcinol / water mass ratio (R / W) were set at 0.5 and 0.4, respectively.

The formaldehyde used is in the form of an aqueous solution (stabilized in the presence of 10 to 15% of methanol), the quantity of water it contains is taken into account in the total volume of water present in the formulation, therefore in the ratio R / W.

Resorcinol (30.62 g, supplied by the SAFC company, 98% grade) is first dissolved in distilled water. The aqueous solution of formaldehyde (Merck, in 37% solution) is then added: 50.05 g The content of added latex particles (Latex Synthomer® 9076 styrenic latex) to the system is defined by the ratio:

M _L M _L + M _R + M _F

This calculated mass represents the mass of latex particles, and not the overall mass of latex solution. The test is carried out with a latex content of 5%. The pH is then adjusted to pH 6.5 by adding a few drops of a solution of sodium carbonate (1M).

The final mixture is placed in test tubes, which are then sealed and placed in an oven at 90 ° C for one day. The gels obtained are washed by immersing them in distilled water for 2 hours, so as to remove traces of reagents still present.

They are then placed in an oven for 6 hours at 85 ° C. B- Preparation of the carbonaceous material

The dried gels (RF Xerogels + styrenic latex) are subjected to pyrolysis at 800 ° C. under a flow of nitrogen 1L / min. C - Results: In the table below, the properties of the product obtained according to the process of the invention are compared with 0.05% of nitrogen latex and at pH 6.5 (RF-L0.05) and the product obtained from the latex. styrenic (0.05%) at pH 6.5 (RF-LStyr 0.05).

Claims

1. Carbonaceous material obtainable by pyrolysis of a xerogel of at least one hydrophilic polymer and at least one nitrogenous latex, the polymer and the latex being co-crosslinked, characterized in that it is in the form of a carbon monolith having 0.1 to 20% graphite, by weight relative to the total mass of the material.

Carbonaceous material according to claim 1, characterized by the presence of at least 3 of the following peaks in the X-ray diffraction spectrum measured on a theta-theta-shaped diffractometer equipped with an anti-copper cathode and expresses in terms of Bragg 2 theta angle:

Angle 2-theta 26.2 (•) 54.4 (*) 56.1 (**)

** values ± 0.5 ° * value ± 1 °

3. Carbonaceous material according to claim 1 or claim 2, which comprises a pore network of which at least 10% is mesoporous and a pore volume of between 0.4 and 1 cm ³ / g.

4. Carbonaceous material according to any one of the preceding claims, which has a solid mass capacity greater than or equal to 75 F / g, measured in a molar aqueous solution of H ₂ SO ₄ .

5. Process for producing a carbonaceous material according to one of claims 1 to 4, this process comprising a step of heating a xerogel of at least one hydrophilic polymer and at least one nitrogen latex at a temperature of between 700 and 1050 ° C for a period of between 5 and 8 hours.

The method of claim 5, wherein the xerogel is obtained by the method comprising the steps of:

(i) mixing in aqueous solution the monomers used in the composition of the hydrophilic polymer;

(ii) introduction of the latex and mixing;

(iii) adding a basic aqueous solution so as to adjust the pH to a value between 5.5 and 7.5;

(iv) gelation; (v) drying.

7. The method of claim 6, wherein the total amount of water is chosen to have a mass ratio M _R / M _W ≤ 1.4, with M _R mass polyhydroxybenzene monomers and Mw water mass.

8. Process according to any one of claims 6 and 7, wherein the gelation is by constant volume heating, preferably under pressure.

The method of any one of claims 6 to 8, wherein the gel is dried by convective drying.

10. Gel suitable for use in the process according to one of claims 5 to 9, at least one hydrophilic polymer of the polyhydroxybenzene / formaldehyde type and at least one nitrogen-containing latex, the polymer and the latex being co- crosslinked, in which the mass ratio of the latex particles (M _L ) to the sum of all the constituents M _L + M _R + M _F , with M _R = mass of polyhydroxybenzene, M _F = mass of formaldehyde, is included in the following limits:

11. The gel of claim 10, wherein the polyhydroxybenzene is selected from resorcinol and a mixture of resorcinol with another compound selected from catechol, hydroquinone, phloroglucinol.

12. Gel according to any one of claims 10 and 11 wherein the nitrogen latex comprises a quantity of nitrogenous monomers which represents between 2 and 90 mol% relative to all the monomers of the latex.

13. Gel according to any one of claims 10 to 12 wherein the latex is selected from: nitrile rubbers.

14. Gel according to any one of claims 10 to 13 wherein the molar ratio of polyhydroxybenzene, designated R, and formaldehyde, designated F, is 0.4 <R / F <0.6, preferably 0.45 < R / F <0.55.

15. Use of a carbon material according to any one of claims 1 to 4 for producing electrodes.

16. Use of a carbon material according to any one of claims 1 to 4 as a filler in plastics for the production of electroconductive parts.