Abstract: An electrochemical capacitor includes a first electrode connected to a positive terminal of a power source during the charge of the electrochemical capacitor and a second electrode connected to a negative terminal of a power source during the charge of the electrochemical capacitor. The first and the second electrodes each have a carbon material. The electrochemical capacitor further includes a porous separator to separate the first and second electrodes and to be impregnated with an almost neutral aqueous electrolyte situated between the two electrodes. The neutral aqueous electrolyte has a salt formed by a metallic cation and an anion.

Abstract: A method of producing a silicon/carbon composite material which includes the following successive steps: providing a silicon/polymer composite material from silicon particles and a carbonaceous polymer compound, precursor of carbon and able to be cross-linked, performing at least partial cross-linking of the polymer of the silicon/polymer composite material so as to obtain a cross-linked silicon/polymer composite material, the polymer having a cross-linking rate greater than or equal to 50% and, pyrolyzing the cross-linked silicon/polymer composite material until said silicon/carbon composite material is obtained.

Abstract: The invention relates to a method for manufacturing activated carbon from tobacco leaves by simultaneous carbonization and self-activation in an inert gas environment. The activated carbon produced by this new method has a specific surface area from 600 to 2000 m2 g?1, preferably 1700 m2 g?1, and has an extensive amount of ultramicropores and mesopores, wherein the ratio of the micropore volume to the mesopore volume is at minimum of 3:1, up to 10:1, preferably 4:1. The average pore size (L0) is in the range of 0.55-1.3 nm, preferably 0.8-1.2 nm, with a total pore volume of 0.2 to 1.25 cm3 g?1. The invention also refers to an electrode comprising the activated carbon having the above properties as well as the electrochemical capacitor with such an electrode.

Abstract: A method is provided for developing a hybrid supercapacitor. The method includes the use of a lithium salt of the electrolyte to carry out the intercalation/insertion of the lithium at the negative electrode but by greatly increasing the concentration of lithium ions of the electrolyte order to subsequently accept a depletion. As the depletion in ions has an impact on the conductivity, the amount and the concentration of the electrolyte are chosen in order to make it possible to accept this depletion white retaining a conductivity of the electrolyte compatible with a powerful system for storage of energy. A portion of the Li+ ions present in the electrolyte is used to form the passivation layer and the compound for intercalation/insertion Li˜0.5C6 at the negative electrode.

Abstract: A cyclic process is provided for reversible adsorption of emerging pollutants or micropollutants for depolluting a contaminated aqueous medium. The process is carried out without oxygen-containing gas, and without the provision of radical initiators, and includes a plurality of cycles, each cycle having the following steps: a. the adsorption of the emerging pollutants and micropollutants contained in the aqueous medium onto an activated carbon felt electrode by bringing the contaminated aqueous medium into contact with the activated carbon felt electrode making it possible to adsorb the emerging pollutants and micropollutants contained in the aqueous medium onto the activated carbon felt electrode; and b.

Abstract: A method of producing a silicon/carbon composite material which includes the following successive steps: providing a silicon/polymer composite material from silicon particles and a carbonaceous polymer compound, precursor of carbon and able to be cross-linked, performing at least partial cross-linking of the polymer of the silicon/polymer composite material so as to obtain a cross-linked silicon/polymer composite material, the polymer having a cross-linking rate greater than or equal to 50% and, pyrolysing the cross-linked silicon/polymer composite material until said silicon/carbon composite material is obtained.

Abstract: The invention relates to a method for developing a hybrid supercapacitor, said method including: at least a step of assembling together a negative electrode, made of at least one non-porous carbon material, and a positive electrode, made of at least one porous carbon material, said electrodes being separated from each other by means of at least one separator impregnated with a liquid electrolyte containing at least one lithium salt dissolved in at least one solvent; and then at least one first charging step, wherein said method is characterized in that: a) the lithium-ion concentration in the liquid electrolyte, before the first charging step, is greater than or equal to 1.

Abstract: An electrochemical capacitor includes a first electrode connected to a positive terminal of a power source during the charge of the electrochemical capacitor and a second electrode connected to a negative terminal of a power source during the charge of the electrochemical capacitor. The first and the second electrodes each have a carbon material. The electrochemical capacitor further includes a porous separator to separate the first and second electrodes and to be impregnated with an almost neutral aqueous electrolyte situated between the two electrodes. The neutral aqueous electrolyte has a salt formed by a metallic cation and an anion.

Abstract: A composite suitable as a charge-storing material for electrochemical capacitors contains carbon nanotubes and a carbonaceous materiel. The carbonaceous material is the carbonization residue of a biopolymer or seaweed rich in heteroatoms. Wherein the carbonization residue of the biopolymer or seaweed is electrically conductive and has a heteroatom content as detected by XPS of at least 6%.

Abstract: A carbon material suitable for the preparation of electrodes for electrochemical capacitors is obtained by single-stage carbonization of biopolymers with a large content of heteroatoms. Neither addition of an activating agent during carbonization nor subsequent gas phase activation is necessary. Several biopolymers which are available by extraction from seaweed are suitable precursors. Alternatively, the seaweed containing such biopolymers is carbonized directly.

Abstract: An electrolytic capacitor (1) includes a first electrode (2) and a second electrode (3) each including carbon and an aqueous electrolyte (4) situated at the interface of the two electrodes. The carbon surface of the first electrode (2) has an atomic degree of functionalization which is at least twice that of the carbon surface of the second electrode (3).

Abstract: An electrolytic capacitor (1) includes a first electrode (2) and a second electrode (3) each including carbon and an aqueous electrolyte (4) situated at the interface of the two electrodes. The carbon surface of the first electrode (2) has an atomic degree of functionalization which is at least twice that of the carbon surface of the second electrode (3).

Abstract: A composite suitable as a charge-storing material for electrochemical capacitors contains carbon nanotubes and a carbonaceous materiel. The carbonaceous material is the carbonization residue of a biopolymer or seaweed rich in heteroatoms. Wherein the carbonization residue of the biopolymer or seaweed is electrically conductive and has a heteroatom content as detected by XPS of at least 6%.

Abstract: A carbon material suitable for the preparation of electrodes for electrochemical capacitors is obtained by single-stage carbonization of biopolymers with a large content of heteroatoms. Neither addition of an activating agent during carbonization nor subsequent gas phase activation is necessary. Several biopolymers which are available by extraction from seaweed are suitable precursors. Alternatively, the seaweed containing such biopolymers is carbonized directly.

Abstract: The invention relates to a hydrogen-air secondary cell that finds application for supplying electrical energy to systems of electric cars and portable equipment such as telephones, photographic equipment and laptops. The hydrogen-air secondary cell is characterized in that it contains an electrode made of a material capable of high hydrogen sorption capacity through the electrochemical decomposition of water, connected to the negative pole, disposed between conventional air diffusion electrodes, with at least one auxiliary electrode with lowered oxygen release overpotential being positioned between the air electrodes and the hydrogen sorption electrode, and connected electrically to an auxiliary pole of the cell and charging the cell, the electrodes being kept apart by a separator.

Abstract: The present invention concerns a process for the mass production of carbon nanotubes and particularly a process for selectively producing multiwalled carbon nanotubes.

Abstract: The invention relates to an efficient and non-damaging method for opening carbon nanotubes, characterized in that it consists of two oxidation stages, the first in liquid phase in a concentrated acid, the second in gaseous phase.

Abstract: The present invention concerns a process for the mass production of carbon nanotubes and particularly a process for selectively producing multiwalled carbon nanotubes.

Abstract: The carbon fibers present a mean lattice surface spacing (d002) not less than 0.36 nm, preferably 0.38 nm, at a crystallite size such that the mean height (Lc) lies in the range 0.7 nm to 0.3 nm and the mean width (La) lies in the range 2 nm to 6 nm, and it presents total porosity lying in the range 10% to 30%. The electrode is preferably a rayon-precursor carbon cloth and it constitutes the anode (10) of a secondary cell having a cathode (20) which includes lithium enabling lithium ions to be inserted and de-inserted, and an electrolyte (30).

Abstract: A ceramic material based on Sialon, in particular on .beta.'-Sialon is obtained by reducing an aluminosilicate precursor by means of a gas phase comprising a mixture of hydrogen and nitrogen doped with a gaseous carbon compound. The gaseous carbon compound is a gas containing carbon in combined form, e.g. an alkane, and its concentration by volume in the gas is less than 3%. The method is particularly suitable for forming Sialon-based coatings on substrates that are solid or fibrous. For composite materials constituted by a fiber preform densified by means of a matrix, the method can be used to form an interphase coating on the fibers of the preform prior to densifying the preform, or the method can be used to form a matrix that is based on Sialon.