Abstract:
The invention relates to a gelled carbon-based composition forming an organic polymeric monolithic gel which is suitable for forming an aerogel by drying, to uses and to a process for preparing this carbon-based composition. The invention applies especially to the production of such gels having a very low density and a very low heat conductivity, a very high specific surface area and a satisfactory compression strength, for their use as thermal superinsulators or as carbon-based electrode precursors of supercondensers.A composition according to the invention comprises a resin at least partly derived from polyhydroxybenzenes H and from formaldehyde(s) F, said polyhydroxybenzenes comprising at least one unsubstituted poly-hydroxybenzene R′ and at least one polyhydroxybenzene substituted with one or two alkyl groups.This composition is such that said polyhydroxybenzenes comprise several said unsubstituted polyhydroxybenzenes R and R′ and in that the composition comprises a water-soluble cationic polyelectrolyte P.
Abstract:
The invention relates to a gelled aqueous polymer composition for forming, by means of drying then pyrolysis, a monolithic porous carbon, to a pyrolysed carbonated composition produced by the drying, followed by the pyrolysis, of said gelled composition, to a porous carbon electrode for a supercapacitor comprising said pyrolysed composition, and to methods for producing said respectively gelled and pyrolysed compositions. A gelled composition according to the invention, produced from the polycondensation of polyhydroxybenzene(s) and hexymethylenetetramine, is such that the hexymethylenetetramine comprised therein represents a mass fraction of between 7% and 15% inclusive. Said gelled composition is produced by a) polycondensation in an aqueous solvent of the polyhydroxybenzene(s) and hexymethylenetetramine, followed by b) gelling by heating of said polycondensate.
Abstract:
The invention relates to a gelled, crosslinked and non-dried aqueous polymeric composition capable of forming a non-monolithic organic aerogel by drying, to this aerogel, to a non-monolithic porous carbon resulting from a pyrolysis of this aerogel, to an electrode based on this porous carbon, and to a process for preparing this composition and this aerogel. The invention applies in particular to supercapacitors. A gelled, crosslinked and non-dried composition according to the invention, which is based on a resin resulting at least partly from a polycondensation of polyhydroxybenzene(s) R and formaldehyde(s) F and which comprises at least one water-soluble cationic polyelectrolyte P, is such that the composition is formed from an aqueous dispersion of microparticles of a shear-thinning physical gel that is crosslinked in an aqueous medium. The composition not yet crosslinked is in particular prepared by dilution of a prepolymer that forms this gel in an aqueous solvent in order to form the aqueous dispersion of microparticles of said gel.