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.