Capacitance properties of ordered porous carbon materials prepared by a templating procedure

The electrochemical performance of carbon materials with a highly ordered nanoporous structure is investigated in two-electrode supercapacitors. The materials were prepared by a templating procedure using a silica matrix (type MCM-48 or SBA-15) with an organized porosity in which carbon was inserted, either by chemical vapor decomposition of propylene or by impregnation with a sucrose solution followed by carbonisation. After the removal of silica, a micro-mesoporous carbon residue is recovered which displays an uniform pore size distribution. Such a well-defined nanostructure is interesting for a fundamental study of the double layer capacitance behavior. The performance of supercapacitors built with electrodes prepared from the templated carbon was tested in acidic, alkaline and organic electrolyte solutions. High values of capacitance in aqueous and organic media were obtained with a rectangular shape of the voltammograms over a wide range of scan rates indicating a quick charge propagation. Especially, the templated carbons prepared by the impregnation of sucrose in MCM-48 display high capacitance values due to the formation of an adequate micro-mesoporous network during their formation. A marked shift of capacitance drop at higher values of frequency is clearly observed for the materials rich in mesopores; the mesopores make easier the diffusion of the ions to the active surface. (C) 2003 Elsevier Ltd. All rights reserved.