An electrochemical supercapacitor in all solid configuration using perfluorosulfonate ionomer as polymer electrolyte has been successfully realized. Electrodes of supercapacitor have been prepared using activated carbon material and Nafion ionomer. This latter had the double function of binder and electrolyte. Nafion 115 membrane has been used as electrolyte separator in the preparation of small scale supercapacitors. The capacitance performance of these devices is comparable or better than traditional systems, which use sulfuric acid as electrolyte. The electrochemical evaluation of studied supercapacitor has been carried out by cyclic voltammetry, dc charge/discharge measurements and electrochemical impedance spectroscopy. A capacitance of 90 F/g (referred to the weight of active carbon material in the electrode) has been obtained with carbon having surface area (SA) of about 1000 m(2)/g and, a capacitance of 130 F/g with activated carbon having SA of 1500 m(2)/g. These interesting results have been tentatively explained with an optimal configuration of electrodes and with the concomitant beneficial effects on the carbon pores of adsorbed water and Nation distribution, which produce low distribute resistance in the carbon composite electrodes. (C) 2004 Elsevier Ltd. All rights reserved.