Electrochemical parameters of the nanoporous carbide-derived carbon/organic electrolyte have been studied by cyclic voltammetry and electrochemical impedance spectroscopy. The gas adsorption measurements have been used for evaluating the specific surface area, pore size distribution and porosity as the essential parameters influencing the double layer performance of carbon. The region of ideal polarizability, values of series and parallel resistance, capacitance and other important electrical double layer parameters were established. It was shown that specific capacitance of typical nanoporous carbon derived from titanium carbide is in the range of 70-90 F cm(-3) or 100-130 F g(-1) and it depends on the synthesis conditions. The influence of the electrolyte solvent to the capacitance was insignificant, although acetonitrile was advantageous with respect of smaller viscosity. (C) 2005 Elsevier Ltd. All rights reserved.