Composite electrodes for supercapacitors were prepared by electropolymerization of polyaniline (PANI) on the surface of activated-porous carbons. The surface morphology and the chemical composition of composite electrodes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of electrodes and the capacitive behavior of the resulting capacitors were systematically studied using cyclic voltammetry (CV), ac impedance and constant current charge-discharge tests. The specific capacitance of PANI-carbon composite electrode was exhibited as high as 160 F/g, in comparison with a value of 95 F/g for the bare-carbon (BC) electrode. An increase in capacitance more than 60% has been achieved, that identifies the significant contribution of pseudocapacitance from PANI on the overall capacitance. (C) 2003 Elsevier Science B.V. All rights reserved.