Chemically prepared polyaniline is tested for its supercapacitive behaviour in an aqueous electrolyte of 1.0 M H2SO4. In order to improve the cycleability of the polyaniline electrode, it is made into a composite with Nation. This composite electrode shows improved cycleability and higher specific capacitance compared with a pure polyaniline electrode. It is therefore used as a matrix for the electrochemical deposition of hydrous RuO2. The resulting ternary composite electrode has a high specific capacitance of 475 F g(-1) at 100 mV s(-1) and 375 F g(-1) at 1000 mV s(-1) in the voltage range of -0.2 to 0.8 V versus Ag/AgCl. All three types of electrode are characterized by cyclic voltammetry and impedance anaylsis. (c) 2007 Elsevier B.V. All rights reserved.