A supercapacitor electrode was synthesized by cyclic voltammetric plating of RuO2 onto a porous and highly conductive, Sb (6 mol %)-doped SnO2 particulate substrate that possessed a large surface area (75 m(2)/g). A specific capacitance of 930 F/g for the RuO2 component in 1 M H2SO4(aq) and an overall specific energy of similar to0.5 Wh/kg at a specific power greater than or equal to 1.5 kW/kg were achieved by an optimized crystallization protocol (150degreesC). Comparative studies demonstrated that this composite electrode exhibited a far superior performance to electrodes having RuO2 similarly plated onto either smooth Ti or porous conductive carbon black. (C) 2003 The Electrochemical Society.