Tin oxide (SnO2) powders with a particle size of similar to20 nm were synthesized by a gas condensation method. Ruthenium oxide was loaded by an incipient-wetness method, in which an aqueous solution of RuCl3 was added to the manufactured SnO2 powder in an amount that was just sufficient to wet completely the powder. And then, the resulting solution was obtained after freeze-drying to synthesis the smallest particle. The as-synthesized SnO2 powder with 1.5 wt.% ruthenium oxide (RuO2) exhibited well-developed facets and had a very uniform particle size. The first discharge capacity was lower than comparing to commercial powder because of forming the second phase, but showed good cyclability. A maximum specific electrode capacitance of similar to20 F/g and a maximum specific power of similar to80 W/kg were achieved by manufactured SnO2 With 1.5 wt.% RuO2. This result indicated that the synthesized SnO2-RuO2 composite powder of nano-size scale is candidate for use in fabricating monolithic hybrid batteries using suitable electrolyte as well. (C) 2004 Elsevier Ltd. All rights reserved.