Preparation and optimization of RuO2-impregnated SnO2 xerogel supercapacitor

A Sb (6 mol%)-doped SnO2 xerogel impregnated with RuO2 nanocrystallites is prepared via an incipient-wetness method and is optimized for its electrochemical capacitance in aqueous 1 M KOH electrolyte by adjusting the calcination temperature and the RuO2 loading, The electrode capacitance does not increase monotonically with increasing RuO2 loading. A maximum electrode capacitance of 15 Fg(-1), which represents a three-fold increase compared with the blank xerogel and a specific RuO2 capacitance of 710 Fg(-1) RuO2, is obtained with a RuO2 loading of 1.4 wt.% and by calcination at 200 degreesC. Higher loadings presumably result in a homogeneous nucleation upon drying, which causes severe reduction in the total surface area of the RuO2 crystallites. (C) 2002 Elsevier Science B.V. All rights reserved.