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 F g−1, which represents a three-fold increase compared with the blank xerogel and a specific RuO2 capacitance of 710 F g−1 RuO2, is obtained with a RuO2 loading of 1.4 wt.% and by calcination at 200 °C. Higher loadings presumably result in a homogeneous nucleation upon drying, which causes severe reduction in the total surface area of the RuO2 crystallites.