Preparation and electrochemical capacitance of high surface area TiO2–RuO2 aerogels

Abstract High surface area RuO2–TiO2 composite aerogels with different RuO2 concentrations were prepared through a modified non-alkoxide sol-gel route, followed by CO2 supercritical drying and evaluated as electrodes for energy storage devices. The TiO2 aerogels were synthesized via an ethanolic solution of TiCl3 with RuO2 being incorporated with an acidic solution of RuCl3.xH2O in different concentrations to obtain composite aerogels with 10 and 15 wt% RuO2. The aerogels were heat treated in different temperatures and characterized to evaluate the effect of the RuO2 on their specific capacitance. A specific capacitance of 25 F/g was obtained from TiO2–RuO2 aerogels containing with 10 wt% RuO2. Aerogels annealed at 450 °C exhibited lower electrochemical capacitance than the as-synthesized ones. Despite the relatively low specific capacitance, TiO2–RuO2 aerogels exhibited a remarkably high specific surface area of 316 m2/g, which make them useful for several other applications.