Effect of Electronic Resistance and Water Content on the Performance of RuO[sub 2] for Supercapacitors

Abstract

Hydrous ruthenium oxide, RuO2∙H2ORuO2∙H2O , was prepared according to a sol-gel process and annealed at different temperatures. The importance of high electronic conductivity for high capacity in aqueous 3M3M H2SO4H2SO4 was revealed through two approaches. The electronic resistivity of RuO2∙H2ORuO2∙H2O measured in situ as a function of the electrode potential shows a marked increase toward low potentials. This trend is more pronounced for the low-temperature annealed oxide (T⩽150°C)(T⩽150°C) where it results in a limitation of the capacitance at E<0.4VET=300°CT=300°C , Z300), the other with optimum capacity ( T=150°CT=150°C , Z150). The observed specific capacity increase of hydrous RuO2RuO2 in the mixture from 738to982F∕g738to982F∕g is attributed to an improvement of the electronic pathway along the particles of high-temperature-treated RuO2RuO2 (Z300) toward the high-capacity Z150 particles.