Capacitive properties of RuO2 and Ru–Co mixed oxide deposited on single-walled carbon nanotubes for high-performance supercapacitors

Abstract Composite electrodes for use in redox supercapacitors were prepared by electrochemical deposition of RuO 2 or the co-deposition of Ru–Co mixed oxides on the surface of single-walled carbon nanotubes. Electrodes coated with the Ru–Co mixed oxide [Ru (13.13 wt%) and Co (2.89 wt%)] or RuO 2 , exhibited a similar specific capacitance (∼620 F g −1 ) at low potential scan rates (10 mV s −1 ). However, at higher scan rates (500 mV s −1 ) the mixed metal oxide electrode showed superior performance (570 F g −1 ) when compared to the RuO 2 electrode (475 F g −1 ). This increase in capacitance at high scan rates is attributed to the role of the Co in providing enhanced electronic conduction.