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

Composite electrodes for use in redox supercapacitors were prepared by electrochemical deposition of RuO2 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 RuO2, xhibited a similar specific capacitance (similar to 620Fg(-1)) at low potential scan rates (10mVs(-1)). However, at higher scan rates (500mVs(-1)) the mixed metal oxide electrode showed superior performance (570Fg(-1)) when compared to the RuO2 electrode (475Fg(-1)). This increase in capacitance at high scan rates is attributed to the role of the Co in providing enhanced electronic conduction. (C) 2009 Elsevier B.V. All rights reserved.