Electrochemical properties of TiO(x)/rGO composite as an electrode for supercapacitors

Transition metal oxides are known as the active materials for capacitors. As a class of transition metal oxide, Magnéli phase TiO(x) is particularly attractive because of its excellent conductivity. This work investigated the electrochemical characteristics of TiO(x) and its composite with reduced graphene oxide (rGO). Two types of TiO(x), i.e. low and high reduction extent, were employed in this research. Electrochemical impedance spectroscopy revealed that TiO(x) with lower reduction extent delivered higher electro-activity and charge transfer resistance at the same time. However, combining 10% of low-reduction state TiO(x) and rGO using a simple mixing process delivered a high specific capacitance (98.8 F g(−1)), which was higher than that of standalone rGO (49.5 F g(−1)). A further improvement in the specific capacitance (102.6 F g(−1)) was given by adding PEDOT:PSS conductive polymer. Results of this research gave a basic understanding in the electrochemical behavior of Magnéli phase TiO(x) for the utilization of this material as supercapacitor in the future.