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.