Chemical Synthesis and Electrochemical Performance of Hausmannite Mn3O4/rGO Composites for Supercapacitor Applications

A simple approach for the preparation of hausmannite Mn3O4/rGO composites for supercapacitor electrodes is reported. The individual Mn3O4 and rGO phases were synthesized by dry ball milling and the modified Hummers method, respectively. Subsequently, composites with different Mn3O4/rGO ratios were prepared by ultrasonic treatment. The physicochemical and electrochemical properties were characterized. In addition, the electrochemical performance of an electrode supercapacitor was tested in two different configurations: a three-electrode cell and a symmetric supercapacitor (SSC). The three-electrode cell showed an excellent specific capacitance of 525 F center dot g-1 at 5 mV center dot s-1. To investigate practical applications, Mn3O4/rGO were used as electrodes to construct symmetric supercapacitors. The composite with a volume ratio of Mn3O4:rGO of 7:3 showed a remarkable stability of 85% after 5000 charge-discharge cycles. This SSC also delivered an energy density of 6.25 W center dot h center dot kg- 1 at a power density of 125 W center dot h center dot kg- 1 with a current density of 0.5 A center dot g- 1, and 5.36 W center dot h center dot kg- 1 at a power density of 500 W center dot h center dot kg- 1 and 2 A center dot g- 1.