SnO2-Modified MnO2 Electrode Materials for Electrochemical Capacitor

MnO2 was prepared by simple redox reaction and SnO2 was synthesized by sol-gel method. The structure and surface morphology of as-prepared MnO2 and SnO2 were characterized by XRD and SEM, respectively. According to different weight ratio, as-prepared samples were mixed as electrode materials. The corresponding electrochemical characteristics were evaluated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in KCl solution. It was shown that the as-prepared composite electrode had excellent properties in capacitance, and the specific capacitance of single electrode with 10 wt% SnO2 was up to 302.1 F g-1 at the current density of 5 mA/cm2. Furthermore, the composite electrode exhibited a very stable capacitance after repeating cycles compared to that of the separate MnO2 or SnO2 electrode. It was concluded that the doped SnO2 had positive effect on the electrochemical performance of MnO2. The composite materials of them could be potential and cost-effective electrode for electrochemical capacitor.