Synthesis and characterization of MnO2-Based mixed oxides as supercapacitors

The development of a high-power-density supercapacitor with a high energy density is one of the critical requirements for high-power-demanding electric devices such as an electric vehicle. Mn/Pb and Mn/Ni mixed oxide were prepared at ambient temperature by reduction of KMnO4 with Mn, Pb, and Ni salts. This low-temperature approach provides amorphous structure of the active material. The specific capacitance of pure MnO2 was estimated to be 166 F/g and increased to 210 and 185 F/g for Mn/Ni and Mn/Pb oxides, respectively. The carbon loading was optimized at 20 wt%. Based on a single electrode, the Mn/Ni mixed oxide showed a high rate capability of 3.12 Wh/kg at constant power discharge of 1 kW/kg.