Manganese oxide-carbon composite as supercapacitor electrode materials

Nano-sized manganese oxide (Mn₂O₃) was incorporated homogeneously in templated mesoporous carbon to prepare Mn₂O₃-carbon nanocomposites, which were used as supercapacitor electrodes. Cyclic voltammetry was employed to investigate the electrochemical properties of the composite materials in an aqueous electrolyte under different scan rates. Results showed that templated mesoporous carbon with layered graphene domains holds a great promise for high-rate supercapacitor applications. With a well-controlled homogeneous insertion of Mn₂O₃ nanoparticles in the carbon matrix, the electrochemical performance of the composite material was significantly improved because of the contribution of pseudocapacitance of the metal oxide. A specific capacitance of over 600 F/g was realized in term of manganese oxide in the composite materials. A volumetric specific capacitance of 253 F/cm³ was obtained on the composite electrode. Good capacity retention of over 85% was achieved by the composite electrode after 800 charge-discharge cycles. The greatly enhanced energy storage and high rate capability are attributed to the homogeneous dispersion of the nano-sized transition metal oxide together with the tailored carbon nanostructure.