Hierarchically porous carbon/ MnO_2 nanocomposites as high-performance electrode for asymmetric supercapacitors

摘要

Hierarchically porous carbon (HPC)/MnO_2 nanocomposites were fabricated for asymmetric supercapacitor applications. The microstructures of HPC/MnO_2 nanocomposites were characterized by X-ray diffraction and scanning electron microscopy. The asymmetric supercapacitor consisting of a HPC/MnO_2 cathode and a HPC anode shows an excellent performance with energy density and power density of 23.8 Wh kg"1 and 12.5 kW kg"1, respectively. In addition, the asymmetric supercapacitor exhibits an excellent cycle life with 91% retention of capacitance after 1000 cycles.