High-rate electrochemical capacitors from highly graphitic carbon-tipped manganese oxide/mesoporous carbon/manganese oxide hybrid nanowires

摘要

In this paper, using manganese oxide as an example, we report the successful design and synthesis of a novel one-dimensional highly graphitic carbon-tipped manganese oxide/mesoporous carbon/ manganese oxide hybrid nanowire. The unique structure significantly improves the conductivity of metal oxide materials, which is a key limitation in pseudocapacitors. The hybrid nanowire with optimal carbon content, when applied as an electrode, exhibits superior capacitive properties in 1 M Na_2SO_4 aqueous solution, such as high specific capacitance (266 F g ' at 1 A g~(-1)), excellent rate capability (56.4% capacity retention at 60 A g~') and outstanding cycling stability (without degradation after 1200 cycles). The energy densities achieved can be as high as 20.8 W h kg~(-1), at a power density of 30 kW kg~(-1). The results demonstrated that the manganese oxide in our hybrid nanomaterial was efficiently utilized with the assistance of the highly conductive graphitic carbon-tipped mesoporous carbon shell. It is reckoned that the present low-cost novel hybrid nanowire can serve as a promising electrode material for supercaDacitors and other electrochemical devices.