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

In this paper, using manganese oxide as an example, we report the successful design and synthesis of \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \na novel one-dimensional highly graphitic carbon-tipped manganese oxide/mesoporous carbon/ \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nmanganese oxide hybrid nanowire. The unique structure significantly improves the conductivity of \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nmetal oxide materials, which is a key limitation in pseudocapacitors. The hybrid nanowire with optimal \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \ncarbon content, when applied as an electrode, exhibits superior capacitive properties in 1 M Na2SO4 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \naqueous solution, such as high specific capacitance (266 F g 1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nat 1 A g 1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n), excellent rate capability \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n(56.4% capacity retention at 60 A g 1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n) and outstanding cycling stability (without degradation after 1200 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \ncycles). The energy densities achieved can be as high as 20.8Wh kg 1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n, at a power density of 30 kWkg 1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n. \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nThe results demonstrated that the manganese oxide in our hybrid nanomaterial was efficiently utilized \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nwith the assistance of the highly conductive graphitic carbon-tipped mesoporous carbon shell. It is \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nreckoned that the present low-cost novel hybrid nanowire can serve as a promising electrode material \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nfor supercapacitors and other electrochemical devices.