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

Abstract

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 Na2SO4

aqueous solution, such as high specific capacitance (266 F g 1

at 1 A g 1

), excellent rate capability

(56.4% capacity retention at 60 A g 1

) and outstanding cycling stability (without degradation after 1200

cycles). The energy densities achieved can be as high as 20.8Wh kg 1

, at a power density of 30 kWkg 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 supercapacitors and other electrochemical devices.