Highly porous honeycomb manganese oxide@carbon fibers core-shell nanocables for flexible supercapacitors

Core-shell electrodes composed of highly porous honeycomb manganese oxide@carbon fibers (HMO@CFs) are synthesized by a facile hydrothermal approach involving an in situ redox replacement reaction between potassium permanganate (KMnO4) and carbon fibers. In this reaction, the carbon fibers serve as not only a sacrificial reductant, but also the substrate. The porous HMO@CFs core shell nanocables deliver remarkable electrochemical performance with a high capacitance (295.24 F g(-1) at 100 mA g(-1)), high good rate capability, and superior cycling stability (about 96.4% specific capacitance retained after 3000 cycles). The maximum energy density of 22.2 W h kg(-1) (at a power density of 400 W kg(-1)) and power density of 12,000 W kg(-1) (at an energy density of 10W h kg(-1)) can be achieved at an operating voltage of 1.6 V. The fabrication method is simple, cost-effective, and readily scalable thereby having large commercial potential. (C) 2015 Elsevier Ltd. All rights reserved.