MnO2 nanoneedles loaded on silicon oxycarbide-derived hierarchically porous carbon for supercapacitor electrodes with enhanced electrochemical performance

Manganese oxide nanoneedle/carbide-derived carbon (MnO2/CDC) composite electrodes with hierarchically porous structure for supercapacitors have been obtained by a convenient hydrothermal technology. MnO2 nanoneedles are homogeneously grown on the surface of CDC obtained by etching silicon oxycarbide (SiOC) using sodium hydroxide (NaOH) according to a self-limiting reaction. The as-prepared MnO2/CDC composites posses: large specific surface area of 1749.3 m(2) g(-1), and facilitate to the enhancement of some certain pseudocapacitance. The MnO2/CDC composite electrodes show a high specific capacitance (255.8 F g(-1) at 1 A g(-1)) in a three electrode system. Additionally, MnO2/CDC electrodes are used to fabricate a symmetrical coin cell super capacitor. The device delivers the remarkable energy density of 12.6 Wh kg(-1) at a power density o 3997.7 W kg(-1) and still maintain 92.2% of the capacitance after 2000 cycles. The electrode materials preparec by combining CDC with transition metal oxide have great potential in supercapacitor applications.