Carbon coated iron oxide (CC-IO) as high performance electrode material for supercapacitor applications

Transition metal oxides are efficient electrode materials for supercapacitors due to their high theoretical specific capacitance. However their poor electrical conductivity needs to be further improved for fast charging and discharging the supercapacitor. There is an effective approach to overcome this issue by combining the carbon based materials with metal oxides. Addition of carbon based materials into transitional metal oxides will enhance the supercapacitor performance. Herein, carbon coated iron oxide (CC-IO) was synthesized using sucrose as a soluble carbon precursor and annealed at different temperatures (1000 degrees C to 1300 degrees C). The structure of the CC-IOs was analysed by X-ray diffraction and Raman spectroscopy. Pore structures and surface chemical compositions of CC-IOs were studied using BET and X-ray photoelectron energy spectrum, respectively. Surface morphology was investigated with scanning and transmission electron microscopy. CC-IO-1300 degrees C showed the maximum specific capacitance of 727 Fg(-1), while CC-IO-1000 degrees C showed the minimum capacitance of 143 Fg(-1) calculated by cyclic voltammetry (CV) at a scan rate of 5 mV/sec. The improvement in the specific capacitance of CC-IOs with increasing temperature is may be due to phase change of iron oxide and improvement in the crystalline nature of carbon coated on the iron oxide surface.