High rate performance carbon nano-cages with oxygen-containing functional groups as supercapacitor electrode materials

Abstract Graphitized carbon nano-cages can be prepared by carbon dioxide and magnesium metal as precursors. The carbon materials can produce a large amount of functional groups by the oxidation of nitric acid. Compared with amorphous carbon, the oxidation treatment can improve capacitive performance of carbon nano-cages, especially rate performance. At high scan rate, specific capacitance of carbon nano-cages is much higher than that of the microporous activated carbon. So carbon nano-cages are promising high rate performance materials. A series of physical and chemical characterization exhibits that excellent capacitive performance is derived from carbon nano-cages structure themselves. It is due to higher electrical conductivity of graphite structure, lower charge transfer resistance of hierarchical porous structure and extra pseudo-capacitance of oxygen-containing functional groups.