Abstract
We report an environmentally friendly strategy for the synthesis of Fe(3)C/Fe/graphitic carbon based on hydrothermal carbonization and graphitization of carbon spheres with potassium ferrate (K(2)FeO(4)) at 800 °C. The obtained sample consisting of Fe(3)C/Fe nanoparticles and graphitic carbon (FC-1-8) delivered an enhanced pseudocapacitance of 428.0 F g(-1) at a current density of 1 A g(-1). After removal of the Fe(3)C/Fe electroactive materials, the graphitic carbon (FC-1-8-HCl) possessed a large specific surface area (SSA) up to 2813.6 m(2) g(-1) with a capacity of 243.3 F g(-1) at 1 A g(-1), far outweighing the other amorphous carbon electrodes of FC-0-8 (carbon spheres annealed at 800 °C without the treatment of K(2)FeO(4)). The graphitic material with a porous structure could offer more electroactive sites and improved conductivity of the sample. This method provided guidelines for the synthesis of superior performance supercapacitors with synchronous graphitic carbon and electroactive species.