Reduced graphene Oxide-MnO2 hollow sphere hybrid nanostructures as high-performance electrochemical capacitors

This paper presents the first successful fabrication of reduced graphene oxide (RGO)-MnO2 hollow sphere (HS) hybrid electrode materials through a solution-based ultrasonic co-assembly method. The porous structure of these MnO2 hollow spheres and the excellent dispersion of active materials give the as-fabricated RGO-MnO2 HS hybrid electrodes excellent specific capacitance and energy density, which can reach up to 578 F g(-1) and 69.8 W h kg(-1), respectively. These values are considerably larger than those of most reported graphene-MnO2 based hybrid electrochemical capacitors. This solution-processed method can also be used for the hybridization of graphene with other metal oxides in the fabrication of high-performance electrochemical capacitors.