Controlled synthesis of hierarchical birnessite-type MnO2 nanoflowers for supercapacitor applications

Birnessite-type MnO2 nanoflowers assembled by hierarchical nanosheets were successfully synthesized via a facile and simple hydrothermal process. The ration of reactants is a critical factor affects formation process of MnO2 nanoflowers. The electrochemical test of the as-synthesized birnessite-type MnO2 exhibits excellent electrochemical property with ideal voltammetry behavior, high specific capacitance (197.3 F g−1 at 1 A g−1) and superior cycling stability (only 5.4% capacitance loss after 1000 cycling test). The distinct hierarchical nanostructure and impressive electrochemical performances suggest the birnessite-type MnO2 is a promising material for supercapacitor applications.