Hierarchical hollow MnO2 nanofibers with enhanced supercapacitor performance.

One dimensional (1D) hollow nanostructures have been considered as one of the most fascinating materials for supercapacitors. Herein, the hollow MnO2 nanofibers are successfully synthesized through a two-step process, in which the electrospun carbon nanofibers acted as sacrificial template. The resulting hollow nanofibers are composed of ultrathin MnO2 nanosheets, which can offer rich electrochemical active sites for electrochemical reactions. Importantly, the open and free interspaces among these ultrathin MnO2 nanosheets can significantly enhance the utilization of the active material even at high current density. Such unique hollow nanostructure endow the hollow MnO2 nanofibers electrode better electrochemical performance with specific capacitance of 291 F/g at 1 A/g, superior rate capability of ∼73% (from 1 to 10 A/g), and excellent cycling stability of 90.9% retention after 5000 cycles, demonstrating the potential for practical application in energy storage devices.