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.