MnO2 nanosilks self-assembled micropowders: Facile one-step hydrothermal synthesis and their application as supercapacitor electrodes

Novel MnO2 nanosilks self-assembled micropowders have been prepared by a simple one-step hydrothermal synthesis method. The structure and morphology of the MnO2 are investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The capacitive properties of the MnO2 are investigated by cyclic voltammetry (CV) and constant current charge-discharge. The SEM results showed that the MnO2 micropowders are assembled by numerous one-dimensional MnO2 nanosilks. These MnO2 nanosilks are found to be 30-50 nm in diameter and characteristic length up to 2 μm. When evaluated for supercapacitor electrode, a desirable specific capacitance of 135 F/g for the single MnO2 electrode is obtained at current density of 0.15 A/g in 1 M Na2SO4 aqueous solution.