Hierarchical multidimensional MnO2 via hydrothermal synthesis for high performance supercapacitors

Manganese dioxide (MnO2) is an ideal electrode material for supercapacitors due to its low cost and large theoretical specific capacity. We reported the hydrothermal synthesis MnO2 nanostructures with different morphologies through the variation of hydrothermal temperature and dwell time. It was found that cauliflower-like δ-MnO2 particles are prepared at a lower temperature while the needle-like α-MnO2 nanorods are formed at a higher temperature. The morphologies of MnO2 were also affected by the hydrothermal dwell time. The needle-like α-MnO2 nanorods have the higher specific surface (114 m2 g−1) than that of the cauliflower-like δ-MnO2 particles. Electrochemical properties were evaluated using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The hierarchical multidimensional MnO2 architecture nanostructured surface with particles and nanorods, shows a maximum specific capacity (311.52 F g-1 at 0.3 A g−1). These results provided a generic guideline in developing different nanostructured electrode materials for electrochemical energy storage.