Porous MnO2 hollow spheres constructed by nanosheets and their application in electrochemical capacitors

Porous MnO2 hollow spheres were successfully prepared by hydrothermal synthesis using hollow carbon spheres as the template. The morphology and structure of the porous MnO2 hollow spheres were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), nitrogen adsorption-desorption analysis. The electrochemical studies indicated that the porous MnO2 hollow spheres have an excellent capacitive performance and high specific capacitance of 352 F/g at the current density of 0.5 A/g. The superior capacitive performance is related to the advantageous structure of porous MnO2 hollow spheres constructed by nanosheets, which were preferred in decreasing ion transfer resistance, shortening diffusion distance as well as improving electron conductivity. These advantages endow this material with good capacitive performance. (C) 2013 Elsevier B.V. All rights reserved.