Effects of Conductive Supports on the Growth and Capacitive Performance of Nanostructured Manganese Oxides

Abstract

The manganese oxide (MnO2) nanocrystals were formed on the surface of graphene oxides (GOs) and multi−walled carbon nanotubes (MWCNTs) through a facial hydrothermal route, respectively. It is found that the similar flower−like MnO2 nanocrystals covered on both conductive supports. Moreover, more dense and less size of MnO2 nanocrystals appeared on the surface of MWCNTs, whereas more perfect crystal structures for MnO2/GOs. Electrochemical measurements showed that both the nanocomposite electrodes exhibited nearly ideal capacitive behavior, and large capacitive value can be obtained for MnO2/GOs, while high stability for MnO2/MWCNTs. The high capacitance performance arises from the unique nanostructure of the nanocrystals, which facilitate the contact of the electrolyte and the active materials, and carbon−based materials provide an effective support for the formation of the nanocrystals and conductive pathway for the nanocomposite electrodes.