Manganese dioxide nanosheet arrays grown on graphene oxide as an advanced electrode material for supercapacitors

A simple hydrothermal method has been provided for synthesis of the MnO2-GO hybrid with bimessite-type manganese dioxide (MnO2) nanosheet arrays on graphene oxide (GO) flakes. To assess the properties of the as-synthesized hybrid for use in supercapacitors, cyclic voltammetry (CV) and galvanostatic charging/discharging (GCD) measurements are performed. The MnO2-GO hybrid exhibits enhanced specific capacitance (213 F g(-1) at current density of 0.1 A g(-1)), rate capability (even 80 F g(-1) at 10 A g(-1)) and capacitance retention ratio (98.1% at 1 A g(-1) after 1,000 cycles) compared with the GO and MnO2. Furthermore, the electrochemical impedance spectroscopy (EIS) demonstrates the electrochemical resistance of MnO2 nanosheet which directly grows on GO is reduced, indicating easier access for intercalation/deintercalation of charges in MnO2-GO hybrid. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.