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

Abstract A simple hydrothermal method has been provided for synthesis of the MnO 2 -GO hybrid with birnessite-type manganese dioxide (MnO 2 ) 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 MnO 2 -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 MnO 2 . Furthermore, the electrochemical impedance spectroscopy (EIS) demonstrates the electrochemical resistance of MnO 2 nanosheet which directly grows on GO is reduced, indicating easier access for intercalation/deintercalation of charges in MnO 2 -GO hybrid.