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

摘要

A simple hydrothermal method has been provided for synthesis of the MnO_2-GO hybrid with birnessitetype 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.