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

• Birnessite MnO2 nanosheet arrays directly grow on graphene oxide flakes.
• Few studies reported the synthesis and capacitive behaviors of this architecture.
• The MnO2-GO hybrid has been synthesized by a simple hydrothermal method.
• The hybrid exhibits enhanced electrochemical performances.

A simple hydrothermal method has been provided for synthesis of the MnO2-GO hybrid with birnessite-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.

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