Graphene/MnO2 hybrid nanosheets as high performance electrode materials for supercapacitors

• Graphene/MnO2 hybrid nanosheets with different ratios were fabricated.
• The specific capacitance is strongly dependent on graphene/MnO2 ratios.
• The graphene/MnO2 hybrid electrode (1:4) exhibited high specific capacitance.
• The electrode retained 84% of the initial specific capacitance after 2000 cycles.

Graphene/MnO2 hybrid nanosheets were prepared by incorporating graphene and MnO2 nanosheets in ethylene glycol. Scanning electron microscopy and transmission electron microscopy analyses confirmed nanosheet morphology of the hybrid materials. Graphene/MnO2 hybrid nanosheets with different ratios were investigated as electrode materials for supercapacitors by cyclic voltammetry (CV) and galvanostatic charge–discharge in 1 M Na2SO4 electrolyte. We found that the graphene/MnO2 hybrid nanosheets with a weight ratio of 1:4 (graphene:MnO2) delivered the highest specific capacitance of 320 F g−1. Graphene/MnO2 hybrid nanosheets also exhibited good capacitance retention on 2000 cycles.