Rapid preparation of the hybrid of MnO2 dispersed on graphene nanosheets with enhanced supercapacitive performance

- MnO2/GNS hybrid has been prepared via a rapid electrochemical codeposition method.
- MnO2 nanoflakes are homogenously dispersed on the surface of GNS.
- The introduction of GNS significantly enhances the capacitive performance of MnO2.
- The as-prepared hybrid shows a high specific capacitance and cycle stability.

MnO2/graphene nanosheets (GNS) hybrid has been readily prepared by a rapid approach of one-pot electrochemical codeposition. Under a negative reduction potential, graphene oxide nanosheets lose oxygen-containing functional group to become GNS, simultaneously MnO2 derived from KMnO4 is also electrochemically deposited on the electrode. The characterizations of scanning electron microscope and transmission electron microscopy show that MnO2 nanoflakes are homogenously dispersed on the surfaces of GNS, such microstructure can effectively enlarge the contact area of MnO2 with electrolyte. The electrochemical measurements indicate that the introduction of GNS significantly enhances the supercapacitive performance of MnO2 electrode. Notably, the resulting MnO2/GNS hybrid exhibits a high specific capacitance of 413.1 F g−1 at 1 A g−1, which is higher than the recently reported MnO2/GNS hybrids prepared by different methods including electrochemical deposition. Furthermore, the hybrid retains 91.2% of initial capacitance after 2500 cycle, while the MnO2 only maintains 63.5%. These obviously boosted performances for MnO2/GNS hybrid are essential for high-efficiency electrochemical energy storage.