One-pot synthesis of manganese oxide/graphene composites via plasma-enhanced electrochemical exfoliation process for supercapacitors.

: In this work, a feasible one-step approach to synthesize manganese oxide/graphene composites, so-called plasma-enhanced electrochemical exfoliation process (PE3P), has been developed. Herein, a composite of graphene decorated with manganese oxides nanoparticles was prepared via PE3P from KMnO4solution and graphite electrode under the voltage of 70 V at ambient condition. By controlling the initial KMnO4concentrations, we obtained distinct MnO2/graphene samples. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. The electrochemical measurements of the MnO2/graphene composites reveal that the specific capacitance of the samples is approximately 320 F g-1at a scan rate of 10 mV s-1, which is comparably very high for manganese oxide/carbon-based supercapacitor electrode materials. Considering the simple, low-cost, one-step and environmentally-friendly preparation, our approach has the potential to be used for the fabrication of MnO2/graphene composites as electrode materials of supercapacitors.