Hydrothermal synthesis of graphene-MnO2-polyaniline composite and its electrochemical performance

High performance Graphene-MnO2-polyaniline (Graphene/MnO2/PANI) nanocomposite was synthesized by hydrothermal process. The structure and morphology of Graphene/MnO2/PANI nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The electrochemical properties of composite were evaluated by constant current charge–discharge, cyclic voltammetry and AC impedance, respectively. The results show that the prepared Graphene/MnO2/PANI nanocomposite exhibits greatly enhanced specific capacitance (305 F g−1) as compared to that of pristine graphene (155 F g−1) and MnO2/PANI (240 F g−1) in 1 M Na2SO4 solution. In addition, the capacity of the Graphene/MnO2/PANI nanocomposite still maintains 90 % after 1000 charge–discharge cycles at a current density of 1 A g−1, exhibiting potential applications in electrode materials for supercapacitors.