▎ 摘　　要

MnO2 materials are prepared through a hydrothermal process. Sn-doping and composite graphene are both achieved simultaneously during the hydrothermal reaction then obtain the electrode materials of supercapacitors. Morphology, structure and electrochemical properties of the samples are evaluated by X-ray diffraction(XRD), scanning electron microscopy (SEM), and electrochemical work station. The results show that, the specific capacitance of 49 F.g(-1), 283 F.g(-1) and 312 F.g(-1) are exhibited for the pure MnO2, Sn-MnO2 and Sn-MnO2 / graphene composite, respectively, indicating that stannum and graphene greatly enhances the electrochemical performance of MnO2.