▎ 摘　　要

Graphene composites containing embedded manganese dioxide (MnO2) were fabricated by simple solvothermal method. 100 nm to 200 nm size of nanoparticles were anchored on reduced graphene oxide layers. The MnO2/RGO composite with optimized molar concentration of manganese precursors in fixed graphene oxide mass was showed the highest specific capacitance of 186 F/g at 1 A/g. In addition, cycle life performance of MnO2/RGO composite was improved by using graphene having high electrical conductivity as a substrate. This result was related with prevention for collapse of the manganese nanoparticle. The structure and morphology analysis was confirmed by field emission scanning electron microscopy (FE-SEM) and Fourier-transform infrared spectroscopy (FT-IR). FE-SEM images explicitly revealed that MnO2 particles were attached on reduced graphene oxide layers.