Preparation of MnO₂/coal-based graphene composites for supercapacitors

The low-cost production of high performance functional materials based on graphene remains a challenging task. One of the options for tackling this problem is to develop new processes based on cheap starting materials such as coal. Coal-based graphene precursors were prepared from purified Taixi anthracite by catalytic graphitization combined with an improved Hummers method. These were mixed with MnO₂ and reduced by a low temperature plasma to make MnO₂/coal-based graphene nanocomposites. The composites were studied by FT-IR, XRD, TEM and SEM. Their electrochemical performance was evaluated using cyclic voltammetry and galvanostatic charge/discharge. Results show that MnO₂ has been even lydeposited on the graphene surface and the specific capacitance of the composite as an electrode in a supercapacitor is much higher than that of coal-based graphene without MnO₂. The highest capacitance is 281.1 F/g, which is 261.2% of the value for coal-based graphene.