Controllable preparation of graphene/MnO2/Co3O4 for supercapacitors

Graphene was successfully prepared using LLDPE (Linear Low-Density Polyethylene) plastic particles as carbon source via a CVD process, and then combined with MnO2/Co3O4 composite prefabricated in our experiment to test the electrochemical performance for supercapacitors. MnO2/Co3O4 has the largest CV area and suggests a larger capacitance potential. The discharge curve of MnO2/Co3O4 is close to that of MnO2, indicating that the capacitance of MnO2/Co3O4 is dominated by MnO2, and the discharge of Graphene/MnO2/Co3O4 is slow at high voltage. The addition of graphene improves specific capacitance of MnO2/Co3O4 electrode materials, reaching 502.3 F/g at current density of 1 A/g. After 1000 charge/discharge cycles, the capacitance of all the materials synthesized in this study remains over 94.7% at the current density of 10 A/g, suggesting great potential for supercapacitors and one can choose the proper material according to various applications. (C) 2017 Published by Elsevier B.V.