▎ 摘　　要

Graphene-based materials have potential applications in supercapacitors, owing to their unique twodimensional structure, high surface area, remarkable chemical stability, and outstanding electrical conductivity. In this work, Hummers method was used to prepare graphene oxide, and then in situ electrochemical method was firstly used to deposit graphene nanosheets on Co/CoO core-shell nano-structure to form a sandwich-type of Co/CoO/graphene electrode materials. The effect of electro-deposition graphene cycles on the electrochemical properties of Co/CoO/graphene composite were investigated. The results showed that the coating of graphene on Co/CoO further enhanced the conductivity of the material, and the specific capacitance reached 7.765 F cm(-2) at the current density of 1 mAcm(-2). The Co/CoO/graphene and AC were assembled into an asymmetric supercapacitor. After 10000 charge/discharge cycles, the total capacitance of the asymmetric supercapacitor was still maintained 79.9%. The coating of graphene not only increased the conductivity of the material, but also increased the stable of structure. (C) 2019 Elsevier B.V. All rights reserved.