Preparation and electrochemical performance of a CuO/graphene composite

Graphene oxide was synthesized from expanded graphite powder by a simple one-step oxidation method. A CuO/graphene composite was then obtained using a hydrothermal method. The samples were characterized using AFM, XRD, SEM, TEM and electrochemical measurements. Results show that CuO acts as a spacer to prevent the agglomeration of graphene sheets. The graphene formed a 3D conducting network for fast electron transfer, as well as space to accommodate the volume expansion/contraction of CuO during the discharge/charge process. The CuO/graphene composite exhibits enhanced electrochemical performance compared with pure CuO and graphene, such as improved initial coulombic efficiency (69.9%) and a reversible capacity of 748.3 mAh/g with 81.3% retention after 50 cycles.