Enhanced Performance of Lithium-Ion Batteries with Copper Oxide Microspheres @ Graphene Oxide Micro/Nanocomposite Electrodes

CuO microspheres are obtained from thermal oxidation of Cu₂O microspheres. A facile approach directed by electrostatic self-assembly is used to fabricate graphene oxide wrapped CuO (CuO@GO). GO nanosheets directly used in batteries could reduce the preparation cost and pollution relative to reduced graphene oxide. As coating layers, GO could be electrochemically reduced to graphene in situ to obtain an additional 3D conductive network. The CuO@GO core–shell micro/nanocomposites exhibit significantly improved lithium storage capacity and cycling performance as compared to CuO microspheres or the physical mixture of CuO microspheres and GO nanosheets (CuO–GO-PM). Under a current density of 100 mA g⁻¹, CuO@GO retains a high discharge capacity of approximately 590 mAh g⁻¹ for up to 50 cycles. After 200 cycles at a current density of 1000 mA g⁻¹, the discharge capacity of the CuO@GO is approximately 313 mAh g⁻¹, which is approximately 3 times larger than that of the CuO microspheres and CuO–GO-PM.