Improved lithium storage performance of urchin-like CuO microspheres by stereotaxically constructed graphene mediating synergistic effect

Abstract

Urchin-like CuO/stereotaxically constructed graphene (SCG) microspheres are synthesized by one-step hydrothermal method. The size of the obtained urchin-like CuO/SCG microspheres is around 7 µm, which are composed of numerous end-connected nanorods with a diameter of about 80 nm. The existence of SCG inhibits the growth of CuO crystallite and CuO/SCG microspheres compared with the bare CuO microspheres. When directly used as anode materials for LIBs, the bare CuO and CuO/SCG microspheres deliver discharge specific capacities of 486.5 and 770.7 mA h g−1 at 0.1 A g−1 in the 80th cycle, respectively. Even if the current density is as high as 3 A g−1, CuO/SCG microsphere can still deliver a specific discharge capacity of 308.8 mA h g−1. Electrochemical performances of CuO/SCG microsphere are significantly higher than those of the bare CuO, which is attributed that SCG with 3D conductive network can enhance electronic conductivity and buffer volume variation of active material CuO during charge/discharge process.