In Situ Fabrication of Hierarchical CuO@Cu Microspheres Composed of Nanosheets as High-Performance Anode Materials for Lithium-Ion Batteries

Transition metal oxides have been regarded as promising anode candidates for high-energy lithium-ion batteries. Herein, we report the fabrication of hierarchical CuO@Cu microspheres composed of nanosheets by an in-situ oxidation process for lithium-ion batteries. As anodes, the composite delivers a reversible specific capacity of 850 mAh g(-1) at 100 mA g(-1), and maintains at 643 mAh g(-1) at 1 A g(-1) for 600 cycles. The superior reversible capacity and cycling stability of the CuO@Cu microspheres can be attributed to their unique hierarchical structure, which not only alleviates the structural variation, shortens the ion diffusion length upon cycling, but also improves the electrical conductivity with remained metallic Cu. The presented results offer an efficient way to design hierarchical micro-nanostructure for high-performance anode materials in lithium-ion batteries.