Engineering hollow cobalt oxide nanospheres with porous carbon coating for stable lithium storage

Abstract Constructing a stable, stress-relieving configuration is imperative to achieve a reversible cobalt oxide (CoO) anode for high-performance lithium-ion batteries. Herein, we propose a porous carbon coated ultrafine CoO nanoparticles assembled hollow nanospheres (CoO@HPC). In thus configuration, the well-designed porous carbon coating has a significant superiority compared to the common carbon coatings without porous structures, that is, the porous carbon coating can not only better buffer the volume change of CoO using its spongy structure featured better flexibility and rich free space, but also accelerate the lithium-ions diffusion by right of its open tunnel-like structure. On this ground, the synergistic effect of porous carbon coating and hollow structure endows CoO@HPC with superior structural durability and improved electrochemical kinetics. In consequence, this CoO@HPC shows superior electrochemical properties, displaying 704 (close to the theoretical capacity of CoO (716 mAh g−1)) and 426.4 mAh g−1 after 120 cycles at 200 and even 1000 mA g−1, respectively. This work highlights the importance of rational structure design of carbon coating for preparing advanced lithium-ion battery CoO-based anodes.