Solvothermal Synthesis of Uniform Co3O4/C Hollow Quasi‐Nanospheres for Enhanced Lithium Ion Intercalation Applications

Nanostructured hollow electrodes can greatly improve the electrochemical performance of lithium ion batteries by reducing the diffusion distance for lithium ion transport, providing more freedom for volume change, which can reduce the overpotential and allow better reaction kinetics at the electrode surface. In this communication, we report the synthesis of carbon‐coated single‐crystalline Co3O4 porous and hollow quasi‐nanospheres by an in situ carbon‐coating and Ostwald ripening solvothermal process. The process of structure evolution from carbon‐coated solid nanocubes to porous and hollow quasi‐nanospheres was demonstrated with SEM and TEM images after different solvothermal reaction times. The carbon‐coated porous and hollow structure facilitates lithium ion transport from the electrolyte solution to the electrode, increases the electronic conductivity of the electrodes, which leads to the formation of uniform and thin solid electrolyte interphase (SEI) films on the surface, and maintains the integrity of the nanoparticles. As a result, these carbon‐coated Co3O4 porous and hollow quasi‐nanospheres exhibit good recyclability and high rate capability (629 and 256 mA h g–1 at 2 C and 15 C, respectively).