Oxygen vacancy derived local build-in electric field in mesoporous hollow Co3O4 microspheres promotes high-performance Li-ion batteries

Abstract

Urchin-like Co₃O₄ microspheres have been obtained through a two-step hydrothermal method followed by a post-calcination process and show a unique hollow structure with mesoporous nanosheets on their surface. Oxygen vacancies on the ultrathin nanosheets were introduced by annealing treatment, inducing a local built-in electric field to promote the migration of Li ions by Coulomb force during cycling and leading to a superior electrochemical performance for lithium-ion batteries. The electrodes containing urchin-like mesoporous hollow Co₃O₄ microspheres delivered a high discharge capacity of 2164.1 mA h g⁻¹ at 0.05 A g⁻¹ after 100 cycles. Even at a higher current density of 1.0 A g⁻¹, a remarkable discharge capacity of 1307.9 mA h g⁻¹ after 1000 cycles could still be achieved.