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

Abstract

Urchin-like Co ₃O ₄ microspheres were prepared by a hydrothermal and sintering method; oxygen vacancies induce a local built-in electric field to boost battery performance.

Abstract

Urchin-like Co ₃O ₄ 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 Co ₃O ₄ 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.