Co₃O₄ Hollow Porous Nanospheres\nwith Oxygen Vacancies for Enhanced Li–O₂ Batteries

Abstract

Creating\noxygen vacancies to tune the surface electronic structure\nis a feasible approach to enhance the electrocatalytic activities\nof noble-metal-free transition-metal oxides for Li–O₂ batteries. Herein, vacancy-rich Co₃O₄ hollow\nporous nanospheres have been obtained through a facile reduction strategy\nfrom Co₃O₄ hollow porous nanospheres, which\nwere prepared in a self-template construction manner through a solvothermal\nsynthesis followed by a heat treatment. The reduced Co₃O₄ hollow porous nanospheres composed of numerous nanoparticles\nshow a unique porous and hollow structure with abundant surface oxygen\nvacancies. The oxygen vacancy defects can produce more electrochemical\nactive sites and improve the electrical conductivity as well as increase\nthe adsorbed oxygen-containing molecules for the enhanced Li–O₂ battery performance. Therefore, the reduced Co₃O₄ sample with oxygen vacancies shows lower overpotential,\nhigher discharge capacity, longer cycling life, and better rate capability\nthan the pristine one.