Heteroatom Doping-Induced Defected Co₃O₄ Electrode for High-Performance Lithium Oxygen Battery

Abstract

Development of electrocatalysts with high activity and stability is crucial for advanced lithium oxygen batteries due to their sluggish reaction kinetics and undesirable parasitic reactions. Herein, we demonstrate that heteroatom doping is a feasible strategy to trigger oxygen vacancies, and remarkably enhance the conductivity and catalytic activity of the Co3O4 electrocatalyst. The optimized Co3O4 cathode with abundant oxygen vacancies regulates the geometric morphology of the discharge product Li2O2, which accelerates the oxygen reduction/evolution reaction kinetics notably and lowers the redox overpotential. Density functional theory calculations reveal that intrinsic LiO2-adsorption ability on the Co3O4 surface is dramatically strengthened after heteroatom doping, thus fundamentally modulating the growth route of Li2O2 and suppressing the parasitic reactions caused by LiO2. In particular, a phosphorus-doped Co3O4 cathode exhibits a decreased polarization potential (1.2 V), large initial discharge capacity (7690 mAh g–1 at 100 mA g–1), and good cyclability (90 cycles at 100 mA g–1). This work provides insight into the vital role of heteroatom doping and oxygen vacancies in tailoring the morphology of Li2O2 and suppressing side reactions, and provides inspiration for cathode catalyst design in lithium oxygen batteries.