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.