Tuning oxygen non-stoichiometric surface via defect engineering to promote the catalysis activity of Co3O4 in Li-O2 batteries

Abstract

The performance of Li-O2 battery is governed by the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics. Adjusting the surface property of catalysts via defect engineering will inaugurate a new complexion on developing efficient oxygen electrodes. In this work, a novel strategy of creating rich oxygen vacancy in Co3O4 is developed via cerium incorporation. The oxygen vacancy in Ce-Co3O4 not only promotes charge migration due to the formation of unsaturated coordination sites where electrons become delocalized but also acts as active site to anchor O2 and Li2O2 thereby leading to synergic enhancement of ORR and OER kinetics. The low overpotential (0.9 V), large specific capacity (8250 mAh g−1) and extended cycling life of the Ce-Co3O4 based Li-O2 battery experimentally confirm its superior bifunctional catalytic activity. This relationship between surface properties and catalytic activity established by defect engineering can serve as an innovative strategy for guiding the further development of high performance electrode materials for Li-O2 batteries in the foreseeable future.