Ultrathin Co3O4 Nanosheets with Edge-Enriched {111} Planes as Efficient Catalysts for Lithium–Oxygen Batteries

Li-O2 batteries have aroused great interest as promising chemical power sources due to their high energy density. However, enhancement of the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the cathodes is still a great challenge. Herein, we design and prepare Co3O4 single-crystal nanosheets with edge-enriched {111} facets via a simple pyrolysis of α-Co(OH)2, which show a high activity as cathode catalysts for Li-O2. The catalytic activity and stability have been significantly improved in comparison with Co3O4 poor-edge {111} facets. This enhancement can be largely attributed to the edge-enriched {111} facets. Co3O4 nanosheets with edge-enriched {111} facets expose more metal atoms to boost the catalytic activity. Moreover, the edge-enriched {111} facets contain a high density of atomic steps and kink atoms which supply a wide space for breaking chemical bonds and increasing the reaction activity. This study also presents some insights into designing high-performance catalysts for metal–air batteries through a strategy of edge-enriched facet engineering.