▎ 摘　　要

A facile hydrothermal route has been developed to prepare graphene-Co3O4 nanocomposites. The graphene-Co3O4 nanocomposite catalyst demonstrates an excellent catalytic activity toward oxygen-reduction reaction including a considerably more positive half-wave potential (-0.23 V) than that of pristine graphene (-0.39 V), as well as higher cathodic currents. More importantly, this catalyst shows better long-term durability than the commercial Pt/C catalyst in an alkaline solution. The preliminary results indicate that the graphene-Co3O4 nanocomposite is an efficient and stable bifunctional catalyst for Li-air batteries and may be an alternative to the high-cost commercial Pt/C catalyst for the ORR/OER in alkaline solutions.