▎ 摘　　要

We synthesized a hybrid graphene/Co3O4 catalyst by a simple chemical reduction method, and demonstrated that a Li-O-2 cell with the hybrid catalyst delivers a highly reversible capacity. We examined the role of the catalyst in Li-O-2 batteries and through careful analyses of the reactions in the battery, we found that the reaction path fundamentally changes with the use of catalyst, and propose a mechanism of how the rechargeability is improved in Li-O-2 batteries. (c) 2012 Elsevier Ltd. All rights reserved.