Wheat-like mesoporous CoO nanorods grown on the reduced graphene oxide (CoO/rGO) is synthesized by a simple hydrothermal method. Owing to synergistic effect between CoO and rGO, the CoO/rGO hybrid exhibits a good initial capacity of 20254 mAh g(-1) along with a high coulombic efficiency (98.9%) at 200 mA g(-1). In addition, the batteries show an excellent rate capability (13952 mAh g(-1) at 800 mA g(-1)) and enhanced cycling stability (69 cycles with the capacity limited to 1000 mAh g(-1) at 200 mA g(-1)). The electrochemical performance is intimately related to the unique architecture (i.e., hierarchical mesoporous structure), facilitating the reversible formation and decomposition of insoluble Li2O2. The results of electrochemical tests confirm that the CoO/rGO hybrid is a promising candidate for the Li-O-2 batteries. (C) 2017 Elsevier B.V. All rights reserved.