A novel Co3O4 nanoparticles (NPs)/exfoliated graphite (EG) composite has been prepared through a stirring-assistant hydrothermal route and a subsequent post-anneal treatment. Results of microstructure characterizations of XRD, FE-SEM and HR-TEM analyses indicate that high-crystallized Co3O4-NPs with a dimension of similar to 5 nm are homogenously anchored on the nanosheets of EG in the form of tiny agglomerates of similar to 20 nm. Restack and shrinkage of the edge regions of EG are distinctly observed after suffering from the hydrothermal process, which exerts a positive influence over the decay-free cycling ability of the Co3O4-NPs/EG electrode. The reversible capacity increases with cycling, and reaches 1183 mAhg(-1) (94th cycle) at 100 mAg(-1) and 739 mAhg(-1) (100th cycle) at 1000 mAg(-1). After suffering from 800 cycles at 2000 mAg(-1) and resetting to 100 mAg(-1), the charge capacity recovers to as high as 1225 mAhg(-1) immediately, and stabilizes in the following cycles. The decay-free cycling performances and good rate capability are ascribed to the favorable synergistic effect between Co3O4-NPs and the robust/conductive skeleton of EG. In addition, an exceeded capacity which much surpasses the calculated theoretical value is achieved, further proving the good synergistic enhancement due to the high-effective integration between Co3O4-NPs and EG. (C) 2016 Elsevier Ltd. All rights reserved.