A Co3O4/carbon-sphere composite was synthesized and demonstrated as an anode with high capacity and good reversibility. The surface of a carbon-sphere framework was homogeneously dotted with Co3O4 nano-particles. The size, shape, and crystallinity of the Co3O4 nano-particles were confirmed by SEM, TEM and XRD analyses. The reversible capacity of the Co3O4/carbon-sphere composites reached as high as similar to 1100 mAhg(-1) at a current density of 150 mAg(-1) and the composites maintained stable capacity during cycling. The superior electrochemical properties of the Co3O4/carbon-sphere composites are likely attributed to the extra-small Co3O4 nano-particles combined with the highly conductive carbon-spheres. (C) 2012 Elsevier B.V. All rights reserved.