This paper reports the study of cobalt disulfide as a promising anode material for lithium ion batteries. The crystal structure and surface morphology have been characterized by using X-ray diffraction (XRD), SEM and Brunauer–Emmett–Teller (BET) techniques. The results of XRD show that the sample is a cubic phase with a space group Pa3. The grain size of the sample was 30μm with a special nano-structured characteristic as observed by means of SEM. Charge–discharge experiments show that the sample with 30wt.% acetylene black at the current density of 50mAg−1 has the best performance, it shows that the first discharge capacity is up to 1280mAhg−1. Ex situ XRD experiments were also carried out to determine the structural changes of delithiated/lithiated anode materials and used to analyze the reaction mechanism. Calculated Gibbs free energy change (ΔrG) and electromotive force (emf, E) values for the reaction CoS2 +4Li+ +4e− →Co+2Li2S are −146kJmol and 1.898V, respectively. Based on the results, a possible reaction mechanism of CoS2 anode during intercalation of Li ions was proposed.