Sub-micron LiCoO2 as a cathode material for lithium rechargeable battery with high rates is easily and economically prepared using eutectic self-mixing method without any artificial mixing procedures of reactants and ultra-miniaturization of products. While the micro-sized LiCoO2 exhibits the discharge capacities of 134.8mAhg−1 at 0.1C and 118.6mAhg−1 at 5.0C, those of the sub-micron LiCoO2 are 137.2mAhg−1 at 0.1C and 131.7mAhg−1 at 5.0C.