LiNi0.8Co0.2−x Al x O2 (0≤ x ≤0.1) cathode powders were prepared with a novel co-precipitation method followed by heat-treating at temperatures between 500 and 900°C. The electrochemical properties as cathode material for lithium batteries were predicted with XRD patterns and examined with capacity retention studies. Among the prepared samples, 800°C heat-treated un-substituted LiNi0.8Co0.2O2 sample showed the best cycling performance. However, the initial specific discharge capacity decreases with increase amount of Al-substitution for the LiNi0.8Co0.2−x Al x O2 powders prepared with the same process. It may due to the increase in the amount of electrochemical inactive Al3+ and the increase in the hindrance of Li+ ions diffusion by increasing Al3+ occupancy of interstitial tetrahedral 6c sites in the Al-substituted cathode materials.