Metal-phosphate coating on LiCoO2 cathodes improved the cycle-life performance with high charge-cutoff voltages. The optimum annealing temperature and coating thickness for the excellent electrochemical properties of the metal-phosphate-coated LiCoO2 cathodes were determined. Among the metal-phosphate-coating materials, the Al-P-O coating enhanced the electrochemical properties most efficiently. The EPMA results (after cycles) with a 4.8 V cutoff confirmed that most of the nanoscale coating layers, particularly the P component, had dissolved during cycling. (c) 2006 Elsevier Ltd. All rights reserved.