Al2O3-coated spinels were investigated with respect to their electrochemical characteristics. A Al2O3 coating on commercial LiMn2-x MxO4 (Nikki, Japan, M = Zr) was prepared by using the sol-gel method. AA analysis showed that manganese and lithium dissolution occur-red during the coating process. XRD patterns show that increase in the lattice parameter of Al2O3-coated spinels is related to formation of a solid solution on the surface of active materials. Impedance results revealed that Al2O3-coated spinel has electronic resistance. However, The cell performance was enhanced with the Al2O3 coating. Al2O3 is regarded as a coating material for stable cycling performance. (C) 2003 Elsevier B.V. All rights reserved.