The lithium-excess layered oxide Li[Li0.2Mn0.54Ni0.13Co0.13]O-2 has been surface modified with Al2O3 films grown with atomic layer deposition (ALD) and examined as cathodes for lithium-ion batteries. Al2O3 was grown on powders prior to electrode fabrication, directly on the electrode, and directly on the electrode followed by a heat-treatment at 300 degrees C in air. Compared to the bare electrode, an Al2O3 film on an as-formed electrode improved the cycle performance significantly. Furthermore, the heat treatment of the ALD-coated electrodes result in significant increase in capacity, due to the transformation of the as-deposited Al2O3 to a better Li+-conductive material. X-ray photoelectron spectroscopy (XPS) results indicate that the heat-treatment leads to an inter-diffusion of atoms between the Al2O3 coating and the Li[Li0.20Mn0.54Ni0.13Co0.13]O-2 core. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.030112jes] All rights reserved.