The Influence of Surface Chemistry on the Rate Capability of LiNi0.5Mn0.5O2 for Lithium Rechargeable Batteries

Subsequent annealing at 700 degrees C enhances the rate capability of LiNi0.5Mn0.5O2, delivering 180 mAh/g at 55 degrees C and 8C rate compared to 50 mAh/g of LiNi0.5Mn0.5O2 quenched from 1000 degrees C. Although Rietvled refinement analyses of X-ray diffraction (XRD) data showed that there were no significant changes in the lattice parameters and cation distributions of the layered structure before and after annealing, XRD and X-ray photoelectron spectroscopy revealed that annealing significantly reduced surface impurity phases such as lithium carbonate and Mn3+-containing species. The influence of surface chemistry changes on the rate capability of LiNi0.5Mn0.5O2 was discussed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479664] All rights reserved.