Effect of Li Content on Electronic Structure by First-Principle Calculation for Li_1+xNi_0.5Mn_0.5O₂ Cathode Active Material of Lithium-Ion Battery

Abstract

We investigated the crystal and electronic structures of Li_1+xNi_0.5Mn_0.5O₂ by Rietveld analysis and first-principle calculations. The crystal structure was well refined by Rietveld analysis using R-3m as the space group, and it was found with MEM using synchrotron X-ray diffraction that the sample showing better cycle performance had higher electron density at a saddle point of 3b–6c. The first-principle calculation clarified that the covalent bond of Ni–O and Mn–O in near a cation mixing position was stronger than that of normal position.