2010 年 78 巻 5 号 p. 367-369
We investigated the crystal and electronic structures of Li1+xNi0.5Mn0.5O2 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.