1A-5
Transition-metal dependence of structural changes during charge-discharge processes in Li-rich layered oxide cathodes, S. Hiroi (Shimane Univ.) et al.

Li-rich layered oxides (LLOs), represented by Li₂MnO₃-LiMeO₂ (Me = Ni, Co, Mn), are promising cathode materials for next-generation lithium-ion batteries owing to their high discharge capacities exceeding 250 mAh/g. In this study, detailed structural analyses of Ni-rich, Co-rich, and Mn-rich LLOs in pristine, charged, and discharged states were performed using crystal PDF full-space refinement based on X-ray total scattering data. Co-rich LLO exhibited remarkable peak broadening and a two-phase behavior in the charged state. Refinement results indicated that transition metal ions in Co-rich and Mn-rich LLOs partially migrated into the Li layers upon charging, whereas most of the transition metal ions in Ni-rich LLO remained within the transition metal layers. These findings demonstrate that transition metal migration strongly depends on the composition and significantly influences the structural evolution of LLO cathodes.