Electron diffraction studies of LiNi_(1/3) Mn_(1/3) Co _(1/3) O_2 after charge-discharge cycling

摘要

The performance of LiNi_(1/3) Mn_(1/3) Co_(1/3) O_2 depends largely on the distribution of transition-metal (TM) ions over the available lattice sites within the layered rocksalt structure. Despite predictions that the TM ions take on an ordered arrangement described by a √3×√3R 30° supercell, little experimental evidence is available to confirm this model. However, the observed cation distribution likely depends on synthesis conditions. Here, we present a study of commercially produced LiNi_(1/3) Mn_(1/3) Co_(1/3) O_2 synthesized at 1000°C before and after charge-discharge cycling. Electron diffraction shows that in-plane ordering is observed to small extents. After charge-discharge cycling, a transformation toward the cubic spinel structure and significant morphology changes are observed.