Understanding voltage decay in lithium-excess layered cathode materials through oxygen-centred structural arrangement.

ABSTRACT: Lithium-excess 3d-transition-metal layered oxides (Li_1+xNi_yCo_zMn_1-x-y-zO₂, >250 mAh g^-1) suffer from severe voltage decay upon cycling, which decreases energy density and hinders further research and development. Nevertheless, the lack of understanding on chemical and structural uniqueness of the material prevents the interpretation of internal degradation chemistry. Here, we discover a fundamental reason of the voltage decay phenomenon by comparing ordered and cation-disordered materials with a combination of X-ray absorption spectroscopy and transmission electron microscopy studies. The cation arrangement determines the transition metal-oxygen covalency and structural reversibility related to voltage decay. The identificat

SUBMITTER: Myeong S 

PROVIDER: S-EPMC6095869 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature