Atomic-scale structural evolution of electrode materials in Li-ion batteries:a review

Owing to the high spatial resolution at the atomic scale,the transmission electron microscopy(TEM)or scanning transmission electron microscopy is demonstrated as a promising characterization method to unveil the charge storage mechanism of electrode materials in Li-ion batteries.The structural evolution of electrode materials during charge/discharge process can be directly observed by using TEM.The detailed analysis establishes a relationship between the structure of electrode material and battery performance.Herein,we present a brief review of the atomic-scale characterization in Li-ion batteries,including Li(de)insertion mechanism(both cations and anions charge-compensation mechanism),migration of transition metal ions,and surface phase transition.The indepth microscopic analysis reveals the detailed structural characteristics,which influence the properties of LIBs,establish the structure-function relationship,and facilitate the development of Li-ion batteries.