Size-Mediated Recurring Spinel Sub-nanodomains in Li- and Mn-Rich Layered Cathode Materials.
Biwei XiaoHanshuo LiuNing ChenMohammad Norouzi BanisHaijun YuJianwen LiangQian SunTsun-Kong ShamRuying LiMei CaiGianluigi A BottonXueliang SunPublished in: Angewandte Chemie (International ed. in English) (2020)
Li- and Mn-rich layered oxides are among the most promising cathode materials for Li-ion batteries with high theoretical energy density. Its practical application is, however, hampered by the capacity and voltage fade after long cycling. Herein, a finite difference method for near-edge structure (FDMNES) code was combined with in situ X-ray absorption spectroscopy (XAS) and transmission electron microscopy/electron energy loss spectroscopy (TEM/EELS) to investigate the evolution of transition metals (TMs) in fresh and heavily cycled electrodes. Theoretical modeling reveals a recurring partially reversible LiMn2 O4 -like sub-nanodomain formation/dissolution process during each charge/discharge, which accumulates gradually and accounts for the Mn phase transition. From the modeling of spectra and maps of the valence state over large regions of the cathodes, it was found that the phase change is size-dependent. After prolonged cycling, the TMs displayed different levels of inactivity.
Keyphrases
- ion batteries
- electron microscopy
- high resolution
- transcranial magnetic stimulation
- solid state
- room temperature
- transition metal
- single molecule
- metal organic framework
- high intensity
- high frequency
- health risk
- reduced graphene oxide
- magnetic resonance imaging
- health risk assessment
- carbon nanotubes
- gold nanoparticles
- density functional theory
- magnetic resonance
- risk assessment
- ionic liquid