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Size‐Mediated Recurring Spinel Sub‐nanodomains in Li‐ and Mn‐Rich Layered Cathode Materials
Author(s) -
Xiao Biwei,
Liu Hanshuo,
Chen Ning,
Banis Mohammad Norouzi,
Yu Haijun,
Liang Jianwen,
Sun Qian,
Sham TsunKong,
Li Ruying,
Cai Mei,
Botton Gianluigi A.,
Sun Xueliang
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202005337
Subject(s) - x ray absorption spectroscopy , cathode , spinel , transmission electron microscopy , materials science , electron energy loss spectroscopy , dissolution , absorption spectroscopy , valence (chemistry) , spectroscopy , phase transition , ion , electrode , chemical physics , analytical chemistry (journal) , nanotechnology , chemistry , condensed matter physics , metallurgy , optics , physics , organic chemistry , quantum mechanics , chromatography
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 LiMn 2 O 4 ‐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.