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Atomic Structure of Li 2 MnO 3 after Partial Delithiation and Re‐Lithiation
Author(s) -
Wang Rui,
He Xiaoqing,
He Lunhua,
Wang Fangwei,
Xiao Ruijuan,
Gu Lin,
Li Hong,
Chen Liquan
Publication year - 2013
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201200842
Subject(s) - materials science , lithium (medication) , manganese , cathode , electrochemistry , scanning transmission electron microscopy , transmission electron microscopy , ion , crystallography , nanotechnology , chemistry , electrode , metallurgy , medicine , organic chemistry , endocrinology
Li 2 MnO 3 is the parent compound of the well‐studied Li‐rich Mn‐based cathode materials x Li 2 MnO 3 ·(1‐ x )LiMO 2 for high‐energy‐density Li‐ion batteries. Li 2 MnO 3 has a very high theoretical capacity of 458 mA h g −1 for extracting 2 Li. However, the delithiation and lithiation behaviors and the corresponding structure evolution mechanism in both Li 2 MnO 3 and Li‐rich Mn‐based cathode materials are still not very clear. In this research, the atomic structures of Li 2 MnO 3 before and after partial delithiation and re‐lithiation are observed with spherical aberration‐corrected scanning transmission electron microscopy (STEM). All atoms in Li 2 MnO 3 can be visualized directly in annular bright‐field images. It is confirmed accordingly that the lithium can be extracted from the LiMn 2 planes and some manganese atoms can migrate into the Li layer after electrochemical delithiation. In addition, the manganese atoms can move reversibly in the (001) plane when ca. 18.6% lithium is extracted and 12.4% lithium is re‐inserted. LiMnO 2 domains are also observed in some areas in Li 1.63 MnO 3 at the first cycle. As for the position and occupancy of oxygen, no significant difference is found between Li 1.63 MnO 3 and Li 2 MnO 3 .