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Improving electrochemical properties and structural stability of lithium manganese silicates as cathode materials for lithium ion batteries via introducing lithium excess
Author(s) -
Wang Min,
Ding Chuan,
Miao Yingchun,
Liu Tianyu,
Hang Kang,
Zhang Jintao
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4932
Subject(s) - lithium (medication) , electrochemistry , ion , materials science , amorphous solid , crystal structure , structural stability , cathode , lithium vanadium phosphate battery , manganese , chemical engineering , chemistry , inorganic chemistry , electrode , crystallography , organic chemistry , metallurgy , structural engineering , engineering , medicine , endocrinology
Summary The serious capacity decay caused by structural amorphization is still a major issue for polyanion‐type lithium manganese silicates (Li 2 MnSiO 4 ) as cathode material for lithium ion batteries. In this work, a new strategy for alleviating the structural instability via the introduction of excess lithium into the host crystal lattice is provided. A comprehensive study demonstrates that the required energy for the extraction/insertion of lithium ions into host crystal lattice was decreased as a result of changed local environment of cations in the compound after the excess lithium occupancy in lattice. Importantly, it was found that Li‐rich samples deliver higher reversible capacity and increased average potential than pristine sample, indicating the improved energy density of polyanion‐type Li 2 + 2x Mn 1 − x SiO 4 /C . Additionally, the structure of Li2.2 sample was kept intact, while the Li2.0 sample was transformed to amorphous state at 200 mA h g −1 during the initial charging process by controlling the charge cut‐off potential. As expected, the introduction of a certain amount of excess lithium into Li 2 MnSiO 4 is explored as a route to achieving increased capacity with more movable lithium, while maintaining its structural stability and cyclic stability.