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XPS investigations of valence changes during cycling of LiCrMnO 4 ‐based cathodes in Li‐ion batteries
Author(s) -
Oswald S.,
Nikolowski K.,
Ehrenberg H.
Publication year - 2010
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3296
Subject(s) - x ray photoelectron spectroscopy , spinel , cathode , manganese , electrode , electrochemistry , valence (chemistry) , chromium , materials science , intercalation (chemistry) , ion , battery (electricity) , analytical chemistry (journal) , chemical engineering , chemistry , inorganic chemistry , metallurgy , power (physics) , physics , organic chemistry , chromatography , engineering , quantum mechanics
Li‐ion batteries have to be improved for high‐performance applications especially for automotive application. One aim is the search for new electrode materials with superior properties and their detailed characterization. We used ‘ quasi in situ ’ X‐ray photoelectron spectroscopy (XPS) to investigate electrode material of the spinel‐type LiCrMnO 4 for the cathode during electrochemical cycling. It was found that during charging (de‐intercalation of Li from the cathode) chromium is converted from Cr 3+ to Cr 6+ , whereas manganese changes from Mn 4+ to Mn 3+ . Especially when charging to the maximum capacity (at about 5.2 V), this conversion seems to be partially irreversible. The chemical and structural changes connected with this conversion are the possible reason for the irreversible capacity loss at such high charging voltages, which is confirmed by the analysis of the electrode material after 100 charging/discharging cycles. Copyright © 2010 John Wiley & Sons, Ltd.