Open AccessXAFS study of LiCo 1‐ x Fe x O 2 cathode for rechargeable lithium battery by laboratory XAFS spectrometer
Author(s) -
Kageyama Hiroyuki,
Shigemura Hikari,
Tabuchi Mitsuharu,
Ado Kazuaki,
Kobayashi Hironori
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049501002606
Subject(s) - xanes , x ray absorption fine structure , extended x ray absorption fine structure , analytical chemistry (journal) , lithium (medication) , intercalation (chemistry) , k edge , absorption (acoustics) , chemistry , x ray absorption spectroscopy , materials science , electrochemistry , absorption spectroscopy , spectral line , crystallography , inorganic chemistry , electrode , spectroscopy , medicine , physics , chromatography , quantum mechanics , astronomy , composite material , endocrinology
The change of local structure in layered‐rock‐salt‐type iron doped lithium cobaltate LiCo 1‐x Fe x O 2 under electrochemical Li de‐intercalation (charge) /re‐intercalation (discharge) was studied by a laboratory type XAFS spectrometer. In Co K‐XANES and Fe K‐XANES of LiCo 0.85 Fe 0.15 O 2 the absorption peak shifted to higher energy by 1.5‐2eV for Co K‐edge and by 2‐2.5eV for Fe K‐edge, respectively, after the first charge. The spectra returned close to initial position and had almost original shape after the first discharge. In Co K‐ and Fe K‐EXAFS of LiCo 0.85 Fe 0.15 O 2 during the first charge and discharge the reversible change of the local structure was observed mainly around the Co atoms although the partly irreversible change of the local structure was found around the Fe atoms. The variation of local structure occurred in similar manner for the samples with x=0.05 and 0.25. This indicates that both Co 3+ /Co 4+ and Fe 3+ /Fe 4+ redox reactions occur reversibly during the first charge and discharge.