Electrochemical properties of hydrothermally obtained LiCo1-xFexO2 as a positive electrode material for rechargeable lithium batteries

Hironori Kobayashi, Hikari Shigemura, Mitsuharu Tabuchi, Hikari Sakaebe, Kazuaki Ado, Hiroyuki Kageyama, Atsushi Hirano, Ryoji Kanno, Masayuki Wakita, Shotaro Morimoto, Saburo Nasu

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)

Abstract

Changes in the crystal structure and transition metal valency in LiFexCo1-xO2 (0 ≤ x ≤ 0.25) positive electrodes during the charge-discharge of Li/LiFexCo1-xO2 cells were examined using ex situ X-ray diffraction measurements, Fe and Co K-X-ray absorption near edge spectroscopy (XANES) and 57Fe Mossbauer spectroscopy. An iron-doped host material with rhombohedral symmetry was obtained up to 25% Fe per formula unit in LiCoO2 by hydrothermal reaction below 300°C from a mixture of Co3+-Fe3+ co-precipitate (iron-doped CoOOH) and LiOH. No symmetry changes were observed during electrochemical charge-discharge tests up to the tenth cycle. The structures of Li-extracted and reinserted samples were determined by a model similar to LiCoO2 prepared at low temperature in which Li ions are located at the interstitial 6c and octahedral 3a sites. 57Fe Mossbauer and Fe and Co K-XANES spectra at 293 K indicated the presence of tetravalent Fe ions upon oxidation up to 4.3 V.

Original languageEnglish
Pages (from-to)960-969
Number of pages10
JournalJournal of the Electrochemical Society
Volume147
Issue number3
DOIs
Publication statusPublished - Mar 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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