Chemical state of Iron of LiFePO4during charge-discharge cycles studied by in-situ X-ray absorption spectroscopy

Katsuya Inoue, Shun Fujieda, Kozo Shinoda, Shigeru Suzuki, Yoshio Waseda

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In-situ X-ray absorption spectroscopy (XAS) at the Fe K-edge X-ray absorption near edge was used to investigate the chemical change of LiFePO 4, which is a candidate cathode material for lithium ion batteries, during charge-discharge cycles. The relative amount of FePO4 formed in the LiFePO4 by the charge-discharge cycles was estimated from the XAS spectra. The results show that the amount Of FePO4 in the LiFePO4 increased with charging and decreased with discharging. While a linear relationship between the relative amount of FePO4 and electrical capacity was observed during the initial charging, it deviated from linearity during the charge-discharge cycles. This may be attributed to the irreversible diffusion paths of lithium ions and/or the partial formation of inactive FePO4 in the LiFePO4 during the charge-discharge cycles. It is shown that in-situ XAS has sufficient potential to nondestructively characterize heteroseneous electrochemical reactions in electrode materials during charge-discharge cycles.

Original languageEnglish
Pages (from-to)2220-2224
Number of pages5
JournalMaterials Transactions
Volume51
Issue number12
DOIs
Publication statusPublished - 2010 Dec 1

Keywords

  • Cathode material
  • In-situ x-ray absorption spectroscopy
  • Iron phosphate
  • Lithium ion battery
  • X-ray absorption near edge structure

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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