Research Update: Retardation and acceleration of phase separation evaluated from observation of imbalance between structure and valence in LiFePO{sub 4}/FePO{sub 4} electrode

Journal Article · Tue Jul 01 04:00:00 EDT 2014 · APL Materials

DOI:https://doi.org/10.1063/1.4886555· OSTI ID:22304482

Tokuda, Kazuya; Kawaguchi, Tomoya; Ichitsubo, Tetsu; Matsubara, Eiichiro ^[1]; Fukuda, Katsutoshi ^[2]

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1. Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan)
2. Office of Society-Academia Collaboration for Innovation, Kyoto University, Kyoto, 615-8520 (Japan)

LiFePO{sub 4} is a potential positive electrode material for lithium ion batteries. We have experimentally observed an imbalance between the valence change of Fe ions and the structure change from the LiFePO{sub 4} phase to the FePO{sub 4} phase during delithiation by simultaneous in situ XRD and XANES measurements in an LiFePO{sub 4}/FePO{sub 4} electrode. The ratio of structure change to valence change clearly indicates that the phase separation from LiFePO{sub 4} to FePO{sub 4} is suppressed at the beginning of delithiation, while it is accelerated at the latter stage, which is due to the coherent strain caused by the lattice misfit between the two phases.

• OSTI ID: 22304482
• Journal Information: APL Materials, Journal Name: APL Materials Journal Issue: 7 Vol. 2; ISSN AMPADS; ISSN 2166-532X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
ELECTRIC BATTERIES
ELECTRODES
IRON IONS
IRON PHOSPHATES
LITHIUM IONS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY