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Title: 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

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.
Authors:
; ; ;  [1] ;  [2]
  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)
Publication Date:
OSTI Identifier:
22304482
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 2; Journal Issue: 7; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ELECTRIC BATTERIES; ELECTRODES; IRON IONS; IRON PHOSPHATES; LITHIUM IONS; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY