Phonons and Thermodynamics of Unmixed and Disordered Li0.6FePO4

The lithium-storage material Li0.6FePO4 was studied by inelastic neutron scattering and differential scanning calorimetry. Li0.6FePO4 undergoes a transformation from a two-phase mixture (heterosite and triphylite) to a disordered solid-solution at 200 °C. Phonon densities of states (DOS) obtained fr...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2006-11, Vol.110 (45), p.22732-22735
Main Authors: Stevens, R, Dodd, J. L, Kresch, M. G, Yazami, R, Fultz, B, Ellis, B, Nazar, L. F
Format: Article
Language:English
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Summary:The lithium-storage material Li0.6FePO4 was studied by inelastic neutron scattering and differential scanning calorimetry. Li0.6FePO4 undergoes a transformation from a two-phase mixture (heterosite and triphylite) to a disordered solid-solution at 200 °C. Phonon densities of states (DOS) obtained from the inelastic neutron scattering were similar for the two-phase sample measured at 180 °C and the disordered sample measured at 220 °C. The vibrational entropy of transformation is 1.8 ±0.9 J/(K mol), which is smaller than the configurational entropy difference of approximately 3.1 J/(K mol). The measured enthalpy of the disordering transition was estimated as 2.5 kJ/mol. The phonon data show a small change in lattice dynamics upon disordering.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp063831l