Valence fluctuations of 57Fe in disordered Li0.6FePO4

被引：23

作者：

Dodd, J. L. ^{[1
]}

Halevy, I. ^{[1
]}

Fultz, B. ^{[1
]}

机构：

[1] CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA

来源：

JOURNAL OF PHYSICAL CHEMISTRY C | 2007年 / 111卷 / 04期

关键词：

D O I：

10.1021/jp067710x

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The local electronic structure around iron ions in Li0.6FePO4 was studied by Fe-57 Mossbauer spectrometry at temperatures from 25 to 240 degrees C. The equilibrium two-phase, triphylite plus heterosite, material was compared to a disordered solid solution that was obtained by quenching from a high temperature. Substantial electronic relaxations were found in the disordered solid solution compared to the two-phase material at temperatures of 130 degrees C and above. Fluctuations in the electric field gradient showed an approximately Arrhenius behavior, with an activation energy of 335 +/- 25meV and a prefactor of 5 x 10(11) Hz, whereas Arrhenius plots for the isomer shift showed activation energies of approximately 600 meV. It is suggested that these spectral relaxations are caused by the motions of Li+ ions. A slight relaxation at 180 degrees C in 10% of the two-phase material can be attributed to defects in the heterosite and triphylite phases. Overall, the disordered solid solution phase shows faster electronic dynamics than the two-phase material.

引用

页码：1563 / 1566

页数：4

共 23 条

[1] Lithium extraction/insertion in LiFePO4:: an X-ray diffraction and Mossbauer spectroscopy study [J].