A <sup>57sup>Fe M枚ssbauer spectroscopy study of iron nanoparticles obtained in situ in conversion ferrite electrodes
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- 作者：Jean-Claude Jumas ; Manfred Womes ; Ricardo Alc谩ntara ; Pedro Lavela and Jos茅 L. Tirado
- 关键词：57Fe M枚ssbauer spectroscopy study ; Iron nanoparticles ; Conversion ferrite electrodes
- 刊名：Hyperfine Interactions
- 出版时间：April, 2008
- 出版年：2008
- 期刊代码：18_03043843
- 类别：cp
- 卷：183
- 期：1-3
- 页码：1-5
- 数据来源：sp
摘要
Transmission M枚ssbauer spectroscopy and CEMS are powerful tools to study the changes in which iron-containing active materials of conversion electrodes are involved during lithium cell charge and discharge. The usual spectrum of pristine CoFe<sub>2sub>O<sub>4sub> spinel with two sextets ascribable to Fe3 + ions in both tetrahedral and octahedral environments, changes dramatically after cell discharge to 0 V vs. Li, and can be interpreted as the result of iron reduction to the metallic state in the form of superparamagnetic metal nanoparticles dispersed in a Li<sub>2sub>O matrix. After cell charge to 3 V, the MS of the pristine sample is not recovered. Instead, two new doublets are visible with IS ascribable to Fe3 + ions. 57Fe CEMS evidences the different environment of iron atoms in the surface of the nanodispersed material found in the used electrodes.