In Situ Mössbauer Effect Study of Lithium Intercalation in LiFe2F6
In Situ Mössbauer Effect Study of Lithium Intercalation in LiFe2F6
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LiFe2F6 中锂嵌入的原位穆斯堡尔效应研究
DOI：
10.1149/1.3473809
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发表时间：
2010
影响因子：
3.9
通讯作者：
J. Dahn
中科院分区：
文献类型：
--
作者：
Peng Liao;R. Dunlap;J. Dahn
采用高能球磨法制备了具有无序三金红石结构的Li1.2Fe2F6.2样品，并利用原位穆斯堡尔谱研究了该材料的可逆嵌锂行为。在首次放电至2.0V（加锂）期间，Fe 3+的百分比随锂含量从46%线性下降至11%，而Fe 2+的百分比从54%线性上升至89%。在此电位范围内没有观察到Fe°的证据，表明在高于2.0 V时不发生置换反应。在第一次充电（去除锂）至4.5 V期间，Fe 3+的百分比从11%增加至68%，而Fe 2+的百分比从89%降低至32%。Li 1.2± zFe2F6.2电池在2.0 ~ 4.5V之间，Fe氧化态的变化与z呈1：1的相关性。当Li/Li 1.2Fe2F6.2电池充电到高于4.5V时，Fe 3+的百分比并不随电池容量线性增加，表明在高于4.5V时会发生副反应。
A sample of Li 1.2 Fe 2 F 6.2 with a disordered trirutile structure was prepared by high energy ball milling, and reversible lithium intercalation in this material was investigated using in situ Mossbauer spectroscopy. During the first discharge to 2.0 V (adding lithium), the percentage of Fe 3+ decreased linearly with lithium content from 46 to 11%, while the percentage of Fe 2+ increased linearly from 54 to 89%. No evidence of Fe° was observed in this potential range indicating that displacement reactions do not occur above 2.0 V. During the first charge (removing lithium) to 4.5 V, the percentage of Fe 3+ increased from 11 to 68%, while the percentage of Fe 2+ decreased from 89 to 32%. The change in the Fe oxidation state showed a 1:1 correlation with z in Li 1.2±z Fe 2 F 6.2 between 2.0 and 4.5 V. When Li/Li 1.2 Fe 2 F 6.2 cells were charged to voltages higher than 4.5 V, the percentage of Fe 3+ did not increase linearly with the cell capacity, indicating that side reactions occur above 4.5 V.