More on the reactivity of olivine LiFePO₄ nano-particles with atmosphere at moderate temperature

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• 作者：Jean-Fré ; dé ; ric Martin ; Marine Cuisinier ; Nicolas Dupré ; Atsuo Yamada ; Ryoji Kanno ; Dominique Guyomard
• 关键词：Lithium batteries ; LiFePO₄ ; Aging
• 刊名：Journal of Power Sources
• 出版年：2011
• 出版时间：15 February 2011
• 年：2011
• 卷：196
• 期：4
• 页码：2155-2163
• 全文大小：962 K

文摘

The changes appearing for LiFePO₄–C nano-composites exposed to atmosphere at 120 °C have been structurally and chemically examined by the use of TGA, XRD, XPS, Mössbauer, ⁷Li MAS NMR and electrochemical methods. The results conclude that a highly disordered phase resulting from the aging of LiFePO₄ appears on the surface of the grains of the material, is assigned to a phosphate phase and can insert lithium around 2.6 V with poor reversibility. The essential role of water has been investigated and clearly demonstrated. Thus, the aging mechanism occurring in hot humid air is completely different from a simple oxidation as well as from the aging process observed above 150 °C and involves the incorporation of hydroxyl groups. In addition, Fe₂O₃ formation has not been observed for such an aging in mild conditions.