What Happens to LiMnPO4 upon Chemical Delithiation?

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• 作者：Yiqing Huang ; Natasha A. Chernova ; Qiyue Yin ; Qi Wang ; Nicholas F. Quackenbush ; Michal Leskes ; Jin Fang ; Fredrick Omenya ; Ruibo Zhang ; Matthew J. Wahila ; Louis F. J. Piper ; Guangwen Zhou ; Clare P. Grey ; M. Stanley Whittingham
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：May 2, 2016
• 年：2016
• 卷：55
• 期：9
• 页码：4335-4343
• 全文大小：661K
• 年卷期：0
• ISSN：1520-510X

文摘

Olivine MnPO₄ is the delithiated phase of the lithium-ion-battery cathode (positive electrode) material LiMnPO₄, which is formed at the end of charge. This phase is metastable under ambient conditions and can only be produced by delithiation of LiMnPO₄. We have revealed the manganese dissolution phenomenon during chemical delithiation of LiMnPO₄, which causes amorphization of olivine MnPO₄. The properties of crystalline MnPO₄ obtained from carbon-coated LiMnPO₄ and of the amorphous product resulting from delithiation of pure LiMnPO₄ were studied and compared. The phosphorus-rich amorphous phases in the latter are considered to be MnHP₂O₇ and MnH₂P₂O₇ from NMR, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy analysis. The thermal stability of MnPO₄ is significantly higher under high vacuum than at ambient condition, which is shown to be related to surface water removal.