Single-Phase Lithiation and Delithiation of Simferite Compounds Li(Mg,Mn,Fe)PO4

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• 作者：Fredrick Omenya ; Joel K. Miller ; Jin Fang ; Bohua Wen ; Ruibo Zhang ; Qi Wang ; Natasha A. Chernova ; M. Stanley Whittingham
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：26
• 期：21
• 页码：6206-6212
• 全文大小：483K
• ISSN：1520-5002

文摘

Understanding the phase transformation behavior of electrode materials for lithium ion batteries is critical in determining the electrode kinetics and battery performance. Here, we demonstrate the lithiation/delithiation mechanism and electrochemical behavior of the simferite compound, LiMg_0.5Fe_0.3Mn_0.2PO₄. In contrast to the equilibrium two-phase nature of LiFePO₄, LiMg_0.5Fe_0.3Mn_0.2PO₄ undergoes a one-phase reaction mechanism as confirmed by ex situ X-ray diffraction at different states of delithiation and electrochemical measurements. The equilibrium voltage measurement by galvanostatic intermittent titration technique shows a continuous change in voltage at Mn³⁺/Mn²⁺ redox couple with addition of Mg²⁺ in LiMn_0.4Fe_0.6PO₄ olivine structure. There is, however, no significant change in the Fe³⁺/Fe²⁺ redox potential.