Co-intercalation of Mg2+ and Na+ in Na0.69Fe2(CN)6 as a High-Voltage Cathode for Magnesium Batteries

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• 作者：Dong-Min Kim ; Youngjin Kim ; Durairaj Arumugam ; Sang Won Woo ; Yong Nam Jo ; Min-Sik Park ; Young-Jun Kim ; Nam-Soon Choi ; Kyu Tae Lee
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 6, 2016
• 年：2016
• 卷：8
• 期：13
• 页码：8554-8560
• 全文大小：483K
• ISSN：1944-8252

文摘

Thanks to the advantages of low cost and good safety, magnesium metal batteries get the limelight as substituent for lithium ion batteries. However, the energy density of state-of-the-art magnesium batteries is not high enough because of their low operating potential; thus, it is necessary to improve the energy density by developing new high-voltage cathode materials. In this study, nanosized Berlin green Fe₂(CN)₆ and Prussian blue Na_0.69Fe₂(CN)₆ are compared as high-voltage cathode materials for magnesium batteries. Interestingly, while Mg²⁺ ions cannot be intercalated in Fe₂(CN)₆, Na_0.69Fe₂(CN)₆ shows reversible intercalation and deintercalation of Mg²⁺ ions, although they have the same crystal structure except for the presence of Na⁺ ions. This phenomenon is attributed to the fact that Mg²⁺ ions are more stable in Na⁺-containing Na_0.69Fe₂(CN)₆ than in Na⁺-free Fe₂(CN)₆, indicating Na⁺ ions in Na_0.69Fe₂(CN)₆ plays a crucial role in stabilizing Mg²⁺ ions. Na_0.69Fe₂(CN)₆ delivers reversible capacity of approximately 70 mA h g^–1 at 3.0 V vs Mg/Mg²⁺ and shows stable cycle performance over 35 cycles. Therefore, Prussian blue analogues are promising structures for high-voltage cathode materials in Mg batteries. Furthermore, this co-intercalation effect suggests new avenues for the development of cathode materials in hybrid magnesium batteries that use both Mg²⁺ and Na⁺ ions as charge carriers.