In Situ Monitoring of Structural and Valence Evolution during Electrochemical Desodiation/Sodiation Process of Na2Fe0.5Mn0.5PO4F
In Situ Monitoring of Structural and Valence Evolution during Electrochemical Desodiation/Sodiation Process of Na2Fe0.5Mn0.5PO4F
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原位监测Na2Fe0.5Mn0.5PO4F电化学脱钠/钠化过程中的结构和价态演化
DOI：
10.1149/2.0281714jes
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发表时间：
2017
影响因子：
3.9
通讯作者：
Jiang Zheng
中科院分区：
文献类型：
--
作者：
Xie Yong;Wang Hongchun;Wang Zhigang;Gong Zhengliang;Liu Rui;Yang Yong;Wen Wen;Jiang Zheng
采用固相法合成了钠离子电池正极材料Na2Fe0.5Mn0.5PO4F。利用同步辐射原位X射线吸收近边结构（XANES）和X射线衍射（XRD）技术研究了Na2Fe0.5Mn0.5PO4F在电化学钠化/去钠化过程中的电子结构和晶体结构的演变，并辅以电化学分析.在12.4 mA/g下可获得107 mAh/g的可逆容量，具有两个明确的电压平台，中心为2.9和3.5 V vs. Na/Na+。在低电流密度（8 mA/g）下，Na2Fe0.5Mn0.5PO4F的K边XANES出现明显的边移，这与Fe 2+/Fe 3+和Mn 2+/Mn 3+氧化还原反应的充电曲线中的两个平台有关.将充电电流密度增加到100 mA/g，观察到Fe K边XANES的类似光谱行为。而Mn 3+/Mn 2+氧化还原电对的K边位移小于8 mA/g时的K边位移，表明Mn 3+/Mn 2+氧化还原电对的反应动力学较为缓慢.在Na2Fe0.5Mn0.5PO4F的原位XRD谱图中，观察到在整个充放电过程中衍射峰连续移动，没有出现新的衍射峰，表明发生了固溶过程。Na2Fe0.5Mn0.5PO4F在电化学钠化/去钠化过程中表现出良好的结构可逆性。
Na 2 Fe 0.5 Mn 0.5 PO 4 F as a cathode material for Na ion batteries is synthesized by a solid-state method. Synchrotron based in situ X-ray absorption near edge structure (XANES) and X-ray diffraction (XRD) techniques are used to study the electronic and crystal structure evolutions of Na 2 Fe 0.5 Mn 0.5 PO 4 F, complemented by electrochemical analyses during the electrochemical sodiation/desodiation. A reversible capacity of 107 mAh/g can be obtained at 12.4 mA/g with two well-defined voltage plateaus centered at 2.9 and 3.5 V vs. Na/Na+. Clear edge shifts in the Fe and Mn K-edge XANES are observed for Na 2 Fe 0.5 Mn 0.5 PO 4 F at low current density (ie, 8 mA/g), relating to the two plateaus in the charging curve associated with the Fe 2+/Fe 3+ and Mn 2+/Mn 3+ redox reactions sequentially. Increasing the charge current density to 100 mA/g, similar spectroscopic behavior is observed for Fe K-edge XANES. While, the Mn K-edge shift is smaller compared with this observed at 8 mA/g, indicating the sluggish reaction kinetic of Mn 3+/Mn 2+ redox couple. Continuous diffraction peaks shifts in in-situ XRD patterns of Na 2 Fe 0.5 Mn 0.5 PO 4 F are observed throughout the charge-discharge process without emergence of new peaks, indicating of solid-solution processes. Na 2 Fe 0.5 Mn 0.5 PO 4 F shows good structural reversibility during the electrochemical sodiation/desodiation.
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影响因子：
8.6
作者：
P. Serras;V. Palomares;J. Alonso;N. Sharma;J. L. Amo;P. Kubiak;M. L. Fdez-Gubieda;T. Rojo
通讯作者：
P. Serras;V. Palomares;J. Alonso;N. Sharma;J. L. Amo;P. Kubiak;M. L. Fdez-Gubieda;T. Rojo
影响因子：
8.6
作者：
N. Sharma;P. Serras;V. Palomares;H. Brand;J. Alonso;P. Kubiak;M. L. Fdez-Gubieda;T. Rojo
通讯作者：
N. Sharma;P. Serras;V. Palomares;H. Brand;J. Alonso;P. Kubiak;M. L. Fdez-Gubieda;T. Rojo
影响因子：
3.9
作者：
von Cresce, Arthur;Xu, Kang
通讯作者：
Xu, Kang
DOI：
10.1039/c2cp40082k
发表时间：
2012-02
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
Sung-Wook Kim;D. Seo;Hyungsub Kim;Kyu‐Young Park;K. Kang
通讯作者：
Sung-Wook Kim;D. Seo;Hyungsub Kim;Kyu‐Young Park;K. Kang
影响因子：
5.4
作者：
K. Nam;W. Yoon;K. Zaghib;K. Chung;Xiao‐Qing Yang
通讯作者：
K. Nam;W. Yoon;K. Zaghib;K. Chung;Xiao‐Qing Yang