Sodium and mixed sodium/lithium iron ortho-pyrophosphates: Synthesis, structure and electrochemical properties
Sodium and mixed sodium/lithium iron ortho-pyrophosphates: Synthesis, structure and electrochemical properties
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DOI：
10.1016/j.electacta.2018.05.034
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发表时间：
2018-07-10
影响因子：
6.6
通讯作者：
Belotserkovsky, Valery A.
中科院分区：
文献类型：
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作者：
Kosova, Nina V.;Belotserkovsky, Valery A.
以草酸铁为前驱体，采用快速简便的机械化学辅助固相法合成了Na4Fe3(PO4)(2)P2O7 （NFPP）。通过XRD、FTIR和M.ssbauer谱分析发现，在450℃下退火制备的NFPP是最均匀的相，并且在Na和Li电池中循环时都表现出最好的电化学行为。在锂电池中循环和用LiBr进行化学处理时，发生Na+/Li+离子交换。结果表明，在这两种情况下，该过程都不完全完成，并导致混合Na/Li化合物的形成。研究了制备的钠/锂铁混合正磷酸铁的相组成、晶体结构和局部结构以及电化学性能。在循环过程中，剩余的Nathorn离子稳定了Na4-xLixFe3(PO4)(2)P2O7 （NLFPP）的结构，并且在杂化Na/Li电池中实现了阴极侧Nathorn/ liton （de）插层。混合NLFPP是一种具有高能量和高功率特性的锂离子电池正极材料。(C) 2018 Elsevier Ltd.版权所有。
Na4Fe3(PO4)(2)P2O7 (NFPP) was synthesized by the fast and facile mechanochemically assisted solid-state route using iron oxalate as a precursor. By means of XRD, FTIR, and M.ssbauer spectroscopy, it was found that NFPP prepared by annealing the activated mixture at 450 degrees C is the most homogeneous phase and shows the best electrochemical behavior when cycling in both Na and Li cells. During its cycling in a Li cell and chemical treatment with LiBr the Na+/Li+ ion exchange occurs. It has been shown that in both cases the process is not fully complete and leads to the formation of the mixed Na/Li compounds. Phase composition, crystal and local structure, and electrochemistry of the as-prepared mixed Na/Li iron orthopyrophosphates were investigated. We concluded that the remaining Nathorn ions stabilize the structure of Na4-xLixFe3(PO4)(2)P2O7 (NLFPP) during cycling, and the simultaneous Nathorn/Lithorn (de) intercalation at the cathode side is realized in the hybrid Na/Li cells. Mixed NLFPP can be considered as promising cathode materials for Li-ion batteries with high energy and power characteristics. (C) 2018 Elsevier Ltd. All rights reserved.