Investigation of phase structure change and electrochemical performance in LiVP2O7-Li3V2(PO4)3-LiVPO4F system
Investigation of phase structure change and electrochemical performance in LiVP2O7-Li3V2(PO4)3-LiVPO4F system
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DOI：
10.1016/j.electacta.2016.03.070
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发表时间：
2016-04
影响因子：
6.6
通讯作者：
Jun‐chao Zheng;Han Yadong;Linbo Tang;Bao Zhang
中科院分区：
文献类型：
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作者：
Jun‐chao Zheng;Han Yadong;Linbo Tang;Bao Zhang
磷酸钒由于具有钒的化学活性和磷酸盐结构的稳定性，在锂离子电池研究中受到了广泛的关注。采用固相法合成了新型LiVP2O7 - Li3V2(PO4)3 - LiVPO4F体系，采用TG-DTA、XRD、TEM等测试手段研究了LiVP2O7、Li3V2(PO4)3、LiVPO4F的化学反应、相形成及相结构变化。结果表明：在575℃烧结时，Li3V2(PO4)3、LiVP2O7和LiVPO4F共存，并随着烧结温度的变化而相互转化。电化学测试表明，通过调节LiVP2O7、Li3V2(PO4)3和LiVPO4F的含量，可以获得不同的电化学性能。由于Li3V2(PO4)3和LiVP2O7之间的协同作用，在625℃下合成的LiVP2O7 - Li3V2(PO4)3样品具有更好的电化学性能。
Vanadium phosphates have attracted considerable attention in Li-ion battery research because they feature the chemical activity of vanadium and the structural stability of phosphate. Novel LiVP2O7–Li3V2(PO4)3–LiVPO4F systems were synthesized through solid-state reaction, and the chemical reaction, phase formation, and phase structure change of LiVP2O7, Li3V2(PO4)3, LiVPO4F were investigated using TG–DTA, XRD, and TEM tests. Results indicate that Li3V2(PO4)3, LiVP2O7, and LiVPO4F coexist in samples sintered at 575 °C, and the three phases transform into one other by changing the sintering temperature. Electrochemical tests show that different electrochemical performances can be obtained by regulating the contents of each phase (LiVP2O7, Li3V2(PO4)3, or LiVPO4F). The LiVP2O7–Li3V2(PO4)3sample synthesized at 625 °C shows much better electrochemical performance because of the synergistic effects between Li3V2(PO4)3and LiVP2O7.