Na3V2O2(PO4)2F3-2 as a stable positive electrode for potassium-ion batteries
Na3V2O2(PO4)2F3-2 as a stable positive electrode for potassium-ion batteries
复制标题
DOI：
10.1016/j.jpowsour.2021.229676
复制
发表时间：
2021-05
影响因子：
9.2
通讯作者：
P. R. Kumar;K. Kubota;Y. Miura;Mirai Ohara;Kazuma Gotoh;S. Komaba
中科院分区：
文献类型：
--
作者：
P. R. Kumar;K. Kubota;Y. Miura;Mirai Ohara;Kazuma Gotoh;S. Komaba
首次证实了钾离子在Na3V3+2(PO4) 2F3-2x和Na3V4+2O2(PO4)2F之间的固溶体Na3V2O2x(PO4)2F3-2x中的可逆插入。采用常规水热反应制备了V3+/V4+-混合Na3V2O2x(PO4) 2f3 -2x-多壁碳纳米管（MWCNT）复合材料。Na3V2O2x(PO4)2F3-2x-MWCNT复合材料由于氟化磷酸氧化物的累积感应效应，在钾电池中表现出3.7 V的平均电极电位。所制备的复合材料在0.1C （13 mA g - 1）倍率下的初始放电容量为118 mAh g - 1，具有良好的循环稳定性和高倍率性能。电化学测量、能量色散x射线分析、非原位和操作x射线衍射为在初始循环中进行电化学K/Na交换过程后的后续循环中的可逆相变提供了新的见解。
Reversible potassium ion insertion into Na3V2O2x(PO4)2F3-2x,which is regarded as a solid solution between Na3V3+2(PO4)2F3and Na3V4+2O2(PO4)2F is demonstrated for the first time. V3+/V4+-mixed Na3V2O2x(PO4)2F3-2x-multiwalled carbon nanotube (MWCNT) composite was prepared by a conventional hydrothermal reaction. Na3V2O2x(PO4)2F3-2x-MWCNT composite exhibiting an average electrode potential of 3.7 V in a potassium cell due to the cumulative inductive effect of phosphate fluoride oxide. The prepared composite delivers an initial discharge capacity of 118 mAh g−1at 0.1C (13 mA g−1) rate with good cycle stability and high-rate capability performances. The electrochemical measurements, energy dispersive X-ray analysis,ex-situ,andoperandoX-ray diffractions provide new insights into reversible phase transformations during the subsequent cycles after an electrochemical K/Na exchange process at the initial cycle.