Baur Christian, Lǎcǎtuşu Monica-Elisabeta, Fichtner Maximilian, Johnsen Rune E
Helmholtz Institute Ulm, Helmholtzstraβe 11, 89081 Ulm, Germany.
Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby, Denmark.
ACS Appl Mater Interfaces. 2020 Jun 17;12(24):27010-27016. doi: 10.1021/acsami.0c02391. Epub 2020 Jun 5.
Disordered rock salt LiVOF cathode material for lithium-ion batteries was investigated using X-ray diffraction and total scattering to gain insight into the structural changes of the short-range and long-range orders during electrochemical cycling. The X-ray powder diffraction data show the well-known pattern of the disordered rock salt cubic structure, whereas the pair distribution function (PDF) analysis reveals significant deviations from the ideal cubic structure. During battery operation, a reversible rock salt-to-amorphous phase transformation is observed, upon Li extraction and reinsertion. The X-ray total scattering data show strong indications of the formation of tetrahedrally coordinated V in a nondisordered rock salt phase of the charged electrode material. The results show that the disordered rock salt LiVOF material undergoes a hidden structural rearrangement during battery operation.
采用X射线衍射和全散射技术对用于锂离子电池的无序岩盐LiVOF正极材料进行了研究，以深入了解电化学循环过程中短程和长程有序结构的变化。X射线粉末衍射数据显示出无序岩盐立方结构的典型图谱，而对分布函数（PDF）分析则揭示了与理想立方结构的显著偏差。在电池运行过程中，在锂的脱出和再嵌入时，观察到了可逆的岩盐到非晶相转变。X射线全散射数据有力地表明，在充电电极材料的无序岩盐相中形成了四面体配位的V。结果表明，无序岩盐LiVOF材料在电池运行过程中经历了隐藏的结构重排。
