Yin S-C, Grondey H, Strobel P, Anne M, Nazar L F
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
J Am Chem Soc. 2003 Aug 27;125(34):10402-11. doi: 10.1021/ja034565h.
Monoclinic lithium vanadium phosphate, alpha-Li(3)V(2)(PO(4))(3), is a highly promising material proposed as a cathode for lithium-ion batteries. It possesses both good ion mobility and high lithium capacity because of its ability to reversibly extract all three lithium ions from the lattice. Here, using a combination of neutron diffraction and (7)Li MAS NMR studies, we are able to correlate the structural features in the series of single-phase materials Li(3-y)V(2)(PO(4))(3) with the electrochemical voltage-composition profile. A combination of charge ordering on the vanadium sites and lithium ordering/disordering among lattice sites is responsible for the features in the electrochemical curve, including the observed hysteresis. Importantly, this work highlights the importance of ion-ion interactions in determining phase transitions in these materials.
单斜晶系的磷酸锂钒，α-Li(3)V(2)(PO(4))(3)，是一种极具潜力的材料，被提议用作锂离子电池的阴极。由于它能够从晶格中可逆地提取所有三个锂离子，因此具有良好的离子迁移率和高锂容量。在此，通过结合中子衍射和(7)Li MAS NMR研究，我们能够将单相材料Li(3-y)V(2)(PO(4))(3)系列中的结构特征与电化学电压-组成曲线相关联。钒位点上的电荷有序和晶格位点之间的锂有序/无序相结合，导致了电化学曲线中的特征，包括观察到的滞后现象。重要的是，这项工作突出了离子-离子相互作用在确定这些材料中的相变方面的重要性。
