锂离子占位情况对钛酸锂结构及性能的影响

The influence of lithium-ion occupation on its structure and properties of Li4Ti5O12

摘要:

Li₄Ti₅O₁₂在快速充放电条件下具有优异的结构稳定性和高安全性,使其受到新能源汽车和储能领域的青睐。大量的研究人员已经对钛酸锂的锂离子插层过程进行了研究,研究表明放电过程中外界和位于8a位的锂离子全部转移到16c位,钛酸锂的容量受限于参与其中晶格位点和可逆锂离子的数量。然而,钛酸锂晶胞结构表明可容纳锂离子的晶格位点不止于此。锂离子可能取代Ti原子占据八面体16d位点,位于四面体48f位点,重新占据相变后空出的四面体的8a位点。本文主要综述了在Li₄Ti₅O₁₂的制备过程或成品中,通过化学或电化学方法处理后,LTO中锂离子占位情况与传统认知发生的改变及其这种变化带来的影响。同时,本文对这种变化和影响之间的内在机理展开了讨论和分析。

Abstract:

Li₄Ti₅O₁₂ has excellent structural stability and high safety under fast charging and discharging conditions. Therefore, it was favored by the field of new energy vehicles and energy storage. Ample researchers have focused on Li ions intercalation process of lithium titanate, Studies have shown that the discharge process is the external and all the lithium ions located at 8a position are transferred to 16c position, and the capacity of lithium titanate is limited by the number of lattice sites and reversible lithium ions involved in it. However, the lithium titanate unit cell structure suggests that the lattice sites that accommoddate lithium ions do not stop there. Li ions may replace Ti atoms occupy the octahedral 16d site, locate in tetrahedral 48f sites, reoccupy with 8a sites of the tetrahedron vacated after the phase change. This article mainly reviews, treated by chemical or electrochemical methods in the preparation process and finished product, compared with the normal LTO discharge start and end, the Li ions occupation changes and influence. Meanwhile, this paper discusses and analyzes the underlying mechanism between this change and effect.