冠醚对废旧锂离子电池浸出液中Li+选择性密度泛函理论研究

本文基于密度泛函理论研究了在水溶液中不同结构冠醚对Li~+的选择性.通过对几何结构、结合能和热力学的计算,发现15-冠-5(15C5)对Li~+的选择性强于12-冠-4(12C4)和18-冠-6(18C6).苯并15-冠-5(B15C5)与Li~+的结合能小于15C5,但在溶液巾结合Li~+时具有更低的自山能.研究了B15C5和Li、Co、Ni水合离子之间的交换反应,表明B15C5与水合锂离子之间的反应占据优势.上述结果表明采用B15C5从废旧钾离子电池浸出液中回收锂具有一定的可行性.

Density Functional Theory Study of Selectivity of Crown Ethers to Li+ in Spent Lithium-Ion Batteries Leaching Solutions

It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries, and crown ethers are potential extractants due to their selectivity to alkali metal ions. The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory. The calculated results of geometries, binding energies, and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4, 15C5, and 18C6. B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li⁺, leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5. The exchange reactions between B15C5 and hydrated Li⁺, Co²⁺, and Ni²⁺ were analyzed and the results show that B15C5 is more likely to capture Li⁺ from the hydrated ions in an aqueous solution containing Li⁺, Co²⁺, and Ni²⁺. This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.