Yan Gangbin, Kim George, Yuan Renliang, Hoenig Eli, Shi Fengyuan, Chen Wenxiang, Han Yu, Chen Qian, Zuo Jian-Min, Chen Wei, Liu Chong
Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA.
Department of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA.
Nat Commun. 2022 Aug 5;13(1):4579. doi: 10.1038/s41467-022-32369-y.
Electrochemical intercalation can enable lithium extraction from dilute water sources. However, during extraction, co-intercalation of lithium and sodium ions occurs, and the response of host materials to this process is not fully understood. This aspect limits the rational materials designs for improving lithium extraction. Here, to address this knowledge gap, we report one-dimensional (1D) olivine iron phosphate (FePO) as a model host to investigate the co-intercalation behavior and demonstrate the control of lithium selectivity through intercalation kinetic manipulations. Via computational and experimental investigations, we show that lithium and sodium tend to phase separate in the host. Exploiting this mechanism, we increase the sodium-ion intercalation energy barrier by using partially filled 1D lithium channels via non-equilibrium solid-solution lithium seeding or remnant lithium in the solid-solution phases. The lithium selectivity enhancement after seeding shows a strong correlation with the fractions of solid-solution phases with high lithium content (i.e., LiFePO with 0.5 ≤ x < 1). Finally, we also demonstrate that the solid-solution formation pathway depends on the host material's particle morphology, size and defect content.
电化学插层能够实现从稀水源中提取锂。然而，在提取过程中，锂离子和钠离子会发生共插层，且主体材料对这一过程的响应尚未完全明晰。这一方面限制了用于改善锂提取的合理材料设计。在此，为填补这一知识空白，我们报道一维（1D）橄榄石型磷酸铁（FePO）作为模型主体，以研究共插层行为，并通过插层动力学操控展示对锂选择性的控制。通过计算和实验研究，我们表明锂和钠在主体中倾向于相分离。利用这一机制，我们通过非平衡固溶体锂晶种或固溶体相中残留的锂，利用部分填充的一维锂通道来提高钠离子的插层能垒。晶种后锂选择性的提高与高锂含量固溶体相（即0.5≤x＜1的LiFePO）的比例密切相关。最后，我们还证明固溶体形成途径取决于主体材料的颗粒形态、尺寸和缺陷含量。
