Constructing Mechanical Shuttles in a Three‐dimensional (3D) Porous Architecture for Selective Transport of Lithium Ions

Abstract

Lithium (Li) extraction from brines is a major barrier to the sustainable development of batteries and alloys; however, current separation technology suffers from a trade-off between ion selectivity and permeability. Herein, a crown ether mechanically interlocked 3D porous organic framework (Crown-POF) was prepared as the porous filler of thin-film nanocomposite membranes. Crown-POF with penta-coordinated (four O crown atoms and one N tert-amine atom) adsorption sites enables a special recognition for Li + ion. Moreover, the four N tertamine atoms on each POF branch facilitate the flipping motion of Li + ion along the skeletal thread, while retaining the specified binding pattern. Accordingly, the crown ether interlocked POF network displays an ultrafast ion transfer rate, over 10 times that of the conventional porous materials. Notably, the nanocomposite membrane gives high speed and selectivity for Li + ion transport as compared with other porous solid-based mixed-matrix membranes.

Highly Selective Transport and Enrichment of Lithium Ions through Bionic Ion Pair Receptor Nanochannels

“…All chemicals were A.R. grade and were purchased from Sinopharm Chemical Reagent Shanghai Co., Ltd. 1 H NMR and 13 C NMR were recorded on the Varian Mercury VX600 instrument at ambient temperature with TMS as the internal standard. Fluorescence spectra were recorded on a Cary Eclipse.…”

“…However, an amount of lithium was distributed in soil and groundwater and coexisted with other alkali and alkaline earth cations. Because of the high hydration energy and small size, it is extremely difficult to selectively recognize and enrich lithium from the natural environment. − Therefore, how to achieve the highly selective transport and enrichment of Li + from the environment to application in reality is an imperative and important scientific issue.…”

Harnessing ion–dipole interactions: a simple and effective approach to high-performance lithium receptors

“…A pioneering work in this domain was exemplied [31][32][33][34][35][36] by Donald Cram's spherands, which displayed an extraordinary binding affinity exceeding 10 16 M −1 for Li + due to their rigid and preorganized binding cavities. In alignment with this foundational principle, numerous macrocyclic scaffolds have been devised for Li + binding, employing molecular design strategies based on crown ether derivatives, 21,27,28,[37][38][39][40][41][42][43] ion pair receptors, 16,25,25,[44][45][46][47][48] mechanically interlocked molecules, 26,[49][50][51][52] and organometallic macrocycles. 18,19,29,53 However, despite the success in achieving strong binding affinity for Li + , the majority of these macrocyclic receptors exhibit limited Li + /Na + selectivity (ratio <1000) and necessitate high-dilution conditions during synthesis.…”

A Bioinspired Free‐Standing 2D Crown‐Ether‐Based Polyimine Membrane for Selective Proton Transport

“…Ion selective transport, [1] especially proton transmembrane transport, shows great applications in several fields, such as ion separation, [2] fuel cells, [3] and ionic energy conversion and storage, [4] etc. Biological proton-selective transport shows high efficiency, low energy consumption, and high selectivity.…”