Engineer Nanoscale Defects into Selective Channels: MOF-Enhanced Li+ Separation by Porous Layered Double Hydroxide Membrane

Abstract

Two-dimensional (2D) membrane-based ion separation technology has been increasingly explored to address the problem of lithium resource shortage, yet it remains a sound challenge to design 2D membranes of high selectivity and permeability for ion separation applications. Zeolitic imidazolate framework functionalized modified layered double hydroxide (ZIF-8@MLDH) composite membranes with high lithium-ion (Li+) permeability and excellent operational stability were obtained in this work by in situ depositing functional ZIF-8 nanoparticles into the nanopores acting as framework defects in MLDH membranes. The defect-rich framework amplified the permeability of Li+, and the site-selective growth of ZIF-8 in the framework defects bettered its selectivity. Specifically speaking, the ZIF-8@MLDH membranes featured a high permeation rate of Li+ up to 1.73 mol m−2 h−1 and a desirable selectivity of Li+/Mg2+ up to 31.9. Simulations supported that the simultaneously enhanced selectivity and permeability of Li+ are attributed to changes in the type of mass transfer channels and the difference in the dehydration capacity of hydrated metal cations when they pass through nanochannels of ZIF-8. This study will inspire the ongoing research of high-performance 2D membranes through the engineering of defects."Image missing"

Advanced Lithium Extraction Membranes Derived from Tagged‐Modification of Polyamide Networks

“…Figure 4j shows that the Li + flux of integrated nanofiltration units maintains stable at ca. 0.45 mol m −2 h −1 in 300‐minute nanofiltration, higher than state‐of‐the‐art Mg 2+ /Li + separation polymer membranes [8b,11a] . Meanwhile, the Mg 2+ /Li + ratio of permeate decreased to about 0.03, which is well suited for Li 2 CO 3 extraction by Na 2 CO 3 precipitation.…”

Archaea-Inspired Switchable Nanochannels for On-Demand Lithium Detection by pH Activation

“…Specific ion recognition is vital to the selective ion detection of biomimetic solid-state nanochannels. − Other alkali (Na + , K + , Rb + , and Cs + ) and alkaline earth (Sr 2+ ) metal ions were used as competitive targets to estimate the specificity of the Li + response of HPBO-modified AAO nanochannels (Figure a). Different from LiCl-treated HPBO-modified AAO nanochannels under alkaline conditions, other metal ions had no abilities to induce the conversion of the “open” state to the “closed” state for nanochannels (Figures b and S13a).…”

Bioinspired 2D nanofluidic membranes for energy applications

“…Li-batteries have attracted considerable attention because they have high energy density and good cycling stability. 249–251 Actually, electrodes and battery separators based on 2D layered membranes can achieve rapid selective ion transport, rich surface-controlled energy storage, long-term structural integrity, and high cycling performance, with reasonable surface engineering modifications. 252 In this section, we introduce the applications of 2D membranes in Li-batteries, covering the aspects of anodes, separators, and cathodes.…”