Mechanistic Engineering of Highly Selective COF-OEt/PSS on the HKUST-1/PSS Membrane for Lithium-Ion Extraction
Reza Maleki, Mohammad Khedri, Yasin Mehdizadeh Chellehbari, Mahsa Golmohammadi, Sima Rezvantalab, Withita Cha‐Umpong, Amir Razmjou
Abstract
The substantial and unexpected increase in the demand for electric vehicles that use lithium-ion batteries has disrupted the Li supply–demand balance. Although metal/covalent organic framework (MOF/COF) membranes have shown promising performance for ion separation, their Li-ion selectivities are not high enough to meet industrial requirements. Herein, we introduce a new concept of the COF-on-MOF system as an approach to boost the Li-ion selectivity. The mechanism and efficiency of the single MOF membrane that is made of HKUST-1 functionalized with polystyrenesulfonate (PSS) have been investigated using molecular simulation. The simulation selectivities for Li + /Na +, Li + /K +, and Li + /Mg 2+ were found to be 3.25, 3.5, and 6.5, respectively. The addition of the PSS-functionalized COF-OEt layer to HKUST-1/PSS provided a chance to control the membrane’s pore size, electrostatic interactions on the atomic scale, and membrane–ions interactions. COF-OEt/PSS on HKUST-1/PSS showed a jump in Li + /Na +, Li + /K +, and Li + /Mg 2+ selectivities of more than 143, 338, and 837, respectively. The concept of this study can be extended to other MOF and COF types, which will open up a new avenue of research for the design of ion-selective membranes.