Molecular Design of Positively Charged 3D Covalent−Organic Framework Membranes for Li+/Mg2+ Separation

3D covalent-organic framework (3D COF) membranes have unique features such as smaller pore sizes and more interconnected networks compared with 2D COF counterparts. However, the complicated and unmanageable fabrication hinders their rapid development. Molecular simulation, which can efficiently explore the structure-performance relationship of membranes, holds great promise in accelerating the development of 3D COF membranes. In this study, a series of 3D-COF membranes (TFPM-Pa-X) is designed with different charge densities (fully charged, partially charged, and neutral) and interpenetration numbers (2-, 3-, 4-, and 5-fold), subsequently investigate their contributions to Li