Oriented UiO‐67 Metal–Organic Framework Membrane with Fast and Selective Lithium‐Ion Transport

Abstract Metal–organic frameworks (MOFs) membranes with high pore density and tunable pore size down to the subnanoscale exhibit great potential in ion separation when appropriately designed and prepared. By a washing‐assisted secondary growing method, a well intergrown UiO‐67 membrane with preferential growth along the [022] direction was synthesized on a polyvinylpyrrolidone (PVP)‐modified AAO substrate. Because of the oriented growth of UiO‐67 nanocrystals, highly interconnected ion‐transporting channels are created throughout the UiO‐67/AAO membrane capable of achieving an ultrahigh Li + permeance of 27.01 mol m −2 h −1 as well as very decent Li + /Mg 2+ selectivity of up to 159.4. Molecular dynamics simulations reveal that the high selectivity is associated with the large disparity of the transport energy barrier between Li + and Mg 2+ , which is caused by different extents of ion dehydration in unique bimodal and oriented membrane channels.