Engineering High‐Flux 2D Separation Membranes: Fundamentals, Strategies, and Future Directions

Abstract Environmental challenges, including carbon emissions, water scarcity, water pollution, etc., have driven the rapid development of 2D membranes as a transformative solution for molecular‐scale separations. 2D nanosheets are ideal building blocks for the construction of advanced lamellar 2D membranes for molecular‐scale separations owing to their excellent processability, highly tunable channel structures, and high surface area. However, it remains a critical challenge to design 2D lamellar membranes with high molecular flux due to the tortuous channels or uncontrollable stacking of nanosheets. In this perspective review, uniquely target providing theoretical analysis and summarizing experimental advances to offer guidelines for designing lamellar membranes with enhanced flux. First, the physicochemical properties of different 2D nanosheets are analyzed by emphasizing their potential and limitations for enabling rapid molecular transport. Next, an in‐depth analysis of transport mechanisms is provided, and based on this, propose systematic optimization strategies for the membrane structure to achieve high flux separation. Last, the most promising future directions for developing high‐flux 2D membranes for real‐world applications are outlook.