Recent Progress in Covalent Organic Framework-Based Membranes: Design, Synthesis, and Applications in the Fields of Energy and the Environment

Covalent organic frameworks (COFs) are crystalline materials composed of lightweight elements (C, H, O, N, S, etc.), distinguished by their long-range ordered structure, tunable pore sizes, high crystallinity, excellent thermal stability, large specific surface areas, and low density, which have been widely applied into many fields. Further applications and large-scale production are limited due to difficulties in recycling the powdered materials. Recent studies have shown that COF-based membrane materials can overcome the defects of powdered materials and broaden their application range. Herein, we present our Viewpoint on strategies for the preparation of COF-based membranes and their applications in energy storage and pollutants removal. First, the design and synthesis strategies of COF-based membranes are reviewed, including interfacial polymerization, solvothermal methods, template methods, and so on. Subsequently, the performance of COF-based membranes in energy storage (lithium-ion extraction, lithium-metal battery, and others) and pollutant removal (heavy metal ions and organic pollutants) is evaluated. Furthermore, the interaction mechanisms between pollutants and COF-based membranes at both macroscopic and microscopic level are summarized, incorporating theoretical computations and advanced spectroscopic techniques. Finally, a summary is given and perspectives on the challenges and future development directions for COF-based membranes in energy storage and pollutants removal are discussed.