Pore Geometry and Surface Engineering of Covalent Organic Frameworks for Anhydrous Proton Conduction

Abstract Developing new materials for anhydrous proton conduction under high‐temperature conditions is significant and challenging. Herein, we create a series of highly crystalline covalent organic frameworks (COFs) via a pore engineering approach. We simultaneously engineer the pore geometry (generating concave dodecagonal nanopores) and pore surface (installing multiple functional groups such as −C=N−, −OH, −N=N− and −CF 3 ) to improve the utilization efficiency and host–guest interaction of proton carriers, hence benefiting the enhancement of anhydrous proton conduction. Upon loading with H 3 PO 4 , COFs can realize a proton conductivity of 2.33×10 −2 S cm −1 under anhydrous conditions, among the highest values of all COF materials. These materials demonstrate good stability and maintain high proton conductivity over a wide temperature range (80–160 °C). This work paves a new way for designing COFs for anhydrous proton conduction applications, which shows great potential as high‐temperature proton exchange membranes.