Covalent Organic Frameworks for Proton Exchange Membrane Fuel Cells

Covalent organic frameworks (COFs), as emerging crystalline porous materials featuring abundant pores, well-defined aligned channels, atomically tunable structures, and easily functionalized backbones, have attracted considerable attention. These characteristics enable them to provide highly efficient mass transfer pathways and precisely engineered active sites and act as hosts for functional guests, thereby enhancing dispersibility, uniformity, and stability while also creating a modifiable microenvironment, which highlights the great potential of COFs in electrochemistry-related applications. In this review, we present recent advances in the application of COFs in proton exchange membrane fuel cells, including as oxygen reduction reaction catalysts, proton exchange membranes, and ionomers. We highlight the roles played by COFs in these applications, focusing on their structural design and modulation, facilitation of electrochemical processes, and enhanced mass transport pathways. Finally, key challenges and future directions for the development of COF-based materials in proton exchange membrane fuel cells are discussed.