Sulfonated covalent organic framework packed Nafion membrane with high proton conductivity for H2/O2 fuel cell applications

Abstract

Developing novel proton exchange membranes with low activation energy and high performance is of great significance. This study reports a multichannel proton conduction membrane constructed from a 2D COF (ZUT-COF-SO₃H) with high water retention as nanofillers, which exhibits high stability, low activation energy (0.086 eV), and excellent proton conductivity (0.1338 S cm⁻¹). Compared to commercial Nafion, the 2.4-fold increase in proton conduction capacity is mainly attributed to COF nanochannels and high-loaded sulfonates providing additional transport paths for protons, resulting in a power density of 304.056 mW cm⁻² in proton exchange fuel cells at a current density of 640.179 mA cm⁻². The introduction of sulfonated COFs can not only effectively solve the proton channel limitation of traditional polymer materials but also provide abundant proton transport sites, which provides a new strategy for constructing high-performance proton transport membranes in H₂/O₂ fuel cells.