Stepwise Fabrication of Proton-conducting Covalent Organic Frameworks for Hydrogen Fuel Cell Applications

Exploring new materials to manufacture proton-conducting membranes(PEMs) for fuel cells is highly significant. In this work, we fabricated two robust and highly crystalline porous covalent organic frameworks(COFs) via a stepwise synthesis strategy. The synthesized COF structures are integrated into high-density azo and amino groups, which allow to anchor acids for accelerating proton conduction. Moreover, the COFs exhibit good chemical stability and high hydrophilicity. These features make them potential platforms for proton conduction applications. Upon loaded with H3PO4, the COFs(H3PO4@COFs) deliver a high proton conductivity of 3.15×10−2 S/cm at 353 K under 95% relative humidity(RH). Furthermore, membrane electrode assemblies are fabricated using H3PO4@COF-26 as the solid electrolyte for a single fuel cell outputting a maximum power density of 18 mW/cm2.