Construction of New Proton Transport Channels in Composite Proton Exchange Membranes by Incorporating Tannic Acid-Coated Sulfonic Acid-Amino Bi-Functionalized MOFs

The design and preparation of low-cost and high-stability proton exchange membranes (PEMs) play an indispensable role in sustainable development and application expansion. In this study, sulfonic acid-amino difunctionalized hydrophilic metal–organic frameworks (MOFs) (named as TA-SNU6) were designed and synthesized as proton transport carriers to be incorporated into sulfonated poly(aryl ether ketone sulfone) (SPAEKS) to obtain high proton conductivity and single-cell performance. The experimental results show that abundant hydroxyl and acid–base groups significantly increase the proton transport efficiency in PEMs and improve the hydrophilicity and electrochemical performance of PEMs. The single-cell performance of the STSN-1% membrane was about 1.8 W cm–2. The proton conductivity was up to 190 mS cm–1, the mechanical properties were significantly improved, and the tensile strength reached 48 MPa. SPAEKS polymer with a specified degree of sulfonation was prepared by a stepwise polycondensation reaction, which showed excellent comprehensive properties after adding TA-SNU6 fillers. The STSN-1% composite membrane performs better than Nafion 211 and Nafion 117 in fuel cells. Therefore, it can be seen that this work has achieved certain results, which makes PEMs have excellent electrochemical performance, and provides a reference for the development of high-performance PEMs.