Enhanced proton conductivity of sulfonated poly(aryl ether ketone sulfone) containing fluorene group by inserting bifunctionalized MOFs

The sulfonated poly(aryl ether ketone sulfone) which contains fluorene groups (F-SPAEKS) as proton exchange membranes (PEMs) matrix is prepared. UiO-66-NH2-PO4H2 (PUIN) is synthesized based on UiO-66-NH2 as a template for immobilizing phosphate groups onto MOFs by chemical bonding via Schiff base reaction. UiO-66-SO3H-PO4H2 (SPUIN) is prepared via ring-opening of 1,3-propanesulfonolactone, where -SO3H is introduced at the -NH2 site of PUIN. The hybridized PEMs (FSSPU-X) are obtained by adding SPUIN as fillers into F-SPAEKS polymers. From all prepared PEMs, FSSPU-7 which means the weight ratio of SPUIN is 7 % shows the best performances in comprehensive aspects. The H+ conductivity of FSSPU-7 is enhanced to 247.38 mS cm−1 and the peak power density is 1140 mW cm−2 with 0.48 mg cm−2 Pt/C loading. At the same time, the swelling ratio of FSSPU-7 remains below 17 %. Besides, FSSPU-7 has a maximum tensile strength up to 32.37 MPa. And the proton conductivity of FSSPU-7 is consistently maintained at about 240 mS cm−1 after 144 h of long-term stability test. Therefore, the preparation of PEMs with a high level of performance is expected by introducing phosphoric acid and sulfonic acid bi-functionalized UiO-66 into F-SPAEKS. © 2025 Elsevier Ltd