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

The sulfonated poly(arylene ether ketone sulfone)s which contains fluorenyl groups (F-SPAEKS) as proton exchange membranes (PEMs) matrix is prepared. UiO-66-NH 2 -PO 4 H 2 (PUIN) is synthesized based on UiO-66-NH 2 as a template for immobilizing phosphate groups onto MOFs by chemical bonding via Schiff base reaction. UiO-66-SO 3 H-PO 4 H 2 (SPUIN) is prepared via ring-opening of 1,3-propanesulfonolactone, where -SO 3 H is introduced at the -NH 2 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 hours 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.