Novel proton exchange membranes based on sulfonated poly (ether-ether-ketone)/phosphonic acid-functionalized siloxane

Novel proton exchange membranes of sulfonated poly (ether-ether-ketone)/phosphonic acid-functionalized siloxane were prepared by sol–gel method using sulfonated poly (ether-ether-ketone) as the matrix and phosphonic acid-functionalized siloxane as the crosslinking agent. Phosphonic acid-functionalized siloxane was prepared from tetra sodium of 1-hydroxyethane-1, 1-diphosphonic acid (HEDP·Na 4 ) and 3-isocyanatopropyltriethoxysilane (IPTES). The FTIR results suggest that HEDP·Na 4 was anchored into IPTES and Si-O-Si crosslinked network was formed successfully. The prepared membranes were stable up to 220 °C without any degradation and exhibited excellent dimensional stability and mechanical performance. The proton conductivity of the AES-X increased with the increase of phosphonic acid groups, especially for AES-3, 4, of which the proton conductivity was higher than that of Nafion117 at 80 °C and the proton conductivity of AES-3 was up to 0.0378 S cm −1 under 140 °C. The power density of the DMFC MEA fabricated with the AES-3 could reach 157 mW cm −2 at 60 °C.