Synthesis and properties of fluorene-containing sulfonated poly (ether ether ketone) as proton-exchange membrane for PEM fuel cell application

A series of sulfonated poly(ether ether ketone)s were successfully synthesized via nucleophilic displacement condensation. The membranes are accordingly cast from their DMSO solutions, and fully characterized by determining the ion-exchange capacity, water uptake, dimensional stabilities, proton conductivity and mechanical properties. Among membranes, the block-7c-3 was successfully synthesized by the reaction of Block-6c with chlorosulfonic acid, with the feed ratio of repeated unit to chlorosulfonic acid of 1:8. The experimental results show that the membrane from block-7c-3 has good mechanical, oxidative and dimensional stabilities together with high proton conductivity (5.15 × 10⁻² Scm⁻¹) at 80 °C under 100 % relative humidity. The membranes also possess excellent thermal and dimensional stabilities, in this respect, they are potential and promising proton conducting membrane material for PEM full cell applications.