Cross-linked high conductive membranes based on water soluble ionomer for high performance proton exchange membrane fuel cells

In this paper, a series of proton exchange membranes prepared by "Click Reaction" are reported. The cross-linked membranes are based on water soluble sulfonated poly (ether ether ketone) containing dipropenyl groups (SDPEEK-nE/nH). Compared with self-crosslinked membranes (SDPEEK-nS), this "Click" cross-linked membranes using 1,2-Ethanedithiol and 1,6-Hexanedithiol as the cross-linker exhibit extremely reduced water uptake and swelling ratio. The lowest proton conductivity at 80 C of the "Click" cross-linked membranes reaches to 0.168 S cm^-1, and the highest methanol permeability of the "Click" cross-linked SDPEEK-8E is only 4.13 × 10^-7 cm² s^-1, which is 5 times lower than that of Nafion 117 membrane. All the results imply that the cross-linked membranes with novel thiol cross-linker are promising alternative material for fuel cell application.