Communication Water induced phase segregation in hydrocarbon proton exchange membranes

摘要

cqvip:Proton exchange membranes(PEMs) are a key material for proton exchange membrane fuel cells(PEMFCs). Non-fluorinated hydrocarbon PEMs are low-cost alternatives to Nafion, but limited by the low proton conductivity, because of the weak phase segregation structure and narrow ion-transport channels.Various efforts have been taken to improve the performance of hydrocarbon PEMs, but mostly with complex methodologies. Here we demonstrate a simple, yet very efficient method to create phase segregation structure inside a typical hydrocarbon PEM, sulfonated poly(ether ether ketone)(SPEEK). By simply adding appropriate amounts of water into the DMF solvent, the resulting SPEEK membrane exhibits widened ion-transport channels, with the phase size of 2.7 nm, as indicated by both molecular dynamic(MD) simulations and transmission electron microscope(TEM) observations, and the proton conductivity is thus improved by 200%. These findings not only further our fundamental understanding of hydrocarbon PEMs, but are also valuable to the development of low-cost and practical fuel cell technologies.