Low-swelling proton-conducting multi-layer composite membranes containing polyarylene ether nitrile and sulfonated carbon nanotubes for fuel cells

Abstract

To overcome the difficulties of excessively swollen or dissolve of sulfonated polyarylene ether nitrile in high temperature, the multi-layer proton exchange composite membranes based on sulfonated polyarylene ether nitrile (SPEN) and sulfonated carbon nanotubes (S-CNTs) were designed via facile step-by-step solution casting technique. The multi-layer structure of membranes can make the membrane more compact and reached the aim of low-swelling. The multi-layer structure of composite membrane was confirmed through scanning electron microscope, exhibiting improved dimensional stability, larger tensile strength and elongation at break than pure SPEN with a certain content of S-CNTs in the wet state. The proton conductivity of composite membranes with 3 wt% S-CNTs achieved 0.094 and 0.275 S/cm at 20 °C and 80 °C, respectively, which is higher than that of Nafion 117. Besides, the methanol permeability of SPEN/S-CNTs/SPEN composite membranes is lower than that of the commercial Nafion 117 membrane. All the data prove that the multi-layer composite membranes may be potential proton exchange membrane for fuel cells applications.