Multilayered hydrocarbon ionomer/PTFE composite electrolytes with enhanced performance for energy conversion devices

A new multilayered composite membrane was prepared by impregnating a sulfonated poly(arylene ether sulfone) (SPAES) ionomer into a porous polytetrafluoroethylene (PTFE) substrate for application in proton exchange membrane fuel cells (PEMFCs) and water electrolyzers (PEMWEs). The PTFE substrate was treated with n-propyl alcohol to mediate the interfacial interactions between the SPAES solution and PTFE. Using the 10-and 5 -mm -thick PTFE substrates, three-layered and five-layered composite membranes were pre-pared, respectively, to investigate the effect of PTFE thickness on impregnation of the SPAES ionomer. When 5 -mm-thick PTFE was applied, the SPAES ionomer was effectively impregnated without noticeable defects, indicating a strong interlocking structure between the two incompatible components. Therefore, the five-layered composite membrane showed enhanced dimensional stability and mechanical properties compared to the SPAES membrane, and the effect of the PTFE on proton conductivity was minimized. Conse-quently, the cell performances of the five-layered composite membrane were reflected by current densities of 1.71 A/cm2 at 0.5 V and 9.76 A/cm2 at 1.9 V for PEMFC and PEMWE, respectively, corresponding to 44% and 32% increases compared to those of Nafion 212, owing to its smaller membrane resistance. Moreover, the prepared composite membrane presented excellent durability, which resulted in stable wet-dry cyclability and low degradation rates.(c) 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

A new multilayered composite membrane was prepared by impregnating a sulfonated poly(arylene ether sulfone) ionomer into a porous polytetrafluoroethylene substrate. The PTFE substrate was treated to improve the interaction between the ionomer and PTFE. The five-layered composite membrane exhibited enhanced dimensional stability, mechanical properties, and cell performance in comparison to Nafion 212.