Engineering Stable Proton Exchange Membrane via Hybridization of Nonsulfonated Poly(ether sulfone) with Sulfonated Amide Organic Frameworks

Proton exchange membranes (PEMs) serve as multifunctional ionic transport platforms for electrochemical systems, necessitating optimization of the proton conduction efficiency, mechanical integrity, and long-term operational stability. This work presents an approach of introducing sulfonic groups that incorporate sulfonated amide organic frameworks (SAOF) into nonsulfonated poly(ether sulfone) (PES) to create rigid proton transport nanoarchitectures. The sulfonated zwitterionic SAOF facilitates sulfonic acid groups and amide structures to function as hydrogen bonds, enabling Grotthuss-dominated dual-mechanism proton migration with low activation energy. Moreover, the reconfigurable hydrogen bonds and sulfonic acid groups of SAOF enhance the hydrophilic nanodomains, allowing the PES-SAOF hybrid membrane to surpass conventional conductivity–swelling trade-offs. The PES-SAOF-20% membrane attains a proton conductivity of 0.19 S cm–1 at 80 °C and 100% relative humidity, exceeding the pristine PES membrane by 200%, while exhibiting a 6.8% loss in conductivity over 30 days of continuous operation.