Ordered Dynamic Networks Proton Exchange Membrane for Humidity-Resilient High-Performance Fuel Cells.

Abstract

Maintaining proton conductivity of sulfonated proton exchange membranes (PEMs) under low humidity remains a critical challenge for fuel cell applications. This study presents an innovative interfacial engineering strategy through the integration of perfluorosulfonic acid nanofibers (PFSANF) with hydroxyl-functionalized Tröger's base polymer containing tertiary amine groups (HTB), constructing an ordered dynamic network membrane. The system achieves multi-level performance optimization via synergistic 3D hydrogen-bond networks and acid-base interactions: 1) Nanofiber create high-speed proton transport networks; 2) Hydroxyl and tertiary amine groups cooperatively enhance water retention while creating additional proton-hopping sites. The resulting ordered dynamic architecture demonstrates remarkable humidity-adaptive proton conduction, achieving a proton conductivity of 123 mS cm-1 - 1.9 times higher than commercial Nafion NC at 90 °C and 30% relative humidity (RH). The optimized membrane demonstrates outstanding peak power density of 1.2 W cm- 2 in H2/O2 fuel cells. This innovative interfacial engineering approach establishes a new paradigm for developing humidity-resilient proton exchange membranes through synergistic molecular design and ordered nanostructure.