Intrinsically Microporous Ion-Pair Membranes for HT-PEMFCs

Fuel cells are electrochemical devices with high energy efficiency expected to be applied economically and eco-friendly across various energy sectors. Low-temperature polymer electrolyte membrane fuel cells (LT-PEMFCs) using Nafion operates at a relatively low operating temperature (60-80°C) and fully hydration condition. HT-PEMFC is operable at high temperatures (140-180°C), but requires anhydrous conditions to avoid loss of doped phosphoric acid (PA). In this presentation, polymer membranes designed through with intrinsic microporosity were synthesized through super acid polycondensation. We demonstrated that high proton conductivity (106.33 mS cm-1 at 180℃) is obtained by forming phosphoric acid filled ion-channels within the interconnected microporous structure. Moreover, ion-pair coordinated PIMs are fabricated by methylation of PIMs to improve PA retention even under humidified conditions. It is suggested that the water tolerance of ion-pair coordinated PIMs is improved and can be operated under various conditions regardless of humidification and operating temperature and exceptional membrane electrode assembly performance and durability achieved even under humidified reformate gas conditions.