Modification, Degradation, and Mitigation of Perfluorosulfonic Acid Proton Exchange Membranes for Fuel Cells: A Review

Proton exchange membrane fuel cells (PEMFCs) offer a transformative solution to mitigate climate change by reducing carbon emissions and global carbon footprints. Perfluorosulfonic acid (PFSA) membranes are crucial components of fuel cell stacks, exhibiting superior proton conductivity, mechanical strength, and chemical stability under hydrated conditions. However, these membranes face significant challenges, including low thermal and chemical steadiness, insufficient mechanical strength, high production costs, and hasty degradation at elevated temperatures during long-term operation. In this review, we comprehensively discuss the recent advancements in the modification of PFSA membranes to overcome these challenges by surface modifications, cross-linking, incorporation of organic-inorganic hybrids, and use of partially fluorinated and nonfluorinated membranes to enhance the performance of PFSA membranes in PEMFC applications. In addition, recent mitigation strategies, such as using protective coatings, incorporating nanocomposites and nanofillers, developing multilayer membrane structures, using platinum alloy catalysts, and integrating free radical scavengers, have been critically evaluated for their effectiveness in reducing PFSA membrane degradation and extending operational lifespan. Collectively, these approaches demonstrate significant potential to enhance the durability, thermal stability, and mechanical integrity of PFSA membranes. Finally, this review provides valuable insights into the enhancements of high-performance PFSA membranes for sustainable PEMFC applications and highlights future research directions to advance fuel cell technology.