Recent Breakthroughs and Future Horizons in Next-generation HT-PEMs for Hydrogen Fuel Cell

High-temperature proton exchange membranes (HT-PEMs) for fuel cells are considered transformative technologies for efficient energy conversion, particularly in hydrogen-based transportation, owing to their ability to deliver high power density and operational efficiency in harsh environments. However, several critical challenges limit their broader adoption, notably the limited durability and high costs associated with core components such as membranes and electrocatalysts under elevated temperature conditions. This review systematically addresses these challenges by examining the role of engineered nanomaterials in overcoming performance and stability limitations. The potential of nanomaterials to improve catalytic activity, proton conductivity, and thermal stability is discussed in detail, emphasizing their impact on the optimization of catalyst layer composition, including catalysts, binders, phosphoric acid electrolytes, and additives. Recent advancements in nanostructured assemblies and 3D morphologies are explored to enhance fuel cell efficiency through synergistic interactions of these components. Additionally, ongoing issues such as catalyst degradation, long-term stability, and resistance to high-temperature operation are critically analyzed. This manuscript offers a comprehensive overview of current HT-PEMs research and proposes future material design strategies that could bridge the gap between laboratory prototypes and large-scale industrial applications.