Durable Proton Exchange Membrane Based on Polymers of Intrinsic Microporosity for Fuel Cells

Abstract High‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) is regarded as a promising energy conversion system owing to simplified water management and enhanced tolerance to fuel impurities. However, phosphoric acid (PA) leaching remains a critical issue, diminishing energy density and durability, posing significant obstacle to the commercial development of HT‐PEMFCs. To address this, composite membranes incorporating the carboxylic acid‐modified polymer of intrinsic microporosity (cPIM‐1) are designed as framework polymer, blended with polyvinylpyrrolidone (PVP) for HT‐PEMFCs. The Lewis acid‐base interactions between cPIM‐1 and PVP created an extensive hydrogen‐bonding network, improving membrane compatibility. The optimized microporous structure and multiple anchoring sites gave rise to “domain‐limited” PA clusters, enhancing the capillary effect. Simultaneously, improved hydrophobicity synergistically optimizes catalytic interface, promoting continuous and stable proton transfer. The HT‐PEMFCs based on PVP/cPIM‐1 composite membrane achieved a peak power density of 1090.0 mW cm ⁻² at 160 °C, representing a 152% improvement compared to PVP/PES membrane. Additionally, it demonstrated excellent durability, with a voltage decay of 0.058 mV h ⁻¹ over 210 h of accelerated stress test corresponds to more than 5000 h of constant current density durability test. This study presents a promising strategy for the development of high‐performance and durable novel membranes in various energy conversion systems.