Prolifically Boosted PEM Fuel Cell Performance and Durability in Pendant Carboxylic‐Acid Tethered 2D Co(II)‐MOF Reinforced Composite Membrane
Sk Miraz Hossain, Rudra Chand, Pratyush Patnaik, Subhadip Neogi, Uma Chatterjee
Abstract
Abstract Developing durable and highly conductive proton exchange membranes (PEMs) is essential for advancing electrochemical energy technologies. Leveraging fluorine‐free sulfonated polyphenylene oxide (SPPO) as membrane backbone and a multifunctionalized 2D metal–organic framework (FMOF) as fillers, composite PEM are devised with improved hydration and stability in humid conditions. The rationally optimized representative membrane SPM‐3 (3% w/w FMOF, IEC = 2.25 meq g −1 ) achieves a remarkable proton conductivity of 44.59 mS cm −1 with 835.92 mA cm −2 current density at 0.6 V, and demonstrates a significant peak power density of 629.64 mW cm −2 , which is 82% superior to the pristine SPPO at 80 °C and 100% RH. Accelerated‐degradation testing shows only 14.79% OCV decay (2.84 mV h −1 ) over 50 h at 30% RH. The fishbone‐shaped FMOF also enhances gas barrier properties, reducing hydrogen crossover by 21.7% due to blocking effect. Performance comparison with an un‐functionalized UNMOF‐based membrane confirms that free ‐COOH moieties, and heteroatoms in the FMOF create a dynamic H‐bonding web within the polyelectrolyte, resulting in compact membrane architecture, restricting water‐induced swelling and impedes the chemical degradation of the composite PEM. These findings underscore a paradigm shift to MOF‐based PEMs as a promising route toward high‐performance fuel cells.