Pratyush Patnaik

Fluorine-free, robust polyethylene-poly- p -methylstyrene interpenetrated network-based crosslinked amphoteric polyelectrolyte separators have been architected for all vanadium redox flow battery (VRFB) applications.

The persistent oxidative degradation and poor performance under low humidity conditions remain major challenges to the advancement of proton exchange membrane fuel cells. In this work, we address these issues by combining the radical scavenging ability of cerium (Ce) with the thermal and chemical stability of zirconium (Zr) based metal organic frameworks (MOFs). An amine functionalized Zr–Ce bimetallic MOF, [(Zr/Ce)U(NH₂)] was synthesized and incorporated into a sulfonated poly(ether ether ketone) (sPEEK) membrane to develop a stable composite proton exchange membrane. This design overcomes key limitations of conventional Ce-based additives including leaching, agglomeration, thermal instability, and low proton conductivity at reduced relative humidity. The optimized membrane SPBM-3 with 3 wt% filler delivered a peak power density of 681.5 mW cm⁻² at 80 °C and 100% RH which is a 78.4% improvement over pristine sPEEK. At 60% RH it retained a high performance of 524.7 mW cm⁻² with only 23% decay, while sPEEK showed 43% degradation. The nanoporous MOF reduced fuel crossover by 37.3% and improved membrane selectivity and efficiency. Durability testing showed only 11.34% decay in open circuit voltage over 100 h with a degradation rate of 1.1 mV h⁻¹ at 30% RH while the pristine membrane failed within 50 h. The integration of Zr–Ce bimetallic MOF fillers with immobilized radical quenching sites and acid–base interactions enabled a strong synergy that enhanced both performance and durability. Thus, this work not only addresses key limitations of Ce-based additives but also opens a new avenue for rationally engineered MOF-integrated membranes.

The long-term operational viability of vanadium redox flow batteries (VRFBs) critically depends on the properties of the membranes.

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.

Herein, oxy-tethered polystyrene grafted PVDF-based comb-shaped proton exchange membranes (PEMs) are developed for proton exchange membrane fuel cells and water electrolyzers.