H 2 -Ambient Air PGM-Free Anion-Exchange Membrane Fuel Cells – the Beginning of a New Fuel Cell Era

Since the first Anion-Exchange Membrane (AEM) Fuel Cell (AEMFC) with practical performance was announced about a decade ago 1 , significant advances have been achieved in this field of research. In the past few years of intensive research on AEMFCs, remarkable progress has been reported, such as new highly stable functional groups for advanced AEMs 2-5 and highly active PGM-free catalysts 6-8 . At the cell level, new AEMFCs based on CRM-free catalysts were successfully demonstrated 9 , AEMFC’s lifetime of 5,000-15,000 hours was theoretically demonstrated for the first time 10-11 , and a cell lifetime of 2,000 hours was experimentally proven 12 . Altogether, the research community has made very impressive progress in such a short time. However, many challenges still need to be overcome to achieve AEMFCs of industrial interest. Among them, cell performance with completely PGM-free catalysts and operation with ambient air, are the most critical ones. We, at Technion, have recently presented the first results of AEMFCs tested at cell temperatures above 100 ℃ 13-17 . At these high temperatures, we could achieve not only high hydroxide ion conductivities close to 300 mS/cm 18 (!) but also improved cell stability (yes, a very counterintuitive result). We have also demonstrated a novel approach to achieve high AEMFC performance while using PGM-free catalysts in both electrodes. Altogether, these breakthroughs allow us for the first time to operate AEMFCs with ambient air and achieve record-high performance. This represents a significant landmark for this technology. In this talk, I will present the achievements and the new state-of-the-art H 2 -air AEMFC. References Dekel; Alkaline Membrane Fuel Cell (AMFC) Materials and System Improvement – State-of-the-Art; ECS Transactions , 50 (2) 2051-2052, 2013. Gjineci et al., Increasing the alkaline stability of N,N-diaryl-carbazolium salts using substituent electronic effects; ACS Appl. Mater. Interf. 12, 49617, 2020. Fan et al., Poly(bis-arylimidazoliums) possessing high hydroxide ion exchange capacity and high alkaline stability”; Nature Commun . 10(1), 2306, 2019. Gjineci et al., The reaction mechanism between tetraarylammonium salts and hydroxide; J. Org. Chem . 21, 3161-3168, 2020. Liu et al., Magnetic-field-oriented mixed-valence-stabilized ferrocenium anion-exchange membrane; Nature Energy 7, 329–339, 2022. Zion et al., Porphyrin aerogel catalysts for oxygen reduction reaction in anion-exchange membrane fuel cells; Functional Mater. 31(24), 2100963, 2021. Lilloja et al., Transition-metal and nitrogen-doped carbide-derived carbon/carbon nanotube composites; ACS Catalysis 11, 1920-1931, 2021. Kisand et al., Templated Nitrogen-, iron-, and cobalt-doped mesoporous nanocarbon derived from an alkylresorcinol mixture for AEMFC application; ACS Catalysis , 12, 14050-14061, Biemolt et al., An anion-exchange membrane fuel cell containing only abundant and affordable materials; Energy Technology 9, 2000909, 2021. Dekel et al., Predicting performance stability in anion exchange membrane fuel cells; Power Sources 420, 118-123, 2019. Yassin et al., Quantifying the critical effect of water diffusivity in anion exchange membranes for fuel cell applications; Membrane Sci. 608, 118206, 2020. Hassan et al., Achieving high-performance 2000h stability in AEMFCs; EnergyMater. 2001986, 2020. Douglin etal, A high-temperature anion-exchange membrane fuel cell; Power Sources Adv. 5, 100023, 2020. Douglin et al., A High-Temperature AEMFC with a Critical Raw Material-free Nitrogen-doped Carbon Cathode; Chemical Engineering J. Adv. 8, 100153, 2021. Yassin et al., A surprising relation between operating temperature and stability of AEMFCs; Power Sources Adv. 11, 100066, 2021. Liu et al., Magnetic-field-oriented mixed-valence-stabilized ferrocenium anion-exchange membrane; Nature Energy 7, 329–339, 2022. Xue et al., High-temperature AEMFCs with remarkable stability; Joule 8, 1457-1477, 2024. Zhegur-Khais et al., Measuring the true hydroxide conductivity of anion exchange membranes; Membrane Sci. 612, 118461, 2020.