(Invited) Novel Design of Low-Loaded Membrane Electrode Assemblies for Advanced Low-Temperature Water Electrolyzers

Abstract

Development of advanced low-temperature (LT) water electrolyzers (WEs) is of crucial importance for implementation of the Hydrogen Economy. This future green economy will eliminate the greenhouse gas emissions and stop the imminent global warming and climate change. “Green” hydrogen can be produced at large scale by integration of WEs with renewable energy sources. Currently, the low-temperature proton exchange membrane (PEM) and anion exchange membrane (AEM) WEs are considered to be the most advanced WEs that can be integrated with solar panels and wind turbines to produce large quantities of green H2. The main challenges that the state-of-the-art membrane electrode assemblies (MEAs) for LTWEs are currently facing are: (i) high cost because of the high platinum group metals (PGM) loadings in their catalysts layers; (ii) limited durability caused by the instability of the catalysts and the other cell components, and (iii) safety concerns associated with the hydrogen gas crossover and the absence of technologies that can effectively keep it below the safety level of the lower flammability limit (LFL) [1, 2, 3].This work is aimed on designing of novel MEAs for LTWEs with dramatically reduced catalysts loadings, enhanced durability, and improved H2 crossover capabilities. Reactive Spray Deposition Technology (RSDT) is used as an innovative methodology for designing of advanced catalysts, catalyst and recombination layers, and MEAs for LTWEs. The RSDT is a flame assisted method [4, 5] that combines the catalysts synthesis and deposition directly on the membrane in one-step, which results in fast and facile fabrication of large scale (up to 1000 cm2) MEAs for application in LT fuel cells and water electrolyzers [5, 6]. As fabricated MEAs with ultra-low PGM catalysts loadings are tested at operating conditions typical for industrial PEM hydrogen production systems, and performance of 1.8 V at 3 A/cm2 is achieved. The MEAs of interest are tested for over 1000 hrs at steady-state conditions at 3 A/cm2. Comprehensive post-test characterization is performed by using high-resolution TEM, STEM, EDS, SEM, ICP, XRF, XCT, and digital optical microscopy and the governing degradation mechanisms are identified and discussed in detail. The impact of the design of low-loaded MEAs for LTWEs on their performance and durability is discussed in detail and their potential to meet and surpass the DOE 2030 targets is demonstrated.References https://www.energy.gov/sites/prod/files/2017/05/f34/fcto_myrdd_fuel_cells.pdf https://www.energy.gov/sites/prod/files/2015/06/f23/fcto_myrdd_production.pdfKlose, P. Trinke, T. Böhm, B. Bensmann, S. Vierrath, R. Hanke-Rauschenbach, and S. Thiele, J. Electrochem. Soc., 165, F1271–F1277 (2018).Kim, S., Myles, Maric, R., et al. Electrochimica Acta, 177, 190-200 (2015).Yu, H., Baricci, A., Bisello, A., Bonville, L., Maric, R., et al. Electrochimica Acta, 247, 1155-1168 (2017).Mirshekari, G., Ouimet, R., Zeng, Z, Yu, H., Bliznakov, S., Bonville, L., Niedzwiecki, A., Errico, S., Capuano, C., Mani, P., Ayers, K., Maric, R. International Journal for Hydrogen Energy, 46(2), 2021, pp. 1526-1539 (2021).