Highly Active and Durable Membrane Electrode Assemblies for Proton Exchange Membrane Water Electrolyzers Fabricated by Reactive Spray Deposition Technology

Abstract

The reactive spray deposition technology (RSDT) that has been developed at UConn, is one of the most promising new methodologies for direct fabrication of large scale MEAs for proton exchange membrane water electrolyzers (PEMWEs) with ultra-low platinum group metals (PGM) loadings in their catalyst layers [1,2]. The RSDT is an open to air flame assisted method for fabrication of MEAs that combines the catalysts synthesis and direct deposition on the Nafion® membrane in one step [2,3]. Thus, this method eliminates multiple time consuming and expensive steps in the MEA manufacturing process and reduces the fabrication time from days and weeks to hours. As a dry spray methodology with integrated system for in-situ quality control of the catalysts and catalyst layers (CLs),[1] the RSDT allows precise control of the catalysts composition, loading, porosity, thickness, and ionomer content. Furthermore, it has been demonstrated that by controlling the precursor solutions flow rates, and the flame deposition parameters, catalyst layers with gradient distribution in the nanoparticle size, as well as in the PGM loading in the CLs can be achieved, which ensures fine tuning of the activity and durability performance of the MEAs of interest [4].Herein, we will demonstrate the capabilities of the RSDT methodology to fabricate large scale MEAs for PEMWEs, that have one order of magnitude lower PGM loadings in the CLs and activity and durability performance comparable to the state-of-the-art commercial MEAs. RSDT fabricated MEAs with geometric area of the electrodes of 86 cm2 and 680 cm2, and loadings of 0.2 mgPt/cm2 in the cathode and 0.3 mgIr/cm2 in the anode have been tested at conditions typical for industrial electrolyzers. The performed long term steady-state test for over 5000 hours, as well as the measured polarization curves and EIS spectra clearly show excellent activity and durability performance of these MEAs. In addition, the RSDT fabricated MEAs have integrated recombination layers that effectively reduce the hydrogen crossover to below 10 %LFL. Furthermore, comprehensive post-test analysis of the MEAs after 5000 hours of operation has been performed and the degradation mechanisms governing their performance loss were identified and will be discussed in detail.References https://www.hydrogen.energy.gov/pdfs/review20/ta027_maric_2020_o.pdf Mirshekari, G., Ouimet, R., Zeng, Z, Yu, H., Bliznakov, S., Bonville, L., Niedzwiecki, A., Errico, S., Capuano, C., Mani, P., Ayers, K., Maric, R., 2021.“High-Performance and Cost-Effective Membrane Electrode Assemblies for Advanced Proton Exchange Membrane Electrolyzers: Long-Term Durability Assessment”, International Journal for Hydrogen Energy, 46(2), 2021, pp. 1526-1539.Roller, J., Maric, R., 2015. A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation, Journal of Thermal Spray Technology, 24(8) December 2015 pp. 1529-1541.Yu, H., Baricci, A., Casalegno, A., Guetaz, L., Bonville, L., Maric, R., 2017. Strategies to mitigate Pt dissolution in low Pt loading proton exchange membrane fuel cell: II. A gradient Pt loading design, Electrochimica Acta, 247(1) 2017, pp. 1169-1179