Catalysts and Electrode Development for AEM Water Electrolysis
Authors: Baranton Steve , Hu Robin , Williams Shazam , Susanto Amelia , Ju Jessie , Zhou Eric Chuanyi , Bialasz Darek , Min Charlie 
Published: December 2024

Water electrolysis is a promising technology that can use renewable energies (solar and wind) to produce green hydrogen [1]. In particular, Anion Exchange Membrane Water Electrolysis (AEMWE) offers the combined advantages of the mature Alkaline Water Electrolysis technology and the high efficiency and high dynamic range of the Proton Exchange Membrane Water Electrolysis [2]. This combination of advantages allows the AEMWE technology to be operated with non-PGM electrodes [3], non-perfluorinated membrane with a high dynamic range favoring its use with intermittent renewable energy for the production of green hydrogen. The development of AEMWE requires production of efficient catalytic materials at industrial scale and integration in membrane electrode assemblies (MEAs).

In this work, we have developed three families of non-noble catalysts: nickel based materials, iron free catalysts [4, 5] and high entropy materials. They are designed for both anode and cathode of AEM electrolyzers. High performances cathodes are developed with low PGM loading alloy catalysts. These materials (cathode and anode) are produced with highly scalable synthesis methods involving water as solvent and the reactants used are low-cost, widely available chemical compounds. The catalysts obtained are high surface area (up to 100 m2/g) nanostructured materials, ensuring a high catalytic activity for AEMWE electrodes. The development of different catalyst families allows the optimization of electrodes in a wide range of operating conditions (temperature, nature of the membrane and hydroxide concentration in the circulating electrolyte)

Catalyst application is critical for preparing efficient MEA’s. The catalyst coating has been performed in two configurations: catalyst coated substrate (CCS) and catalyst coated membrane (CCM). In both configurations, the ink formulation is optimized to improve the catalyst dispersion and the catalyst/polymer coating on the substrate or membrane. The best coating conditions have been determined for both anodes and cathodes to prepare electrodes that improve the catalyst performances. This phase is crucial to avoid negative interactions between the different components of the electrode [6] and create a good interface with the membrane.

The resulting MEAs were tested in our electrolyzer with different configurations (5 and 50 cm2) for performance and durability in a temperature range from 60°C to 80°C. Depending on the operating conditions and the catalyst families chosen, the performance exceeded 3 A/cm2 with a cell voltage below 2 V (Figure 1).

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Figure 1