Anion exchange membrane (AEM) water electrolyzers is an attractive alternative approach for green hydrogen production. The alkaline environment allows the use of non-PGM catalysts and, based on recent research in catalysts and membranes, may soon challenge the established proton exchange membrane water electrolyzers^1,2. Transition metal-based catalysts have attracted much attention because they provide an excellent oxygen evolution reaction in alkaline media³. In particular, Ni-Fe-layered double hydroxides (LDH) have been intensively studied in recent years and have shown fast intrinsic electrocatalytic activity for water splitting^4,5. In this work, we used Ni₃Fe-LDH as an anode catalyst, DURAION® as ionomer and membrane and investigated the effects of electrode design and cell operation on the performance and stability of AEM electrolyzers. The optimized electrode was operated stably for 1000 hours at 1 A cm^-2 with an overall degradation rate of 0.014 V h^-1. At the end of the lifetime, the cell was disassembled and subjected to a series of experiments to investigate the physical and chemical degradation.

This work provides a fundamental understanding and specific approach to the use of nickel-iron-based electrodes and promotes the further development of AEM water electrolyzers through highly stabilized, Ni-rich, and low-cost anodic electrocatalysts.

This work has been performed in the frame of the CHANNEL project. This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under grant agreement No 875088. This Joint undertaking receives support from the European Union's Horizon 2020 Research and Innovation program, Hydrogen Europe and Hydrogen Europe Research.

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