Development and characterization of Ni₃Fe layered double hydroxide-based oxygen-evolution electrodes for anion exchange membrane water electrolysis

Anion exchange membrane water electrolysis (AEMWE) is a promising technology for sustainable hydrogen production, combining the prospect of high current-density operation with the potential for reduced reliance on scarce materials. This thesis investigates the integration of nickel–iron layered double hydroxide (Ni3Fe-LDH) as an oxygen evolution reaction (OER) catalyst into AEMWE systems, with the goal of developing and validating membrane electrode assemblies (MEAs) suitable for scalable fabrication and future stack integration. The work establishes a translation pathway from catalyst powder to realistic device operation by focusing on catalyst implementation and quality control during MEA fabrication, followed by systematic single-cell testing under industrially relevant conditions. It clarifies how electrode design parameters, such as catalyst loading, binder content, ink formulation, and catalyst layer microstructure, together with operating conditions such as temperature and electrolyte concentration, govern performance and stability, highlighting the significant role of catalyst utilization and transport within the catalyst layer. Long-term operation is investigated through extended electrochemical testing coupled with time-resolved post-mortem electrode analysis, enabling separation of conditioning effects from subsequent degradation and providing insight into time-dependent anode evolution, including chemical reconstruction of the active state and microstructural changes of the catalyst layer. To improve manufacturability and reproducibility, electrode engineering is introduced through catalyst powder post-treatment and systematic dispersion control, linking processing to ink stability, catalyst layer homogeneity, and accessibility of active sites. The thesis further assesses MEA architecture by comparing catalyst-coated substrate and catalyst-coated membrane configurations and shows that architecture-specific optimization depends on balancing ionic, electronic and mass transport, and interface integrity. Robustness is strengthened by evaluating both pre-commercial and commercial anion-conducting materials, while material variability and batch effects are treated explicitly through repeat testing and complementary characterization. Overall, the work provides validated strategies for electrode engineering, durability assessment, architecture selection, and reproducible testing to support the development of robust, scalable Ni3Fe-LDH-based AEMWE MEAs.