Edge-Type Reference Electrode Application for AEM-WE Durability Testing

Anion-exchange membrane water electrolyzers (AEM-WE) have been identified as a promising solution to deliver green hydrogen at a lower cost than alkaline water electrolyzers (AWEs) and proton-exchange membrane water electrolyzers (PEM-WEs). However, scaling AEM-WE is limited by high voltage degradation rates which can become amplified and more complicated during operation as components within the membrane electrode assembly (MEA) evolve and interact with one another. These phenomena necessitate testing protocols that capture the degradation of individual MEA components in situ. Herein, an edge-type reference electrode and a novel flow plate design enabled decoupling of anode and cathode degradation over stability tests >200 h. A critical assessment of the overpotential measurements is provided, utilizing half-cell impedance measurements to highlight the effects of electrode misalignment. 3-electrode cyclic voltammetry is presented as an effective in situ tool to evaluate electrode degradation. These findings demonstrate the utility of edge-type reference electrode configurations in stability tests for the development of commercial scale AEM-WE.