Optimization of AEM Electrolyzer Anodes Leading to High Performance and Durability

Abstract

Anion Exchange Membrane Water Electrolyzers (AEMWEs) have received a significant amount of attention in recent years. It is believed that AEMWEs have the ability to combine the advantages of traditional alkaline electrolyzers (low cost materials) with Proton Exchange Membrane Electrolyzers (high current density, facile pressurization). However, many of the AEMWEs reported in the literature have shown limited performance and longevity. It is known that the properties of the active materials (e.g. catalyst and membranes) themselves can have an impact on the AEMWE performance. However, less has been presented in the literature regarding the composition of the electrode. In addition, very few studies have dealt with the influence of inactive components, such as the gas diffusion layer.Therefore, in this presentation, the effects of catalyst loading, catalyst chemistry, gas diffusion layer (GDL) type and inclusion of a conductive additive will be discussed. The influence of each factor will be elucidated through a two-stage Design of Experiments (DoE) approach with a full statistical analysis. Such an analysis allows for the rational design of future generations of the anode electrode, including predictions for output voltage response. In the first stage of the DoE, a 24 factorial experiment matrix was designed (four factors at two levels). In the second stage, two factors are analyzed with 4 levels to better resolve their dynamic effects on performance. Finally, the knowledge gained is used to assemble a AEMWE that is able to operate stably for a continuous 720 hours (30 days).