Optimization of Ionomer Content in Anode Catalyst Layer for Improving Performance of Anion Exchange Membrane Water Electrolyzer

Abstract

Anion exchange membrane (AEM) water electrolyzers, which are considered next-generation hydrogen production energy devices, generate hydrogen using a nonprecious metal as the electrocatalyst. However, most current studies tend to focus on the development of highly active electrocatalysts based on nonprecious metals, and there have been few attempts to develop improved electrodes for these devices. In particular, the catalyst layer of the electrode is the key component that directly affects the performance of AEM electrolyzers. In this study, we developed a high-performance anode for the AEM water electrolyzer by optimizing the ionomer content of the anode catalyst layer. In particular, the electrochemical behavior of the AEM electrolyzer was systematically analyzed while varying the amount of ionomer present within the anode catalyst layer. The ionomer content significantly affects the ohmic and mass transport losses of the AEM electrolyzer and consequently plays an important role in determining its performance. Upon employing the optimized ionomer, a current density of 1.44 A/cm2 was achieved at 1.8 V, representing a 25% improvement compared to using a nonoptimized ionomer. In addition, the ionomer content also significantly affects the durability of the system. Thus, this study highlights the importance of developing improved electrodes for the realization of high-performance AEM water electrolyzers.