(Invited) Electrode and Cell-Level Insights to Achieve High Performance and Long-Life AEM Fuel Cells and Electrolyzers

Abstract

The past several years have seen an explosion in the level of interest in anion exchange membrane (AEM)-based energy conversion devices. However, most of the studies in the literature have reported very low achieved performance and durability in such systems. Despite this, or perhaps even because of it, there is a large body of literature emerging pushing for the design of new materials to concomitantly increase both performance and durability. Therefore, the first topic in this talk will be the effect of electrode design and cell operation on the performance and stability of AEM fuel cells and electrolyzers. It will be shown that in many cases significant improvements in both can be made without any new active materials – only new electrode design and cell optimization. In fact, it is only after the device operation is well-understood that new materials can be fairly evaluated and their impact on the performance and durability elucidated.The second topic in this talk will be the durability of AEM fuel cells. Here, an optimized AEM fuel cell was stably operated for a continuous 3600 hours (150 days). At the end of life, the cell was disassembled and subjected to a number of experiments probing the physical and chemical degradation that occurred during normal operation – including high resolution STEM imaging and chemical mapping. Based on the combination of data that well-described the physical and electrochemical evolution of the cell, degradation mechanisms will be discussed and those pathways leading to both reversible and irreversible performance loss will be identified.The final topic of this talk will be durability of AEM electrolyzers. Specifically, we will report a highly durable AEM electrolyzer that was operated continuously for 720 hours (30 days) at a constant current density of 1.0 A/cm2 with no significant degradation in performance. Akin to the fuel cell work, end-of-life characterization is done to explore the degradation mechanisms at work during “normal” operation.In total, the purpose of this presentation is to unveil important insights into the performance-limiting and lifetime-limiting aspects of these electrochemical devices and to help the field to take active steps towards their commercial viability.