Catalyst degradation in PEM fuel cells: from physical understanding to mitigation

点击翻译按钮获取中文摘要

We propose a three-year research collaboration designed to understand and mitigate catalyst degradation mechanisms in polymer electrolyte fuel cells (PEFC) for automotive applications. The main modules focus on the development of a consistent suite of modeling tools. Modeling will be conducted in close coordination with experimental and testing work, conducted by collaborators in academia and industry. An automotive PEFC, during its lifetime, is subjected to thousands of normal operational events such as start-up/shut-down, acceleration, steady climbs, or idling. Stringent levels of performance need to be maintained over this lifetime. Correspondingly, industry and governments have set strict limits on degradation. Therefore, activities in research focus on unraveling interrelated aspects of electrocatalytic activity, stability and cost of Platinum-based electrocatalyst systems. Theoretical portions of the planned collaborative and interdisciplinary research program will produce a consistent understanding of catalyst degradation phenomena. The research will span the relevant hierarchy of scales, encompassing atomistic studies on extended surface catalysts, mesoscopic studies on model systems of catalyst nanoparticles distributed at plain substrate surfaces, and macroscopic studies on fully functional cathode catalyst layers in PEFC. Models will be corroborated and successively refined by systematic comparison with both ex situ experiments and in situ tests on single operational fuel cells. The impact of varying reaction conditions and typical voltage variation protocols of accelerated stress tests on catalyst mass loss and redistribution will be explored. The anticipated outcomes include fundamental understanding of how fuel cells degrade, diagnostic understanding of how materials parameters and local reaction conditions affect durability, and practical understanding of what operational system management can do to mitigate stressors. This understanding will lead to a list of practical recommendations for structural design of catalyst layers and fine-tuning of operating conditions in order to extend the lifetime of Pt-based catalysts in PEFC.