Polymer Electrolyte Membrane Degradation Mechanisms in Fuel Cells - Findings Over the Past 30 Years and Comparison with Electrolyzers

This paper summarizes some of the progress that has been made over the past 30 years in identifying chemical and mechanical degradation mechanisms in proton-exchange membrane fuel cells (PEMFCs), as well as approaches in refining stack operating conditions, cell hardware configurations and membrane- electrode assembly (MEA) stabilization to mitigate degradation and extend life. New analytical methods have been brought to bear to understand the relationships between PEM degradation and fuel cell operating conditions, especially low relative humidity, elevated temperatures, and frequent open-circuit periods. PEM/MEA degradation similar to that observed in PEMFC may also occur under certain accelerating conditions for proton-exchange membrane water electrolyzers (PEMELCs) that typically operate for 30 to 100 thousand hours without incident when properly hydrated, thermally managed and mechanically supported. A comparison is made of common hardware and operational factors for PEMELCs and PEMFCs that can lead to PEM/MEA degradation.