Degradation Mechanisms in PEM Water Electrolysis: Diagnosis and Impact

ABSTRACT Proton electrolyte membrane (PEM) water electrolyzers (WE) represent a pivotal technology for the electrochemical production of hydrogen. However, a persistent challenge is the loss of efficiency and performance, along with a shortened lifetime caused by degradation of the materials in PEMWE. This review examines the degradation mechanisms of PEMWE components, including the electrolyte membrane, catalyst layers, porous transport layers, bipolar plates, and gaskets. Furthermore, it places particular emphasis on measurement techniques used to examine and differentiate the degradation mechanisms, including a discussion of less‐studied mechanisms and measurement methods. A survey was conducted among PEMWE experts to analyse prevailing opinions on the severity and frequency of different degradation mechanisms. It supplements the literature review and allows for a comprehensive understanding of the impacts of degradation.