Automotive PEM fuel cell catalyst layer degradation mechanisms and characterisation techniques, Part I: Carbon corrosion and binder degradation

This review comprehensively examines two major degradation mechanisms in Pt/C-based catalyst layers widely used in automotive polymer exchange membrane fuel cells: carbon corrosion and perfluorosulfonic acid–based binder degradation. Carbon corrosion, accelerated under high potential conditions, leads to structural collapse, loss of electrochemical surface area, and performance decline, while binder degradation compromises ionomer integrity, impacting proton conductivity and cell stability. In this work, a kinetic approach is employed to critically analyse the various degradation pathways, reaction rates, and key thermodynamic and kinetic parameters, providing a detailed and in-depth understanding of the degradation mechanisms under investigation. Additionally, this work systematically explores the key material and operational parameters influencing these degradation phenomena and assesses their degree of impact. Furthermore, it evaluates advanced characterisation techniques, including microscopy, spectroscopy, and electrochemical methods, to quantify degradation progression and identify failure modes. Mitigation strategies, such as the development of novel materials with enhanced properties and the optimisation of operational parameters, are also analysed. Finally, this review identifies gaps in the literature and outlines future research directions. By integrating recent findings, it contributes to advancing knowledge and driving future innovations towards more durable fuel cells.