Joel Mata Edjokola, Mathias Heidinger, Amir Niroumand, Viktor Hacker and Merit Bodner
Gas diffusion layers (GDLs) are critical in polymer electrolyte fuel cells, facilitating gas and water transport while providing structural support, but they are prone to chemical degradation, particularly oxidation, which can affect long-term performance. This study explores GDL degradation using accelerated stress testing with Fenton's reagent, revealing a significant reduction in surface fluorine content, hydroxyl group formation, and a 3% decrease in contact angle, which alters the GDL's hydrophobicity and structure. Surprisingly, aged GDLs exhibit a 17% improvement in fuel cell performance due to pore widening and a 51% reduction in mass transport resistance. However, these benefits are diminished under high humidity, where fluorine loss leads to water management issues and voltage instability. The study highlights the dual impact of GDL degradation, with short-term performance gains masking long-term challenges, underscoring the need for improved GDL materials resistant to chemical degradation for sustained fuel cell efficiency.
Journal of The Electrochemical Society, 2024