Chemo-mechanical durability of reinforced fuel cell membranes in the presence of metallic foreign particles: Part 2 – geometrical effect

This article is the second part of a three-part series analyzing the chemo-mechanical membrane degradation in fuel cells caused by metallic foreign particles, which are envisioned to originate from the fuel cell production machinery and are deposited within the membrane electrode assembly (MEA). While Part 1 examined the impact of the chemical composition of Fe and stainless steel 316L (SS316L) with a nominal particle size of 55 ± 5 μm, this work (Part 2) focuses on the geometrical effect arising from flake-like and randomly shaped Fe and SS316L particles with prominent 3D features and larger dimensions of 500 ± 60 μm. Upon subjecting particle-laden MEAs to accelerated chemo-mechanical degradation, both Fe and SS particles are observed to inflict significant convective hydrogen crossover, leading to early failure. Four-dimensional in-situ X-ray computed tomography characterization reveals severe localized membrane rupture due to the relatively large particle dimensions and 3D features on their surface that protruded deeply into the MEA layers during fabrication. Furthermore, the extent of damage of Fe particles is exacerbated due to dissolution and localized membrane thinning. To ensure good durability, it is therefore essential to eliminate large (>500 μm) metallic particles with rough surface features in the production process. • Geometrical impacts of metallic particles on membrane durability are explored. • 4D in-situ XCT shows GDL deformation, membrane indentations, and CCM rupture. • The membrane durability is severely compromised in the presence of large particles. • Complex sharp features on the particle surface cause deep penetration into the MEA.