Abstract
Understanding the respective morphology changes with compression of the gas diffusion layer (GDL) and microporous layer (MPL) in unitized gas diffusion media (GDM) is critical for polymer electrolyte fuel cell (PEFC) high-power performance, as the compression affects the ohmic resistance and the porosity that influences mass-transport resistance. We present a comprehensive study of morphology of two types of GDM (paper-type SGL 29BC and felt-type Freudenberg H2315 C2) under varied levels of compression using X-ray computed tomography (CT) to link GDM microstructure to fuel cell performance. The SGL 29BC morphology evolves more significantly with compression in ways that we expect to occlude oxygen diffusivity, while transitions in the Freudenberg H2315 C2 are more gradual. Upon compression by 0–34% its initial thickness, the 29BC pore-size distribution (PSD) shifts from bimodal (12.6 and 34.9 μm average pore radii) to unimodal (9.67 μm), extensive MPL surface cracks decrease in surface area and depth (5–2...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
