Gas-diffusion-layer structural properties under compression via X-ray tomography

Gas-diffusion-layer structural properties under compression via X-ray tomography

TitleGas-diffusion-layer structural properties under compression via X-ray tomography
Publication TypeJournal Article
Year of Publication2016
AuthorsIryna V Zenyuk, Dilworth Y Parkinson, Liam G Connolly, Adam Z Weber
JournalJournal of Power Sources
Volume328
Pagination364 - 376
Date Published01/2016
ISSN03787753
Abstract

There is a need to understand the structure properties of gas-diffusion layers (GDLs) in order to optimize their performance in various electrochemical devices. This information is important for mathematical modelers, experimentalists, and designers. In this article, a comprehensive study of a large set of commercially available GDLs' porosity, tortuosity, and pore-size distribution (PSD) under varying compression is presented in a single study using X-ray computed tomography (CT), which allows for a noninvasive measurement. Porosities and PSDs are directly obtained from reconstructed stacks of images, whereas tortuosity is computed with a finite-element simulation. Bimodal PSDs due to the presence of binder are observed for most of the GDLs, approaching unimodal distributions at high compressions. Sample to sample variability is conducted to show that morphological properties hold across various locations. Tortuosity values are the lowest for MRC and Freudenberg, highest for TGP, and in-between for SGL papers. The exponents for the MRC and Freudenberg tortuosity demonstrate a very small dependence on compression because the shapes of the pores are spherical indicating minimal heterogeneity. From the representative-elementary-volume studies it is shown that domains of 1 × 1 mm in-plane and full thickness in through-plane directions accurately represent GDL properties.

DOI10.1016/j.jpowsour.2016.08.020
Short TitleJournal of Power Sources
Refereed DesignationRefereed