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

JOURNAL OF POWER SOURCES

卷:328

Article

Zenyuk, Iryna V.¹  Parkinson, Dilworth Y.²  Connolly, Liam G.¹  Weber, Adam Z.³ 

[1] Tufts Univ, Dept Mech Engn, 200 Boston Ave,2500, Medford, MA 02155 USA

[2] Lawrence Berkeley Natl Lab, Energy Sci Area, Adv Light Source, 1 Cyclotron Rd, Berkeley, CA 94720 USA

[3] Lawrence Berkeley Natl Lab, Energy Technol Area, Energy Convers Grp, 1 Cyclotron Rd, Berkeley, CA 94720 USA

关键词: Fuel-cells;    Gas diffusion layers;    Porosity;    Pore-size distribution;    Tortuosity;    Compression;   

DOI  :  10.1016/j.jpowsour.2016.08.020

来源: Elsevier

【 摘 要 】

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 x 1 mm in-plane and full thickness in through-plane directions accurately represent GDL properties. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free