UWSpace is currently experiencing technical difficulties resulting from its recent migration to a new version of its software. These technical issues are not affecting the submission and browse features of the site. UWaterloo community members may continue submitting items to UWSpace. We apologize for the inconvenience, and are actively working to resolve these technical issues.
 

Implications of inherent inhomogeneities in thin carbon fiber-based gas diffusion layers: A comparative modeling study

Thumbnail Image

Files

1-s2.0-S0013468618320759-main.pdf (2.01 MB)

Date

2019-02-01

Authors

García-Salaberri, Pablo
Zenyuk, Iryna
Hwang, Gisuk
Vera, Marcos
Weber, Adam Z.
Gostick, Jeff

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

Thin porous media are present in multiple electrochemical energy devices, where they provide key transport and structural functions. The prototypical example is gas diffusion layers (GDLs) in polymer-electrolyte fuel cells (PEFCs). While modeling has traditionally been used to explore PEFC operation, this is often accomplished using volume-averaged (VA) formulations, where the intrinsic inhomogeneities of the GDL are smoothed out and the lack of defining a representative elementary volume is an ever-present issue. In this work, the predictions of a single-phase VA PEFC model are compared to those of a pore-scale PEFC model using GDL tomograms as a part of the meshed domain to delineate important aspects that VA models cannot address. The results demonstrate that while VA models equipped with suitable effective properties can provide a good average estimate for overall performance, the lack of accounting for real structures limits their predictive power, especially for durability and degradation behavior where large deviations are found in the spatial distributions. Furthermore, interfacial effects between the GDL and the microporous layer are explored with the pore-scale model to understand the implications of the layered geometry. It is shown that the actual microstructure of the GDL/MPL transition region can significantly affect the fluxes across the sandwich, something that VA models cannot easily consider. Interfacial design is recognized as a key quality control parameter for large-scale MEA manufacturing and assembly.

Description

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.electacta.2018.09.089. © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

gas diffusion layer, inhomogeneities, modeling, polymer electrolyte fuel cell, pore scale

LC Keywords

Citation

URI

https://doi.org/10.1016/j.electacta.2018.09.089
 http://hdl.handle.net/10012/14258

Collections

Waterloo Research
Chemical Engineering