## Abstract It has now been well recognized that both the performance and durability of proton exchange membrane fuel cells (PEMFCs) are closely related to the water accumulation and transport inside its porous components, particularly in the gas diffusion layer (GDL), and microporous layer (MPL).
Determination of effective water vapor diffusion coefficient in pemfc gas diffusion layers
β Scribed by Jacob M. LaManna; Satish G. Kandlikar
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 803 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0360-3199
No coin nor oath required. For personal study only.
β¦ Synopsis
The primary removal of product water in proton exchange membrane (PEM) fuel cells is through the cathode gas diffusion layer (GDL) which necessitates the understanding of vapor and liquid transport of water through porous media. In this investigation, the effect of microporous layer (MPL) coatings, GDL thickness, and polytetrafluorethylene (PTFE) loading on the effective water vapor diffusion coefficient is studied. MRC Grafil, SGL Sigracet, and Toray TGP-H GDL samples are tested experimentally with and without MPL coatings and varying PTFE loadings. A dynamic diffusion test cell is developed to produce a water vapor concentration gradient across the GDL and induce diffusion mass transfer.
Tests are conducted at ambient temperature and flow rates of 500, 625, and 750 sccm. MPL coatings and increasing levels of PTFE content introduce significant resistance to diffusion while thickness has negligible effects.
π SIMILAR VOLUMES
The self-diffusion coefficient D of water in ferrierite at an average density of 6.6 molecules per unit cell and 298 K has been computed from a molecular dynamics simulation and the Einstein relation. The estimated value of D is 0.5 x 10mJ cm's\_ ' and agrees with experimental results.