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Artikel
Insight into the 3D water distribution in PEFC Gas Diffusion Layer by In-situ
X-ray Tomographic Microscopy
| Författare: |
Eller, J. , Rosén, T., Prasianakis, N.I., Kang, J. , Mantzaras, J. , Roth, J. , Marone, F. , Stampanoni, M. , Wokaun, A. , Büchi, F.N. |
| Dokumenttyp: |
Konferens |
| Tillstånd: |
Publicerad |
| Tidskrift: |
9th Symposium on Fuel Cell and Battery Modeling and Experimental Validation (ModVal 9), Campus Sursee, Switzerland (2012) |
| Volym: |
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| År: |
2012 |
AbstractEfficient water removal and water management is crucial for the performance of polymer electrolyte fuel cells (PEFC), in particular at high current density operation. In order to better understand the distribution and transport of liquid water in the GDL, an in-situ X-ray tomographic microscopy (XTM) setup at the TOMCAT beamline of the Swiss Light Source (SLS) was developed [1] and used to study the liquid water distribution and the carbonaceous structures on the pore scale level with pixel sizes of 2-3 micron. Due to use of the high flux ionizing synchrotron radiation, significant radiation damage may be induced during the measurement [2, 3]. Using new CMOS camera technologies, ultra fast in-situ XTM PEFC scans can be realized within 2 to 20 s seconds. This facilitates to avoid radiation damage and subsequent measurement biasing for several XTM scans [4]. It allowed to study the 3D liquid water distribution in porous GDL structures with reasonable temporal resolution such as i.e. the stability of the water distribution over time, the reproducibility of the water distribution during wet-dry cycling, and the response of the water distribution on increased gas flow rates. The availability of the phase segmented data enables the quantitative analysis of the 3D water distribution (i.e. local saturation, water cluster size, water cluster connectivity, and local pore/water diameter analysis). Insight into the saturation dependent GDL permeability and diffusivity was provided in combination with CFD methods. Power law relationships were found which can be compared to previously used model assumptions. [1] J. Eller, T. Rosén, F. Marone, M. Stampanoni, A. Wokaun, F.N. Büchi, J. Electrochem. Society, 158 (2011), B963-B970 [2] A. Schneider, C. Wieser, J. Roth, L. Helfen, J.Power Sources, 195 (2010), 6349-6355 [3] J. Roth, J. Eller, F.N. Büchi, ECS Trans. 41 (2011), 371-387 [4] J. Eller, J. Roth, F. Marone, M. Stampanoni, A. Wokaun, F.N. Büchi, ECS Trans. 41 (2011), 387-394
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