Small angle X-ray scattering (SAXS) technique is proposed as a non-destructive diagnostic tool to investigate the catalyst layer saturation in operating conditions. SAXS is well suited for diagnosing the presence of liquid water during operando experiments because of its sensitivity to electron density contrast, nanoscale observation window, high temporal resolution and adequate spatial resolution to distinguish the components in PEFCs. Herein, SAXS intensity profiles measured at cSAXS, Swiss Light Source, Paul Scherrer Institut, Switzerland, with a recently developed SAXS-compatible operando PEFC (Figure 1 middle and right) are interpreted using representative morphology models and assuming different water filling mechanisms (Figure 1 middle and left). The presentation will provide insights into the wetting phenomena in the catalyst layer of PEFC during operation using a representative morphology modelling approach. This work has been presented in XVIII edition of the International Small-Angle Scattering Conference.
(1) Xu, H.; Buhrer, M.; Marone, F.; Schmidt, T. J.; Buchi, F. N.; Eller, J. Effects of Gas Diffusion Layer Substrates on PEFC Water Management: Part I. Operando Liquid Water Saturation and Gas Diffusion Properties. J Electrochem Soc 2021, 168 (7).
(2) Eller, J.; Rosen, T.; Marone, F.; Stampanoni, M.; Wokaun, A.; Buchi, F. N. Progress in In Situ X-Ray Tomographic Microscopy of Liquid Water in Gas Diffusion Layers of PEFC. J Electrochem Soc 2011, 158 (8), B963-B970.
(3) Mularczyk, A.; Lin, Q. Y.; Niblett, D.; Vasile, A.; Blunt, M. J.; Niasar, V.; Marone, F.; Schmidt, T. J.; Buchi, F. N.; Eller, J. Operando Liquid Pressure Determination in Polymer Electrolyte Fuel Cells. Acs Appl Mater Inter 2021, 13 (29), 34003-34011.
(4) Sabharwal, M.; Buchi, F. N.; Nagashima, S.; Marone, F.; Eller, J. Investigation of the transient freeze start behavior of polymer electrolyte fuel cells. J Power Sources 2021, 489.
(5) Chen, Y. C.; Berger, A.; De Angelis, S.; Schuler, T.; Bozzetti, M.; Eller, J.; Tileli, V.; Schmidt, T. J.; Buchi, F. N. A Method for Spatial Quantification of Water in Microporous Layers of Polymer Electrolyte Fuel Cells by X-ray Tomographic Microscopy. Acs Appl Mater Inter 2021, 13 (14), 16227-16237.
(6) Babu, S. K.; Spernjak, D.; Mukundan, R.; Hussey, D. S.; Jacobson, D. L.; Chung, H. T.; Wu, G.; Steinbach, A. J.; Litster, S.; Borup, R. L.; Zelenay, P. Understanding water management in platinum group metal-free electrodes using neutron imaging. J Power Sources 2020, 472.