In this work, we are presenting a comprehensive approach for 2D and 3D imaging and quantification of fuel cell electrodes, at several scales, and the correlation to their properties and performance:
2D imaging and analysis of catalyst layers (beginning of life and end of life) using STEM-EDS will be presented with a novel, practical approach to quantify a number of parameters, such as Pt loading, loss and distribution, ionomer loading and I/C ratio, layer porosity, and oxygen evolution reaction (OER) agglomerate size. The method enables 2D visualization of component distribution at a whole layer scale, as well as at an agglomerate scale. Quantification of changes after degradation of fuel cells offers very valuable learning about possible processes occurring during degradation - information that was not available until now. Challenges with the method and potential development will be presented as well.
3D imaging and quantification of catalyst powders and catalyst layers on multiple scales will be presented, correlatively utilizing ET, FIB-SEM, and x-CT microscopy. Spatial distribution of all phases – Pt catalyst, carbon support, ionomer and pores will be revealed. A number of microstructural parameters will be quantified from the 3D data sets. Direct numerical simulation of the 3D data sets to obtain effective transport properties such as electrical and thermal conductivity, and gas diffusivity will also be reported. The approach shows promise for improved modeling, design and optimization of the fuel cell catalyst layers.
Finally, the talk will conclude with the new capabilities and possible prospects for advanced imaging and quantification for further fuel cell development and commercialization.