PEMFC catalyst layer manufacturing drying step: on the slurry film consolidation volume fraction

A better understanding of the PEMFC catalyst layer (CL) manufacturing process can help develop improved CL design in a shorter time. Here, the drying step of the manufacturing process is studied in the case of CL manufacturing via blade coating and drying at a temperature of 60 °C, focusing on the slurry film evaporation step. Analyses are performed given the ink composition and experimental data on the CL final thickness and porosity for three ionomer/carbon ratios. Modeling confirms that all alcohols initially present in the slurry film have evaporated when the film consolidation occurs. The maximum solid volume fraction marking the occurrence of the slurry film consolidation is studied. Contrary to simpler slurry film evaporation situations, a single value of the consolidation volume fraction cannot be identified. Although relatively narrow ranges of values are identified for two indicators of the consolidation, the results suggest that the consolidation volume fraction should be considered as depending on the ionomer/carbon ratio.