Modeling of Liquid Water and Mass Transport in Porous Electrodes with Microcracks of Polymer Electrolyte Fuel Cells

Polymer electrolyte fuel cell (PEFC) is one of the most promising electrochemical energy devices for portable applications as it can convert chemical to electrical energy with high efficiency, provide large power density, and possess low operating temperature and pressure. Compared to widely accepted technology like lithium-ion batteries, PEFCs use less critical raw materials. Therefore, they can serve as an alternative to ease the scarcity of materials in the future. For widespread commercialization, the improvement of PEFC performance is necessary. Previous studies kept a homogeneity of the electrodes as primary importance. However, recent studies on perforation in the electrodes have shown that perforations can positively or negatively affect cell performance depending on the operating conditions. The challenge is understanding the impact of cracks on transport phenomena in the electrodes. In this study, a model to investigate mass and liquid water transport in porous media with the presence of microcracks was proposed. The 2D half-cell model was developed in FreeFEM++ software to investigate the effects of cracks' position, number, and depth. The results revealed that, based on the considered condition, the under-channel crack could significantly enhance cell performance by 7%, while the under-rib crack did not provide any significant benefits. The results of this study will provide a fundamental understanding of improving the efficiency of PEFCs by intentionally creating cracks in the electrodes.