Modeling a polymer electrolyte fuel cell cathode for investigating the effects of cracks in a microporous layer.

Water management at high current densities poses a significant technological challenge for polymer electrolyte fuel cells (PEFCs). Accumulation of water generated by the oxygen reduction reaction can impede oxygen transport and lead to substantial concentration overpotential, limiting cell performance. Therefore, precise modeling of cell physics and optimization of electrode structures for effective water management are vital to enhance PEFC performance. In this study, a 3D model was developed to simulate phenomena occurring at the cathode of PEFCs. The mathematical model, implemented using FreeFEM++, enabled analysis of intricate interactions within the PEFC cathode, including water and mass transport, as well as various reactions. The model consisted of three components, a gas diffusion layer, microporous layer, and catalyst layer. To model potential real-world scenarios, micro-scale cracks were intentionally introduced to the microporous layer, mimicking fabrication-induced heterogeneities. Contrary to previous studies that typically avoided heterogeneities, this research revealed that under certain circumstances, micro-scale cracks can enhance cell performance, especially when perforations were incorporated into the gas diffusion layer. In our previous work, it was observed that isolated cracks located under the rib structure resulted in water flooding, hampering oxygen access. Therefore, interconnected cracks in this study were identified as a favorable configuration, emphasizing the need to develop fabrication processes enabling controlled crack connections at minimal or no additional cost. Such advancements hold promise for future PEFC development, paving the way towards improved performance and efficiency. [ABSTRACT FROM AUTHOR]