Nanoscale modeling of frosting process in catalyst layer of PEM fuel cells

In this study, a nanoscale frosting process model within the catalyst layer was established. The effects of initial temperature, cooling temperature, gaseous water particle number, carbon support diameter, and carbon support volume fraction were investigated. The results showed that the frosting process had the following pattern: nucleation on the cold surface—growth along the pathway—breakthrough. By increasing the initial temperature, more time was required to decrease the temperature of the catalyst layer inside to the sublimation temperature. Increasing the cooling temperature significantly delayed frost nuclei formation and greatly slowed the frost growth. With an increase in the number of released particles, the frost layer thickness did not increase considerably. The size of the carbon support diameter was related to the number of particles reaching the cold surface. When the volume fraction of the carbon support was small, there was a significant increase in breakthrough locations. When the initial temperature was 363 K, the highest Fourier number required for the breakthrough was 1.28. This research offers valuable insights into the design enhancement of catalyst layers in fuel cells and the improvement of fuel cell performance during a cold start in low-temperature conditions.