Two-dimensional pore-scale investigation of liquid water evolution in the cathode of proton exchange membrane fuel cells

Water management is crucial to the performance of proton exchange membrane fuel cells (PEMFC). In this work, a pore-scale model is developed based on lattice Boltzmann (LB) method for the simulation of multicomponent multiphase reactive transport in an operating PEMFC, with the aim to capture the water vapor generation, condensation, and subsequent transport in the entire porous cathode, including the catalyst layer, gas diffusion layer, and gas channel. The current LB model considers the effect of liquid/vapor condensation on the dynamic evolution of liquid water. The transportation of oxygen and dynamic water evolution is coupled by the electrochemical reactions occurring at the active site of the catalyst layer. Effects of the microstructure and wettability of gas diffusion layer, vapor generation rate, temperature distribution, and existence of the rib on the dynamic evolution of liquid water are elaborated. The insights provided in this work would facilitate the understanding of liquid water evolution in the PEMFC and reduce its water flooding issues.