Numerical Modeling of Two-Phase Behavior in the PEFC Gas Diffusion Layer

A critical performance limitation in the polymer electrolyte fuel cell (PEFC) is attributed to the mass transport loss originating from suboptimal liquid water transport and flooding phenomena. Liquid water can block the porous pathways in the fibrous gas diffusion layer (GDL) and the catalyst layer (CL), thus hindering oxygen transport from the flow field to the electrochemically actives sites in the catalyst layer. The cathode GDL is the component primarily responsible for facilitating gas and liquid transport, therefore plays a major role in determining the water management of a PEFC and hence the mass transport loss. The underlying pore morphology and wetting characteristics have significant influence on the flooding dynamics in the GDL. In this paper, the study of the two-phase behavior and the durability implications due to the wetting characteristics in the carbon paper GDL are presented using a pore-scale modeling framework.