Analytical modeling of liquid saturation jump effect for hydrogen alkaline anion exchange membrane fuel cell

Abstract

Alkaline anion exchange membrane fuel cell (AEMFC) has been recognized as a promising zero-emission power source for portable, mobile and stationary application in recent years. To ensure high ionic conductivity and efficient reactants delivery, water management is regarded as one of the most critical issues for AEMFC. In this study, an analytical model is formulated to investigate the effect of electrode wettability on the water transport and resultant AEMFC performance. The pressure continuity method is considered to simulate liquid saturation jump on the interfaces of adjacent electrode layers. The results show that decreasing the cathode catalyst layer (CL) contact angle improves the performance because more water can be kept in the cathode CL decreasing polarization losses. The anode micro porous layer (MPL) is generally helpful, by forcing the liquid water to back-diffuse to the cathode. However, cathode MPL hinders the water transport to the cathode CL, leading to a lower reaction rate and membrane conductivity. The liquid water injection into the cathode has great potential to further improve the performance of AEMFC, however it may cause flooding in the flow channel and GDL. The cathode reaction kinetics should be considered as one of the most significant factors dragging the cell performance.