Modeling investigation into effects of diffusion and catalyst layers on performance of direct methanol fuel cell

A two-dimensional single phase full cell model for a direct methanol fuel cell (DMFC) is developed to investigate the effects of structure parameters, such as the porosity of diffusion layer (DL) and catalyst layer (CL), and the width of DL and CL, on cell performance and methanol crossover rate. In this model, the electrochemical kinetics, hydrodynamics, fluid flow and methanol crossover are considered. The agglomerate models are utilized for both anode catalyst layer and cathode catalyst layer to modify the methanol oxidation reaction kinetics and the oxygen reduction reaction kinetics. A program based on the finite volume method is coded to solve the equations, and the results show that the cell performance depends strongly on the parameters of DLs rather than CLs. The trend in the effects of DL width is reversed for different cell current density. Although a higher porosity of DL and CL leads to a better cell performance, the methanol crossover becomes heavier.