Porosity and Pt content in the catalyst layer of PEMFC: effects on diffusion and polarization characteristics

摘要

A three-dimensional (3-D) pore network model of polymer electrolyte membrane fuel cell (PEMFC)is presented in order to evaluate the effect of pore size and the effective diffusion coefficient inrandom porous media. The model of pseudo cathode catalyst layer (CCL) consists of pores and arandom distribution of carbon supported platinum (Pt/C) and electrolytes, which were generated on acomputer by means of Monte Carlo method. In this study, we utilized this 3-D meso-scale porousmodel of the CCL, and investigated tortuosity of pores, electrolyte connectivity. The effectiveKnudsen diffusion coefficient can be successfully obtained. This meso-scale model is applied to studythe effects of porosity, pore size and Pt content on the polarization characteristics of the PEMFC. Therelation between the composition of the CCL and the characteristics of polarization curve has beenclarified.