Unveiling the impact of pore structure of cathode catalyst layer on proton exchange membrane cell performance

Abstract

This work quantitatively explores the impact of pore structure of cathode catalyst layer (CCL) on the overall performance of low-Pt loading electrodes in Proton Exchange Membrane Fuel Cell (PEMFCs), providing guidelines for designing high-performance CCL. The model predictions align closely with experimental measurements. The results reveal that the best cell performance occurs when the ratio of secondary to primary pores is 2, which is attributed to the balance between liquid water saturation and the diffusivity of gaseous species within the catalyst layer. In addition, higher total porosity or higher Pt loading require more primary pores to achieve a remarkable improvement in performance. Furthermore, the influence of total porosity on the peak power density of fuel cell depends on pore size distribution. The optima total porosities are 0.5 and 0.7 when the ratios of secondary to primary pores are 2 and 1, respectively.