Effects of cathode catalyst layer fabrication parameters on the performance of high-temperature polymer electrolyte membrane fuel cells

Abstract

In this work, cathode catalyst layers (CLs) are prepared via the different fabrication techniques of spraying, screen printing, and bar coating to examine the effect of the CL fabrication method on the performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). The differences in structural characterizations of CL are caused by the intrinsic characteristics of each fabrication process. The CL deposition and fabrication methods strongly affect the morphology of CL. The CL morphology is investigated with surficial and cross-sectional scanning electron microscopy images, which showed that cracks are generated deeply inside the bar coated CL, but not detected on the sprayed CL. The large cracks in bar- coated CL leads to low proton conductivity resistance in the CL but also makes it difficult for oxygen to approach the reaction sites resulting in high mass transport resistance. The pore size distributions of the CL are also examined by mercury intrusion porosimetry and the results show that the membrane electrode assembly (MEA) with the sprayed CL contains a well-developed pore structure with pore diameters of < 1 mu m that can be facilitated the mass transfer, yields a peak power density of 383 mW cm(-2).