One simple design to improve the mass transfer of low Pt-loaded membrane electrode assembly to realize operation under low humidity

Abstract

The low Pt-loaded cathode catalyst layer (CCL) design is critical for mass transfer in proton exchange membrane fuel cells (PEMFCs). Meanwhile, the drying of the CCL can lead to high voltage loss of membrane-electrode assemblies (MEAs) at low relative humidity (RH). Here, we use silica (SiO2) as a pore-forming agent to design CCL with a gradient pore structure. The oxygen transport resistance (OTR) test results show that the gas transport capacity of the CCL is significantly improved. According to the polarization curve at low RH, the gradient pore structure in CCL can improve the performance of the MEA. The accelerated stress test (AST) is conducted to explore the durability of these MEAs. The results show that the use of SiO2 to create pores in the CCL does not accelerate the loss of Pt. This optimization method can be practically applied to improve the performance under low RH.