Measurement and Analysis of Gas Transport Properties in Catalyst Layers of Polymer Electrolyte Fuel Cells with Different Ionomer to Carbon Ratio

Abstract

Gas transport properties in catalyst layers of polymer electrolyte fuel cells are key factors for improving cell performance. It is necessary to clarify the relationship between the gas transport properties and the microstructure in catalyst layers. In this study, the oxygen diffusivities in catalyst layers with different ionomer-to-carbon ratio (I/C) were evaluated using a microfluidic device, and tortuosity factors were obtained. The porous structures of catalyst layers were evaluated by the nitrogen physisorption method and observation using a field emission scanning electron microscope. It was revealed that the tortuosity factor of the catalyst layers with high and low I/C was larger than that of catalyst layers with middle I/C. This can be attributed to the segregation of ionomers in high-I/C catalyst layers and the agglomeration of carbon particles in low-I/C catalyst layers.

A Numerical Simulation of Evolution Processes and Entropy Generation for Optimal Architecture of an Electrochemical Reaction-Diffusion System: Comparison of Two Optimization Strategies

“…However, the transport properties and effective utilization of the catalyst material strongly depend on the structural design of the porous electrode. 11,12 A better design solution might improve the transport phenomena and consequently lead to a more effective utilization of the catalyst material. Modifying the composition of an electrode is an approach used by previous researchers [13][14][15] to get an appropriate compromise between various processes.…”