Investigation of Gas Transport Properties of PEMFC Catalyst Layers by Using a Microfluidic Device

摘要

Effective gas diffusivity and tortuosity factor of catalyst layers used in proton exchange membrane fuel cells were evaluated by using an in-house microfluidic device. Gas transport properties of the catalyst layers are one of the key factors to have high-performance catalyst layers and fuel cells. Two catalyst layers with different thickness were fabricated and evaluated. The only difference between the two catalyst layers in their fabrication processes was a blading gap in the applying process by a doctor blade method. The resultant thicknesses of the catalyst layers were 5 and 11 μm. Porosity and pore size distribution were almost the same, while crack area ratio of the thick catalyst layer was larger than that of the thin catalyst layer. The effective diffusivity of the thick catalyst layer was slightly larger than that of the thin catalyst layer. The crack area can affect the gas diffusivity.