Moisture control in gas diffusion layer of polymer electrolyte fuel cell (characteristics of water distribution in new type microporous media applying X-ray radiography)

The mass transfer characteristics of gas diffusion layer (GDL) are closely related to cell performance in PEFC. In this study, the observation method of internal water distribution in microporous media for GDL by using X-ray radiography was examined to elucidate the enhancement mechanisms of oxygen diffusivity of new type microporous media shown in the previous report. It was shown that the distinction between the areas of void and water in microporous media was possible by using X-ray computer tomography. Further, the water distributions in the stracture of new type microporous media, in which two kinds of porous media having different wettability are arranged alternately (Hybrid type GDL), was visualized and the mechanism of high oxygen diffusivity of Hybrid structure of microporous media was clarified.