Abstract
Mass transfer characteristics in gas diffusion layer (GDL) are closely related to performance of polymer electrolyte fuel cell (PEFC). Thus, it is necessary to clarify the characteristics of liquid water distribution, microscopic conformation and oxygen diffusivity in the GDL. In this study, a hybrid type GDL was examined to control the liquid water movement in the GDL and achieve both oxygen diffusion and moisture retention. In particular, the oxygen diffusivity and visualization of liquid water in the GDL were simultaneously measured using a galvanic cell oxygen absorber and X-ray radiography using beam line at SPring-8. As the result, the formation of oxygen diffusion paths was visualized; the pores in the hybrid GDL were formed from hydrophobic region, and the pores spread to the untreated region after the formation of the pores in the hydrophobic region. Thus, the formation of oxygen diffusion paths in the hydrophobic region enhanced the oxygen diffusion characteristics.
