Investigation of synergetic effect of PDMS polymer hydrophobicity and polystyrene-silica particles roughness in the content of microporous layer on water management in PEM fuel cell

Abstract

Water management is still challenging issue in PEM fuel cells and many researchers have tried to elucidate the behavior of liquid water in cell media. Gas Diffusion Layer (GDL) or Microporous Layer (MPL) are usually chosen to modify their surfaces with hydrophobic materials for better water removal ability. Distinctly, this study deals with using both hydrophobicity of polydimethylsiloxane (PDMS) and roughness of polystyrene (PS) - silica particles together in the content of MPL. The best fuel cell performance was obtained with the MPL included binary of PDMS-1 (3% wt.) and PS-silica (1% wt.) particles. The highest current density value of this MPL was recorded as 287.5 mA/cm2 (@0.6 V) which is corresponded to the 172 mW/cm2 power density with 0.1 mg Pt/cm2 catalyst loading. Contact angle and avearge surface roughness were respectively measured as 122° ± 4.7 and 2.63 µm for the mentioned MPL. It was assumed that optimum hydrophobicity and surface roughness distinguished this MPL from the other prepared MPLs in terms of PEM fuel cell performance.