Novel superhydrophobic microporous layers for enhanced performance and efficient water management in PEM fuel cells

Microporous layers (MPLs) obtained from inks containing three fluorinated polymers (perfluoroalcoxy, fluorinated ethylene propylene and a fluorinated polyurethane based on perfluoropolyether blocks) replacing conventional PTFE were prepared. Inks composition and rheological behaviour were fixed in order to apply the blade coating technique for MPL deposition. Superhydrophobic layers were obtained since contact angles higher than 150° were measured. The samples, tested in a single fuel cell at lab scale, at 60 °C and different relative humidity (RH 80/100 and 80/60, hydrogen/air) evidenced that new polymers are able to improve electrical performances reaching maximum power density values higher than those showed by conventional MPLs based fuel cells. Electrochemical impedance spectroscopy (EIS) was also carried out on the running cell using a Frequency Response Analyzer to assess the different dissipation phenomena and related losses.