Investigation of the use of polypyrrole and pedot: PSS coated electrospun polymer nanofibers as gas diffusion layer in pem fuel cells

The aim of this study is to produce novel gas difusion layers for proton exchange membrane fuel cells with high performances and consisting entirely of nanofibers without the need of traditional macroporous substrate and microporous layer. Another objective is to overcome the negative impacts of the interface between macroporous substrate and microporous layer inducing some resistance to the system and decreasing the cell performance. For this purpose, polymethyl methacrylate nanofiber mats were produced by electrospinning. These layers were coated with polypyrrole and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate conjugated polymers by oxidative polymerization. Polypyrrole nanofiber gas diffusiın layer and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer were produced. According to the results, cylindrical and homogeneous polymethyl methacrylate nanofibers were obtained. In polypyrrole nanofiber gas diffusiın layer, the polymethyl methacrylate nanofibers were perfectly well coated by polypyrrole whereas voids are observed at the interface between poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and polymethyl methacrylate nanofibers. Bulk porosity measurements at twenty four hours of water immersion also revealed that no dimensional variation was observed for the novel polypyrrole nanofiber gas diffusiın layer which presents a better dimensional stability in wet conditions. The highest conductivity was obtained for poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer. Cell performance tests revealed a remarkable power density for novel polypyrrole nanofiber gas diffusion layer. For the first time in the literature, high-performance gas diffusion layers totally made of conductive polymer coated nanofibers are proposed as low cost alternatives to commercial systems.