Characterization of Gas Diffusion Electrodes for Polymer Electrolyte Fuel Cells

Gas diffusion electrodes (GDEs), applied in polymer electrolyte fuel cells, are composed of a multilayer structure containing porous carbon materials and noble metal catalyst. Gas diffusion layer (GDL), a GDE component, consists of a thin layer of carbon black mixed with an organic binder, frequently polytetrafluoroethylene, which is coated onto a sheet of macroporous carbon backing cloth or paper. GDL serves as a current collector that allows ready access of fuel and oxidant to the anode and the cathode catalyst surfaces, respectively. In this work, a complete GDL state-of-the-art is first presented. Then, the effects of different fabrication methods and composition of gas diffusion layer are investigated and discussed in the light of gas permeability, thermal analysis, morphology, and electrical resistance. Besides, performances in H-2/air fed cell at 50 degrees C in different humidity conditions were discussed, and a comparison with own products and commercial GDLs was carried out. It was found that the different preparation methods influence the GDL properties, allowing the most suitable choice depending on the cell humidity conditions.