Fabrication of catalyst-coated membrane-electrode assemblies by doctor blade method and their performance in fuel cells

Membrane-electrode assemblies (MEAs) have been fabricated with a direct coating of the catalyst slurry by a doctor blade method on the pre-swollen Nafion membrane for proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC). The effects of various swelling agents with different boiling points such as ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TEEG), and glycerol in the swelling step of the membrane and the drying step of the coated catalyst have been investigated. Also, the use of dimethyl sulfoxide (DMSO) as a dispersing agent in the catalyst slurry has been investigated. Among the various swelling agents investigated, EG gives the best results with the dispersing agent DMSO offering further improvement. The MEAs fabricated with the EG-swollen membranes and DMSO as a dispersing agent in the catalyst layer show good performance in single fuel cells with hydrogen and methanol fuels.