Gas Diffusion Layer

Gas diffusion layer (GDLs) perform the significant functions in the proton exchange membrane fuel cells (PEMFCs), such as maintaining the water balance in the membrane electrode assem-bly (MEA) by allowing appropriate amount of water to move in and out from the reaction zone, providing the mechanical sup-port for the MEA and electrical contact between the electrodes and the current collectors. The key characteristics of GDLs include structural design, porosity, hydrophobicity, hydrophilicity, gas permeability/transport properties, watermanagement and surface morphology. The GDLs consist of a micro-porous layer made of teflonized carbon black on the top of macro-porous carbon paperor cloth substrate. The effects of macro-porous carbon substrateon the GDL performance have been reported in our previous study. Alcohol based solvents are widely used for preparing homoge-nous dispersion of teflonized carbon slurries for GDL fabricationof micro-porous layers. However, the alcohols pose environmental and health safety issues when used in large rvolume for any commercial manufacturing.