Hydrogen fueled PEMFC (Proton Exchange Membrane Fuel Cell) systems for automobiles offer an excellent opportunity for the United States to reduce its dependence on foreign oil and to reduce transportation related emissions. However, cost of the fuel cells has been a substantial hindrance to their adoption. The achievable power density is the single most dominant factor affecting cost of PEMFC stacks, and current/power density of the stack should be maximized to minimize cost.
One operational parameter affecting PEMFC performance is the presence of liquid water. Water management in PEMFCs is challenging because of the inherent conflicts in providing water to maintain adequate membrane proton conductivity while removing water produced by the electrochemical reactions to allow gaseous reactants access to the reaction catalysts. The GDL (Gas Diffusion Layer) allows appropriate drainage of liquid water, keeping the gas flow channels open for the reactants to reach catalyst surface and for the residual reactants to diffuse out. Inability of the GDL to drain water will lead to flooding of the gas flow channels and shut down the PEMFC.
In a Phase I SBIR project sponsored by U.S. DOE, Techverse, Inc. is developing a novel Teflon impregnation technique for hydrophobic treatment of GDL material which provides better GDL hydrophobic properties than those of commercially available GDLs increasing the power output of the PEM fuel cells without increasing its cost.