Wet lamination process for reducing mud cracking in fuel cell components
Methods of making a substantially crack-free electrode layer are described. The methods include depositing an electrode ink on a substrate; placing a layer of porous reinforcement layer on a surface of the wet electrode ink; and drying the electrode ink to form the substantially crack-free electrode layer on the substrate. Substantially crack-free electrode layers and fuel cells incorporating substantially crack-free electrode layers are also described.
1. A method of forming a substantially crack-free fuel cell component that is made of an electrode, a gas diffusion medium, and a proton-transmissive ionomer, the method comprising:
depositing an electrode ink directly onto the gas diffusion medium, the electrode ink comprising a wet film construction containing a solvent, the ionomer, and a catalyst;
placing a porous reinforcement layer on the wet electrode ink such that the surface of the wet film construction on the gas diffusion medium is reinforced while it is drying;
drying the electrode ink with a first heating step to remove the solvent in the electrode ink and to form the substantially crack-free electrode layer on the gas diffusion medium;
coating an ionomer film on the substantially crack-free electrode; and
drying the coated ionomer film with a second heating step.
2. The method of claim 1 wherein the porous reinforcement layer is a polymer film, a metal screen, or a woven material.
3. The method of claim 1 wherein the porous reinforcement layer is expanded polytetrafluoroethylene.
4. The method of claim 1 wherein the solvent comprises an organic solvent, water, or combinations thereof.
5. The method of claim 4 wherein the organic solvent is isopropyl alcohol, n-propyl alcohol, ethanol, butanol, diacetone alcohol, pentanol, or combinations thereof.
6. The method of claim 1 wherein the ionomer is perfluorosulfonic acid polymer, sulfonated polyether ketone, aryl ketone, or polybenzimidazole.
7. The method of claim 1 wherein the catalyst is a platinum group metal.
8. The method of claim 1 wherein the catalyst is disposed on electrically conductive support particles.
9. The method of claim 1 wherein drying the electrode ink comprises exposing the electrode ink to an infrared lamp or convectively heating the electrode ink to remove a solvent in the electrode ink.