Method of making a stable hydrophilic coating/surface on carbon-based materials for fuel cell applications
View Patent ↗One exemplary embodiment includes a fuel cell component having comprising a carbon chain, and a material grafted to the coating/surface, wherein the material includes ionic or polar groups. One embodiment includes composite plates which include carbon that can be activated and treated to make their surface hydrophilic.
1. A method comprising:
providing a fuel cell component comprising carbon and a surface including active groups thereon,
providing a hydrophilic polymer comprising ionic or polar groups and capable of reacting with said active groups;
grafting said polymer onto the component by reaction with the active groups.
2. A method as set forth in claim 1 wherein the providing a fuel cell component including carbon and a surface with reactive groups thereon comprises providing a substrate having a coating comprising carbon thereon and exposing the component to atmospheric plasma to produce the active groups on the surface of the coating.
3. A method as set forth in claim 2 wherein the coating comprises at least one of epoxies, silicones with graphite particles, polyamide-imides, polyether-imides, polyphenols, fluro-elastomers, polyesters, phenoxy-phenolics, epoxide-phenolics, acrylics, or urethanes polymers, and wherein said active groups comprise oxygenated groups.
4. A method as set forth in claim 2 wherein the coating comprises an epoxy coating.
5. A method as set forth in claim 4 wherein the polymer comprises polyethylenimine and the ionic groups comprise amine groups.
6. A method as set forth in claim 4 wherein the polymer comprises a polyvinyl alcohol and the ionic groups comprise hydroxyl groups.
7. A method as set forth in claim 1 wherein the fuel cell component comprises a diffusion media layer.
8. A method as set forth in claim 1 wherein the fuel cell component comprises a fuel cell bipolar plate having a coating thereon.
9. A method as set forth in claim 8 with a proviso that no low contact resistant metal is provided on the bipolar plate.
10. A method as set forth in claim 8 wherein no gold is provided over the bipolar plate.
11. A method as set forth in claim 8 wherein the coating comprises a polymer and electrically conductive filler particles.
12. A method as set forth in claim 8 wherein the coating comprises graphite.
13. A method as set forth in claim 12 wherein the coating further comprises a second polymer.
14. A method as set forth in claim 1 wherein the fuel cell component is a carbon composite bipolar plate.
15. A method as set forth in claim 1 wherein the fuel cell component comprises a diffusion media layer and wherein the providing the fuel cell component comprising carbon and a surface including active groups, comprises exposing the diffusion media layer to an open-air plasma to create the active groups on a surface of the diffusion media layer.
16. A method as set forth in claim 1 wherein the fuel cell component comprises a bipolar plate having a reactant gas flow field defined in a face thereof by a plurality of lands and channels, and a coating deposited in the channels leaving the lands substantially uncoated, and wherein the carbon is part of the coating.