Passivated metallic bipolar plates and a method for producing the same
View Patent ↗A method including providing a substrate; treating the substrate to form a passive layer, wherein the passive layer has a thickness of at least 3 nm; and depositing an electrically conductive coating over the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
1. A method comprising:
providing a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface;
treating the first substrate to form a passive oxide layer on the substrate with a thickness of at least 3 nm, wherein the treating comprises at least one of soaking the substrate in boiling de-ionized water, or applying to the substrate a heat treatment above 400° C.;
depositing an electrically conductive metal coating on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
2. A method as set forth in claim 1 wherein the treating the first substrate further comprises removing residual iron from the first substrate.
3. A method as set forth in claim 1 wherein the depositing comprises at least one of magnetron sputtering, electron beam evaporation, or ion assisted deposition.
4. A method as set forth in claim 1 wherein the passive layer has a thickness such that the thickness will not increase subsequent to the treating of the first substrate to form the passive layer when used in a fuel cell.
5. A method as set forth in claim 1 wherein the electrically conductive metal coating comprises at least one of platinum, ruthenium, or iridium.
6. A method as set forth in claim 1 wherein the first substrate comprises at least one of stainless steel, titanium, aluminum, or nickel base alloy.
7. A method as set forth in claim 1 wherein the first substrate comprises a bipolar plate.
8. A method as set forth in claim 1 wherein the electrically conductive metal coating has a thickness of about 0.1 nm to about 2 nm.
9. A method as set forth in claim 1 further comprising:
providing a second fuel cell substrate, wherein the first fuel cell substrate comprises a first bipolar plate and wherein the second fuel cell substrate comprises a second bipolar plate;
providing a soft goods portion comprising a polymer electrolyte membrane comprising a first face and a second face, a cathode electrode overlying the first face of the polymer electrolyte membrane, a first gas diffusion media layer overlying the cathode electrode, an anode electrode underlying the second face of the polymer electrolyte membrane, and a second gas diffusion media layer underlying the anode electrode; and
wherein the first bipolar plate overlies the first gas diffusion media layer, and the second bipolar plate underlies the second gas diffusion media layer.
10. A method as set forth in claim 9 further comprising providing a first microporous layer between the first gas diffusion media layer and the cathode electrode.
11. A method as set forth in claim 9 further comprising providing a second microporous layer between the second gas diffusion media layer and the anode electrode.
12. A method as set forth in claim 1 wherein the electrically conductive metal coating consists essentially of platinum, ruthenium, or iridium.
13. A method as set forth in claim 1 wherein the electrically conductive metal coating is porous.
14. A method as set forth in claim 9 wherein one of the first gas diffusion media layer and the second gas diffusion media layer includes a woven carbon cloth treated with a hydrophobic material.
15. A method as set forth in claim 9 wherein one of the first gas diffusion media layer and the second gas diffusion media layer has an average pore size of between 5 and 40 micrometers.
16. A method as set forth in claim 9 wherein one of the first gas diffusion media layer and the second gas diffusion media layer has an thickness of between 100 and 500 micrometers.
17. A method as set forth in claim 10 wherein the first microporous layer comprises a plurality of particles and a binder, wherein the binder and the plurality of particles are in a liquid phase comprising a mixture of organic solvent and water.
18. A method as set forth in claim 17 wherein the first microporous layer is dried and results in the first microporous layer comprising 60-90 weight percent particles and 10-40 weight percent binder.
19. A product comprising:
a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface comprising a passive oxide layer thereon, wherein the passive layer has a thickness of at least 3 nm; and
a porous electrically conductive metal coating with the proviso that the electrically conductive metal coating does not include gold or platinum or vanadium on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
20. A product as set forth in claim 19 wherein the electrically conductive metal coating comprises at least one of ruthenium, or iridium.
21. A product as set forth in claim 19 wherein the substrate comprises at least one of stainless steel, titanium, aluminum, or nickel base alloy.
22. A product as set forth in claim 19 wherein the electrically conductive metal coating has a thickness of about 0.1 nm to about 2 nm.
23. A product as set forth in claim 19 wherein the first fuel cell substrate comprises a first bipolar plate.
24. A product as set forth in claim 19 further comprising:
a second fuel cell substrate, wherein the first fuel cell substrate comprises a first bipolar plate and the second fuel cell substrate comprises a second bipolar plate;
a soft goods portion comprising a polymer electrolyte membrane comprising a first face and a second face, a cathode electrode overlying the first face of the polymer electrolyte membrane, a first gas diffusion media layer overlying the cathode electrode, an anode electrode underlying the second face of the polymer electrolyte membrane, and a second gas diffusion media layer underlying the anode electrode;
wherein the first bipolar plate overlies the first gas diffusion media layer, and the second bipolar plate underlies the second gas diffusion media layer.
25. A product as set forth in claim 24 further comprising a first microporous layer between the first gas diffusion media layer and the cathode electrode.
26. A product as set forth in claim 24 further comprising a second microporous layer between the second gas diffusion media layer and the anode electrode.
27. A product as set forth in claim 19 wherein the electrically conductive metal coating comprises at least one of ruthenium or iridium; wherein the substrate comprises at least one of stainless steel, titanium, aluminum, or nickel base alloy; and wherein the electrically conductive coating has a thickness of about 0.1 nm to about 2 nm.
28. A product as set forth in claim 19 wherein the electrically conductive metal coating consists essentially of ruthenium, or iridium.
29. A product as set forth in claim 25 wherein the first microporous layer comprises a plurality of particles and a binder, wherein the binder and the plurality of particles are in a liquid phase comprising a mixture of organic solvent and water.
30. A product as set forth in claim 29 wherein the first microporous layer is dried and results in the first microporous layer comprising 60-90 weight percent particles and 10-40 weight percent binder.
31. A method comprising:
providing a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface;
treating the substrate to form a passive oxide layer on the substrate with a thickness of at least 3 nm, wherein the treating comprises contacting the substrate with a nitric acid solution;
depositing an electrically conductive metal coating with the proviso that the electrically conductive metal coating does not include gold or platinum or vanadium on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
32. A method comprising:
providing a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface;
treating the substrate to form a passive oxide layer on the substrate with a thickness of at least 3 nm, wherein the treating comprises soaking the substrate in boiling de-ionized water;
depositing an electrically conductive metal coating on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
33. A method comprising:
providing a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface;
treating the first substrate to form a passive oxide layer on the substrate with a thickness of at least 3 nm, wherein the treating comprises applying to the substrate a heat treatment above 400° C.;
depositing an electrically conductive metal coating on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.
34. A method comprising:
providing a first fuel cell bipolar plate substrate having a reactant gas flow field defined in a surface;
treating the first substrate to form a passive oxide layer on the substrate with a thickness of at least 3 nm, wherein the treating comprises at least one of contacting the substrate with a nitric acid solution, soaking the substrate in boiling de-ionized water, or applying to the substrate a heat treatment above 400° C.;
depositing an electrically conductive metal coating with the proviso that the electrically conductive metal coating does not include gold or platinum or vanadium on the passive oxide layer on the substrate, wherein the coating has a thickness of about 0.1 nm to about 50 nm.