Method of producing membrane electrode assemblies for use in proton exchange membrane and direct methanol fuel cells
Compositions and methods for the manufacture of electrodes for fuel cells. The compositions and methods are particularly useful for the manufacture of anodes and cathodes for proton exchange membrane fuel cells, particularly direct methanol fuel cells. The methods can utilize direct-write tools to deposit ink compositions and form functional layers of a membrane electrode assembly having controlled properties and enhanced performance.
1. A method for the fabrication of a catalyst layer, comprising the steps of:
a) depositing an ink composition onto a substrate, said ink composition comprising a liquid vehicle, a particulate support phase and a molecular precursor to an active species phase; and
b) heating said ink composition to a temperature of not greater than about 200° to convert said molecular precursor to an active species phase dispersed on said support phase and form a catalyst layer.
2. A method as recited in claim 1 , wherein said depositing step comprises depositing said ink composition using a direct-write tool.
3. A method as recited in claim 1 , wherein said depositing step comprises depositing said ink composition using an ink-jet device.
4. A method as recited in claim 1 , wherein said substrate is an ion exchange membrane.
5. A method as recited in claim 1 , wherein said heating step comprises heating said ink composition to a temperature of not greater than about 150° C.
6. A method as recited in claim 1 , wherein said active species phase comprises platinum metal.
7. A method as recited in claim 1 , wherein said ink composition comprises a molecular precursor selected from the group consisting of nitrates, carboxylates, beta-diketonates and compounds containing metal-carbon bonds.
8. A method as recited in claim 1 , wherein said ink comprises a divalent platinum(II) complex.
9. A method as recited in claim 1 , wherein said ink composition has a viscosity of not greater than about 100 centipoise.
10. A method as recited in claim 1 , wherein said ink composition has a viscosity of not greater than about 50 centipoise.
11. A method as recited in claim 1 , wherein said ink composition further comprises a reducing agent.
12. A method as recited in claim 1 , wherein said molecular precursor is a volatile molecular precursor.
13. A method as recited in claim 1 , wherein said particulate support phase comprises carbon particles.
14. A method as recited in claim 1 , wherein said particulate support phase comprises a metal oxide.
15. A method for the fabrication of an electrocatalyst layer, comprising the steps of:
a) depositing an ink precursor composition onto a substrate, said ink composition comprising a liquid vehicle, particulate carbon and a molecular precursor to an active species phase; and
b) reacting said precursor composition with a reducing agent to convert said active species phase precursor to an active species phase and form an electrocatalyst layer.
16. A method as recited in claim 15 , wherein said depositing step comprises depositing said ink composition using a direct-write tool.
17. A method as recited in claim 15 , wherein said depositing step comprises depositing said ink composition using an ink-jet device.
18. A method as recited in claim 15 , wherein said substrate is an ion exchange membrane.
19. A method as recited in claim 15 , further comprising the step of heating said ink composition to a temperature of not greater than about 200° C.
20. A method as recited in claim 15 , wherein said active species phase comprises platinum metal.
21. A method as recited in claim 15 , wherein said molecular precursor comprises a divalent platinum(II) complex.
22. A method as recited in claim 15 , wherein said ink composition comprises a molecular precursor selected from the group consisting of nitrates, carboxylates beta-diketonates, and compounds with carbon-platinum bonds.
23. A method as recited in claim 15 , wherein said ink composition has a viscosity of not greater than about 100 centipoise.
24. A method as recited in claim 15 , further comprising the step of heating said ink composition.
25. A method for the fabrication of an electrocatalyst layer, comprising the steps of:
a) depositing an ink composition onto a substrate, said ink composition comprising a liquid vehicle, particulate carbon and a molecular precursor to an active species phase; and
b) reacting said ink composition with a form of radiation to convert said active species phase precursor to an active species phase and form an electrocatalyst layer.
26. A method as recited in claim 25 , wherein said radiation is in the form of ultraviolet radiation.
27. A method as recited in claim 25 , wherein said depositing step comprises depositing said ink composition using a direct-write tool.
28. A method as recited in claim 25 , wherein said depositing step comprises depositing said ink composition using an ink-jet device.
29. A method as recited in claim 25 , wherein said substrate is an ion exchange membrane.
30. A method as recited in claim 25 , wherein said substrate is a proton exchange membrane.
31. A method as recited in claim 25 , wherein said reacting step comprises heating said precursor composition to a temperature of not greater than about 200° C.
32. A method as recited in claim 25 , wherein said active species phase comprises platinum metal.
33. A method as recited in claim 25 , wherein said molecular precursor comprises a divalent platinum(II) complex.
34. A method as recited in claim 25 , wherein said ink composition comprises a molecular precursor selected from the group consisting of nitrates, carboxylates beta-diketonates, and compounds with carbon-platinum bonds.
35. A method as recited in claim 25 , wherein said ink composition has a viscosity of not greater than about 100 centipoise.
36. A method as recited in claim 25 , wherein said ink composition further comprises a reducing agent.
37. A method for the fabrication of a catalyst layer, comprising the steps of:
a) depositing an ink composition onto a substrate, said ink composition comprising a liquid vehicle, a first particulate material and a second particulate material comprising nanoparticles; and
b) converting said ink composition into an catalyst layer.
38. A method as recited in claim 37 , wherein said depositing step comprises depositing said ink composition using a direct-write tool.
39. A method as recited in claim 37 , wherein said depositing step comprises depositing said ink composition using an ink-jet device.
40. A method as recited in claim 37 , wherein said first particulate material is carbon.
41. A method as recited in claim 37 , wherein said first particulate material is a metal oxide.
42. A method as recited in claim 37 , wherein said substrate is an ion exchange membrane.
43. A method as recited in claim 37 , wherein said substrate is gas diffusion layer.
44. A method as recited in claim 37 , wherein said substrate is liquid diffusion layer.
45. A method as recited in claim 37 , wherein said converting step comprises heating said ink composition to a temperature of not greater than about 150° C.
46. A method as recited in claim 37 , wherein said nanoparticles are selected from the group consisting of platinum, rhodium, ruthenium, cobalt, nickel and palladium nanoparticles.
47. A method as recited in claim 37 , wherein said ink composition has a viscosity of not greater than about 100 centipoise.
48. A method as recited in claim 37 , wherein said ink composition has a viscosity of not greater than about 50 centipoise.