Methods of making membrane electrode assemblies
View Patent ↗Method of making a membrane electrode assembly comprising: providing a membrane comprising a perfluorinated sulfonic acid; providing a first transfer substrate; applying to a surface of the first transfer substrate a first ink, said first ink comprising an ionomer and a catalyst; applying to the first ink a suitable non-aqueous swelling agent; forming an assembly comprising: the membrane; and the first transfer substrate, wherein the surface of the first transfer substrate comprising the first ink and the non-aqueous swelling agent is disposed upon one surface of the membrane; and heating the assembly at a temperature of 150° C. or less and at a pressure of from about 250 kPa to about 3000 kPa or less for a time suitable to allow substantially complete transfer of the first ink and the second ink to the membrane; and cooling the assembly to room temperature and removing the first transfer substrate and the second transfer substrate.
1. A method of making a membrane electrode assembly, the method comprising steps of:
applying a first ink to a surface of a first transfer substrate, the first ink comprising a protonated ionomer and a catalyst;
drying the applied first ink by baking;
applying to the dried first ink a suitable non-aqueous swelling agent selected from the group consisting of n-propanol, 1,5-pentanediol, and dimethyl acetamide;
forming an assembly of the first transfer substrate and a membrane by contacting a first surface of the membrane with the first ink via the applied swelling agent, the membrane comprising a protonated perfluorinated sulfonic acid;
hot-pressing the assembly at a temperature in a range from about 30° C. to about 90° C. and at a pressure of from about 250 kPa to about 3000 kPa for a length of time resulting in substantially complete transfer the first ink to the membrane;
cooling the hot-pressed assembly to room temperature; and
removing the first transfer substrate.
2. The method of claim 1 , further comprising:
applying a second ink to a surface of a second transfer substrate, the second ink comprising a protonated ionomer and a catalyst;
drying the applied second ink by baking;
applying to the dried second ink a suitable non-aqueous swelling agent selected from the group consisting of n-propanol, 1,5-pentanediol, and dimethyl acetamide;
prior to said hot-pressing, forming the assembly to also comprise the second transfer substrate by contacting an opposing second surface of the membrane with the second ink via the applied non-aqueous swelling agent; and
after said hot-pressing, also removing the second transfer substrate after cooling the assembly to room temperature.
3. The method of claim 2 , further comprising applying a releasing agent to the first transfer substrate, the second transfer substrate, or both.
4. The method of claim 2 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is n-propanol and the hot-pressing temperature is 30° C.
5. The method of claim 2 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is dimethyl acetamide and the hot-pressing temperature is 70° C.
6. The method of claim 2 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is 1,5-pentanediol and the hot-pressing temperature is 90° C.
7. The method of claim 2 , wherein one of the first and second inks is a cathode ink and the other of the first and second inks is an anode ink.
8. The method of claim 1 , wherein the non-aqueous swelling agent is n-propanol and the hot-pressing temperature is about 30° C.
9. The method of claim 1 , wherein the non-aqueous swelling agent is 1,5-pentanediol and the hot-pressing temperature is about 90° C.
10. The method of claim 1 , wherein the non-aqueous swelling agent is dimethyl acetamide and the hot-pressing temperature is 70° C.
11. The method of claim 1 , wherein the hot-pressing time is about 6 minutes.
12. The method of claim 1 , wherein the hot-pressing pressure is about 500 kPa to about 3000 kPa.
13. A method of making a membrane electrode assembly, the method comprising steps of:
applying a first ink to a surface of a first transfer substrate, the first ink comprising an ionomer salt and a catalyst;
drying the applied first ink by baking;
applying to the dried first ink a suitable non-aqueous swelling agent selected from the group consisting of n-propanol, 1,5-pentanediol, acetone, dimethyl acetamide, and N-methyl pyrrolidone;
forming an assembly of the first transfer substrate and a membrane by contacting a first surface of the membrane with the first ink via the applied non-aqueous swelling agent, the membrane comprising a salt of perfluorinated sulfonic acid;
hot-pressing the assembly at a temperature in a range from about 30° C. to about 125° C. and at a pressure of from about 250 kPa to about 3000 kPa for a length of time resulting in substantially complete transfer the first ink to the membrane;
cooling the hot-pressed assembly to room temperature; and
removing the first transfer substrate.
14. The method of claim 13 , further comprising:
applying a second ink to a surface of a second transfer substrate, the second ink comprising an ionomer salt and a catalyst;
drying the applied second ink by baking;
applying to the dried second ink a suitable non-aqueous swelling agent selected from the group consisting of n-propanol, 1,5-pentanediol, acetone, dimethyl acetamide, and N-methyl pyrrolidone;
prior to said hot-pressing, forming the assembly to also comprise the second transfer substrate by contacting an opposing second surface of the membrane with the second ink via the applied swelling agent; and
after said hot-pressing, also removing the second transfer substrate after cooling the assembly to room temperature.
15. The method of claim 14 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is n-propanol and the temperature is 40° C.
16. The method of claim 14 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is 1,5-pentanediol and the hot-pressing temperature is 100° C.
17. The method of claim 14 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is acetone and the hot-pressing temperature is 30° C.
18. The method of claim 14 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is dimethyl acetamide and the hot-pressing temperature is 30° C.
19. The method of claim 14 , wherein the non-aqueous swelling agent applied to each of the dried first and second inks is N-methyl pyrrolidone and the hot-pressing temperature is 125° C.
20. The method of claim 14 , wherein one of the first and second inks is a cathode ink and the other of the first and second inks is an anode ink.
21. The method of claim 14 , further comprising applying a releasing agent to the first transfer substrate, the second transfer substrate, or both.
22. The method of claim 13 , wherein the non-aqueous swelling agent is acetone and the hot-pressing temperature is from about 30° C. to about 50° C.
23. The method of claim 13 , wherein the salt of the perfluorinated sulfonic is a sodium salt, a potassium salt, or combinations thereof.
24. The method of claim 13 , wherein the non-aqueous swelling agent is n-propanol and the hot-pressing temperature is from about 30° C. to about 50° C.
25. The method of claim 13 , wherein the non-aqueous swelling agent is n-propanol and the hot-pressing temperature is about 40° C.
26. The method of claim 13 , wherein the non-aqueous swelling agent is 1,5-pentanediol and the hot-pressing temperature is from about 80° C. to about 120° C.
27. The method of claim 13 , wherein the non-aqueous swelling agent is 1,5-pentanediol and the hot-pressing temperature is 100° C.
28. The method of claim 13 , wherein the non-aqueous swelling agent is acetone and the hot-pressing temperature is 30° C.
29. The method of claim 13 , wherein the non-aqueous swelling agent is dimethyl acetamide and the hot-pressing temperature is 30° C.
30. The method of claim 13 , wherein the non-aqueous swelling agent is N-methyl pyrrolidone and the hot-pressing temperature is 125° C.
31. The method of claim 13 , wherein the hot-pressing time is in a range from about 6-10 minutes.
32. The method of claim 13 , wherein the hot-pressing pressure is about 1000 kPa.