Claims
- 1. A method of making an anode electrode for a REDOX cell comprising the steps, in the following order, of
- soaking a carbon felt in methanol for at least 15 minutes;
- rinsing said felt in water;
- simmering said felt in a 30-to-50 weight percent KOH solution at a temperature of approximately 100.degree. C. for 1 to 3 hours;
- rinsing said felt in tap water;
- soaking said felt in deionized water for at least 8 hours; damp drying said felt;
- moistening said felt with a methanol-water solution which is from 50 to 80 volume percent methanol and which has dissolved therein HAuCl.sub.3.3H.sub.2 O whereby all the surfaces of said felt are coated with the gold-containing solution;
- storing said felt in the dark at a temperature of from 0.degree. C. to 35.degree. C. for 10 to 14 hours;
- drying said felt at a temperature of from about 90.degree. C. to 130.degree. C.; and,
- heat treating said felt at a temperature of from about 250.degree. C. to 280.degree. C. for a period of from about 2 hours to about 3 hours.
- 2. The method of claim 1 wherein the moistening step of the methanol-water solution has dissolved therein from 55 to 75 micrograms per milliliter of Au in the form of HAuCl.sub.3.3H.sub.2 O and wherein the solution is applied to the felt surfaces evenly in the amount of 0.18 to 0.25 cc per square cm.
- 3. The method of claim 2 wherein the methanol-water solution is approximately 75 volume percent methanol.
- 4. The method of claim 3 wherein the dissolved Au in the form of HAuCl.sub.3.3H.sub.2 O is in the amount of about 62.5 micrograms per milliliter of solution.
- 5. The method of claim 4 wherein the methanol-water-HAuCl.sub.3.3H.sub.2 O solution is applied to the surfaces of said felt in the amount of approximately 0.22 cc per square cm.
- 6. The method of claim 5 wherein the felt is maintained at a temperature of approximately 25.degree. C. while stored in the dark.
- 7. The method of claim 5 wherein the drying of said felt after removal from the light-tight container is ccomplished at a temperature of about 100.degree..
- 8. The method of claim 5 wherein the heat treating step is carried out at a temperature between 260.degree. C. and 270.degree. C. for a period of approximately 21/2 hours.
- 9. The method of claim 1 wherein the step of soaking said felt in deionized water is over a period of about 10 hours and is preceded by rinsing said felt in deionized water.
- 10. A method of making a REDOX cell of the type having an ion conductive membrane separating a container into two compartments, one of which contains an anode fluid having a chromic/chromous couple and the other of which contains a cathode fluid having a ferrous/ferric couple, and further including an inert electrically conductive electrode disposed in said anode fluid to develop a negative charge thereon, the method comprising the steps, in the following order, of:
- soaking a carbon felt in methanol for at least 15 minutes;
- rinsing said felt in water;
- simmering said felt in a 30 to 50 volume percent KOH solution at a temperature of approximately 100.degree. C. for 1 to 3 hours;
- rinsing said felt in tap water;
- soaking said felt in deionized water for at least 8 hours;
- damp drying said felt;
- moistening said felt with a methanol-water solution which is from 50 to 80 volume percent methanol and which has dissolved therein HAuCl.sub.3.3H.sub.2 O whereby the surface areas of said felt are coated with the gold-containing solution;
- disposing said felt in a dark enclosure at a temperature of from 0.degree. C. to 35.degree. C. for 10 to 14 hours;
- drying said felt at a temperature of from about 90.degree. C. to 130.degree. C.; and,
- heat treating said felt at a temperature of from about 250.degree. C. to 280.degree. C. for a period of from about 2 hours to about 3 hours;
- wetting said felt with deionized water; and,
- disposing said felt in the anode fluid compartment of the REDOX cell to serve as a negative electrode.
- 11. The method of claim 10 wherein in the moistening step the methanol-water solution has dissolved therein from 55 to 75 micrograms per milliliter of Au in the form of HAuCl.sub.3.3H.sub.2 O and wherein the solution is applied to the felt evenly in the amount of 0.18 to 0.25 cc per square cm.
- 12. The method of claim 11 wherein the methanol-water solution is approximately 75 volume percent methanol.
- 13. The method of claim 12 wherein the dissolved Au in the form of HAuCl.sub.3.3H.sub.2 O is in the amount of about 62.5 micrograms per milliliter of solution.
- 14. The method of claim 13 wherein the methanol-water-HAuCl.sub.3.3H.sub.2 O solution is applied to said felt in the amount of approximately 0.22 cc per square cm.
- 15. The method of claim 14 wherein the felt is maintained at a temperature of approximately 25.degree. C. while in the dark enclosure.
- 16. The method of claim 14 wherein the drying of said felt after removal from the dark enclosure is accomplished at a temperature of about 100.degree. C.
- 17. The method of claim 14 wherein the heat treating step is carried out at a temperature between 260.degree. C. and 270.degree. C. for a period of approximately 21/2 hours.
- 18. The method of claim 10 wherein the step of soaking said felt in deionized water is over a period of about 10 hours and is preceded by rinsing said felt in deionized water.
- 19. The method of claim 10 wherein the amount of HAuCl.sub.3.3H.sub.2 O dissolved in said methanol-water solution is sufficient to produce a gold coating at least 2 monolayers thick on the surface areas of said felt.
- 20. The method of claim 10 wherein the wetting of said felt electrode prior to disposed in the anode fluid compartment is by a 1 to 2 molar HCl solution.
- 21. The method of claim 1 wherein the amount of HAuCl.sub.3.3H.sub.2 O dissolved in said methanol-water solution is sufficient to produce on said felt a coating providing 12.5-15 micrograms of gold per cm.sup.2 of projected area.
DESCRIPTION
The invention described herein was made by Government employees and a contractor employee in the performance of work under a NASA contract. It is subject to the provisions of Section 305 of the National Aeronautics & Space Act of 1958, Public Law 85-568 (72 Stat. 435, 42 USC 2457).
US Referenced Citations (10)