Porous electrode

• US 4,536,272 A
• Filed: 05/16/1984
• Issued: 08/20/1985
• Est. Priority Date: 05/19/1983
• Status: Expired due to Fees

• Current Assignee: Electrochemische Energieconversie NV
• Original Assignee: Electrochemische Energieconversie NV
• Inventors: Blanchart, Alain P. O., Adriaensen, Ludovicus C. M.
• Primary Examiner(s): Andrews, R. L.
• Application Number:
  US06/610,802
• Time in Patent Office: 461 Days
• Field of Search: 204/290 R, 204/292, 204/294, 429/218, 429/42, 429/45, 427/372.2
• US Class Current: 204/294
• CPC Class Codes: H01M 4/86 Inert electrodes with catalytic activity, e.g. for fuel cells
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The invention relates to a porous electrode at least containing a porous catalytic layer, which layer at least contains 3-30 parts by weight of mouldable polymeric binder, 50-94 parts by weight of carbon particles and 3-47 parts by weight of hard hydrophobic polymer particles.

Claims

1. A porous electrode including a porous catalytic layer which comprises at least 3-30 parts by weight of moldable polymeric binder, 50-94 parts by weight of carbon particles, and 3-47 parts by weight of hard hydrophobic polymer particles.

2. A porous electrode according to claim 1, wherein a major portion of the moldable polymeric binder is polytetrafluoroethylene.

3. A porous electrode according to claim 2, wherein the moldable polymeric binder is at most 5% by weight amorphous polymer.

4. A porous electrode according to claim 1, wherein a major portion of the hard hydrophobic polymer is hard polytetrafluoroethylene.

5. A porous electrode according to claim 1, wherein a major portion of the hard hydrophobic polymer is hard tetrafluoroethylene-hexafluoropropylene-copolymer.

6. A porous electrode according to claim 1, wherein a major portion of the hard hydrophobic polymer consists of a mixture of hard polytetrafluoroethylene and hard tetrafluoroethylene-hexafluoropropylene-copolymer.

7. A porous electrode according to claim 1, wherein a major portion of the moldable polymeric binder is moldable polytetrafluoroethylene and a major portion of the hard hydrophobic polymer is hard polytetrafluoroethylene prepared from the same moldable polytetrafluoroethylene.

8. A porous electrode according to claim 1, wherein the hard hydrophobic polymer particles contain at least 10% (wt) amorphous polymer.

9. A porous electrode according to claim 1, wherein the hard hydrophobic polymer particles contain at most 60% (wt) amorphous polymer.

10. A porous electrode according to claim 1, wherein the hard hydrophobic polymer particles contain at most 50% (wt) amorphous polymer.

11. A porous electrode according to claim 1, wherein the hard hydrophobic polymer particles contain at most 40% (wt) amorphous polymer.

12. A porous electrode according to claim 1, wherein a major portion of the hydrophobic polymer is polytetrafluoroethylene that has been subjected, before being used in the production of the catalytic layer, to a heat treatment at 550-700 K. for 1s-5 hours.

13. A porous electrode according to claim 1, wherein a major portion the hydrophobic polymer is polytetrafluoroethylene that has been subjected, before being used in the production of the catalytic layer, to a heat treatment at 550-700 K. for 5s-2 hours.

14. A porous electrode according to claim 1, wherein a major portion of the hydrophobic polymer is polytetrafluoroethylene that has been subjected, before being used in the production of the catalytic layer, to a heat treatment at 600-650 K. for 5s-2 hours.

15. A porous electrode according to claim 1, further comprising a porous metal collector.

16. A porous electrode according to claim 1, wherein at least part of the carbon particles is provided with catalytically active noble metal.

17. A porous electrode according to claim 1, wherein at least part of the carbon particles is provided with catalytically active noble metal and the catalytically active noble metal is palladium and/or platinum.

18. A porous electrode according to claim 1, wherein 10-90% (wt) of the carbon particles is provided with catalytically active noble metal.