초록 ▼

The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reductio

The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reduction of oxygen to water, and has a structure that supports the flow of both water and gases between the catalytically active surface and a flow field or electrode chamber for bulk flow of the fluids. The electrode has an electrocatalyst layer and a diffusion backing layer interspersed with hydrophilic and hydrophobic regions. The diffusion backing layer consists of a metal core having gas diffusion structures bonded to the metal core.

대표청구항 ▼

1. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen

1. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder, and a gas diffusion backing layer having hydrophobic and hydrophilic region on a continuous conductive matrix, wherein the gas diffusion backing layer is in intimate contact with the electrocatalyst layer, wherein the at least one electrocatalyst active for the evolution of oxygen is a solid solution of iridium oxide and ruthenium oxide, wherein the solid solution comprises between about 5 mol % and about 85 mol % ruthenium oxide with the remainder of the solid solution being iridium oxide. 2. The structure of claim 1, wherein the solid solution comprises 50 mol % ruthenium oxide and 50 mol % iridium oxide.3. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder; and a gas diffusion backing layer having hydrophobic and hydrophilic regions on a continuous conductive matrix, wherein the gas diffusion backing layer is in intimate contact with the electrocatalyst layer, wherein the electrocatalyst active for the reduction of oxygen is an alloy of platinum and another metal selected from the group consisting of ruthenium, iridium, palladium, gold, and cobalt. 4. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder; and a gas diffusion backing layer having hydrophobic and hydrophilic regions on a continuous conductive matrix, wherein the gas diffusion backing layer is in intimate contact with the electrocatalyst layer, wherein the at least one electrocatalyst active for the evolution of oxygen and the at least one electrocatalyst active for the reduction of oxygen is an electrocatalyst mixture comprising between about 40 wt % and about 70 wt % platinum black with the remainder of the mixture being an equimolar ruthenium-iridium oxide solid solution. 5. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder; and a gas diffusion backing layer having hydrophobic and hydrophilic regions on a continuous conductive matrix, wherein the gas diffusion backing layer is in intimate contact with the electrocatalyst layer, wherein the binder as a perfluorosulfonic acid polymer, the electrocatalyst layer comprises about 40 vol % binder blended with the remainder being the at least one electrocatalyst active for the evolution of oxygen and the at least one electrocatalyst active for the reduction of oxygen. 6. An electrode structure for use in a unitized hydrogen-oxygen regenerative fuel cell, the electrode structure comprising:an electrocatalyst layer comprising a mixture of at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder; and a gas diffusion backing layer having hydrophobic and hydrophilic regions on a continuous conductive matrix, wherein the gas diffusion backing layer is in intimate contact with the electrocatalyst layer, wherein the gas diffusion backing layer further comprises a metal core having gas diffusion supports bonded to the metal core with a binder. 7. The structure of claim 6,wherein the metal core is selected from the group consisting of woven metal cloth, perforated metal sheet, thin metal felts, expanded metal sheet and metal foam.8. The structure of claim 6, wherein the metal core is plated with a noble metal to prevent formation of an oxide film.9. The structure of claim 6, wherein the material of the metal core is a metal selected from the group consisting of titanium, zirconium, hafnium, niobium, aluminum, copper, nickel and tantalum.10. The structure of claim 6, wherein the material of the metal core is selected from oxidation resistant alloys consisting of stainless steels, INCONELS and HASTELLOYS.11. The structure of claim 6, wherein the material of the metal core is a precious metal selected from the group consisting of platinum, gold, ruthenium, iridium and palladium.12. The structure of claim 6, wherein gas diffusion supports comprise an electrically conductive compound and a polymeric binder.13. The structure of claim 12, wherein the polymeric binder is selected from the group consisting of polytetrafluoroethylene, perfluorosulfonic acids or combinations thereof.14. The structure of claim 12, wherein the electrically conductive compound is a nitride selected from the group consisting of tantalum nitride, zirconium nitride, niobium nitride and titanium nitride.15. The structure of claim 12, wherein the electrically conductive compound is titanium boride.16. The structure of claim 12, wherein the electrically conductive compound is titanium carbide.17. The structure of claim 12, wherein the electrically conductive compound is a ruthenium compound selected from the group consisting of ruthenium oxide and titanium-ruthenium oxide.18. The structure of claim 12, wherein the electrically conductive compound comprises a solid solution of ruthenium oxide and titanium oxide, wherein the solid solution comprises between about 30 mol % and about 90 mol % ruthenium oxide with the remainder of the solid solution being titanium oxide.19. The structure of claim 18, wherein the solid solution comprises 60 mol % ruthenium oxide and 40 mol % titanium oxide.20. The structure of claim 12, wherein the metal core is treated with a fluorocarbon wet proofing agent, the binder is hydrophobic, and the electrically conductive compound is hydrophilic, and wherein the hydrophobic binder decreases the hydrophilic character of the conductive compound, thereby forming the hydrophilic and hydrophobic regions.21. The structure of claim 20, wherein the hydrophilic and hydrophobic regions are randomly mixed and the regions have dimensions in any direction of about 10?6 meters.22. The structure of claim 12, wherein the hydrophilic and hydrophobic regions have dimensions in any direction of about 0.1 mm.23. The structure of claim 12, wherein the hydrophilic and hydrophobic regions have dimensions in any direction less than 1 mm.24. The structure of claim 12, wherein the hydrophilic and hydrophobic regions are uniform in thickness and uniform across the surface area in two directions.25. The structure of claim 12, wherein the hydrophilic and hydrophobic regions are uniform in thickness and uniform across the surface area in at least one direction.26. The structure of claim 12, wherein the hydrophobic and hydrophilic regions are greater than 1 mm in at least one dimension.27. A unitized hydrogen-oxygen regenerative fuel cell comprising:a first electrode structure comprising an electrocatalyst layer and a gas diffusion backing layer, wherein the electrocatalyst layer comprises at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder, and wherein the gas diffusion backing layer comprises hydrophobic and hydrophilic region on a continuous conductive matrix; an electronically insulating polymer film, having a first side and a second side, capable of exchanging cations with an aqueous solution; and a second electrode structure comprised of an electrocatalyst for the reduction and oxidation of hydrogen, and a binders, wherein the electrocatalyst layer of the first electrode is in intimate contact with the first side of the polymer film and the second electrode structure is in intimate contact with the second side of the polymer film, wherein the at least one electrocatalyst active for the evolution of oxygen is a solid solution of iridium oxide and ruthenium oxide, wherein the solid solution comprises between about 5 mol % and about 85 mol % ruthenium oxide with the remainder of the solid solution being iridium oxide. 28. The unitized regenerative cell of claim 27, wherein the solid solution comprises 50 mol % ruthenium oxide and 50 mol % iridium oxide.29. A unitized hydrogen-oxygen regenerative fuel cell comprising:a first electrode structure comprising an electrocatalyst layer and a gas diffusion backing layer, wherein the electrocatalyst layer comprises at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder, and wherein the gas diffusion backing layer comprises hydrophobic and hydrophilic regions on a continuous conductive matrix; an electronically insulating polymer film, having a first side and a second side, capable of exchanging cations with an aqueous solution; and a second electrode structure comprised of an electrocatalyst for the reduction and oxidation of hydrogen, and a binder, wherein the electrocatalyst layer of the first electrode is in intimate contact with the first side of the polymer film and the second electrode structure is in intimate contact with the second side of the polymer film, wherein the at least one electrocatalyst active for the reduction of oxygen is an alloy of platinum and another metal selected from the group consisting of ruthenium, iridium, palladium, gold, and cobalt. 30. A unitized hydrogen-oxygen regenerative fuel cell comprising;a first electrode structure comprising an electrocatalyst layer and a gas diffusion backing layer, wherein the electrocatalyst layer comprises at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder, and wherein the gas diffusion backing layer comprises hydrophobic and hydrophilic regions on a continuous conductive matrix; an electronically insulating polymer film, having a first side and a second side, capable of exchanging cations with an aqueous solution; and a second electrode structure comprised of an electrocatalyst for the reduction and oxidation of hydrogen, and a binder, wherein the electrocatalyst layer of the first electrode is in intimate contact with the first side of the polymer film and the second electrode structure is in intimate contact with the second side of the polymer film, wherein the at least one electrocatalyst active for the evolution of oxygen and the at least one electrocatalyst active for the reduction of oxygen is an electrocatalyst mixture comprising between about 40 wt % and about 70 wt % platinum black with the remainder of the mixture being an equimolar ruthenium-iridium oxides. 31. A unitized hydrogen-oxygen regenerative fuel cell comprising;a first electrode structure comprising an electrocatalyst layer and a gas diffusion backing layer, wherein the electrocatalyst layer comprises at least one electrocatalyst active for the evolution of oxygen, at least one electrocatalyst active for the reduction of oxygen, and a binder, and wherein the gas diffusion backing layer comprises hydrophobic and hydrophilic regions on a continuous conductive matrix; an electronically insulating polymer film, having a first side and second side, capable of exchanging cations with an aqueous solution; and a second electrode structure comprised of an electrocatalyst for the reduction and oxidation of hydrogen, and a binder, wherein the electrocatalyst layer of the first electrode is in intimate contact with the first side of the polymer film and the second electrode structure is in intimate contact with the second side of the polymer film, wherein the first electrode structure binder is a perfluorosulfonic acid polymer, the electrocatalyst layer comprises about 40 vol % binder blended with the remainder being the at least one electrocatalyst active for the evolution of oxygen and the at least one electrocatalyst active for the reduction of oxygen. 32. A unitized hydrogen-oxygen regenerative fuel cell comprising:a first electrode structure comprising an electrocatalyst layer and a gas diffusion backing layer, wherein the electrocatalyst layer comprises at least one electrocatalyst active for the evolution of oxygen, at least electrocatalyst active for the reduction of oxygen, and a binder, and wherein the gas diffusion backing layer comprises hydrophobic and hydrophilic regions on a continuous conductive matrix; an electronically insulating polymer film, having a first side and a second side, capable of exchanging cations with an aqueous solution; and a second electrode structure comprised of an electrocatalyst for the reduction and oxidation of hydrogen, and a binder, wherein the electrocatalyst layer of the first electrode is in intimate contact with the first side of the polymer film and the second electrode structure is in intimate contact with the second side of the polymer film, wherein the gas diffusion backing layer further comprises a metal core having gas diffusion supports bonded to the metal core with a binder. 33. The unitized regenerative cell of claim 32, wherein the metal core is selected from the group consisting of woven metal cloth, perforated metal sheet, thin metal felts, expanded metal sheet and metal foam.34. The unitized regenerative cell of claim 32, wherein the metal core is plated with a noble metal to prevent formation of an oxide film.35. The unitized regenerative cell of claim 32, wherein the material of the metal core is a metal selected from the group consisting of titanium, zirconium, hafnium, niobium, aluminum, copper, nickel and tantalum.36. The unitized regenerative cell of claim 32, wherein the material of the metal core is selected from the group of oxidation resistant alloys consisting of stainless steels, INCONELS and HASTELLOYS.37. The unitized regenerative cell of claim 32, wherein the material of the metal core is a precious metal selected from the group of consisting of platinum, gold, ruthenium, iridium and palladium.38. The unitized regenerative cell of claim 32, wherein the gas diffusion supports comprise an electrically conductive compound and a polymeric binder.39. The unitized regenerative cell of claim 38, wherein the polymeric binder is selected from the group consisting of polytetrafluoroethylene, perfluorosulfonic acids or combinations thereof.40. The unitized regenerative cell of claim 38, wherein the electrically conductive compound is a nitride selected from the group consisting of tantalum nitride, zirconium nitride, niobium nitride and titanium nitride.41. The unitized regenerative cell of claim 38, wherein the electrically conductive compound is titanium boride.42. The unitized regenerative cell of claim 38, wherein the electrically conductive compound is titanium carbide.43. The unitized regenerative cell of claim 38, wherein the electrically conductive compound is selected from the group comprising ruthenium oxide and titanium-ruthenium oxide.44. The unitized regenerative cell of claim 38, wherein the electrically conductive compound comprises a solid solution of ruthenium oxide and titanium oxide, wherein the solid solution comprises between about 30 mol % and about 90 mol % ruthenium oxide with the remainder of the solid solution being titanium oxide.45. The unitized regenerative cell of claim 44, wherein the solid solution comprises about 60 mol and about 40 mol % titanium oxide.46. The unitized regenerative cell of claim 38, wherein the metal core is treated with a fluorocarbon wet proofing agent, the binder is hydrophobic, and the electrically conductive compound is hydrophilic, and wherein the hydrophobic binder decreases the hydrophilic character of the conductive compound, thereby forming the hydrophilic and hydrophobic regions.47. The unitized regenerative cell of claim 46, wherein the hydrophilic and hydrophobic regions are randomly mixed and the regions have dimensions in any direction of about 10?6 meters.48. The unitized regenerative cell of claim 38, wherein the hydrophilic and hydrophobic regions have dimensions in any direction of about 0.1 mm.49. The unitized regenerative cell of claim 38, wherein the hydrophilic and hydrophobic regions have dimensions in any direction less than 1 mm.50. The unitized regenerative cell of claim 38, wherein the hydrophilic and hydrophobic regions are uniform in thickness and uniform across the surface area in two directions.51. The unitized regenerative cell of claim 38, wherein the hydrophilic and hydrophobic regions are uniform in thickness and uniform across the surface area in at least one direction.52. The unitized regenerative cell of claim 38, wherein the hydrophobic and hydrophilic regions are greater than 1 mm in at least one dimension.