Carbon-oxygen fuel cell

• US 6,692,861 B2
• Filed: 03/28/2001
• Issued: 02/17/2004
• Est. Priority Date: 03/03/1998
• Status: Expired due to Fees

• Current Assignee: Sofc Holdings LLC
• Original Assignee: Celltech Power, Inc.
• Inventors: Tao, Tao T.
• Primary Examiner(s): Valentine, Donald R.
• Application Number:
  US09/819,886
• Publication Number:
  US 20020015877A1
• Time in Patent Office: 1,056 Days
• Field of Search: 429/26, 429/40, 429/44, 429/29, 429/30, 429/31
• US Class Current: 429/442
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 2008/147 Fuel cells with molten carbonates
• CPC Class Codes: H01M 2300/0051 Carbonates
• CPC Class Codes: H01M 2300/0074 Ion conductive at high temperature
• CPC Class Codes: H01M 4/9025 Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
• CPC Class Codes: H01M 4/9033 Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
• CPC Class Codes: H01M 8/1233 with one of the reactants being liquid, solid or liquid-charged
• CPC Class Codes: H01M 8/1253 the electrolyte containing zirconium oxide
• CPC Class Codes: H01M 8/14 Fuel cells with fused electrolytes
• CPC Class Codes: H01M 8/143 with liquid, solid or electrolyte-charged reactants
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present invention relates to a fuel cell that use carbon and oxygen as fuel sources. In particular, the fuel cell comprises a carbon-containing anode, an electrolyte and a solid state cathode. Heating the fuel cell to temperatures of 400° C.-2000° C. provides an electrical output of at least 1 mW·cm⁻². The present invention also discloses a method for generating electricity with a fuel cell comprising a carbon-containing anode, an electrolyte and a solid state cathode.

Claims

1. An electricity producing fuel cell comprising:

a carbon-containing anode;

an electrolyte having a melting temperature of between about 300°

C. and about 2000°

C. in contact with said anode at a first contact surface area, allowing passage of oxygen anions to said anode; and

a solid state cathode in contact with said electrolyte at a second contact surface area, for ionizing oxygen to the oxygen anions, said fuel cell being operable at a temperature of between about 700°

C. and about 1200°

C.

2. The fuel cell as in claim 1, wherein said anode is selected from the group consisting of graphite, quasi-graphite, coal, coke, charcoal, fullerene, buckminsterfullerene, carbon black, activated carbon, decolorizing carbon and mixtures thereof.

3. The fuel cell as in claim 1, wherein said anode is selected from the group consisting of a solid material and a particulate material.

4. The fuel cell as in claim 1, wherein said electrolyte is selected from the group consisting of metal carbonate, metal oxide, a plurality of metal carbonates, a plurality of metal oxides and mixtures thereof.

5. The fuel cell as in claim 4, wherein said electrolyte is selected from the group consisting of lithium carbonate, sodium carbonate, potassium carbonate, strontium carbonate, barium carbonate, magnesium carbonate, calcium carbonate, beryllium carbonate, cesium carbonate, rubidium carbonate, PbCl₂.2PbO, PbO, Bi₂O₃, Bi₂O₅, molybdenum oxide, Cs₂O, Cs₂O₃, Sb₂O₃, Sb₂O₄, Sb₂O₅, CuO, CuO₂, GeO₂, GeO, lithium oxide, palladium oxide, K₂O, KO₂, NaO₂, Na₂O₂, RbO₂, Rb₂O₃, Rb₂O₂, SnO, SnO₂, tellurium oxide, Tl₂O, Tl₂O₃, vanadium oxide, As₄O₆, As₂O₅, In₂O, In₂O₃, and mixtures thereof.

6. The fuel cell as in claim 1, wherein said solid state cathode has an oxygen ionization rate of between about 10⁻

8 g·

s<sup>−

1</sup>·

cm<sup>−

2</sup> and about 10<sup>−

3</sup> g·

s<sup>−

1</sup> cm<sup>−

2</sup>.

7. The fuel cell as in claim 1, wherein said solid state cathode has an oxygen ionization rate of between about 5×

10<sup>−

6</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup> and about 10 <sup>−

4</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup>.

8. The fuel cell as in claim 1, wherein said solid state cathode has an electrical resistivity of between about 10⁻

9 ohm-cm and about 100 ohm-cm.

9. The fuel cell as in claim 2, wherein said solid state cathode is selected from the group consisting of a metal, a metal oxide, a plurality of metal oxides and mixtures thereof.

10. The fuel cell as in claim 9, wherein said solid state cathode is selected from the group consisting of platinum, palladium, gold, silver, stainless steel, copper, nickel, cobalt, titanium, vanadium, chromium, iron and zirconium.

11. The fuel cell as in claim 9, wherein said solid state cathode has a formula La_xMn_yA_aB_bC_cO_d where A is an alkaline earth metal, B is selected from the group consisting of scandium, yttrium and a lanthanide metal, C is selected from the group consisting of titanium, vanadium, chromium, iron, cobalt, nickel, copper, zinc, zirconium, hafnium, aluminum and antimony, x is from 0 to about 1.05, y is from 0 to about 1, a is from 0 to about 0.5, b is from 0 to about 0.5, c is from 0 to about 0.5 and d is between about 1 and about 5, and at least one of x, y, a, b and c is greater than zero.

12. The fuel cell as in claim 11, wherein said solid state cathode is a physical mixture of La_xMn_yA_aB_bC_cO_d and (ZrO₂)(HfO₂)_e(Y₂O₃)_f at a ratio from 1:

0 to about 1;

2 where e is from 0 to about 0.2 and f is from 0 to about 0.5.

13. The fuel cell as in claim 12, wherein said physical mixture further comprises a binding reagent selected from the group consisting of water, polyols, polyesters and polysaccharides.

14. The fuel cell as in claim 9, wherein said solid state cathode has a formula Li_xM_1-xO where M is a metal selected from the group consisting of nickel and cobalt and x is from 0 to about 0.25.

15. The fuel cell as in claim 9, wherein said solid state cathode is Cr₂O₃.

16. The fuel cell as in claim 1, wherein said solid state cathode is selected from the group consisting of LaMnO₃, La_0.84Sr_0.16MnO₃, La_0.84Ca_0.16MnO₃, La_0.84Ba_0.16MnO₃, La_0.65Sr_0.35Mn_0.8Co_0.2O₃, La_0.79Sr_0.16Mn_0.85Co_0.15O₃, La_0.84Sr_0.16Mn_0.8Ni_0.2O₃, La_0.84Sr_0.16Mn_0.8Fe_0.2O₃, La_0.84Sr_0.16Mn_0.8Ce_0.2O₃, La_0.84Sr_0.16Mn_0.8Mg_0.2O₃, La_0.84Sr_0.16Mn_0.8Cr_0.2O₃, La_0.6Sr_0.35Mn_0.8Al_0.2O₃, La_0.84Sc_0.16MnO₃, and La_0.84Y_0.16MnO₃.

17. The fuel cell as in claim 1, wherein said solid state cathode has a thickness of at least 1 μ

m.

18. The fuel cell as in claim 1, further comprising a substrate in contact with said solid state cathode at a surface other than said second contact surface area, for providing support to said cathode.

19. The fuel cell as in claim 18, wherein said substrate is selected from the group consisting of Al₂O₃, TiO₂, ZrO₂, zirconia stabilized by CaO and zirconia stabilized by Y₂O₃.

20. The fuel cell as in claim 1, further comprising an inert gas to isolate said anode from a surrounding environment.

21. The fuel cell as in claim 1, further comprising a source for directing an oxygen-containing gas flow to said solid state cathode.

22. The fuel cell as in claim 1, further comprising a mechanical device in operative relationship to said anode and acting to increase said first contact surface area.

23. The fuel cell as in claim 1, further comprising a heater positioned to heat said fuel cell to a temperature of between about 400°

C. and 2000°

C.

24. An electricity producing fuel cell comprising:

a carbon-containing anode;

an electrolyte having a melting temperature of between about 300°

C. and about 2000°

C. in contact with said anode at a first contact surface area, allowing passage of oxygen anions to said anode; and

a solid state cathode in contact with said electrolyte at a second contact surface area, for ionizing oxygen to the oxygen anions, said fuel cell being operable at a temperature of between about 400°

C. and about 2000°

C.,

said fuel cell having an electrical output of at least 1 mW·

cm<sup>−

2</sup> of said second contact surface area.

25. The fuel cell as in claim 24, wherein said fuel cell has an electrical output of from about 1 mW·

cm<sup>−

2</sup> to about 5000 mW·

cm<sup>−

2</sup> of said second contact surface area.

26. The fuel cell as in claim 24, wherein said fuel cell has an electrical output of from about 10 mW·

cm<sup>−

2</sup> to about 5000 mW·

cm<sup>−

2</sup> of said second contact surface area.

27. The fuel cell as in claim 24, wherein said electrolyte is selected from the group consisting of metal carbonate, metal oxide, a plurality of metal carbonates, a plurality of metal oxides and mixtures thereof.

28. The fuel cell as in claim 24, wherein said solid state cathode has an oxygen ionization rate of between about 10⁻

8 g·

s<sup>−

1</sup>·

cm<sup>−

2</sup> and about 10<sup>−

3</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup>.

29. The fuel cell as in claim 24, wherein said solid state cathode has an electrical resistivity of between about 10⁹ ohm-cm and about 100 ohm-cm.

30. The fuel cell as in claim 24, wherein said solid state cathode is selected from the group consisting of a metal, a metal oxide, a plurality of metal oxides and mixtures thereof.

31. The fuel cell as in claim 24, wherein said solid state cathode has a thickness of at least 1 μ

m.

32. The fuel cell as in claim 24, further comprising a substrate in contact with said solid state cathode at a surface other than said second contact surface area, for providing support to said cathode.

33. The fuel cell as in claim 24, further comprising an inert gas to isolate said anode from a surrounding environment.

34. The fuel cell as in claim 24, further comprising a source for directing an oxygen-containing gas flow to said solid state cathode.

35. The fuel cell as in claim 24, further comprising a mechanical device in operative relationship to said anode and acting to increase said first contact surface area.

36. An electricity producing fuel cell comprising:

a carbon-containing anode comprising conductive carbon having a resistivity of between about 10<sup>−

5</sup> ohm-cm and about 100 ohm-cm;

an electrolyte having a melting temperature of between about 300°

C. and about 2000°

C. in contact with said anode at a first contact surface area, allowing passage of oxygen anions to said anode; and

a solid state cathode in contact with said electrolyte at a second contact surface area, for ionizing oxygen to the oxygen anions, said fuel cell being operable at a temperature of between about 400°

C. and about 2000°

C.

37. The fuel cell as in claim 36, wherein said anode comprises conductive carbon having a resistivity of between about 10⁻

3 ohm-cm and about 10<sup>−

1</sup> ohm-cm.

38. The fuel cell as in claim 36, wherein said electrolyte is selected from the group consisting of metal carbonate, metal oxide, a plurality of metal carbonates, a plurality of metal oxides and mixtures thereof.

39. The fuel cell as in claim 36, wherein said solid state cathode has an oxygen ionization rate of between about 10⁻

8 g·

s<sup>−

1</sup>·

cm<sup>−

2</sup> and about 10<sup>−

3</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup>.

40. The fuel cell as in claim 36, wherein said solid state cathode has an electrical resistivity of between about 10⁻

9 ohm-cm and about 100 ohm-cm.

41. The fuel cell as in claim 36, wherein said solid state cathode is selected from the group consisting of a metal, a metal oxide, a plurality of metal oxides and mixtures thereof.

42. The fuel cell as in claim 36, wherein said solid state cathode has a thickness of at least 1 μ

m.

43. The fuel cell as in claim 36, further comprising a substrate in contact with said solid state cathode at a surface other than said second contact surface area, for providing support to said cathode.

44. The fuel cell as in claim 36, further comprising an inert gas to isolate said anode from a surrounding environment.

45. The fuel cell as in claim 36, further comprising a source for directing an oxygen-containing gas flow to said solid state cathode.

46. The fuel cell as in claim 36, further comprising a mechanical device in operative relationship to said anode and acting to increase said first contact surface area.

47. An electricity producing fuel cell comprising:

a carbon-containing anode;

a solid state electrolyte having a melting temperature of between about 300°

C. and about 2000°

C. in contact with said anode at a first contact surface area, allowing passage of oxygen anions to said anode;

a solid state cathode in contact with said electrolyte at a second contact surface area, for ionizing oxygen to the oxygen anions, said fuel cell being operable at a temperature of between about 400°

C. and about 2000°

C.;

said electrolyte defining a distance therethrough from said first contact surface area to said second contact surface area of between about 1 μ

m to 1000 μ

m.

48. The fuel cell as in claim 47, wherein said electrolyte defines a distance therethru from said first contact surface area to said second contact surface area of between about 1 μ

m to 600 μ

m.

49. The fuel cell as in claim 47, wherein said electrolyte defines a distance therethru from said first contact surface area to said second contact surface area of between about 1 μ

m to 100 μ

m.

50. The fuel cell as in claim 47, wherein said electrolyte is selected from the group consisting of metal carbonate, metal oxide, a plurality of metal carbonates, a plurality of metal oxides and mixtures thereof.

51. The fuel cell as in claim 47, wherein said solid state cathode has an oxygen ionization rate of between about 10⁻

8 g·

s<sup>−

1</sup>·

cm<sup>−

2</sup> and about 10<sup>−

3</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup>.

52. The fuel cell as in claim 47, wherein said solid state cathode has an electrical resistivity of between about 10⁻

9 ohm-cm and about 100 ohm-cm.

53. The fuel cell as in claim 47, wherein said solid state cathode is selected from the group consisting of a metal, a metal oxide, a plurality of metal oxides and mixtures thereof.

54. The fuel cell as in claim 47, wherein said solid state cathode has a thickness of at least 1 μ

m.

55. The fuel cell as in claim 47, further comprising a substrate in contact with said solid state cathode at a surface other than said second contact surface area, for providing support to said cathode.

56. The fuel cell as in claim 47, further comprising an inert gas to isolate said anode from a surrounding environment.

57. The fuel cell as in claim 47, further comprising a source for directing an oxygen-containing gas flow to said solid state cathode.

58. The fuel cell as in claim 47, further comprising a mechanical device in operative relationship to said anode and acting to increase said first contact surface area.

59. An electricity producing fuel cell comprising:

a carbon-containing anode;

a solid state electrolyte having a melting temperature of between about 300°

C. and about 2000°

C. in contact with said anode at a first contact surface area, allowing passage of oxygen anions to said anode, said solid state electrolyte selected from the group consisting of a metal oxide and a plurality of metal oxides; and

a solid state cathode in contact with said electrolyte at a second contact surface area, for ionizing oxygen to the oxygen anions, said fuel cell being operable at a temperature of between about 400°

C. and about 2000°

C.

60. The fuel cell as in claim 59, wherein said solid state electrolyte has a formula (ZrO₂)(HfO₂)(TiO₂)(Al₂O₃)(Y₂O₃)(M_xO_y) where a is from 0 to about 0.2, b is from 0 to about 0.5, c is from 0 to about 0.5, d is from 0 to about 0.5, x is an integer greater than 0 and less than or equal to 2, y is an integer greater than 0 and less than or equal to 3, e is from 0 to about 0.15, and M is selected from the group consisting of manganese, iron, cobalt, nickel, copper, and zinc.

61. The fuel cell as in claim 60, wherein said solid state electrolyte is selected from the group consisting of (ZrO₂), (ZrO₂)(Y₂O₃)_0.08, (ZrO₂)(HfO₂)_0.02(Y₂O₃)_0.08, (ZrO₂)(HfO₂)_0.02(Y₂O₃)_0.05, (ZrO₂)(HfO₂)_0.02(Y₂O₃)_0.08(TiO₂)_0.10, (ZrO₂)(HfO₂)_0.02(Y₂O₃)_0.08(Al₂O₃)_0.10, (ZrO₂)(Y₂O₃)_0.08(Fe₂O₃)_0.05, (ZrO₂)(Y₂O₃)_0.08(CoO)_0.05, (ZrO₂)(Y₂O₃)_0.08(ZnO)_0.05, (ZrO₂)(Y₂O₃)_0.08(NiO)_0.05, (ZrO₂)(Y₂O₃)_0.08(CuO)_0.05, and (ZrO₂)(Y₂O₃)_0.08(MnO)_0.05.

62. The fuel cell as in claim 60, wherein said electrolyte is a blend comprising (ZrO₂)(HfO₂)_a(TiO₂)_b(Al₂O₃)_c(Y₂O₃)_d(M_xO_y) and a maximum of 80% of at least one organic binder selected from the group consisting of water, polyols, polyesters and polysaccharides.

63. The fuel cell as in claim 59, wherein said electrolyte is selected from the group consisting of metal carbonate, metal oxide, a plurality of metal carbonates, a plurality of metal oxides and mixtures thereof.

64. The fuel cell as in claim 59, wherein said solid state cathode has an oxygen ionization rate of between about 10⁻

8 g·

s<sup>−

1</sup> cm and about 10<sup>−

3</sup> g·

s<sup>−

1</sup>·

cm<sup>−

2</sup>.

65. The fuel cell as in claim 59, wherein said solid state cathode has an electrical resistivity of between about 10⁻

9 ohm-cm and about 100 ohm-cm.

66. The fuel cell as in claim 59, wherein said solid state cathode is selected from the group consisting of a metal, a metal oxide, a plurality of metal oxides and mixtures thereof.

67. The fuel cell as in claim 59, wherein said solid state cathode has a thickness of at least 1 μ

m.

68. The fuel cell as in claim 59, further comprising a substrate in contact with said solid state cathode at a surface other than said second contact surface area, for providing support to said cathode.

69. The fuel cell as in claim 59, further comprising an inert gas to isolate said anode from a surrounding environment.

70. The fuel cell as in claim 59, further comprising a source for directing an oxygen-containing gas flow to said solid state cathode.

71. The fuel cell as in claim 59, further comprising a mechanical device in operative relationship to said anode and acting to increase said first contact surface area.