Proton conducting membrane using a solid acid
A solid acid material is used as a proton conducting membrane in an electrochemical device. The solid acid material can be one of a plurality of different kinds of materials. A binder can be added, and that binder can be either a nonconducting or a conducting binder. Nonconducting binders can be, for example, a polymer or a glass. A conducting binder enables the device to be both proton conducting and electron conducting.
1. A proton conducting membrane for use in a fuel cell comprising:
a solid acid material defined by the chemical formula:
M a H b (XO t ) c
where M is a cation having a charge from +1 to +2, X is selected from the group consisting of S, Se, P, As, Si and Ge and a, b, c, and t are non-zero integers, wherein the solid acid material exhibits a superprotonic phase such that the solid acid material is capable of conducting protons in a solid state through a superprotonic mechanism, wherein said membrane is in a fuel cell.
2. The proton conducting membrane described in claim 1 , wherein the solid acid is CsH 2 PO 4 .
3. The proton conducting membrane described in claim 1 , wherein the solid acid is RbH 2 PO 4 .
4. The proton conducting membrane described in claim 1 , wherein the solid acid comprises MH 2 PO 4 , wherein M comprises one or more cations selected from the group consisting of Li, Na, K, Rb, Cs and NH 4 + .
5. The proton conducting membrane described in claim 1 , wherein the solid acid is CsHSO 4 .
6. The proton conducting membrane described in claim 1 , wherein the solid acid is CsHSeO 4 .
7. The proton conducting membrane described in claim 1 , wherein the membrane is insoluble in water.
8. The proton conducting membrane described in claim 1 , wherein the membrane is thermally stable at temperatures of at least about 100° C.
9. The proton conducting membrane described in claim 1 , wherein the membrane is insoluble in a water containing environment and thermally stable at temperatures of at least about 100° C.
10. The proton conducting membrane described in claim 1 , wherein the membrane is stable in a hydrated atmosphere and thermally stable at temperatures of at least about 100° C.
11. The proton conducting membrane described in claim 1 , further comprising a structural binder selected from the group consisting of an electrically conducting carbon material, polymers, ceramics, glasses, metals, and mixtures thereof.
12. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a hydrocarbon fuel.
13. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a fuel selected from the group consisting of hydrogen, methanol, methane and gasoline.
14. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with gas feeds selected from the group consisting of hydrogen/oxygen and methanol/oxygen.
15. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with gas feeds selected from the group consisting of H 2 O+H 2 /H 2 O+O 2 and H 2 O+methanol/H 2 O+O 2 .
16. The proton conducting membrane described in claim 1 , further comprising an additional separate electrically conducting material.
17. The proton conducting membrane described in claim 16 , wherein the conducting material is selected from the group consisting of conducting polymers, metals and an electrically conducting carbon material.
18. The proton conducting membrane described in claim 1 , wherein said membrane has a proton conductivity of about 10 −5 Ω 31 1 cm −1 or higher at the temperature of utilization.
19. A fuel cell comprising a proton conducting membrane, said proton conducting membrane comprising:
a solid acid material defined by the chemical formula:
M a H b (XO t ) c
Where X is selected from the group consisting of S, Se, P, As, Si and Ge, and a, b, c, and t are non-zero integers, wherein the solid acid material is capable of conducting protons in a solid state through a superprotonic mechanism, wherein M has a variable valence and said membrane conducts both protons and electrons.
20. A fuel cell system comprising a proton conducting membrane as described in claim 1 , wherein the fuel cell system provides electrical power to an external device.
21. A fuel cell comprising a proton conducting membrane for use in the presence of H 2 O, said proton conducting membrane comprising:
a solid acid material defined by the chemical formula:
M a H b (XO t ) c
where M is a cation having a charge from +1 to +2, X is selected from the group consisting of S, Se, P, As, Si and Ge, and a, b, c, and t are non-zero integers, wherein the solid acid material is capable of conducting protons in a solid state through a superprotonic mechanism.
22. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a fuel.
23. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a gas feed comprising fuel on one side of the membrane and oxygen on the other side of the membrane.
24. The proton conducting membrane described in claim 23 , wherein the oxygen source is ambient air.
25. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a gas feed comprising hydrocarbon fuel on one side of the membrane and oxygen on the other side of the membrane.
26. The proton conducting membrane described in claim 25 , wherein the oxygen source is ambient air.
27. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a gas feed comprising H 2 O+fuel on one side of the membrane and H 2 O+O 2 on the other side of the membrane.
28. The proton conducting membrane described in claim 27 , wherein the oxygen source is ambient air.
29. The proton conducting membrane described in claim 1 , wherein the fuel cell is operable with a gas feed comprising H 2 O+hydrocarbon fuel on one side of the membrane and H 2 O+O 2 on the other side of the membrane.
30. The proton conducting membrane described in claim 29 , wherein the oxygen source is ambient air.
31. The proton conducting membrane described in claim 1 , further comprising a structural binder.
32. A fuel cell comprising a proton conducting membrane, said proton conducting membrane comprising:
a solid acid material defined by the chemical formula:
M a H b (XO t ) c
Where X is selected from the group consisting of S, Se, P, As, Si and Ge, and a, b, c, and t are non-zero integers, wherein the solid acid material is capable of conducting protons in a solid state through a superprotonic mechanism, the membrane further comprising a structural binder, wherein the structural binder is an electrically conducting carbon material.
33. The fuel cell described in claim 32 , wherein the electrically conducting carbon material is graphite.
34. A fuel cell comprising a proton conducting membrane for use in the presence of H 2 O, said proton conducting membrane comprising:
a solid acid material defined by the chemical formula:
M a H b (XO t ) c
wherein M is Cs, X is selected from the group consisting of S, Se, P, As, Si and Ge, and a, b, c, and t are non-zero integers, the XO t groups being linked together by hydrogen bonds, and the membrane further comprising a structural binder forming a membrane with the solid acid material.
35. The proton conducting membrane described in claim 31 , wherein the structural binder is selected from the group consisting of polyvinylidene fluoride, polydicyclopentadiene, polytetrafluoroethylene, polyetheretherketone, polyethersulfone, dimethyl siloxane polymers, polypyrrole, polyaniline, SiO 2 , Al 2 O 3 , MgO, cordierite, Ag, Au, Cu, Al, Ni, Fe, Zn, graphite and silicon.
36. The proton conducting membrane described in claim 2 , further comprising a structural binder.
37. The proton conducting membrane described in claim 36 , wherein the structural binder is selected from the group consisting of graphite, polymers, ceramics, glasses, metals, and mixtures thereof.
38. The proton conducting membrane described in claim 36 , wherein the structural binder is selected from the group consisting of polyvinylidene fluoride, polydicyclopentadiene, polytetrafluoroethylene, polyetheretherketone, polyethersulfone, dimethyl siloxane polymers, polypyrrole, polyaniline, SiO 2 , Al 2 O 3 , MgO, cordierite, Ag, Au, Cu, Al, Ni, Fe, Zn, graphite and silicon.
39. The proton conducting membrane described in claim 36 , wherein the structural binder comprises SiO 2 .
40. The proton conducting membrane described in claim 1 , wherein X is a member selected from the group consisting of S, Se, P, and Si.
41. The fuel cell described in claims 19 , 21 , 32 and 34 , wherein X is a member selected from the group consisting of S, Se, P, and Si.
42. The proton conducting membrane described in claim 1 , wherein X is a member selected from the group consisting of As and Ge.
43. The fuel cell described in claims 19 , 21 , 32 and 34 , wherein X is a member selected from the group consisting of As and Ge.