Carbon-based fuel cell
A direct-electrochemical-oxidation fuel cell and method for generating electrical energy from a solid-state organic fuel. The fuel cell includes a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode, an anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state organic fuel in the presence of the oxygen ions to produce electrical energy, and a solid-oxide electrolyte disposed to transmit the oxygen ions from the cathode to the anode. The electrochemical oxidation catalyst can optionally include a sulfur resistant material.
1. A direct-electrochemical-oxidation fuel cell for generating electrical energy from a solid-state organic fuel at an operating temperature of from 600° C. to 1000° C. comprising:
a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode;
a solid state anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state organic fuel in the presence of the oxygen ions to produce electrical energy, said solid state anode being solid at the operating temperature; and
a solid-oxide electrolyte disposed to transmit the oxygen ions from the cathode to the anode.
wherein electricity is generated by direct electrochemical oxidation at the anode according to the reaction:
C+2O 2− →CO 2 +4 e − .
2. The fuel cell according to claim 1 , wherein formation of the oxygen ions at the cathode proceeds according to the reaction:
O 2 +4 e − →2O 2− .
3. The fuel cell according to claim 1 , wherein the solid-state organic fuel is coal, graphite, biomass or a combination thereof.
4. The fuel cell according to claim 3 , wherein the biomass is selected from a group consisting of peat, rice hulls, and corn husks.
5. The fuel cell according to claim 1 , wherein the direct electrochemical oxidation at said anode produces a product comprising a CO 2 concentration of at least 50 mol %.
6. The fuel cell according to claim 1 , wherein the electrochemical reduction catalyst is lanthanum strontium manganese oxide.
7. The fuel cell according to claim 1 , wherein the electrochemical-reduction catalyst is selected from La 0.8 Sr 0.2 FeO 3 (LSF); LA 0.6 SR 0.4 FE 0.8 CO 0.2 O 3 (LSCF); Sm 0.5 Sr 0.5 CoO 3 (SSC); YBa 2 Cu 3 O y , wherein y is an integer having values within a range of 7 to 9; La 0.99 MnO 3 ; LaMnO 3 ; La x Sr y Mn 3 and La x Ca y MnO 3 , wherein x is a number having values within a range of 0.6 to 0.95, and y is a number having values within a range of 0.1 to 0.4.
8. The fuel cell according to claim 1 , wherein the electrochemical-reduction catalyst is selected from a material having a general formula of A x B y CO 3 , wherein A is selected from La, Gd, Sm, Nd, Pr, Tb and Sr, B is selected from Sr, Ce, and Co, x is a number having values within a range of 0.6 to 0.94, and y is a number having values within a range of 0.1 to 0.4.
9. The fuel cell according to claim 1 , wherein the electrochemical-oxidation catalyst provided to the anode includes platinum.
10. The fuel cell according to claim 1 , wherein the electrochemical-oxidation catalyst includes rhenium.
11. The fuel cell according to claim 10 , wherein the electrochemical-electrochemical oxidation catalyst is R3-NiO/YSZ.
12. The fuel cell according to claim 10 , wherein the electrochemical-oxidation catalyst is Cu oxide-Pt.
13. The fuel cell according to claim 1 , wherein the solid-oxide electrolyte is selected from doped oxides of Bi, Zr, Hf, Th, and Ce with either alkaline earth oxides such as CaO or MgO, or rare-earth oxides selected from sc 2 o 3 , Y 2 O 3 , and Yb 2 O 3 .
14. The fuel cell according to claim 1 , wherein the solid-oxide electrolyte is selected from the group consisting of yttrium-stabilized zirconium and bismuth oxide.
15. The fuel cell according to claim 1 , further comprising a housing that encloses the anode for receiving the solid-state organic fuel.
16. The fuel cell according to claim 15 , further comprising feed passage through which the solid-state organic fuel can be inserted into the housing.
17. The fuel cell according to claim 1 , wherein the electrochemical oxidation that occurs at the anode produces a product comprising a NO x concentration of less than 5 mol %, wherein x is an integer within a range of 1 to 3.
18. The fuel cell according to claim 17 , wherein the fuel cell has a maximum operating temperature of about 1200° C.
19. The fuel cell according to claim 1 , wherein the direct electrochemical oxidation that occurs at the cathode results in a product comprising a CO concentration that is less than 10 mol %.
20. The fuel cell according to claim 19 , wherein the fuel cell has a maximum operating temperature of about 1200°.
21. The fuel cell according to claim 1 , wherein the fuel cell produces an electrical current of at least 100 mA/cm 2 for a period of time lasting at least 48 hours.
22. The fuel cell according to claim 1 , wherein the fuel-conversion efficiency of the fuel cell is at least 30 mol % at 950° C.
23. The fuel cell according to claim 1 wherein said anode includes a sulfur-resistant material.
24. The fuel cell according to claim 23 , wherein the sulfur-resistant material includes at least one of Re, Mn and Mo.
25. The fuel cell according to claim 24 , wherein the sulfur-resistant material is selected from Re—NiO/YSZ and Cu oxide-Pt.
26. The fuel cell according to claim 23 , wherein the electrochemical-reduction catalyst is lanthanum strontium manganese oxide.
27. The fuel cell according to claim 23 , wherein the electrochemical-reduction catalyst is selected from La 0.8 Sr 0.2 FeO 3 (LSF); La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3 (LSCF); Sm 0.5 Sr 0.5 CoO 3 (SSC); YBa 2 Cu 3 O y , wherein y is an integer having values within a range of 7 to 9; La 0.99 MnO 3 ; LaMnO 3 ; La x Sr y Mn 3 and La x Ca y MnO 3 , wherein x is a number having values within a range of 0.6 to 0.95, and y is a number having values within a range of 0.1 to 0.4.
28. The fuel cell according to claim 23 , wherein the solid-oxide electrolyte is selected from doped oxides of Bi, Zr, Hf, Th, and Ce with either alkaline earth oxides such as CaO or MgO, or rare-earth oxides selected from sc 2 , o 3 , Y 2 O 3 , and Yb 2 O 3 .
29. The fuel cell according to claim 28 , wherein the solid-oxide electrolyte is selected from the group consisting of yttrium-stabilized zirconium and bismuth oxide.
30. The fuel cell according to claim 23 , wherein electrochemical oxidation of the solid-state organic fuel at the anode produces a product having a CO 2 concentration of at least 50 mol %.
31. The fuel cell according to claim 30 , wherein the fuel cell has a maximum operating temperature that is less than 1200° C.
32. The fuel cell according to claim 23 , wherein electrochemical oxidation of the solid-state organic fuel at the anode produces a product having a NO x concentration that is less than 0.1 mol %, wherein x represents integers ranging from 1 to 3.
33. The fuel cell according to claim 23 , wherein the electrochemical-oxidation catalyst is selected from a noble metal, group VIII metal/metal oxide, oxides of sulfur-resistant materials, oxides of Ce, Cr, Fe, and Pb, combinations thereof, multiple oxides, Cu oxide-Pt, and Re—NiO/YSZ, wherein the electrochemical-oxidation catalysts including non-noble metals also include a sulfur-resistant substance selected from Re, Mn, Mo, Ag, Cu, and Au.
34. The fuel cell according to claim 13 , wherein the solid oxide electrolyte comprises at least one of Bi 2 O 2 , (Bi 2 O 7 ) 0.75 (Y 2 O 3 ) 0.25 , BaTh 0.9 Gd 0.1 O 3 , La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3 , (Ce 2 ) 0.8 (GdO 0.5 ) 0.2 , (ZrO 2 ) 0.9 (Sc 2 O 3 ) 0.1 , (ZrO 2 ) 0.9 (Y 2 O 3 ) 0.1 , (ZrO 2 ) 0.87 (CaO) 0.13, (La 2 O 3 ) 0.95 (SrO) 0.05 .
35. The fuel cell according to claim 28 , wherein the solid oxide electrolyte comprises at least one of Bi 2 O 2 , (Bi 2 O 7 ) 0.75 (Y 2 O 3 ) 0.25 , BaTh 0.9 Gd 0.1 O 3 , La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3 , (Ce 2 ) 0.8 (GdO 0.5 ) 0.2 , (ZrO 2 ) 0.9 (SC 2 O 3 ) 0.1 (ZrO 2 ) 0.9 (Y 2 O 3 ) 0.1 , (ZrO 2 ) 0.87 (CaO) 0.13 , (La 2 O 3 ) 0.95 (SrO) 0.05 .