# US 7,745,031 B2 · Solid oxide fuel cell

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- Number: US 7,745,031 B2
- Document ID: US7745031B2
- Status: Granted
- Kind: B2
- Application number: 11/570,320
- Filed: 2005-06-09
- Published: 2007-11-22
- Granted: 2010-06-29
- Earliest claimed: 2004-06-10
- Assignees: Technical University of Denmark
- Inventors: Peter Halvor Larsen; Mogens Bjerg Mogensen; Soren Linderoth; Kent Kammer Hansen; Weiguo Wang
- Web page: https://patentgrep.com/patent/US7745031B2

## CPC

- H01M 8/0223: Composites
- H01M 4/8621: {containing only metallic or ceramic material, e.g. made by sintering or sputtering}
- H01M 4/8885: {Sintering or firing}
- H01M 4/9016: {Oxides, hydroxides or oxygenated metallic salts}
- H01M 4/9025: {Oxides specially used in fuel cell operating at high temperature, e.g. SOFC}
- H01M 4/9066: {of metal-ceramic composites or mixtures, e.g. cermets}
- H01M 8/021: Alloys based on iron
- H01M 8/0232: Metals or alloys
- H01M 8/0236: Glass; Ceramics; Cermets
- H01M 8/0243: in the form of mixtures
- H01M 8/0247: characterised by the form (characterised by a channel configuration H01M8/0258)
- H01M 8/1226: characterised by the supporting layer
- H01M 8/126: the electrolyte containing cerium oxide
- 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}
- H01M 8/0217: Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y10T 29/49115: including coating or impregnating
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

SOFC cell comprising a metallic support 1 ending in a substantially pure electron conducting oxide, an active anode layer 2 consisting of doped ceria, ScYSZ, Ni—Fe alloy, an electrolyte layer 3 consisting of co-doped zirconia based on oxygen ionic conductor, an active cathode layer 5 and a layer of a mixture of LSM and a ferrite as a transition layer 6 to a cathode current collector 7 of single phase LSM. The use of a metallic support instead of a Ni—YSZ anode support increases the mechanical strength of the support and secures redox stability of the support. The porous ferrite stainless steel ends in a pure electron conducting oxide so as to prevent reactivity between the metals in the active anode which tends to dissolve into the ferrite stainless steel causing a detrimental phase shift from ferrite to austenite structure.

## Claims

### Claim 1

SOFC cell comprising
a metallic support material,
an active anode layer comprising a hydrocarbon cracking catalyst,
an electrolyte layer,
an active cathode layer, and
a transition layer comprising a mixture of LSM and a ferrite between the active cathode layer and a cathode current collector with means being provided for preventing diffusion between the metallic support and the active anode, wherein the diffusion between the metallic support and the active anode has been prevented by the metallic support being graded with an electron conducting oxide ending in a substantially pure electron conducting oxide.

### Claim 2 (depends on 1)

SOFC cell according to claim 1, wherein the metallic support comprises a metal alloy of the type FeCrMx, Mx being Ni, Ti, Ce, Mn, Mo, W, Co, La, Y or Al.

### Claim 3 (depends on 1)

SOFC cell according to claim 1, wherein the active anode layer comprising a hydrocarbon cracking catalyst comprises a mixture of doped ceria and a Ni—Fe alloy.

### Claim 4 (depends on 1)

SOFC cell according to claim 1, wherein the transition layer comprises a mixture of LSM and a ferrite, and ends in a cathode current collector consisting of single phase LSM.

### Claim 5 (depends on 1)

SOFC cell according to claim 1, further comprising a reaction barrier layer of doped ceria between the electrolyte layer and the active cathode layer.

### Claim 6 (depends on 5)

SOFC according to claim 5, wherein the reaction barrier has a thickness of 0.1-1 μm.

### Claim 7 (depends on 1)

SOFC cell according to claim 1, wherein the active cathode comprises one material chosen among ScYSZ or doped ceria, and one material chosen among LSM, LnSrMn, LnSrFeCo, (Y1-xCax)Fe1-yCoyO3, (Gd1-xSrx)Fe1-yCoyO3 or (Gd1-xCax)sFe1-yCoyO3.

### Claim 8 (depends on 1)

SOFC cell according to claim 1, wherein the electrolyte layer comprises a co-doped zirconia or a co-doped ceria based oxygen ionic conductor.

### Claim 9 (depends on 8)

SOFC cell according to claim 8, wherein the electrolyte layer has a thickness of about 0.1-20 μm.

### Claim 10 (depends on 1)

SOFC cell according to claim 1, wherein the active anode has a thickness of 1-50 μm.

### Claim 11 (depends on 1)

SOFC cell according to claim 1, wherein the transition layer is composed of single phase LSM.

### Claim 12 (depends on 1)

SOFC cell according to claim 1, further comprising a coating of the internal and external surfaces of the Fe—Cr Mx metal support, wherein the Fe—Cr Mx, metal support is porous.

### Claim 13 (depends on 1)

SOFC cell according to claim 1, wherein the metallic support is made of a Fe—Cr containing alloy with an addition of 0-50% metal oxides.

### Claim 14

SOFC cell comprising
a metallic support material,
an active anode layer comprising a hydrocarbon cracking catalyst and an impregnated porous material, said porous material being impregnated after sintering,
an electrolyte layer,
an active cathode layer, and
a transition layer comprising a mixture of LSM and a ferrite between the active cathode layer and a cathode current collector with means being provided for preventing diffusion between the metallic support and the active anode.

### Claim 15 (depends on 14)

SOFC according to claim 14, wherein the metallic support material comprises metal oxides selected from the group consisting of doped zirconia, doped ceria, Al2O3, TiO2, MgO, CaO, Cr2O3, FeOx and combinations thereof.

### Claim 16 (depends on 14)

SOFC cell according to claim 14, wherein the impregnation layer comprises doped zirconia or doped ceria.

### Claim 17 (depends on 16)

SOFC cell according to claim 16, wherein the impregnation layer comprises doped zirconia or ceria mixed with metal alloy.

### Claim 18 (depends on 14)

SOFC cell according to claim 14, wherein the electrolyte layer comprises doped zirconia or doped ceria.

### Claim 19 (depends on 14)

SOFC cell according to claim 14, wherein the active anode comprises a porous layer of doped zirconia or doped ceria with a metallic catalyst selected from Ni, Ni—Fe, or a combination thereof.

### Claim 20 (depends on 1)

SOFC cell according to claim 1, wherein the active cathode layer comprises a mixture of doped zirconia and XYO3-5, or doped ceria and XYO3-5, wherein X is La, Gd or Sr and Y is Fe or Co.

### Claim 21 (depends on 1)

SOFC cell according to claim 1, wherein the active cathode layer comprises a porous layer, into which active cathode is impregnated after sintering.

### Claim 22 (depends on 21)

SOFC cell according to claim 21, wherein the impregnation layer comprises doped zirconia or doped ceria.

### Claim 23 (depends on 22)

SOFC cell according to claim 22, wherein the impregnation layer comprises doped zirconia or doped ceria mixed with a metal alloy.

### Claim 24 (depends on 21)

SOFC cell according to claim 21, wherein the electrolyte comprises doped zirconia or ceria.

### Claim 25 (depends on 21)

SOFC cell according to claim 21, wherein the active anode comprises a porous layer of doped zirconia or doped ceria with a metallic catalyst.

### Claim 26 (depends on 21)

SOFC cell according to claim 21, wherein the active cathode comprises mixture of doped zirconia and XYO3-5, or doped ceria and XYO3-5, wherein X is La, Gd or Sr and Y is Fe or Co.