Current collector to conduct an electrical current to or from an electrode layer

• US 7,449,262 B2
• Filed: 12/09/2004
• Issued: 11/11/2008
• Est. Priority Date: 12/09/2004
• Status: Expired due to Fees

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Christie, Gervase Maxwell, Lane, Jonathan Andrew
• Primary Examiner(s): Crepeau; Jonathan
• Assistant Examiner(s): CHUO, TONY SHENG HSIANG
• Application Number:
  US11/007,220
• Publication Number:
  US 20060127749A1
• Time in Patent Office: 1,433 Days
• Field of Search: 429/30
• US Class Current: 429/483
• CPC Class Codes: B22F 1/16 Metallic particles coated with a non-metal coated with lubricating or binding agents or with organic material B22F1/10
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/11 Making porous workpieces or articles
• CPC Class Codes: B22F 7/002 of porous nature
• CPC Class Codes: C22C 32/001 with only oxides
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 4/8621 containing only metallic or ceramic material, e.g. made by sintering or sputtering
• CPC Class Codes: H01M 4/8889 Cosintering or cofiring of a catalytic active layer with another type of layer
• CPC Class Codes: H01M 8/0232 Metals or alloys
• CPC Class Codes: H01M 8/0236 Glass; Ceramics; Cermets
• CPC Class Codes: H01M 8/0245 in the form of layered or coated products
• CPC Class Codes: H01M 8/1231 with both reactants being gaseous or vaporised
• 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

A current collector and method of forming the same in which a slurry is prepared that contains electrically conductive particles having surface deposits of a metallic oxide on a metal or metal alloy conductor that has a lower weight percentage of the electrically conductive particles than the metal or metal alloy. The slurry is applied to a structure that contains an electrolyte and electrode layers. The resultant coated form is then fired to partly sinter the electrically conductive particles and thereby to obtain porous current collector layers affixed to the electrode layers. The current collector of the present invention is between about 5 microns and about 100 microns thick and preferably has a porosity of between about 10 percent and about 70 percent with pores having a pore size of between about 0.1 microns and about 20 microns.

Claims

1. A current collector to conduct an electrical current from or to an electrode layer of an electrochemical device said current collector comprising:

a porous layer in contact with and affixed to said electrode layer, said electrode layer capable of conducting electrons produced in connection with oxygen ion transport through an electrolyte of the electrochemical device at elevated temperatures, said porous layer formed of a partially sintered mass of granular, electrically conductive particles, each said electrically conductive particles composed of a metal or metal alloy having surface deposits of a metallic oxide, the surface deposits of the metallic oxide constituting a lower weight percentage of the electrically conductive particles than the metal or metal alloy; and

said porous layer being between about 5 microns and about 100 microns thick and having a porosity of between about 10 percent and about 70 percent and pores having a pore size of between about 0.1 microns and about 20 microns.

2. The current collector of claim 1, wherein:

the porosity is between about 30 percent and about 50 percent; and

the pore size is between about 1 microns and about 10 microns.

3. The current collector of claim 1, wherein the metallic oxide is between about 0.02 percent and about 10 percent by weight of the porous layer.

4. The current collector of claim 1, wherein said metallic oxide surface deposit is between about 0.05 percent and about 1.0 percent by weight of said porous layer.

5. The current collector of claim 1, wherein said metallic oxide surface deposit is about 0.25 percent by weight of said porous layer.

6. The current collector of claim 1, wherein:

the metallic oxide is ZrO₂, CeO₂, doped-ZrO₂, doped-CeO₂, Y₂O₃, Al₂O₃, Cr₂O₃, MoO₃, Nb₂O₅, TiO₂, Ta₂O₅, SnO₂, La_0.6Sr_0.4Co_0.2Fe_0.8O₃, La_0.8Sr_0.2MnO₃, La_0.8Sr_0.2FeO₃, La_0.8Sr_0.2CrO₃, or La_0.8Sr_0.2CoO₃; and

the metal or metal alloy is Ag, Au, Pd, Pt, Ni, Ru, Rh, Ir, or alloys thereof.

7. The current collector of claim 6, wherein:

the porous layer is composed of silver and zirconia or ceria;

the porosity is between about 30 percent and about 50 percent; and

the pore size is between about 1 microns and about 10 microns.