Manufacturing method and current collector

Abstract

A method of forming a current collector layer on electrode layers of an electrochemical air separation element and a current collector. A slurry is prepared that contains electrically conductive particles having surface deposits of a metallic oxide on a metal or metal alloy conductor. The metallic oxide surface deposit constitutes 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 slurry can be applied by dip coating techniques. 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.

1 . A method of forming a porous current collector layers on electrode layers of an electrochemical air separation element, said method comprising:
 preparing a slurry containing electrically conductive particles formed of a metal or metal alloy and metallic oxide surface deposits on the metal or metal alloy, the metallic oxide surface deposit constituting a lower weight percentage of the electrically conductive particles than the metal or metal alloy;   applying said slurry to opposed electrode surfaces of the electrode layers of a layered structure having an electrolyte layer located between said electrode layers; and   firing said layered structure after having applied said slurry at a temperature above intended operational temperatures of the electrochemical air separation element and so that at least the electrically conductive particles partly sinter and thereby form porous current conductor layers on said opposed electrode surfaces.   
     
     
         2 . The method of  claim 1 , wherein:
 the metallic oxide surface deposit is ZrO 2 , CeO 2 , doped-ZrO 2 , doped-CeO 2 , Y 2 O 3 , Al 2 O 3 , Cr 2 O 3 , MoO 3 , Nb 2 O 5 , TiO 2 , Ta 2 O 5 , SnO 2 , La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 , La 0.8 Sr 0.2 MnO 3 , La 0.8 Sr 0.2 FeO 3 , La 0.8 Sr 0.2 CrO 3 , or La 0.8 Sr 0.2 CoO 3 ; and   the metal or metal alloy is Ag, Au, Pd, Pt, Ni, Ru, Rh, Ir, or alloys thereof.   
     
     
         3 . The method of  claim 1 , wherein the electrically conductive particles are formed from silver particles having surface deposits of ZrO 2  or CeO 2 . 
     
     
         4 . The method of  claim 2 , wherein said slurry is applied by dip coating. 
     
     
         5 . The method of  claim 4 , wherein the layered structure is in a sintered state prior to the application of the slurry. 
     
     
         6 . The method of  claim 5 , wherein said electrically conductive particles are between about 45 percent and about 75 percent by weight of the slurry and have a particle size of between about 0.1 and about 20 microns and said surface deposit of the metallic oxide is between about 0.02 percent and about 10 percent by weight of said electrically conductive particles. 
     
     
         7 . The method of  claim 6 , wherein said metallic oxide surface deposit is between about 0.05 percent and about 1.0 percent by weight of said electrically conductive particles. 
     
     
         8 . The method of  claim 6 , wherein said metallic oxide surface deposit is about 0.25 percent by weight of said electrically conductive particles. 
     
     
         9 . The method of  claim 8 , wherein said electrically conductive particles are silver, have a particle size of between about 3 and about 10 microns and a specific area of about 0.2 m 2 /gram. 
     
     
         10 . The method of  claim 9 , wherein said slurry is applied by dip coating. 
     
     
         11 . The method of  claim 10 , wherein said layered structure is in a sintered state prior to application of said slurry.