Mixed oxide material, electrode and method of manufacturing the electrode and electrochemical cell comprising it

Abstract

The invention relates to a mixed oxide material with a high electron conductivity of empirical formula ABO Y , where y≠3 and where A comprises at least one metal selected from Na, K, Rb, Ca, Ba, La, Pr, Sr, Ce, Nb, Pb, Nd, Sm and Gd, and B comprises at least one metal selected from the group consisting of Cu, Mg, Ti, V, Cr, Mn, Fe, Co, Nb, Mo, W and Zr, where A and B cannot both be Nb and where the compound SrVO 2.5 is excluded. The material may be a perovskite-type material, in which y=3−δ and δ≠0, with values for δ in the range from approximately −0.2 to approximately, −0.05 or in the range from +0.05 to +0.7. The material may also be a Brown-Millerite-type material, for which y=2.5−ξ and ξ has a value in the range from approximately −0.2 to approximately −0.05 or in the range from +0.05 to approximately 0.3. The invention also describes an electrode for an electrochemical cell which can he produced from a mixed oxide material of this type, a method for producing an electrode from a mixed oxide material and an electrochemical cell which comprises at least one electrode of this type made from mixed oxide material according to the invention.

1 . Mixed oxide material with a high electron conductivity, characterized by 
 an empirical formula ABO y , where y≠3 and where A comprises at least one metal selected from Na, K, Rb, Ca, Ba, La, Pr, Sr, Ce, Nb, Pb, Nd, Sm and Gd, and B comprises at least one metal selected from the group consisting of Cu, Mg, Ti, V, Cr, Mn, Fe, Co, Nb, Mo, W and Zr, where A and B cannot both be Nb and where the compound SrVO 2.5  is excluded.    
     
     
         2 . Mixed oxide material according to  claim 1 , characterized in that 
 the material is a perovskite-type material, for which y=3−δ, where δ≠0 and δ has values in the range from approximately −0.2 to approximately −0.05 or in the range from approximately +0.05 to approximately +0.7.    
     
     
         3 . Mixed oxide material according to  claim 1 , characterized in that 
 the material is a Brown-Millerite-type material, for which y=2.5−ξ and ξ has values in the range from approximately −0.2 to approximately −0.05 or in the range from approximately +0.05 to approximately +0.3.    
     
     
         4 . Mixed oxide material according to one or more of claims  1 - 3 , characterized in that 
 A and/or B comprise(s) a metal doped with another metal, the doping metals for A and B being selected from the options given for A and B.    
     
     
         5 . Mixed oxide material according to  claim 4 , characterized in that 
 A comprises Sm x Sr (1-x) , with x lying in the range from approximately 0.4 to approximately 0.6.    
     
     
         6 . Mixed oxide material according to  claim 4 , characterized in that 
 A comprises Nd x Sr (1-x) , with x lying in the range from approximately 0.4 to approximately 0.6.    
     
     
         7 . Mixed oxide material according to one or more of the preceding claims  1 - 6 , characterized in that 
 B comprises Co.    
     
     
         8 . Mixed oxide material according to one or more of the preceding claims  1 - 6 , characterized in that 
 B comprises Fe.    
     
     
         9 . Mixed oxide material according to claims  7  and  8 , characterized in that 
 B comprises Co (1-x) Fe x , with x lying in the range from approximately 0.2 to approximately 0.6.  
 
     
     
         10 . Electrode for an electrochemical cell which can be produced from a material with a high electron conductivity, characterized in that 
 the electrode comprises a mixed oxide material according to one or more of claims  1 - 9 .    
     
     
         11 . Method for producing an electrode for an electrochemical cell, comprising the steps of providing a suitable substrate, and forming a cohesive layer of a mixed oxide thereon by applying a mixture of a mixed oxide, one or more binders and at least one solvent, followed by removal of the solvent and, if appropriate, followed by a heat treatment, characterized in that 
 a cohesive layer which includes a mixed oxide material according to one or more of claims  1 - 10  is formed on the substrate.    
     
     
         12 . Method according to  claim 11 , characterized in that 
 the substrate is a matrix and the mixed oxide is accommodated in the matrix and forms a cohesive unit therewith.    
     
     
         13 . Method according to  claim 11 , characterized in that 
 the substrate has a release property, and the layer which comprises a mixed oxide material, after application on the substrate, is removed and is subjected to a heat treatment if appropriate.    
     
     
         14 . Electrochemical cell which comprises at least two electrodes and an electrolyte, characterized in that 
 it comprises at least one electrode according to  claim 10 .    
     
     
         15 . Electrochemical cell according to  claim 14 , characterized in that 
 it comprises a further electrode selected from a carbon electrode, an RuO 2  electrode and an RuO 2 .xH 2 O electrode.