Electrical conductivity and performance of doped LaCrO3 perovskite oxides for solid oxide fuel cells

The crystalline structure, redox stability and electrical conductivity of LaCrO3, (La1-xMx)CrO3 (M = Mg, Ca, Ba for x = 0.3 and M = Sr for x=0.25), and (La0.75Sr0.25)(Cr0.5Mn0.5)O-3 (LSCM) perovskites are studied from 500 to 800 degrees C in both oxidizing and reducing atmospheres. Dopability, redox stability and electrical conductivity are compared and examined. A-site doping with alkaline elements is found to improve significantly the electrical conductivity, particularly if properly doped. The highest conductivity is obtained with Ca- and Sr-doped LaCrO3. A-site doping also reduces the activation energy of the electrical conductivity, particularly under a reducing environment. Preliminary electrochemical results indicate that Ca-doped LaCrO3 shows promise as a cathode for solid oxide fuel cells. (c) 2007 Elsevier B.V. All rights reserved.