Electrical conductivity and performance of doped LaCrO 3 perovskite oxides for solid oxide fuel cells

Abstract

The crystalline structure, redox stability and electrical conductivity of LaCrO 3, (La 1− x M x )CrO 3 (M = Mg, Ca, Ba for x = 0.3 and M = Sr for x = 0.25), and (La 0.75Sr 0.25)(Cr 0.5Mn 0.5)O 3 (LSCM) perovskites are studied from 500 to 800 °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 LaCrO 3. A-site doping also reduces the activation energy of the electrical conductivity, particularly under a reducing environment. Preliminary electrochemical results indicate that Ca-doped LaCrO 3 shows promise as a cathode for solid oxide fuel cells.