Lanthanum Alkaline‐Earth Manganites as a Cathode Material in High‐Temperature Solid Oxide Fuel Cells

Abstract

The effect of RE (RE = Ce and Pr) doping perovskite on crystallographic properties, phase relationships, conductivity, thermal expansion, sintering, and reaction with electrolyte is presented. showed a single perovskite phase in the region 0 ≤ x ≤ 0.05 for Ce substitution and over the entire composition range of Pr content. No effect of RE doping of on conductivity was observed. A decrease in thermal expansion coefficients of accompanied RE doping. Ce doping of increased its morphological stability and suppressed its reaction with the electrolyte. (Ln: lanthanum concentration with La, Ce, and Pr, AE = Sr, Ca) materials were examined as cathodes in solid oxide fuel cells. X‐ray diffraction analysis indicated that (0 ≤ x ≤ 0.3) 7:19 AM 7/22/01 showed a single perovskite phase. Conductivities of these oxides increased with AE content and ranged from 80 to 200 S/cm at 1000°C in air, and thermal expansion coefficients ranged from 9.5 to . showed less reactivity with the electrolyte compared with . The cathodic polarization of the at 1000°C was 60 mV at in air. © 1999 The Electrochemical Society. All rights reserved.