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Sr-doped lanthanum cuprate was recently investigated as a potential cathode material for the intermediate temperature solid oxide fuel cell using yittria-stabilized zirconia as an electrolyte. The material thermal stability of cathode material against an electrolyte at an operating temperature plays an important role in the fuel cell's performance. In this study, the structural stability between Sr-doped lanthanum cuprate and 8 mol% yittria-stabilized zirconia was investigated by using the powder mixture and diffusion couple. The chemical reaction between these two materials in the temperature ranging from 800° to 1000°C was examined by X-ray diffraction analyses. The interfacial reaction behavior between electrode and electrolyte pellets of the reaction couple was examined by a grazing X-ray diffractometer, wavelength-dispersive X-ray analysis, and an electron probe microanalyzer. No reaction products were observed as these two materials co-fired at 800°C. The reaction products of pyrochlore La2Zr2O7 and perovskite SrZrO3 were formed when the specimens were heat treated at over 900°C. Because of the formation of these reaction products, the CuO was precipitated. Furthermore, an excess of SrZrO3 formation leads to the phase decomposition of perovskite Sr-doped lanthanum cuprate to La2− xSr xCuO4 and CuO due to a decrease in strontium concentration in Sr-doped lanthanum cuprate. [ABSTRACT FROM AUTHOR]

La1−xSrxCuO2.5−δ (LSCu), which exhibit excellent electrical conductivity and oxygen vacancies were investigated as potential cathode materials for solid oxide fuel cell (SOFC) applications. The structure stability, electrical conductivity, cathodic overpotential, and the reactivity with yttria-stabilized zirconia (YSZ) were examined in this study. It was found that the LSCu perovskite was obtained only when the addition of strontium fell in the range between 15 and 30%. With more than 20% of strontium addition, this material showed excellent electrical property and immunity to the reaction with YSZ at 800 °C. The conductivities of LSCu were as high as 900 S/cm at 600 °C, and 800 S/cm at 800 °C. The cathodic overpotential of this material was approximately 3.8 and 10.6 mV at a current density of 100 mA/cm2 at 850 and 750 °C, respectively. These properties are superior to Sr-doped lanthanum manganite (LSM), which is the state-of-the-art cathode material of SOFCs. [Copyright &y& Elsevier]