Tuning Cu-Content La(1−x)Sr(x)Ni(1−y)Cu(y)O(3−δ) with Strontium Doping as Cobalt-Free Cathode Materials for High-Performance Anode-Supported IT-SOFCs

Cu-content La(1−x)Sr(x)Ni(1−y)Cu(y)O(3−δ) perovskites with A-site strontium doping have been tuned as cobalt-free cathode materials for high-performance anode-supported SOFCs, working at an intermediate-temperature range. All obtained oxides belong to the R-3c trigonal system, and phase transitions from the R-3c space group to a Pm-3m simple perovskite have been observed by HT-XRD studies. The substitution of lanthanum with strontium lowers the phase transition temperature, while increasing the thermal expansion coefficient (TEC) and oxygen non-stoichiometry δ of the studied materials. The thermal expansion is anisotropic, and TEC values are similar to commonly used solid electrolytes (e.g., 14.1 × 10(−6) K(−1) for La(0.95)Sr(0.05)Ni(0.5)Cu(0.5)O(3−δ)). The oxygen content of investigated compounds has been determined as a function of temperature. All studied materials are chemically compatible with GDC-10 but react with LSGM and 8YSZ electrolytes. The anode-supported SOFC with a La(0.95)Sr(0.05)Ni(0.5)Cu(0.5)O(3−δ) cathode presents an excellent power density of 445 mW·cm(−2) at 650 °C in humidified H(2). The results indicate that La(1−x)Sr(x)Ni(1−y)Cu(y)O(3−δ) perovskites with strontium doping at the A-site can be qualified as promising cathode candidates for anode-supported SOFCs, yielding promising electrochemical performance in the intermediate-temperature range.