<i>Ln</i> ₂ NiO _{4+ <i>δ</i>} -based oxygen electrodes for proton-conducting Sr _0.98 Zr _0.95 Yb _0.05 O _{3– <i>δ</i>} electrolyte for application in IT-SOFCs

Layered lanthanide nickelates Ln2NiO4+δ are considered as potential cathode materials in solid oxide fuel cells. In this study, the chemical stability, thermal expansion and electrical conductivity of a number of layered nickelates, namely Lа2NiO4+δ, Pr1.7Sr0.3NiO4+δ, Pr1.7Ca0.3NiO4+δ and Nd1.9Ca0.1NiO4+δ, are investigated. Based on the chemical stability, thermal expansion and electrical conductivity studies, the composite material consisting of Pr1.7Ca0.3NiO4+δ and Sr0.98Zr0.95Yb0.05O3–δ oxides (PCN-SZYb) was selected as a suitable oxygen electrode for the proton-conducting Sr0.98Zr0.95Yb0.05O3–δ electrolyte. The electrochemical behavior of the electrolyte-supported cells with the symmetrical porous PCN-SZYb electrodes was investigated in air with different humidities in the temperature range of 350–800 °C. The impregnation of a porous electrode backbone with the praseodymium nitrate solution enhanced the activity of the electrodes by approximately 3 times. The electrochemical behavior of the composite electrode in contact with the Sr0.98Zr0.95Yb0.05O3–δ electrolyte is consistent with the literature data on the Ln2NiO4+δ-based electrodes and related proton-conducting electrolytes.