Synthesizing and investigation on the electrochemical behavior of (Nd0.9La0.1)1.95Sr0.05Ni0.75Cu0.25O4-d and (Nd0.9La0.1)1.9Sr0.1Ni0.75Cu0.25O4-d cathode electrode for solid oxide fuel cell

High operating temperature solid oxide fuel cells can cause damage to the cells over time, so lowering the operating temperature of solid oxide fuel cells is desirable. Although, in most cases decreasing the temperature leads to an increase of the cell components resistance, especially in the cathode. Hence, the use of cathodic materials with a good conductivity at low temperatures is interested. In this research, Ruddlesden-Popper phase, (Nd0.9La0.1)1.95Sr0.05Ni0.75Cu0.25O4-d (NLSNC0.05) and (Nd0.9La0.1)1.9Sr0.1Ni0.75Cu0.25O4-d (NLSNC0.1) has been synthesized for the first time by solid state reaction and their electrochemical performance was investigated. X-ray diffraction analysis was also performed to determine the crystalline structure of the cathode powders. Scanning electron microscopy was used to analyze the morphology of powders and microstructure of symmetric cell. Electrical conductivity of the cathode samples was measured at 300-800℃ in ambient air by DC four-probe method. Maximum total electrical conductivity of 117.65 S.cm-1 at 500℃ was obtained for NLSNC0.1. Electrochemical impedance analysis was used to measure the polarization resistance of cathodes with Sm0.2Ce0.8O1.9 (SDC) electrolyte in the symmetric cell. The lowest values of the polarization resistance for NLSNC0.05 and NLSNC0.1 compounds were 0.22 and 0.26 Ω.cm2 at 800 °C, respectively.