Preparation and Electrochemical Properties of Cathode Materials Ln2-XYXCuO4+δ for Solid Oxide Fuel Cell

Ln2-xYxCuO4+6(Ln = Pr, Nd, Sm; x = 0, 0.025, 0.05, 0.1) cathode materials were synthesized using a sol-gel method and calcination at 1000 & DEG;C for 24 h. The phase structure, coefficient of thermal expansion (CTE), electrical conductivity, and electrochemical impedance of cathode materials were characterized. X-ray diffraction (XRD) patterns show that the cell volume of each cathode material decreases with the increase in the Y3+ doping amount and has good chemical compatibility with the Sm0.2Ce0.8O1.9 electrolyte. The thermal expansion test shows that the increase in Y3+ doping reduces the average CTE of Ln2CuO4+6. The conductivity test shows that Y3+ doping increases the conductivity of Ln2CuO4+6, and Pr1.975Y0.025CuO4+6 has the highest conductivity of 256 S & BULL;cm-1 at 800 & DEG;C. The AC impedance test shows that Y3+ doping reduces the polarization impedance of Ln2CuO4+6, and Pr1.9Y0.1CuO4+6 has a minimum area-specific resistance (ASR) of 0.204 omega & BULL;cm2 at 800 & DEG;C. In conclusion, Pr1.975Y0.025CuO4+6 has the best performance and is more suitable as a cathode material for a solid oxide fuel cell (SOFC).