Preparation and Electrochemical Properties of Cathode Materials Ln(2-x) Y (x) CuO(4+δ) for Solid Oxide Fuel Cell.

Ln(2-x) Y (x) CuO(4+δ) (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 °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 Y(3+) doping amount and has good chemical compatibility with the Sm(0.2)Ce(0.8)O(1.9) electrolyte. The thermal expansion test shows that the increase in Y(3+) doping reduces the average CTE of Ln(2)CuO(4+δ). The conductivity test shows that Y(3+) doping increases the conductivity of Ln(2)CuO(4+δ), and Pr(1.975)Y(0.025)CuO(4+δ) has the highest conductivity of 256 S·cm(-1) at 800 °C. The AC impedance test shows that Y(3+) doping reduces the polarization impedance of Ln(2)CuO(4+δ), and Pr(1.9)Y(0.1)CuO(4+δ) has a minimum area-specific resistance (ASR) of 0.204 Ω·cm(2) at 800 °C. In conclusion, Pr(1.975)Y(0.025)CuO(4+δ) has the best performance and is more suitable as a cathode material for a solid oxide fuel cell (SOFC).