Combustion synthesized Nd2−xCexCuO4 (x = 0–0.25) cathode materials for intermediate temperature solid oxide fuel cell applications

It is found that the solid solubility of Ce in Nd2−xCexCuO4±δ is limited up to x = 0.2. A semiconductor to metallic transition is observed at 600 °C in d.c. conductivity data, which coincides with a transition in temperature-dependent area-specific resistance (ASR). Nd1.8Ce0.2CuO4±δ is thermodynamically and chemically stable against gadolinia-doped ceria (GDC) up to 1200 °C. On the other hand, it reacts with a yttria-stabilized zirconia electrolyte to form Nd2Zr2O7. At 700 °C, the ASR of a Nd1.8Ce0.2CuO4±δ/GDC/Nd1.8Ce0.2CuO4±δ cell sintered at 800 °C is 0.13 ohm cm2, and the ASR proportionally improves with increase in the sintering temperature of the electrochemical cell. The improved ASR and electrochemical performance are attributed to the nanocrystalline nature of the cathode material.