Synthesis of GD-doped CeO₂ by ultrasonic spray pyrolysis with salt-assisted decomposition and its electrical and mechanical properties

Much attention has been paid to acceptor doped-ceria as a promising solid electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to its high oxygen-ion conductivity. However, poor sinterability leading to high grain boundary resistance and weak mechanical properties have limited its commercialization. In this work, ceria nanoparticles were synthesized via ultrasonic spray pyrolysis using salt-assisted decomposition (SA-USP) to enhance the sinterabililty of the ceria. The effects of the quantity of added salt on the nanoparticle-characteristics were examined. Highly dense ceria (relative density ~ 97.5%) was obtained by sintering the nanoparticles at a temperature as low as 1300 °C and its mechanical and electrical properties were investigated. The hardness and the oxygen-ion conductivity of the ceria with high density were reasonably good, ~ 14 GPa and above 10⁻³ S/cm at the IT-SOFC operating temperatures.