Improved microstructure and sintering temperature of bismuth nano-doped GDC powders synthesized by direct sol-gel combustion

Abstract

To improve the microstructural and electrochemical properties of Gadolinium-doped ceria (GDC) electrolytes, materials co-doped ceria with bismuth oxide (1-5 mol%) have been successfully prepared in a one-step sol-gel combustion synthetic route. Sol-gel combustion facilitates molecular mixing of the precursors and substitution of the large Bi3+ cations into the fluorite structure, considerably reducing the sintering temperature. Adding Bi2O3 as a dopant increases the GDC densification to above 99.7% and reduces its traditional sintering temperature by 300 C. Impedance analyses show that the addition of bismuth enhances the conductivity (3.110(-2)-1.7.\10(-1) Scm(-1) in the temperature range 600-800 degrees C) and improves the performance of the solid electrolyte in intermediate-temperature solid oxide fuel cells.