FABRICATION AND CHARACTERIZATION OF TB-SM-GD CO-DOPED BI 2 O 3 ELECTROLYTES FOR INTERMEDIATE TEMPERATURES

1 st BİLSEL INTERNATIONAL WORLD SCIENCE AND RESEARCH CONGRESS, İstanbul, Türkiye, 24 - 25 Haziran 2023, ss.504

A high ion conductivity, face-centered cubic δ-Bi2O3 material is regarded as a significant solid electrolyte

option, particularly for low-temperature SOFC applications. Stabilizing this phase while retaining the majority

ion conductivity might allow it a competitive advantage in IT-SOFC electrolyte candidacy. It is well accepted

that δ-Bi2O3 has stronger conductivity than the YSZ electrolytes commonly utilized in HT-SOFC units. The

current work focuses on the structural, thermal, surface, and conductivity properties of Bi2O3 electrolytes co-

doped with Tb-Sm-Gd. With the exception of sample 20Tb20Sm20Gd, the XRD outcomes suggest that all

samples are stabilized by cubic δ-phase at room temperature. The computed lattice constants also show unit cell

shrinkage, showing that the partial cation substitutions of Bi3+ and lanthanide cations are successful. There are

no endothermic or exothermic peaks on the DTA curves, indicating a probable phase transition. Conductivity

Arrhenius graphs show that conductivity decreases as the dopant ratio increases, suggesting a decrease in

polarization power due to cationic substitution. This study's highest conductivity is 0.131 S/cm for sample

10Tb10Sm10Gd, with a total doping rate of 30%. The FE-SEM images clearly point out that doping has a

significant impact on grain size and boundaries. Moreover, the pores on the surface are probably responsible for

the decrease in conductivity resulting from doping. The EDAX pattern of sample 10Tb10Sm10Gd also proves

the combination includes all of the elements, as there are no peaks implying impurities.