Programme

O.17 -- Oral, VCTP-50

Date: Tuesday, 5 August 2025

Time: 16:00 - 16:25

Understanding the mechanism of the co-doping effect on ionic conductivity of Gd3+ and M3+ (M = Nd, Pr) co-doped ceria for solid oxide fuel cell applications

Ho Khac Hieu (1,2), Le Thu Lam (3)

(1) Institute of Research and Development, Duy Tan University, 03 Quang Trung, Hai Chau, Danang 550000, Viet Nam (2) Faculty of Environmental and Natural Sciences, Duy Tan University, 03 Quang Trung, Hai Chau, Danang 550000, Viet Nam (3) Faculty of Natural Sciences and Technology, Tay Bac University, Sonla, Viet Nam

In this work, statistical moment method (SMM) is first developed to illuminate the atomic mechanism of the co-doping effect on improving ionic conductivity of Gd3+ and M3+ (M = Nd, Pr) co-doped ceria (CeO2) electrolytes. The simultaneous existence of co-dopants with the different characters in ionic size and oxygen vacancy trapping effect alters the lattice’s local structure, the component interactions between charged defects, and causes the asymmetric profiles with a reduced energy barrier. These factors work together to minimize the activation energy and provide more transferable oxygen vacancies with high ionic mobility for ionic conduction. The SMM results of dopant-oxygen vacancy binding, migration, and activation energies exhibit as a non-linear function of the co-dopant content. The lower activation energy and higher bulk ionic conductivity of doubly doped ceria compared to singly doped ceria in the low and high temperature regimes demonstrate the synergistic role of co-doping effect. The maximum values of bulk ionic conductivity are found with Ce0.8Gd0.12Nd0.08O2−𝛿 (𝜎773𝐾 = 6.25 x 10−3 S/cm) and Ce0.8Gd0.14Pr0.06O2−𝛿 (𝜎773𝐾 = 5.88 x 10−3 S/cm) for a series of co-dopant contents. Our results are completely compared with experiments.

Presenter: Le Thu Lam