Validation of defect association energy on modulating oxygen ionic conductivity in low temperature solid oxide fuel cell

TitleValidation of defect association energy on modulating oxygen ionic conductivity in low temperature solid oxide fuel cell
Publication TypeJournal Article
Year of Publication2020
AuthorsA. Pandiyan, A. Uthayakumar, C. Lim, V. Ganesan, W. Yu, A. Das, S. Lee, M.N Tsampas, S. Omar, J.W Han, S.BKrishna Moorthy, S.W Cha
JournalJournal of Power Sources
Volume480
Pagination229106
Date Published12/2020
Abstract

The defect association modifies the energy barrier for oxygen ion hopping between the vacancies, which is sensitive to the dopant ionic size in the CeO2-δ. Here, the work focuses on the co-dopant strategy of M0.1Sm0.1Ce0.8O2-δ (M = Yb, Gd, Sm, Nd, La) to study the defect association energy, and its subsequent effect on ionic conduction and power density. The electrolyte material with different co-dopants modifies the lattice parameter and bond length of cation–anion, which changes the defect–dopant interactions. Among the tested dopant, Nd0.1Sm0.1Ce0.8O2-δ exhibits the highest ionic conductivity of 34 mS cm−1 at 550 °C, which is nearly 2.3 times higher than the conventional Sm0.2Ce0.8O2-δ. This experimental observation validates the theoretically proposed concept of the balanced defect–dopant interactions at different sites leading to the reduction in defect association enthalpy. The experimental results were rationalized by calculating the defect association enthalpy for the co-doped system using density functional theory via one-cell method. The cell with Nd0.1Sm0.1Ce0.8O2-δ as an electrolyte shows a peak power density of 466 mW cm−2 at 550 °C, which is twice higher than the cell containing standard Sm0.2Ce0.8O2-δ electrolyte (212 mW cm−2). The results confirm that Nd0.1Sm0.1Ce0.8O2-δ is the potential electrolyte for low temperature SOFC operation. (Graphical abstract available)

DOI10.1016/j.jpowsour.2020.229106
Division

MaSF

Department

CEPEA

PID

710510ec07eeecdd4d1d69c536efae7e

Alternate TitleJ. Power Sources

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