Critical role of acceptor dopants in designing highly stable and compatible proton-conducting electrolytes for reversible solid oxide cells

Abstract

BaHf0.1Ce0.7Yb0.2O3−δ proton-conducting electrolyte exhibits high conductivity, excellent ionic transference number, remarkable chemical stability, and great compatibility with NiO, as confirmed by experimental and computational results.

Highly Conductive and Durable Nb(Ta)-Doped Proton Conductors for Reversible Solid Oxide Cells

“…It is possible to further improve the conductivity of Nb­(Ta)-doped electrolytes by Y and Yb codoping on the B-site. As reported in our previous work, replacing Yb by Y slightly increases the conductivity at the expense of chemical stability . In this work, Yb is used as the only acceptor dopant to enhance durability.…”

“…As shown in Figure , while substituting Ce with Zr significantly improves the chemical stability against both H 2 O and CO 2 , the Nb- and Ta-doped compositions exhibit even better tolerance to the contaminants. Also, all calculated compositions have inferior chemical stability against CO 2 compared to H 2 O, which is typical for barium cerate-based proton conductors . While the energies for decomposition of the perovskite to BaCO 3 /Ba­(OH) 2 and metal oxides are a more accurate measure of electrolyte stability, the CO 2 /H 2 O adsorption energies are used as a proxy.…”

“…Also, all calculated compositions have inferior chemical stability against CO 2 compared to H 2 O, which is typical for barium cerate-based proton conductors. 23 While the energies for decomposition of the perovskite to BaCO 3 / Ba(OH) 2 and metal oxides are a more accurate measure of electrolyte stability, the CO 2 /H 2 O adsorption energies are used as a proxy. Although successful examples have shown that the incorporation of Nb can enhance the chemical stability of doped barium cerates, a study on the detailed comparison between the durability of Zr-and Nb-substituted compositions is lacking.…”

“…As reported in our previous work, replacing Yb by Y slightly increases the conductivity at the expense of chemical stability. 23 In this work, Yb is used as the only acceptor dopant to enhance durability.…”

“…Moreover, it is worth noting that the Y site in BZCYYb exhibits the lowest H 2 O tolerance, which is consistent with our previous results. 23 Accordingly, the better chemical stability of BN/TCYb is attributed to markedly improved resistance to contamination on the Nb and Ta sites.…”