Enhancement of bromide ion conductivity in lanthanum oxybromide based solids by doping divalent zinc ion with high electronegativity

Abstract

Bromide (Br−) ion conductivity in the LaOBr-type solid was successfully improved by partial replacement of the La3+ ion sites in LaOBr with lower valent Zn2+ and Sr2+ ion. Here, Zn2+ ion having high electronegativity was introduced together with Sr2+ ion to form large number of Br− ion vacancies for Br− ion migration, since higher electronegativity of cation is effective for building a strong bond with the surrounding anions inside the LaOBr lattice. As a result, a high concentration of Br− vacancies was successfully introduced with prohibiting the lattice collapse, and the extraordinary high Br− ion conductivity was obtained for the La0.80Sr0.15Zn0.05OBr0.80 solid.