Crystal structure and electrical conductivity of Ba<i>R</i>₂ZnO₅ (<i>R</i> = Sm, Gd, Dy, Ho, and Er)—a new structure family of oxide-ion conductors

Abstract

. In the present study, we have found a new structure family of oxide-ion conductors, BaY 2 CuO 5 -type (BaCuY 2 O 5 -type) BaR 2 ZnO 5 compounds (R = rare earths). BaR 2 ZnO 5 compounds with a BaY 2 CuO 5 -type structure were found to be good candidates for oxide-ion conductors by the bond-valence method. BaR 2 ZnO 5 compounds (R = Sm, Gd, Dy, Er, and Ho) were synthesized by solid-state reactions, and their electrical conductivities and crystal structures were investigated. Rietveld analyses of BaR 2 ZnO 5 (R = Sm, Gd, Dy, Er, and Ho) using synchrotron X-ray powder diffraction data gave good fitting for the BaY 2 CuO 5 -type structure. BaHo 2 ZnO 5 had the highest total electrical conductivity in air among BaR 2 ZnO 5 compounds (R = Sm, Gd, Dy, Er, Ho). Oxide-ion conduction was confirmed for BaHo 2 ZnO 5 by electrical conductivity measurements conducted under various oxygen partial pressures. Neutron powder diffraction data of BaHo 2 ZnO 5 were analyzed by the Rietveld method, and the oxide-ion conduction paths were investigated by the bond-valence method.

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+doping in LaNbO4

“…[59][60][61][62] BVEL mapping has also been used successfully to screen known database structures for oxide-ionic conductivity which was subsequently conrmed experimentally in several materials for the rst time. 63,64 A BVEL map that we calculated for a geometry-optimised undoped LaNbO 4 supercell produced low-energy pathways that show good qualitative agreement with those derived from the nudged elastic band calculations of Toyoura et al 27 (ESI Fig. S8 †).…”

Discovery of a Rare-Earth-Free Oxide-Ion Conductor Ca3Ga4O9 by Screening through Bond Valence-Based Energy Calculations, Synthesis, and Characterization of Structural and Transport Properties

“…Oxide-ion conducting ceramics have attracted much interest because of their potential applications as oxygen separation membranes, electrolytes, and electrodes in solid oxide fuel cells (SOFCs). − A high oxide-ion (O 2– ) mobility is achieved in a limited number of structure families such as the cubic and distorted fluorite type, pyrochlore type, , sheelite type, perovskite type, − K 2 NiF 4 type, − melilite type, , apatite type, , and few others. − Therefore, it is necessary to discover a new structure family of oxide-ion conductors for the development of inorganic chemistry and solid-state ionics.…”

Discovery of Oxide-Ion Conductors with a New Crystal Structure, BaSc2–xAxSi3O10–x/2 (A = Mg, Ca) by Screening Sc-Containing Oxides through the Bond-Valence Method and Experiments

“…Ceramic oxide-ion conductors are utilized as high-temperature electrochemical devices, such as solid oxide fuel cells (SOFCs), batteries, catalysts, and oxygen permeation membranes. − The oxide-ion conductors have been studied by many research groups. The main materials exhibiting high oxide-ion mobility have a limited range of structure types, such as fluorite-type, − perovskite-type, − pyrochlore-type, − K 2 NiF 4 -type, − and others. − Therefore, the discovery of new structure-type oxide-ion conductors is important for the development of innovative devices based on oxide-ion conductors. The first aim of this study was to search for Sc-containing oxide-ion conductors with a new structure by the bond-valence (BV) method.…”