Discovery of a new crystal structure family of oxide-ion conductors: NdBaInO4

May 12, 2016

Oxide-ion conducting ceramic materials have received considerable attention because of their potential applications in solid oxide fuel cells, oxygen separation membranes, and gas sensors.

Currently, most research about oxide-ion conducting ceramics is limited to materials with specific structure-types, such as fluorites, perovskites, K₂NiF₄, mellilites, and apatites. However, it is necessary to investigate new structure-type ceramics for the further development of oxide-ion conductors.

Recently, a research group led by Masatomo Yashima and Kotaro Fujii of Tokyo Institute of Technology discovered the new crystal structure family of oxide-ion conductors of NdBaInO₄ using a concept of structure design based on ionic size.

NdBaInO₄ was synthesized by a solid-state reaction and the crystal structure was determined from synchrotron and neutron powder diffraction data.

The crystal structure analysis revealed that NdBaInO₄ belongs to a completely new structure family. The oxide-ion conduction was confirmed by electrical conductivity measurements. Furthermore, the research group succeeded in improving the oxide-ion conductivity by about 20 times by Sr doping at Nd sites that yielded the composition of Nd_0.9Sr_0.1BaInO_3.95.

The discovery of this new material of NdBaInO₄ is expected to lead to the development of new ionic conductors for better solid oxide fuel cells, oxygen concentrators, and electronic materials.

Crystal structure of NdBaInO4

Figure 1. Crystal structure of NdBaInO₄

Reference1

Authors:	Kotaro Fujii, Yuichi Esaki, Kazuki Omoto, Masatomo Yashima, Akinori Hoshikawa, Toru Ishigaki, James R. Hester
Title of original paper:	New Perovskite-Related Structure Family of Oxide-Ion Conducting Materials NdBaInO₄
Journal, volume, pages and year:	Chemistry of Materials, 26, 2488 (2014).
DOI :	10.1021/cm500776x
Affiliations:	Department of Chemistry, School of Science, Tokyo Institute of Technology; Frontier Research Center for Applied Atomic Sciences, Ibaraki University; The Bragg Institute, Australian Nuclear Science and Technology Organisation

Reference2

Authors:	Kotaro Fujii, Masahiro Shiraiwa, Yuichi Esaki, Masatomo Yashima, Su Jae Kim, Seongsu Lee
Title of original paper:	Improved oxide-ion conductivity of NdBaInO₄ by Sr doping
Journal, volume, pages and year:	Journal of Materials Chemistry A, 3, 11985 (2015).
DOI :	10.1039/C5TA01336D
Affiliations:	Department of Chemistry, School of Science, Tokyo Institute of Technology; Neutron Science Division, Research Reactor Utilization Department, Korea Atomic Energy Research Institute