High oxide ion and proton conductivity in a disordered hexagonal perovskite

• Published in: Nature materials Vol. 19; no. 7; pp. 752 - 757
• Main Authors: Fop, Sacha, McCombie, Kirstie S., Wildman, Eve J., Skakle, Jan M. S., Irvine, John T. S., Connor, Paul A., Savaniu, Cristian, Ritter, Clemens, Mclaughlin, Abbie C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2020; Nature Publishing Group
• Subjects: 639/301/299/893; 639/638/161/893; 639/638/263/915; Biomaterials; Ceramics; Chemistry and Materials Science; Condensed Matter Physics; Conduction; Conductivity; Conductors; Crystal structure; Electrical resistivity; Electrolytes; Electrolytic cells; Fuel cells; Fuel technology; Materials Science; Nanotechnology; Optical and Electronic Materials; Performance enhancement; Perovskites; Protons; Solid electrolytes
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-020-0629-4

Oxide ion and proton conductors, which exhibit high conductivity at intermediate temperature, are necessary to improve the performance of ceramic fuel cells. The crystal structure plays a pivotal role in defining the ionic conduction properties, and the discovery of new materials is a challenging research focus. Here, we show that the undoped hexagonal perovskite Ba 7 Nb 4 MoO 20 supports pure ionic conduction with high proton and oxide ion conductivity at 510 °C (the bulk conductivity is 4.0 mS cm −1 ), and hence is an exceptional candidate for application as a dual-ion solid electrolyte in a ceramic fuel cell that will combine the advantages of both oxide ion and proton-conducting electrolytes. Ba 7 Nb 4 MoO 20 also showcases excellent chemical and electrical stability. Hexagonal perovskites form an important new family of materials for obtaining novel ionic conductors with potential applications in a range of energy-related technologies. Fast oxide ion and proton conductors at intermediate temperature are required to improve the performance of ceramic fuel cells. An undoped hexagonal perovskite Ba 7 Nb 4 MoO 20 electrolyte with high proton and oxide ion conductivity (4.0 mS cm −1 ) at 510 °C is now reported.