High oxide-ion conductivity in acceptor-doped Bi-based perovskites at modest doping levels

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 19; pp. 11327 - 11333
• Main Authors: Li, Linhao, Kler, Joe, West, Anthony R, De Souza, Roger A, Sinclair, Derek C
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 19.05.2021
• Subjects: Bismuth; Doping; Ions; Lithium; Optimization; Perovskites; Secondary ion mass spectrometry
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp01120k

A combination of impedance spectroscopy, time-of-flight secondary ion mass spectrometry and literature data are used to show that, (i) the bulk oxide ion conductivity of A-site, alkaline earth-doped BiFeO 3 (BF) is independent of the ionic radius of the alkaline earth ion (Ca, Sr, Ba) and, (ii) despite very different A-site environments in (Na 1/2 Bi 1/2 )TiO 3 and BF, similar high levels and optimisation of bulk oxide ion conductivity in these Bi-based tilted perovskites is achieved at modest acceptor doping levels of ∼1-10%. These results clearly demonstrate that optimisation of oxide ion conductivity in these materials requires concepts beyond a simple crystallochemical approach based on matching the ionic radii of acceptor dopant and host lattice ions. High oxide ion conductivity is achieved in A-site alkaline earth doped BiFeO 3 at modest levels. The similar levels of conductivity suggest oxide-ion conduction in Bi-based tilted perovskites is beyond a simple radius-based crystallochemical approach.