Yang, F. orcid.org/0000-0002-6428-7755, Wu, P. and Sinclair, D. (2017) Enhanced bulk conductivity of A-site divalent acceptor-doped non-stoichiometric sodium bismuth titanate. Solid State Ionics, 299. pp. 38-45. ISSN 1872-7689
Abstract
Bismuth-deficient sodium bismuth titanate (nominally Na0.5Bi0.49TiO2.985, NB0.49T) is a good oxide-ion conductor. Here we report the influence of A-site divalent ions, M2 + = Ca2 +, Sr2 + and Ba2 +, on the electrical properties of NB0.49T. A-site divalent doping for Bi3 + enhances the bulk (grain) conductivity by ~ one order of magnitude without changing the conduction mechanism, which is attributed to an increase in the oxygen vacancy concentration based on the doping mechanism Bi3 + + ½ O2 − → M2 +. Among these three dopants, Sr2 + is the most effective in increasing the bulk conductivity due to a combination of its smaller mismatch in ion size with Bi3 +, its intermediate polarisability and lower bond strength to oxygen compared to Ca2 + and Ba2 +. Doping strategies for further improvements to bulk conductivity of NBT materials are discussed based on these results. Comparison with other oxide-ion conductors and initial stability test under reducing atmosphere show the doped non-stoichiometric NBT materials are promising for low and intermediate temperature applications.
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Copyright, Publisher and Additional Information: | © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). | ||||
Keywords: | Sodium bismuth titanate; Oxide-ion conductors; Doping; Non-stoichiometry | ||||
Dates: |
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Institution: | The University of Sheffield | ||||
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) | ||||
Funding Information: |
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Depositing User: | Symplectic Sheffield | ||||
Date Deposited: | 19 Sep 2016 08:30 | ||||
Last Modified: | 28 Feb 2017 15:14 | ||||
Published Version: | http://dx.doi.org/10.1016/j.ssi.2016.09.016 | ||||
Status: | Published | ||||
Publisher: | Elsevier | ||||
Refereed: | Yes | ||||
Identification Number: | https://doi.org/10.1016/j.ssi.2016.09.016 |