Issue 43, 2018

Electrical conductivity and conduction mechanisms in (Na0.5Bi0.5TiO3)1−x(BiScO3)x (0.00 ≤ x ≤ 0.25) solid solutions

Abstract

The electrical properties of (Na0.5Bi0.5TiO3)1−x(BiScO3)x (NBT-BS, 0.00 ≤ x ≤ 0.25) solid solutions are established by ac impedance spectroscopy and electromotive force transport number measurements. The bulk conductivity decreases with increasing BS incorporation but the oxide-ion transport number remains high (>0.85) over a wide compositional range 0.00 ≤ x ≤ 0.15 and drops to ∼0.7 for x ≥ 0.20. NBT-BS solid solutions can only present either predominant oxide-ion conduction or mixed ionic-electronic conduction behaviour, indicating that oxide-ion conduction cannot be fully eliminated by incorporation of BS. This is in contrast from our previous study where incorporation of ∼7% BiAlO3 (BA) can fully suppress the oxide-ion conduction in NBT. The conductivity–composition relationships of NBT-BS solid solutions are attributed to a competing effect from lattice expansion, which enlarges the channel for oxygen ion migration, with trapping between B-site acceptor ions, Image ID:c8tc04679d-t1.gif, and oxygen vacancies, Image ID:c8tc04679d-t2.gif, which decreases oxygen ion migration. Comparisons between NBT-BS, NBT-BA and NBT-BiGaO3 (BG) solid solutions suggest that small acceptor ions on the B-site are more effective in trapping oxygen vacancies and consequently more effective to suppress the oxide-ion conduction and thus reduce dielectric loss at elevated temperatures.

Graphical abstract: Electrical conductivity and conduction mechanisms in (Na0.5Bi0.5TiO3)1−x(BiScO3)x (0.00 ≤ x ≤ 0.25) solid solutions

Article information

Article type
Paper
Submitted
15 Sep 2018
Accepted
11 Oct 2018
First published
14 Oct 2018

J. Mater. Chem. C, 2018,6, 11598-11607

Electrical conductivity and conduction mechanisms in (Na0.5Bi0.5TiO3)1−x(BiScO3)x (0.00 ≤ x ≤ 0.25) solid solutions

F. Yang, P. Wu and D. C. Sinclair, J. Mater. Chem. C, 2018, 6, 11598 DOI: 10.1039/C8TC04679D

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