The fate of aluminium in (Na,Bi)TiO3-based ionic conductors

Groszewicz PB, Koch L, Steiner S, Ayrikyan A, Webber KG, Frömling T, Albe K, Buntkowsky G (2020)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2020

Journal

Journal of Materials Chemistry A Royal Society of Chemistry

Book Volume: 8

Pages Range: 18188-18197

Journal Issue: 35

DOI: 10.1039/d0ta03554h

Abstract

The formation of associated defects (e.g.[AlTi-VO]˙) upon acceptor doping is commonly seen as a reason for trapping of mobile vacancies in perovskite ionic conductors and electromechanical hardening in piezoelectric perovskites. In order to clarify the presence of associated defects in Al-doped (Na1/2,Bi1/2)TiO3(NBT-Al) and Al-substituted ((Na,K)1/2Bi1/2)TiO3-BiAlO3(NKBT-BA), we employ a combination of impedance spectroscopy,²⁷Al NMR spectroscopy, and electronic structure calculations. Our results indicate that associated defects between and oxygen vacancies can only be found in case of low acceptor doping concentrations. This suggests a decreased driving force for defect association at high doping concentrations as the reason for the non-linear dependence between acceptor concentration and oxygen ionic conductivity for NBT-based ceramics. Furthermore, the combination of experimental and theoretical techniques provides clear evidence for the successive occupation of the B-site, the A-site, and finally the formation of a secondary phase with increasing Al³⁺content. Altogether, these results call for a new evaluation of the interaction between aliovalent dopants and O²⁻vacancies in acceptor-doped functional oxides, with implications for the design of ionic conductors as well as ferroelectric materials.

Authors with CRIS profile

Azatuhi Ayrikyan Lehrstuhl für Glas und Keramik Kyle Grant Webber Professur für Werkstoffwissenschaften (Funktionskeramik)

Involved external institutions

Technische Universität Darmstadt

Germany (DE)

How to cite

APA:

Groszewicz, P.B., Koch, L., Steiner, S., Ayrikyan, A., Webber, K.G., Frömling, T.,... Buntkowsky, G. (2020). The fate of aluminium in (Na,Bi)TiO3-based ionic conductors. Journal of Materials Chemistry A, 8(35), 18188-18197. https://doi.org/10.1039/d0ta03554h

MLA:

Groszewicz, Pedro B., et al. "The fate of aluminium in (Na,Bi)TiO3-based ionic conductors." Journal of Materials Chemistry A 8.35 (2020): 18188-18197.

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