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Polyanion Conduction Mechanism in Solid Scandium Tungstate

Published online by Cambridge University Press:  31 January 2011

Yongkai Zhou ,
Stefan Adams  and
Arkady Neiman
Yongkai Zhou
Affiliation:
g0501179@nus.edu.sg, National University of Singapore, Department of Materials Science and Engineering, Singapore, Singapore
Stefan Adams
Affiliation:
mseasn@nus.edu.sg, National University of Singapore, Blk E3A, #04-10, 7 Engineering Drive 1, National University of Singapore, Singapore 117574, Singapore, 117574, Singapore
Arkady Neiman
Affiliation:
Arkady.Neiman@usu.ru, Ural State University, Chemical Department, Ekaterinburg, Russian Federation
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Abstract

Scandium tungstate is investigated as a model material for solid electrolytes in which polyatomic anions, here WO42–, are mobile in the solid state. Simulations using structures with artificially induced WO42– vacancy, Frenkel defect and Schottky defects produced lower activation energy compared to the initially defect-free model. Simulations with Frenkel defect structures show low activation energy but the interstitial WO42– has initially a strong preference to return to the vacant tungstate site. The vacancy defect model reproduces the activation energy to the experimental conductivity studies more closely. Qualitative considerations support the idea that vacancies formed during the sample preparation are the most abundant mobile defect among the investigated cases. Nonstoichiometric samples with varying initial Sc2O3:WO3 ratios Sc2O3 - x WO3, where x = 2.9, 3.0 and 3.1, are synthesized and characterized by XRD and impedance measurements, but a significant influence on the conductivity could not be confirmed experimentally.

Keywords

ionic conductorsimulationceramic
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1177: Symposium Z – Computational Nanoscience–How to Exploit Synergy between Predictive Simulations and Experiment , 2009 , 1177-Z09-20
Copyright
Copyright © Materials Research Society 2009

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