Oxygen Vacancy Ordering and the Conductivity Maximum in Y(2)O(3)-Doped CeO(2)
Artikel i vetenskaplig tidskrift, 2012

The defect structure and ionic diffusion processes within the anion-deficient, fluorite structured system Ce(1-x)Y(x)O(2-x/2) have been investigated at high temperatures (873 K-1073 K) as a function of dopant concentration, x, using a combination of neutron diffraction studies, impedance spectroscopy measurements, and molecular dynamics (MD) simulations using interionic potentials developed from ab initio calculations. Particular attention is paid to the short-range ion-ion correlations, with no strong evidence that the anion vacancies prefer, at high temperature, to reside in the vicinity of either cationic species. However, the vacancy-vacancy interactions play a more important role, with preferential ordering of vacancy pairs along the < 111 > directions, driven by their strong repulsion at closer distances, becoming dominant at high values of x. This effect explains the presence of a maximum in the ionic conductivity in the intermediate temperature range as a function of increasing x. The wider implications of these conclusions for understanding the structure property relationships within anion-deficient fluorite structured oxides are briefly discussed, with reference to complementary studies of yttria and/or scandia doped zirconia published previously.

molecular dynamics (MD)

ionic-conductivity

construction

oxygen vacancy

molecular-dynamics

fuel-cells

ordering

doped ceria (CeO(2))

cation interactions

energy

SOFC electrolytes

solid oxide electrolyte

reverse Monte Carlo (RMC)

yttria-doped ceria

zirconia

Författare

M. Burbano

Trinity College Dublin

Stefan Norberg

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

S. Hull

ISIS Facility

Sten Eriksson

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Dario Marrocchelli

Massachusetts Institute of Technology (MIT)

Trinity College Dublin

Paul Madden

University of Oxford

G. W. Watson

Trinity College Dublin

Chemistry of Materials

0897-4756 (ISSN) 1520-5002 (eISSN)

Vol. 24 1 222-229

Ämneskategorier

Kemi

DOI

10.1021/cm2031152

Mer information

Senast uppdaterat

2018-07-04