Engineering site disorder to give rise to enhanced conductivity in a scandia-stabilised zirconia electrolyte via disruption of short-range ordering

Shuoshuo Zhang; Andrea Veronese; David N. Miller; Cristian D. Savaniu; John T. S. Irvine

doi:10.1016/j.ssi.2026.117162

Engineering site disorder to give rise to enhanced conductivity in a scandia-stabilised zirconia electrolyte via disruption of short-range ordering

Shuoshuo Zhang, Andrea Veronese, David N. Miller, Cristian D. Savaniu, John T. S. Irvine^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Conductivity degradation is the key limitation associated with zirconia electrolytes, especially within the scandia doped compositions. This is strongly associated with defect ordering, suggesting that introduction of cation disorder could overcome such degradation. The system Sc_0.15+x[In_0.05Mg_0.0125]Zr_0.7875-xO_1.8875-x/2, x = −0.125, 0 (IMSSZ), 0.125 addressed in this study shows an unusual conductivity degradation-recovery-enhancement profile where the conductivity degrades for a short period of time then recovers and exceeds its initial value. The conductivity at 850 °C in air was found to recover to the initial value of 0.096 S cm⁻¹ in less than 25 h, and then it continues to improve up to 0. 11 S cm⁻¹ after 250 h. Starting with a brief introduction on the origin of short-range ordering hence long-term conductivity degradation in the fluorite materials, this paper presents a detailed structural characterisation of this special composition with a focus on short-range structure through electron diffraction, TOF neutron diffraction and impedance spectroscopy. We conclude that the conductivity degradation is caused by pyrochlore and rare-earth C-type related short-range ordering, whereas the conductivity increase and stabilisation observed in this composition is a result of dopant segregation to grain boundaries, with the altered bulk composition destabilising and eliminating such defect short-range ordering and moving towards a stable disordered fluorite structure.

Original language	English
Article number	117162
Number of pages	12
Journal	Solid State Ionics
Volume	439
Early online date	5 Mar 2026
DOIs	https://doi.org/10.1016/j.ssi.2026.117162
Publication status	Published - 1 May 2026

Keywords

Oxide ion conduction
Scandia
Zirconia
Defect ordering

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Engineering site disorder to give rise to enhanced conductivity in a scandiastabilised zirconia electrolyte via disruption of short-range ordering (dataset)
Zhang, S. (Creator), Veronese, A. (Creator), Miller, D. (Creator), Savaniu, C. (Creator) & Irvine, J. (Creator), University of St Andrews, 12 Mar 2026
DOI: 10.17630/cbee8ae8-9c11-45ac-a42b-d7295bff2532
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title = "Engineering site disorder to give rise to enhanced conductivity in a scandia-stabilised zirconia electrolyte via disruption of short-range ordering",

abstract = "Conductivity degradation is the key limitation associated with zirconia electrolytes, especially within the scandia doped compositions. This is strongly associated with defect ordering, suggesting that introduction of cation disorder could overcome such degradation. The system Sc0.15+x[In0.05Mg0.0125]Zr0.7875-xO1.8875-x/2, x = −0.125, 0 (IMSSZ), 0.125 addressed in this study shows an unusual conductivity degradation-recovery-enhancement profile where the conductivity degrades for a short period of time then recovers and exceeds its initial value. The conductivity at 850 °C in air was found to recover to the initial value of 0.096 S cm−1 in less than 25 h, and then it continues to improve up to 0. 11 S cm−1 after 250 h. Starting with a brief introduction on the origin of short-range ordering hence long-term conductivity degradation in the fluorite materials, this paper presents a detailed structural characterisation of this special composition with a focus on short-range structure through electron diffraction, TOF neutron diffraction and impedance spectroscopy. We conclude that the conductivity degradation is caused by pyrochlore and rare-earth C-type related short-range ordering, whereas the conductivity increase and stabilisation observed in this composition is a result of dopant segregation to grain boundaries, with the altered bulk composition destabilising and eliminating such defect short-range ordering and moving towards a stable disordered fluorite structure.",

keywords = "Oxide ion conduction, Scandia, Zirconia, Defect ordering",

author = "Shuoshuo Zhang and Andrea Veronese and Miller, \{David N.\} and Savaniu, \{Cristian D.\} and Irvine, \{John T. S.\}",

note = "Funding: The authors would like to thank EPSRC (Grant code: EP/L017008/1) for the funding of electron microscopes and China Scholarship Council for supporting Dr. Shuoshuo Zhang{\textquoteright} s postgraduate study. We are grateful to ISIS Polars beamline for provision of neutron beamtime (experimental proposal RB1820223).",

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month = may,

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doi = "10.1016/j.ssi.2026.117162",

language = "English",

volume = "439",

journal = "Solid State Ionics",

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TY - JOUR

T1 - Engineering site disorder to give rise to enhanced conductivity in a scandia-stabilised zirconia electrolyte via disruption of short-range ordering

AU - Zhang, Shuoshuo

AU - Veronese, Andrea

AU - Miller, David N.

AU - Savaniu, Cristian D.

AU - Irvine, John T. S.

N1 - Funding: The authors would like to thank EPSRC (Grant code: EP/L017008/1) for the funding of electron microscopes and China Scholarship Council for supporting Dr. Shuoshuo Zhang’ s postgraduate study. We are grateful to ISIS Polars beamline for provision of neutron beamtime (experimental proposal RB1820223).

PY - 2026/5/1

Y1 - 2026/5/1

N2 - Conductivity degradation is the key limitation associated with zirconia electrolytes, especially within the scandia doped compositions. This is strongly associated with defect ordering, suggesting that introduction of cation disorder could overcome such degradation. The system Sc0.15+x[In0.05Mg0.0125]Zr0.7875-xO1.8875-x/2, x = −0.125, 0 (IMSSZ), 0.125 addressed in this study shows an unusual conductivity degradation-recovery-enhancement profile where the conductivity degrades for a short period of time then recovers and exceeds its initial value. The conductivity at 850 °C in air was found to recover to the initial value of 0.096 S cm−1 in less than 25 h, and then it continues to improve up to 0. 11 S cm−1 after 250 h. Starting with a brief introduction on the origin of short-range ordering hence long-term conductivity degradation in the fluorite materials, this paper presents a detailed structural characterisation of this special composition with a focus on short-range structure through electron diffraction, TOF neutron diffraction and impedance spectroscopy. We conclude that the conductivity degradation is caused by pyrochlore and rare-earth C-type related short-range ordering, whereas the conductivity increase and stabilisation observed in this composition is a result of dopant segregation to grain boundaries, with the altered bulk composition destabilising and eliminating such defect short-range ordering and moving towards a stable disordered fluorite structure.

AB - Conductivity degradation is the key limitation associated with zirconia electrolytes, especially within the scandia doped compositions. This is strongly associated with defect ordering, suggesting that introduction of cation disorder could overcome such degradation. The system Sc0.15+x[In0.05Mg0.0125]Zr0.7875-xO1.8875-x/2, x = −0.125, 0 (IMSSZ), 0.125 addressed in this study shows an unusual conductivity degradation-recovery-enhancement profile where the conductivity degrades for a short period of time then recovers and exceeds its initial value. The conductivity at 850 °C in air was found to recover to the initial value of 0.096 S cm−1 in less than 25 h, and then it continues to improve up to 0. 11 S cm−1 after 250 h. Starting with a brief introduction on the origin of short-range ordering hence long-term conductivity degradation in the fluorite materials, this paper presents a detailed structural characterisation of this special composition with a focus on short-range structure through electron diffraction, TOF neutron diffraction and impedance spectroscopy. We conclude that the conductivity degradation is caused by pyrochlore and rare-earth C-type related short-range ordering, whereas the conductivity increase and stabilisation observed in this composition is a result of dopant segregation to grain boundaries, with the altered bulk composition destabilising and eliminating such defect short-range ordering and moving towards a stable disordered fluorite structure.

KW - Oxide ion conduction

KW - Scandia

KW - Zirconia

KW - Defect ordering

U2 - 10.1016/j.ssi.2026.117162

DO - 10.1016/j.ssi.2026.117162

M3 - Article

SN - 0167-2738

VL - 439

JO - Solid State Ionics

JF - Solid State Ionics

M1 - 117162

ER -

Engineering site disorder to give rise to enhanced conductivity in a scandia-stabilised zirconia electrolyte via disruption of short-range ordering

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Engineering site disorder to give rise to enhanced conductivity in a scandiastabilised zirconia electrolyte via disruption of short-range ordering (dataset)

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