Ionic conductivity of yttrium-doped zirconia and the “composite effect”

Filal, M.

doi:10.1016/0167-2738(95)00137-u

Cited by 169 publications

(122 citation statements)

References 18 publications

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“…Differences between maximal and minimal σ-values become less pronounced with increasing temperature, in accordance with literature: 6,8 At 400…”

Section: Results Of the Conductivity Measurementssupporting

confidence: 76%

“…It is interpreted in terms of a defect interaction model with free (mobile) vacancies and immobile vacancies trapped in defect complexes (clusters, associates) such as (Y x . [5][6][7][8][9][39][40][41] Defect complex formation was indeed successfully used to quantitatively describe the temperature dependent conductivity of low-doped silver halides and similar systems, and the corresponding models were already suggested in the 1940s. 42,43 A typical defect association reaction in Cd-doped AgCl, for example, is V / Ag + Cd…”

mentioning

confidence: 99%

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Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Ahamer

Opitz

Rupp

et al. 2017

J. Electrochem. Soc.

135

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The temperature dependent conductivity of yttria stabilized zirconia (YSZ) exhibits a bending in Arrhenius' plots which is frequently discussed in terms of free and associated oxygen vacancies. However, the very high doping concentration in YSZ leads to such a strong defect interaction that the concept of free vacancies becomes highly questionable. Therefore, the temperature dependent conductivity of YSZ is reconsidered. The conductivity of YSZ with different doping concentration was measured in a broad temperature range. The data are analyzed in terms of two different barrier heights that have to be passed along an average path of an oxygen vacancy in YSZ (two barrier model). For 8-10 mol% yttria, the two barriers are in the range of 0.6 eV and 1.1-1.2 eV, respectively. The conductivity and thus the barrier heights also depend on the cooling rate after a high temperature pre-treatment. This indicates that different frozen-in distributions of dopants affect the vacancy motion by different energy landscapes. Temporarily existing defect configurations, possibly with a strong effect of repulsive oxygen vacancy interaction, are suggested as the reason of high barriers. Future dynamic ab-initio calculations may reveal whether this modified model of the YSZ conductivity is mechanistically meaningful. Yttria stabilized zirconia (YSZ) is among the most important ion conducting solids and acts as a kind of model material representing fast oxide ion conductors. Owing to this model character of YSZ, but also due to its application in solid oxide fuel cells (SOFCs), solid oxide electrolysis cells (SOECs) and oxygen sensors, a vast amount of papers can be found dealing with its oxide ion conduction. The ionic conductivity is based on the motion of oxygen vacancies, introduced by Y 3+ ions replacing Zr 4+ . For concentrations above ca. 8 mol%, yttria doping also stabilizes the cubic structure down to room temperature. A detailed review of the science of YSZ and related materials is far beyond the scope of this paper but a few important facts regarding the ionic conductivity of zirconia-based solid electrolytes can be briefly summarized as follows:1-9 i) Doping concentrations above ca. 8 mol% Y 2 O 3 lead to a decrease of the conductivity, despite increasing oxygen vacancy concentration. ii) The conductivity not only depends on the vacancy concentration but also on the kind of dopant. For example, Sc-doped zirconia shows significantly higher conductivity than YSZ. iii) The temperature dependence of the conductivity cannot be described by a single activation energy (E act ) but shows higher E act values at lower temperatures.Numerous theoretical studies were performed in order to understand these experimental observations and to get a deeper insight into defect thermodynamics and kinetics of doped zirconia and of the closely related ceria-based ion conductors, see e.g. Refs. 10-29. Those model studies employed different simulation approaches such as molecular dynamics (MD), density functional theory (DFT) and kinetic Monte Carl...

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“…Differences between maximal and minimal σ-values become less pronounced with increasing temperature, in accordance with literature: 6,8 At 400…”

Section: Results Of the Conductivity Measurementssupporting

confidence: 76%

mentioning

confidence: 99%

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Ahamer

Opitz

Rupp

et al. 2017

J. Electrochem. Soc.

135

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“…Figure 8 shows the temperature dependence of electrical conductivity for YSZ films measured in this study and reported values. [9][10][11][12][13][14] The activation energy (E a ) for the film prepared was about 1.0 eV that was in good agreement with reported values. The electrical conductivity of YSZ film measured with actuator vibration ( f v ¼ 115 kHz and E v ¼ 40 V) is indicated in Fig.…”

Section: Resultssupporting

confidence: 77%

Ionic Conductivity Enhancement of YSZ Film Induced by Piezoelectric Vibration

Masumoto

Goto

2004

Mater. Trans.

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To improve electric properties of oxide ion conducting yttria-stabilized zirconia (YSZ) films at low temperatures, a mechanical distortion was induced by a piezoelectric actuator. YSZ films containing 8 mol%Y 2 O 3 were prepared by metalorganic chemical vapor deposition. The YSZ film was placed on a PZT (lead zirconate titanate) multilayer piezoelectric actuator. The effect of piezoelectric vibration on electric properties of the YSZ film was investigated. The resistivity of the YSZ film decreased with increasing amplitude of the piezoelectric vibration. Electrical conductivity of the YSZ film at 353 K vibrated by the actuator was 2 Â 10 À6 Sm À1 , 10 3 times greater than that without vibration.

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“…The SOM can be made of a variety of oxides such as rare earth or alkaline earth-doped zirconia-, ceria-, hafnia-, or thoria-based materials [46]. YSZ is the most studied material as the membrane for SOM electrolysis, and it shows high ionic conductivity [47] and excellent stability in contact with well-tailored molten flux electrolytes.…”

Section: Anode Assemblymentioning

confidence: 99%

Clean Metals Production by Solid Oxide Membrane Electrolysis Process

Guan

Pal

Jiang

et al. 2016

J. Sustain. Metall.

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This paper reviews a clean metals, production technology that utilizes an oxygen-ion-conducting solid oxide membrane (SOM) to directly electrolyze metal oxides dissolved in a non-consumable molten salts. During the SOM electrolysis process, the desired metal such as magnesium, aluminum, silicon, or a rare earth is produced at the cathode while pure oxygen gas evolves at the anode. Compared with current state-of-the-art metal production processes, such as a chloride-based electrolysis process for magnesium production and the Hall-Héroult process for smelting aluminum, the SOM process brings various advantages such as simplified design, lower cost, lower energy use, and zero emissions. It provides a general route for producing various metals and has great potential to replace current metals, production processes. This paper examines the past and present progress of the SOM process, the challenges faced in commercialization, and the directions for future work.

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Ionic conductivity of yttrium-doped zirconia and the “composite effect”

Cited by 169 publications

References 18 publications

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Revisiting the Temperature Dependent Ionic Conductivity of Yttria Stabilized Zirconia (YSZ)

Ionic Conductivity Enhancement of YSZ Film Induced by Piezoelectric Vibration

Clean Metals Production by Solid Oxide Membrane Electrolysis Process

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