Effect of Aging on Yttria‐Stabilized Zirconia: I. A Study of Its Electrochemical Properties

Kondoh, Junya; Kawashima, T.; Kikuchi, Shiomi; Tomii, Yoichi; Ito, Yasuhiko

doi:10.1149/1.1838515

Cited by 101 publications

(102 citation statements)

References 5 publications

(7 reference statements)

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“…Again, the ohmic resistance increase contributed significantly to the overall cell degradation. There has been a number of degradation mechanisms proposed in the literature [16][17][18][19][20][21][22], such as metal oxidation and Cr poisoning of the oxygen electrode. In addition to the metal oxidation and Cr poisoning to the electrode, another possibility is the reaction of Cr volatile species with LSCF electrode and contact material to form resistive phase SrCrO x .…”

Section: Baseline Performancementioning

confidence: 99%

Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

Guan¹,

Minh²

2007

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This report summarizes the work performed for the program entitled "High Performance Flexible Reversible Solid Oxide Fuel Cell" under Cooperative Agreement DE-FC36-04GO14351 for the U. S. Department of Energy. The overall objective of this project is to demonstrate a single modular stack that generates electricity from a variety of fuels (hydrogen and other fuels such as biomass, distributed natural gas, etc.) and when operated in the reverse mode, produces hydrogen from steam. This project has evaluated and selected baseline cell materials, developed a set of materials for oxygen and hydrogen electrodes, and optimized electrode microstructures for reversible solid oxide fuel cells (RSOFCs); and demonstrated the feasibility and operation of a RSOFC multi-cell stack. A 10-cell reversible SOFC stack was operated over 1000 hours alternating between fuel cell (with hydrogen and methane as fuel) and steam electrolysis modes. The stack ran very successfully with high power density of 480 mW/cm 2 at 0.7V and 80% fuel utilization in fuel cell mode and >6 SLPM hydrogen production in steam electrolysis mode using about 1

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Section: Baseline Performancementioning

confidence: 99%

Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

Guan¹,

Minh²

2007

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“…• C. [51][52][53][54][55] Future simulation studies with spatially and temporarily varying defect interaction and defect motion are encouraged to use the fit parameters of our two barrier analysis for the sake of comparison. Those could also clarify whether a dynamic bimodal barrier height distribution can indeed approximate the vacancy motion in YSZ, and whether our experimentally determined activation energies and prefactors have simple meanings.…”

mentioning

confidence: 99%

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

Ahamer

Opitz

Rupp

et al. 2017

J. Electrochem. Soc.

124

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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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“…29,[48][49][50] Kondoh et al has attributed this behavior to a short-range ordering and trapping of oxygen ion vacancies, which requires higher activation energy for conduction after aging. 48 The short-range ordering of oxygen ion vacancies was associated by Kondoh et al to a shrinkage of the "hump on the left shoulder" in the X-ray diffractograms. 28 Our X-ray data also displays a decrease in the intensity of this feature for the aged samples, along with the formation of a small quantity of monoclinic zirconia for aging times longer than 2500 h (see Figure 2).…”

Section: -39mentioning

confidence: 99%

Effect of Aging on the Electrochemical Performance of LSM-YSZ Cathodes

Baqué

Jørgensen

Zhang

et al. 2015

J. Electrochem. Soc.

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Effect of Aging on Yttria‐Stabilized Zirconia: I. A Study of Its Electrochemical Properties

Cited by 101 publications

References 5 publications

Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

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

Effect of Aging on the Electrochemical Performance of LSM-YSZ Cathodes

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