Direct Observation of Oxygen Vacancy Distribution across Yttria-Stabilized Zirconia Grain Boundaries

Feng, Bin; Lugg, Nathan; Kumamoto, Akihito; Ikuhara, Yuichi; Shibata, Naoya

doi:10.1021/acsnano.7b05943

Cited by 60 publications

(48 citation statements)

References 41 publications

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“…Solute drag phenomena creates specific grain boundary configurations and non-stoichiometry, which acts as blocking barriers to migrate charge species in the material, significantly affect intrinsic properties [21]. Moreover, Shibata et al experimentally showed that the long-range electric interaction is the governing factor in controlling the local charge distribution at the crystal interface [27].…”

Section: Introductionmentioning

confidence: 99%

Effect of oxygen defects blocking barriers on gadolinium doped ceria (GDC) electro-chemo-mechanical properties

et al. 2019

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Some oxygen defective metal oxides, such as cerium and bismuth oxides, have recently shown exceptional electrostrictive properties that are even superior to the best performing lead-based electrostrictors, e.g. lead-magnesium-niobates (PMN). Compared to piezoelectric ceramics, electromechanical mechanisms of such materials do not depend on crystalline symmetry, but on the concentration of oxygen vacancy (V O •• ) in the lattice. In this work, we investigate for the first time the role of oxygen defect configuration on the electro-chemomechanical properties. This is achieved by tuning the oxygen defects blocking barrier density in polycrystalline gadolinium doped ceria with known oxygen vacancy concentration, Ce0.9Gd0.1O2-δ, δ = 0.05. Nanometric starting powders of ca. 12 nm are sintered in different conditions, including field assisted spark plasma sintering (SPS), fast firing and conventional method at high temperatures. These approaches allow controlling grain size and Gd-dopant diffusion, i.e. via thermally driven solute drag mechanism. By correlating the electro-chemomechanical properties, we show that oxygen vacancy distribution in the materials play a key role in ceria electrostriction, overcoming the expected contributions from grain size and dopant concentration.

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Section: Introductionmentioning

confidence: 99%

Effect of oxygen defects blocking barriers on gadolinium doped ceria (GDC) electro-chemo-mechanical properties

et al. 2019

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“…Second, that dopant accumulation will have occurred at sintering temperatures. Atomic‐level characterization by means of transmission electron microscopy (TEM) or atom probe tomography (APT) has found significant accumulation of the acceptor cation at grain boundaries in CeO 2 solid solutions (grain boundaries in the related ZrO 2 ‐Y 2 O 3 materials also show accumulation of the Y cations). Acceptor‐cation accumulation can only take place at sintering temperatures because cation transport in fluorite‐structured oxides, such as CeO 2 and ZrO 2 , is extremely slow (orders of magnitude slower than oxygen transport) and because it is characterized by much higher activation energies .…”

Section: Introductionmentioning

confidence: 99%

Analyzing the grain‐boundary resistance of oxide‐ion conducting electrolytes: Poisson‐Cahn vs Poisson‐Boltzmann theories

2019

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The diminished conductivity of pristine grain boundaries in oxide‐ion conducting electrolytes, such as (Ce,Gd)O2 and (Zr,Y)O2, is widely interpreted with the Mott‐Schottky space‐charge model, or less frequently, with the Gouy‐Chapman space‐charge model. Although routinely applied to the entire compositional range of solid solutions, from dilute to concentrated, these models, being based on the Poisson‐Boltzmann formalism, are limited in their range of validity to dilute solutions of point defects. Analyzing the grain‐boundary properties of concentrated solid solutions with such models is expected to lead to errors and inconsistencies. In this study, we employ Poisson‐Cahn theory to analyze literature data for the grain‐boundary resistance of CeO2‐Gd2O3 materials as a function of Gd concentration. Poisson‐Cahn theory combines the Cahn‐Hilliard theory of inhomogeneous systems with the Poisson equation of electrostatics and it is valid over the entire compositional range. We treat the realistic case of a restricted equilibrium: Gd accumulation profiles are frozen‐in from sintering temperatures, while the oxygen‐vacancy distributions are in equilibrium at sintering and (much lower) measurement temperatures. Data for the grain‐boundary resistance are also analyzed with the standard analytical expressions from the Mott‐Schottky and Gouy‐Chapman models. Outside the domain of their validity, these expressions are found to perform poorly. In general, we emphasize the importance of treating the interfacial properties of concentrated solid solutions with physically appropriate theories.

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“…This segregation is well documented by experimental findings as well as computer simulation results and explained by binding energetics of grain boundaries [25,27,[62][63][64][65][66][67]. The same binding arguments can be applied to mobile species like oxygen vacancies in oxides or Li ions [66,68,69]. The typical binding energies are of the order of several tenths of eV.…”

Section:  mentioning

confidence: 70%

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

et al. 2019

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A simple lattice model of a solid electrolyte presented as a xy-slab geometry system of mobile cations on a background of energetic landscape of the host system and a compensating field of uniformly distributed anions is studied. The system is confined in the z-direction between two oppositely charged walls, which are in parallel to xy-plane. Besides the long-range Coulomb interactions appearing in the system, the short-range attractive potential between cations is considered in our study. We propose the mean field description of this model and extend it by taking into account correlation effects at short distances. Using the free energy minimization at each of z-coordinates, the corresponding set of non-linear equations for the chemical potential is derived. The set of equations was solved numerically with respect to the charge density distribution in order to calculate the cations distribution profile and the electrostatic potential in the system along z-direction under different conditions. An asymmetry of charge distribution profile with respect to the midplane of the system is observed. The effects of the short-range interactions and pair correlations on the charge and electric field distributions are demonstrated.

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Direct Observation of Oxygen Vacancy Distribution across Yttria-Stabilized Zirconia Grain Boundaries

Cited by 60 publications

References 41 publications

Effect of oxygen defects blocking barriers on gadolinium doped ceria (GDC) electro-chemo-mechanical properties

Effect of oxygen defects blocking barriers on gadolinium doped ceria (GDC) electro-chemo-mechanical properties

Analyzing the grain‐boundary resistance of oxide‐ion conducting electrolytes: Poisson‐Cahn vs Poisson‐Boltzmann theories

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

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