How to interpret current–voltage relationships of blocking grain boundaries in oxygen ionic conductors

Kim, Seong K.; Khodorov, Sergey; Chen, Chien-Ting; Kim, Sangtae; Lubomirsky, Igor

doi:10.1039/c3cp00145h

Cited by 23 publications

(55 citation statements)

References 24 publications

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“…Despite intriguing, some questions about the role of oxygen vacancies and microstructure on electrostriction still remains unexplored [12]. Besides, Lubomirsky and coworkers suggested a power law dependence of I-V relationship in grain boundary blocking behavior based on space charge mechanisms [18] [19] and demonstrated that an increase of grain boundary resistance leads to a decrease in the portion of applied voltage drop in the bulk, decreasing electromechanical properties [20].…”

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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“…Charge transfer processes in solid electrolytes are frequently described by the transport equations for continuum models [32][33][34]. On this basis, the linear diffusion model for the grain boundary resistance was suggested and used for a calculation of the current-voltage characteristics of blocking grain boundaries in some oxygen-ion and proton conductors [35][36][37]. The model reproduces experimentally observed power dependence of current on voltage and results in considerably smaller intergrain energy barrier heights as compared to the results of the conventional SCM.…”

Section: Introductionmentioning

confidence: 93%

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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“…Thus, the functional form of the current‐voltage curve can be used to establish whether space charge effects underly or, at a minimum, contribute to the grain boundary response. [ 3,4,12,47,49–51 ]…”

Section: Transport Properties Of Individually Isolated Grain Boundariesmentioning

confidence: 99%

Local Multimodal Electro‐Chemical‐Structural Characterization of Solid‐Electrolyte Grain Boundaries

Carr

Chen

et al. 2021

Advanced Energy Materials

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Typical models of polycrystalline ionic materials treat the grain boundary properties as single valued, without consideration of the full range of values that define the macroscopically measured average. Here a unique experimental platform suitable for local multimodal characterization of individual grain boundaries in bicrystal fibers is reported. A variation of three orders of magnitude in the grain boundary conductivity of ceria is observed, as measured across six individual bicrystals by both alternating current impedance spectroscopy and direct current (D.C.) linear sweep voltammetry. Nonlinear behavior of the D.C. measurements is consistent with resistance due to a space charge effect. Time‐of‐flight secondary ion beam spectroscopy reveals a correlation between grain boundary resistance and the concentration of impurities Si, Al, and Ca segregated at the grain boundaries, although the bulk concentrations of these impurities are negligible. Electron backscatter diffraction analysis of the crystal orientations suggests a correlation between the misorientation across the grain boundaries and grain boundary resistance. These correlations point towards a grain boundary resistance that arises from impurity‐generated space charge effects and variations in impurity concentration and hence resistivity driven by the energetics of impurity segregation to grain boundaries of differing surface energies.

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How to interpret current–voltage relationships of blocking grain boundaries in oxygen ionic conductors

Cited by 23 publications

References 24 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

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

Local Multimodal Electro‐Chemical‐Structural Characterization of Solid‐Electrolyte Grain Boundaries

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