On determining the height of the potential barrier at grain boundaries in ion-conducting oxides

2016 ◽  
Vol 18 (4) ◽  
pp. 3023-3031 ◽  
Author(s):  
Sangtae Kim ◽  
Seong K. Kim ◽  
Sergey Khodorov ◽  
Joachim Maier ◽  
Igor Lubomirsky
Keyword(s):  
Grain Boundary ◽  
Space Charge ◽  
Grain Boundaries ◽  
Potential Barrier ◽  
Boundary Resistance ◽  
Resistivity Ratio ◽  
Linear Diffusion ◽  
Conducting Oxides ◽  
Ion Conducting

Combining the linear diffusion and resistivity ratio models, one can distinguish the grain boundary resistance related to space charge from the resistance from other sources.

The exceptionally large height of the potential barrier at the grain boundary of a LaGaO3-based solid solution deduced from a linear diffusion model

2018 ◽  
Vol 20 (13) ◽  
pp. 8719-8723 ◽  
Author(s):  
Chih-Yuan S. Chang ◽  
Igor Lubomirsky ◽  
Sangtae Kim
Keyword(s):  
Solid Solution ◽  
Grain Boundary ◽  
Diffusion Model ◽  
Potential Barrier ◽  
Experimental Verification ◽  
Resistivity Ratio ◽  
Linear Diffusion ◽  
Boundary Potential

Experimental verification of consistency in the grain boundary potential heights deduced from the linear diffusion and the resistivity ratio methods.

scholarly journals Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3294
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Pornjuk Srepusharawoot ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Barrier Height ◽  
Potential Barrier ◽  
Charge Compensation ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Potential Barrier Height

The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.

Atomic-scale origin of the large grain-boundary resistance in perovskite Li-ion-conducting solid electrolytes

2014 ◽  
Vol 7 (5) ◽  
pp. 1638 ◽  
Author(s):  
Cheng Ma ◽  
Kai Chen ◽  
Chengdu Liang ◽  
Ce-Wen Nan ◽  
Ryo Ishikawa ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Solid Electrolytes ◽  
Boundary Resistance ◽  
Atomic Scale ◽  
Li Ion ◽  
Ion Conducting

scholarly journals Influence of microstructure and crystalline phases on impedance spectra of sodium conducting glass ceramics produced from glass powder

2021 ◽  
Author(s):  
Mihails Kusnezoff ◽  
Dörte Wagner ◽  
Jochen Schilm ◽  
Christian Heubner ◽  
Björn Matthey ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Crystalline Phase ◽  
Glass Phase ◽  
Boundary Resistance ◽  
Phase Content ◽  
Impedance Spectra ◽  
Temperature Dependent ◽  
Crystalline Phases ◽  
Parent Glass ◽  
Ion Conducting

AbstractCrystallization of highly ionic conductive N5 (Na5YSi4O12) phase from melted Na3+3x-1Y1-xPySi3-yO9 parent glass provides an attractive pathway for cost-effective manufacturing of Na-ion conducting thin electrolyte substrates. The temperature-dependent crystallization of parent glass results in several crystalline phases in the microstructure (N3 (Na3YSi2O7), N5 and N8 (Na8.1Y Si6O18) phases) as well as in rest glass phase with temperature dependent viscosity. The electrical properties of dense parent glass and of compositions densified and crystallized at 700 °C, 800 °C, 900 °C, 1000 °C, and 1100 °C are investigated by impedance spectroscopy and linked to their microstructure and crystalline phase content determined by Rietveld refinement. The parent glass has high isolation resistance and predominantly electrons as charge carriers. For sintering at ≥ 900 °C, sufficient N5 phase content is formed to exceed the percolation limit and form ion-conducting pathways. At the same time, the highest content of crystalline phase and the lowest grain boundary resistance are observed. Further increase of the sintering temperature leads to a decrease of the grain resistance and an increase of grain boundary resistance. The grain boundary resistance increases remarkably for samples sintered at 1100 °C due to softening of the residual glass phase and wetting of the grain boundaries. The conductivity of fully crystallized N5 phase (grain conductivity) is calculated from thorough impedance spectra analysis using its volume content estimated from Rietveld analysis, density measurements and assuming reasonable tortuosity to 2.8 10−3 S cm−1 at room temperature. The excellent conductivity and easy processing demonstrate the great potential for the use of this phase in the preparation of solid-state sodium electrolytes.

Applicability of a linear diffusion model to determination of the height of the potential barrier at the grain boundaries of Fe-doped SrTiO3

2018 ◽  
Vol 20 (28) ◽  
pp. 19250-19256 ◽  
Author(s):  
Chih-Yuan S. Chang ◽  
Igor Lubomirsky ◽  
Sangtae Kim
Keyword(s):  
Grain Boundaries ◽  
Diffusion Model ◽  
Potential Barrier ◽  
Experimental Verification ◽  
Electron Hole ◽  
Linear Diffusion

Experimental verification of a linear diffusion model on a lightly doped electron–hole conductor, Fe-doped SrTiO3.

scholarly journals Towards Understanding the Different Influences of Grain Boundaries on Ion Transport in Sulfide and Oxide Solid Electrolytes

2019 ◽  
Author(s):  
James Dawson ◽  
Pieremanuele Canepa ◽  
Matthew Clarke ◽  
Theodosios Famprikis ◽  
Dibyajyoti Ghosh ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Ion Transport ◽  
Grain Boundaries ◽  
Solid Electrolytes ◽  
Ionic Conductivities ◽  
Liquid Electrolyte ◽  
Boundary Resistance ◽  
Polycrystalline Materials ◽  
Solid State Batteries ◽  
And Performance

Solid electrolytes provide a route to the development of all-solid-state batteries that can potentially surpass the safety and performance of conventional liquid electrolyte-based devices. Sulfide solid electrolytes have received particular attention as a result of their high ionic conductivities. One of the main reasons for such high ionic conductivity is the apparently reduced grain boundary resistance of sulfide solid electrolytes compared to their oxide counterparts, but this is not fully established. Using two model electrolyte systems, Na3PS4 and Na3PO4, we apply a novel microscale simulation approach to analyze ionic transport in polycrystalline materials with various grain volumes. For Na3PO4, high grain boundary resistance is found, with the Na-ion conductivity decreasing with decreasing grain volume. For Na3PS4, the overall influence of grain boundaries is significantly reduced compared to the oxide. Detailed analysis reveals a minimal change in the local structures and Na-ion conduction mechanism between bulk and polycrystalline Na3PS4, whereas the change is far more substantial for Na3PO4, with evidence of over-coordination of Na ions at the grain boundaries. Our microscale approach helps to explain the fundamentally different influences of grain boundaries on ion transport in phosphate and thiophosphate solid electrolytes.

Minimizing the Grain Boundary Resistance of Li-Ion-Conducting Oxide Electrolyte by Controlling Liquid-Phase Formation During Sintering

2018 ◽  
Vol 1 (11) ◽  
pp. 6303-6311 ◽  
Author(s):  
Toyoki Okumura ◽  
Sou Taminato ◽  
Tomonari Takeuchi ◽  
Hironori Kobayashi
Keyword(s):  
Liquid Phase ◽  
Grain Boundary ◽  
Phase Formation ◽  
Boundary Resistance ◽  
Li Ion ◽  
Ion Conducting ◽  
Oxide Electrolyte

Reversible Force-Resistivity Behavior of Thin Films of the TTF-Tcnq Family

1996 ◽  
Vol 436 ◽  
Author(s):  
W. Vollmann ◽  
H.-U. Sonntag
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Potential Barrier ◽  
Film Plane ◽  
Barrier Width ◽  
Dependent Potential ◽  
Sample Resistance

AbstractThe electrical properties of vacuum sublimed thin films of TTF-TCNQ and its derivatives mainly are determined by electron barriers at grain boundaries. The electrical conductivity is thermal activated and exhibits a significant dependence on a force acting perpenticularly to the film plane. The sample resistance R decreases continiously with increasing force F. TCNQ thin films on steel show a similar R-F relation. The effect has been observed already at forces of 1 N, but also up to about 60 kN. An explanation of these phenomena is given by a grain boundary limited hopping mechanism with pressure dependent potential barrier width and height. Morphology investigations by SEM support the model.

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