Multi-scale simulation of proton diffusion in dislocation cores in BaZrO<sub>3</sub>

Yue, Shaofeng; Zhao, Jiang; Sun, Yi; Niu, Hongwei; Li, Huyang; Jing, Yuhang; Aluru, N. R.

doi:10.1039/d2cp02989h

Cited by 2 publications

(3 citation statements)

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“…For example, Yue et al. using quantum mechanical and molecular mechanical simulations found that in the regions of grain boundaries and dislocation cores in BaZrO 3 , the activation energy of proton transfer is increased because of the contribution of local lattice deformation . In addition, a more prosaic reason, that is, the presence of NiO, which was used as a sintering aid, may partially explain high activation energy.…”

Section: Resultsmentioning

confidence: 99%

Charge Transport in High-Entropy Oxides

et al. 2023

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x perovskite oxide with special focus on proton transport. The presented study is part of broader work in which we focus on multiple different chemical compositions with the cation number varying from 5 up to 12 (in B-sublattice). The presence of proton defects is analyzed with thermogravimetry, whereas the results of electrochemical impedance spectroscopy in dry, H 2 O-, and D 2 O-containing synthetic air in the 300−800 °C temperature range enable the evaluation of the proton and deuterium conductivities. The isotope effect is observed and discussed. The obtained data allow us to establish the contribution of proton conductivity to the total one and the transport numbers for proton/deuterium conductivity. Based on the bulk and grain boundary conductivities, the potential at a grain boundary φ 0 , Debye length L D , and space-charge layer (SCL) thickness λ for proton defects is calculated. The potential barrier heights were found to be significantly lower than those observed for typical polycrystalline-doped barium zirconates. For the first time in the case of high-entropy oxides, the electrical conductivity relaxation (ECR) studies are performed, allowing the calculation of water kinetic coefficients. The ECR in the 300−600 °C temperature range revealed a single-fold nature, which indicates a negligible component of the electronic hole conductivity in the hydrated material. The chemical diffusion coefficient of water D OH • and the chemical surface exchange coefficient of water k OH • along with their activation energies are determined. The chemical diffusion coefficient D OH • is in a range of 10(1) −8 −10(1) −6 cm 2 s −1 , and the chemical surface exchange coefficient k OH • is in a range of 10(1) −6 −10(1) −4 cm s −1 .

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Section: Resultsmentioning

confidence: 99%

Charge Transport in High-Entropy Oxides

et al. 2023

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“…Molecular dynamics (MD) simulations have been used to probe ion conduction in many systems, including ionic solids. − In systems where moves can be cataloged, kinetic Monte Carlo (KMC) allows different time scale moves by choosing a move based on its probability and advancing the simulation clock based on the move’s rate constant. − To overcome the challenges of both the distinct time and length scale important to ion conduction, a variety of multiscale methods have been developed and applied successfully to shed light on critical ion conduction technologies. , Many of these methods generate trajectories that can be probed to understand the system dynamics. Trajectories of ion conduction in solids may include many conducting ion diffusion steps near traps and a few escapes to fast conduction regions intermingled with smaller movements of other ions.…”

Section: Introductionmentioning

confidence: 99%

“… 6 − 9 To overcome the challenges of both the distinct time and length scale important to ion conduction, a variety of multiscale methods have been developed and applied successfully to shed light on critical ion conduction technologies. 10 , 11 Many of these methods generate trajectories that can be probed to understand the system dynamics. Trajectories of ion conduction in solids may include many conducting ion diffusion steps near traps and a few escapes to fast conduction regions intermingled with smaller movements of other ions.…”

Section: Introductionmentioning

confidence: 99%

Revised Centrality Measures Tell a Robust Story of Ion Conduction in Solids

Gomez-Haibach,

Gomez

2023

J. Phys. Chem. B

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The three most commonly used centrality measures in network theory have been adapted to consider ion conduction time rather than the number of steps. Flow-IN centrality highlights sites with the largest flow of ions from the nearest neighbor sites. Return-flow centrality highlights sites with a fast rate of first returns for the conducting ion. Flow-through centrality highlights which sites support significant flow of conducting ions and appears more robust to removal of the most central vertices. Exploring these centrality measures with the sample system of proton conduction in yttrium doped barium zirconate shows flow-through centrality to provide a robust picture with high contrast between sites involved in the most probable long-range periodic conduction paths and kinetic Monte Carlo trajectories versus sites rarely visited. The flow-through centrality, including all paths further highlights that when the most central proton site is filled, the remaining highest flow-through centrality sites are nearby, corroborating earlier studies suggesting proton pair motion. Finally, while both return-flow and flow-through centrality measure images deteriorate with noise, image restoration is possible when a detailed balance is used to calculate the smaller rate constant in a forward/backward pair.

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Multi-scale simulation of proton diffusion in dislocation cores in BaZrO₃

Abstract: Dislocations are important for their effects on the chemical, electrical, magnetic, and transport properties of oxide materials, especially for electrochemical devices such as solid fuel cells and resistive memories, but...

Cited by 2 publications

References 70 publications

Charge Transport in High-Entropy Oxides

Charge Transport in High-Entropy Oxides

Revised Centrality Measures Tell a Robust Story of Ion Conduction in Solids

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Multi-scale simulation of proton diffusion in dislocation cores in BaZrO3

Abstract: Dislocations are important for their effects on the chemical, electrical, magnetic, and transport properties of oxide materials, especially for electrochemical devices such as solid fuel cells and resistive memories, but...

Cited by 2 publications

References 70 publications

Charge Transport in High-Entropy Oxides

Charge Transport in High-Entropy Oxides

Revised Centrality Measures Tell a Robust Story of Ion Conduction in Solids

Contact Info

Product

Resources

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Multi-scale simulation of proton diffusion in dislocation cores in BaZrO₃