First-principles molecular dynamics simulations of proton diffusion in cubic BaZrO $$_3$$ 3 perovskite under strain conditions

Fronzi, Marco; Tateyama, Yoshitaka; Marzari, Nicola; Nolan, Michael; Traversa, Enrico

doi:10.1007/s40243-016-0078-9

Cited by 17 publications

(13 citation statements)

References 42 publications

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“…Car‐Parrinello molecular dynamics, as implemented in the cp.x program of the Quantum‐ESPRESSO distribution, was used to perform efficient density‐functional theory simulations using the PBE exchange‐correlation functional. Norm‐conserving pseudopotentials from the extensively tested SSSP library were used, with a planewave cutoff of 70 Ryd.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

et al. 2017

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The effects of stress‐induced lattice distortions (strain) on the conductivity of Y‐doped BaZrO3, a high‐temperature proton conductor with key technological applications for sustainable electrochemical energy conversion, are studied. Highly ordered epitaxial thin films are grown in different strain states while monitoring the stress generation and evolution in situ. Enhanced proton conductivity due to lower activation energies is discovered under controlled conditions of tensile strain. In particular, a twofold increased conductivity is measured at 200 °C along a 0.7% tensile strained lattice. This is at variance with conclusions coming from force‐field simulations or the static calculations of diffusion barriers. Here, extensive first‐principles molecular dynamic simulations of proton diffusivity in the proton‐trapping regime are therefore performed and found to agree with the experiments. The simulations highlight that compressive strain confines protons in planes parallel to the substrate, while tensile strain boosts diffusivity in the perpendicular direction, with the net result that the overall conductivity is enhanced. It is indeed the presence of the dopant and the proton‐trapping effect that makes tensile strain favorable for proton conduction.

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Section: Methodsmentioning

confidence: 99%

Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

et al. 2017

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“… 19 − 21 More recently, Fronzi et al applied DFT-MD simulations on proton conduction in undoped BaZrO 3 and reported that proton diffusion is enhanced when compressive strain is applied on the structure. 22 The authors interpret this increase in diffusion to the shorter O–O distances observed in the compressed material. The effect of strain on proton diffusion has also been demonstrated in Y-doped BaZrO 3 for two dopant concentrations (1% and 12.5%) using MD simulations with a reactive force field based on an Empirical Valence Bond description.…”

Section: Introductionmentioning

confidence: 97%

Local Distortions and Dynamics in Hydrated Y-Doped BaZrO₃

et al. 2020

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Y-doped BaZrO 3 is a promising proton conductor for intermediate temperature solid oxide fuel cells. In this work, a combination of static DFT calculations and DFT based molecular dynamics (DFT-MD) was used to study proton conduction in this material. Geometry optimizations of 100 structures with a 12.5% dopant concentration allowed us to identify a clear correlation between the bending of the metal–oxygen–metal angle and the energies of the simulated cells. Depending on the type of bending, two configurations, designated as inward bending and outward bending, were defined. The results demonstrate that a larger bending decreases the energy and that the lowest energies are observed for structures combining inward bending with protons being close to the dopant atoms. These lowest energy structures are the ones with the strongest hydrogen bonds. DFT-MD simulations in cells with different yttrium distributions provide complementary microscopic information on proton diffusion as they capture the dynamic distortions of the lattice caused by thermal motion. A careful analysis of the proton jumps between different environments confirmed that the inward and outward bending states are relevant for the understanding of proton diffusion. Indeed, intra-octahedral jumps were shown to only occur starting from an outward configuration while the inward configuration seems to favor rotations around the oxygen. On average, in the DFT-MD simulations, the hydrogen bond lengths are shorter for the outward configuration which facilitates the intra-octahedral jumps. Diffusion coefficients and activation energies were also determined and compared to previous theoretical and experimental data, showing a good agreement with previous data measuring local proton motion.

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“…Plane-wave based DFT calculation demonstrate that the proton diffusion coe cient is affected by applied strain in ABO 3 perovskite structure [223], and the enhanced proton diffusion is explained by the formation of preferable proton transport path due to compressive strain in the structure. To analyze the proton diffusion mechanism in the cubic perovskite structure at high temperature, rst-principles MD simulation was performed, which showed that proton diffusion could be enhanced under the application of compressive condition due to the formation of preferential diffusion path (which can be attributed to charge redistribution under this condition).…”

Section: Theoretical Studies On Bzo Proton Conductormentioning

confidence: 97%

“…Induced charge density due to the proton's introduction can be visualized by Fig. 9, which shows that there could be a signi cant difference between the charge distribution of stoichiometric and protonated bulk [223]. However, ab initio MD simulation on a hydrated sample of BZO shows that it is possible for overlapping INS spectra of protons to exist in the local structural environment, clari ed by O-H bend, O-H stretch, and higher-order transitions.…”

Section: Studiesmentioning

confidence: 99%

“…To analyze the proton diffusion mechanism in the cubic perovskite structure at high temperature, rst-principles MD simulation was performed, which showed that proton diffusion could be enhanced under the application of compressive condition due to the formation of preferential diffusion path (which can be attributed to charge redistribution under this condition). However, there is no evidence of enhancing diffusion from the application of tensile strain or relaxed bulk condition [223]. Speci cally, the proton-oxygen pair correlation is highly affected by the compressive strain.…”

Section: Theoretical Studies On Bzo Proton Conductormentioning

confidence: 99%

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Recent progress in the experimental and theoretical studies on the barium zirconate proton conductors: A review

Hossain¹,

Biswas²,

Chanda³

et al. 2021

Preprint

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There have been significant developments of solid-state-ion conducting energy materials and perovskite-based oxides those exhibit excellent proton conduction at intermediate temperatures. In contrast to high-temperature oxygen ion-conducting oxides or low-temperature proton-conducting polymers, perovskite oxides have obtained distinguished attention because of their diversified structural aspects and potential applications. Highly stable and conductive electrolytes with improved electrochemical and thermochemical properties are in great demand in numerous fields such as portable electronics and transport systems, energy storage, fuel cells, etc. This review focuses on recent development in the proton-conducting performance of BaZrO 3 (BZO) energy materials. This study aims to integrate the fundamentals of proton conducting BZO perovskites in the prospect of the recent development in materials science and computational engineering. Therefore, in the first half of this review, the basic overview of the BZO perovskites structure, fundamentals of working principles, fabrication, and processing methods underlying the successful development of these materials with superior performance is discussed. The second part principally concentrates on the significant improvement towards higher conductive BZO perovskite fabrication with the help of theoretical studies via density functional theory (DFT) based first-principles calculation and molecular dynamics (MD) simulation followed by the prominent applications in low-temperature solid oxide fuel cells. The presented information on in-depth analysis of the physical properties of barium zirconate from experimental and theoretical studies will guide aspirants in further conducting research in this field near future.

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First-principles molecular dynamics simulations of proton diffusion in cubic BaZrO $$_3$$ 3 perovskite under strain conditions

Cited by 17 publications

References 42 publications

Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

Local Distortions and Dynamics in Hydrated Y-Doped BaZrO₃

Recent progress in the experimental and theoretical studies on the barium zirconate proton conductors: A review

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First-principles molecular dynamics simulations of proton diffusion in cubic BaZrO $$_3$$ 3 perovskite under strain conditions

Cited by 17 publications

References 42 publications

Enhanced Proton Conductivity in Y‐Doped BaZrO3 via Strain Engineering

Enhanced Proton Conductivity in Y‐Doped BaZrO3 via Strain Engineering

Local Distortions and Dynamics in Hydrated Y-Doped BaZrO3

Recent progress in the experimental and theoretical studies on the barium zirconate proton conductors: A review

Contact Info

Product

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Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

Enhanced Proton Conductivity in Y‐Doped BaZrO₃ via Strain Engineering

Local Distortions and Dynamics in Hydrated Y-Doped BaZrO₃