Unveiling of interstice-occupying dopant segregation at grain boundaries in perovskite oxide dielectrics for a new class of ceramic capacitors

An, Ji-Sang; Lee, Hae-Seung; Byeon, Pilgyu; Kim, Dongho; Bae, Hyung Bin; Choi, Si‐Young; Ryu, Jungho; Chung, Sung‐Yoon

doi:10.1039/d2ee03152c

Cited by 12 publications

(2 citation statements)

References 61 publications

(84 reference statements)

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“…While substantial overlap between the O 2p and Co 3d states is featured below the Fermi level (see Figure S5 for the density of states of LaCoO 3 ), the La 5p states do not overlap with the O 2p states (see Figure S5), as consistently suggested in other perovskite oxides. 41,61 This directly represents considerably ionic bond characteristics of La−O, in contrast to a high degree of covalency in Co−O. Consequently, electrostatically strong repulsion should be induced between two La 3+ cations if an O 2− anion is missing, thereby leading to increment of the La−La distance for lattice stabilization.…”

Section: Resultsmentioning

confidence: 99%

Comparing the Impacts of Strain Types on Oxygen-Vacancy Formation in a Perovskite Oxide via Nanometer-Scale Strain Fields

Yoo,

Hwang,

Jang

et al. 2024

ACS Nano

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The utilization of an in-plane lattice misfit in an oxide epitaxially grown on another oxide with a different lattice parameter is a well-known approach to induce strains in oxide materials. However, achieving a sufficiently large misfit strain in this heteroepitaxial configuration is usually challenging, unless the thickness of the grown oxide is kept well below a critical value to prevent the formation of misfit dislocations at the interface for relaxation. Instead of adhering to this conventional approach, here, we employ nanometer-scale large strain fields built around misfit dislocations to examine the effects of two distinct types of strains�tension and compression�on the generation of oxygen vacancies in heteroepitaxial LaCoO 3 films. Our atomic-level observations, coupled with local electron-beam irradiation, clarify that the in-plane compression notably suppresses the creation of oxygen vacancies, whereas the formation of vacancies is facilitated under tensile strain. Demonstrating that the defect generation can considerably vary with the type of strain, our study highlights that the experimental approach adopted in this work is applicable to other oxide systems when investigating the strain effects on vacancy formation.

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Section: Resultsmentioning

confidence: 99%

Comparing the Impacts of Strain Types on Oxygen-Vacancy Formation in a Perovskite Oxide via Nanometer-Scale Strain Fields

Yoo,

Hwang,

Jang

et al. 2024

ACS Nano

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“…1j) are directly verified. A chemical map obtained by energy dispersive x-ray spectroscopy (EDS) at an atomic scale [29][30][31][32] is also provided in Supplementary Fig. 2 for confirmation.…”

Section: Observation Of Ruddlesden−popper Faultsmentioning

confidence: 99%

Atomic-scale observation of premelting at 2D lattice defects inside oxide crystals

Kim

Bae

et al. 2023

Nat Commun

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Since two major criteria for melting were proposed by Lindemann and Born in the early 1900s, many simulations and observations have been carried out to elucidate the premelting phenomena largely at the crystal surfaces and grain boundaries below the bulk melting point. Although dislocations and clusters of vacancies and interstitials were predicted as possible origins to trigger the melting, experimental direct observations demonstrating the correlation of premelting with lattice defects inside a crystal remain elusive. Using atomic-column-resolved imaging with scanning transmission electron microscopy in polycrystalline BaCeO3, here we clarify the initiation of melting at two-dimensional faults inside the crystals below the melting temperature. In particular, melting in a layer-by-layer manner rather than random nucleation at the early stage was identified as a notable finding. Emphasizing the value of direct atomistic observation, our study suggests that lattice defects inside crystals should not be overlooked as preferential nucleation sites for phase transformation including melting.

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Metal Ions versus Protons: Tracking of Charge‐Carrier Insertion into a Cathode Oxide in Aqueous Rechargeable Batteries

Lee

Hong

Kim

et al. 2023

Adv Funct Materials

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Protons in aqueous electrolytes can perform as an additional type of charge carrier for insertion/extraction in addition to the primary carrier cations in aqueous rechargeable batteries. Despite many diverse claims regarding the effect of protons, mutually conflicting experimental results and their interpretations without direct evidence have been reported over the last decade. Systematic examinations and analyses are thus imperative to clarify the conditions of proton insertion in aqueous rechargeable batteries. Utilizing V2O5 as a model cathode and beaker‐type cells with a sufficient amount of ZnSO4 aqueous electrolytes in this work, it is demonstrated that protons are inserted into the cathode prior to Zn‐ions in low‐pH conditions (pH ≤ 3.0). In stark contrast, the influence of protons on the discharge voltage and capacity is insignificant, when either the pH becomes higher (pH ≥ 4.0) or the electrolyte volume is considerably low in coin‐type cells. Similar behavior of pH‐dependent proton insertion is also verified in Na–, Mg–, and Al‐ion electrolytes. Providing a resolution to the controversy regarding proton insertion, the present study emphasizes that the influence of protons substantially varies depending on the pH and relative volume of electrolytes in aqueous batteries.

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Unveiling of interstice-occupying dopant segregation at grain boundaries in perovskite oxide dielectrics for a new class of ceramic capacitors

Abstract: We elucidate that the peculiar segregation behavior of indium have a critical contribution to achieving unprecedented dielectric properties for a new class of high-reliability ceramic capacitors.

Cited by 12 publications

References 61 publications

Comparing the Impacts of Strain Types on Oxygen-Vacancy Formation in a Perovskite Oxide via Nanometer-Scale Strain Fields

Comparing the Impacts of Strain Types on Oxygen-Vacancy Formation in a Perovskite Oxide via Nanometer-Scale Strain Fields

Atomic-scale observation of premelting at 2D lattice defects inside oxide crystals

Metal Ions versus Protons: Tracking of Charge‐Carrier Insertion into a Cathode Oxide in Aqueous Rechargeable Batteries

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