Structure and properties of layered perovskites Ba1-Ln Fe1-Co O3-δ (Ln = Pr, Sm, Gd)

Volkova, N.E.; Mychinko, Mikhail; Golovachev, I. B.; Макарова, А. Э.; Bazueva, M.V.; Zyaikin, E.I.; Gavrilova, L. Ya.; Черепанов, В.А.

doi:10.1016/j.jallcom.2018.12.391

Cited by 17 publications

(26 citation statements)

References 18 publications

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“…These domains adopt the tetragonal structure which forms due to the ordering of Nd and Ba cation along c ‐axis in the quite regular sequence “Nd–Ba–(Nd,Ba)–(Nd,Ba)–Ba–Nd”, where pure Ba and pure Nd layers alternate with mixed (Nd,Ba) layers. This type of superstructure, first found in SmFeO 3‐ δ –BaFeO 3‐ δ system and presented by formula Sm 2‐ ε Ba 3+ ε Fe 5 O 15‐ δ , 53 is very sensitive to a number of factors, such as size difference and ratio of A‐site cations (Ln/Ba), cobalt substitution in B‐site sublattice, oxygen content 53–56 . In contrast to Sm‐based system where deviation from the ideal ratio of A‐site cations ( ε = 0.125) is necessary for the formation of quintuple structure, Nd‐enriched oxide (in regards to ideal Nd 2 Ba 3 Fe 5 O 15‐ δ composition) Nd 0.3 Ba 0.7 FeO 3‐ δ is completely disordered 52,55 .…”

Section: Resultsmentioning

confidence: 96%

“…This results from the smaller size difference between Pr and Ba ions. It was shown earlier that XRD could not detect the formation of a p × a p × 5 a p superstructure due to nanoscale twinning of crystallites in orthogonal directions 53–56 …”

Section: Resultsmentioning

confidence: 99%

“…52,55 With the larger Pr no layered superstructure is formed but only disordered perovskites, no matter what Ln/Ba ratio was. 55,56 This results from the smaller size difference between Pr and Ba ions. It was shown earlier that XRD could not detect the formation of a p × a p × 5a p superstructure due to nanoscale twinning of crystallites in orthogonal directions.…”

Section: Ndfeo 3 -Bafeo 3-δ Cross-sectionmentioning

confidence: 99%

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Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

et al. 2022

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The phase equilibria in the ½Nd 2 O 3 -BaO-½Fe 2 O 3 system were systematically studied at 1373 K in air and presented in the form of a phase diagram. By X-ray diffraction (XRD) analysis of quenched samples, the homogeneity ranges and crystal structure were determined for the following intermediate oxides: Nd 1-x Ba x FeO 3-δ with 0.0 ≤ x ≤ 0.05 (space group (SG) Pnma) and with 0.6 ≤ x ≤ 0.7 (SG Pm-3m), Ba 6+y Nd 2-y Fe 4 O 15-δ with 0.0 ≤ y ≤ 0.4 (SG P6 3 mc), and Ba 1.1 Nd 1.9 Fe 2 O 7-δ (SG P4 2 /mnm). The structural parameters of single-phase oxides were refined by the Rietveld method. The changes in oxygen content for Nd 1-x Ba x FeO 3-δ (0.6 ≤ x ≤ 0.7), Ba 6 Nd 2 Fe 4 O 15-δ , and Ba 1.1 Nd 1.9 Fe 2 O 7-δ versus temperature in air were determined by thermogravimetric analysis. Gradual substitution of neodymium by barium in the Nd 1-x Ba x FeO 3-δ (0.6 ≤ x ≤ 0.7) oxides leads to a decrease of oxygen content. Partial ordering via formation of separate domains with a p × a p × 5a p superstructure in Nd 0.4 Ba 0.6 FeO 3-δ , which cannot be detected by XRD, noticeably influence its thermal expansion and electrical conductivity.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Ndfeo 3 -Bafeo 3-δ Cross-sectionmentioning

confidence: 99%

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Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

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“…LSCF is an often-used cathode material for comparison in papers reporting new cathode materials working in the IT range. Recently, layered double perovskites are intensively studied due to excellent ORR kinetics [3,4]. Although many new cathode materials have been developed [2,[5][6][7][8][9], improvement of physicochemical properties and electrochemical performance of the LSM material remains an urgent task.…”

Section: Introductionmentioning

confidence: 99%

“…O ads + 2e − + V .. O = O x O (2) m = 0.375, the one electron charge transfer process. O ads + e − = O − ads (3) m = 0.5, dissociation of adsorbed oxygen molecule.O 2,ads = 2O ad(4)…”

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confidence: 99%

Improvement of La0.8Sr0.2MnO3−δ Cathode Material for Solid Oxide Fuel Cells by Addition of YFe0.5Co0.5O3

et al. 2022

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The high efficiency of solid oxide fuel cells with La0.8Sr0.2MnO3−δ (LSM) cathodes working in the range of 800–1000 °C, rapidly decreases below 800 °C. The goal of this study is to improve the properties of LSM cathodes working in the range of 500–800 °C by the addition of YFe0.5Co0.5O3 (YFC). Monophasic YFC is synthesized and sintered at 950 °C. Composite cathodes are prepared on Ce0.8Sm0.2O1.9 electrolyte disks using pastes containing YFC and LSM powders mixed in 0:1, 1:19, and 1:1 weight ratios denoted LSM, LSM1, and LSM1, respectively. X-ray diffraction patterns of tested composites reveal the presence of pure perovskite phases in samples sintered at 950 °C and the presence of Sr4Fe4O11, YMnO3, and La0.775Sr0.225MnO3.047 phases in samples sintered at 1100 °C. Electrochemical impedance spectroscopy reveals that polarization resistance increases from LSM1, by LSM, to LSM2. Differences in polarization resistance increase with decreasing operating temperatures because activation energy rises in the same order and equals to 1.33, 1.34, and 1.58 eV for LSM1, LSM, and LSM2, respectively. The lower polarization resistance of LSM1 electrodes is caused by the lower resistance associated with the charge transfer process.

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Synthesis, structure, oxygen content and properties of layered Dy_1.2Ba_1.8Fe_1.8Co_1.2O_8‐δ

Bastron,

Volkova,

Suntsov

et al. 2023

Zeitschrift anorg allge chemie

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It is shown that an excess of Dy in A‐site (in amount of 0.2 in formula units) allows synthesizing a single‐phase perovskite‐related oxide with the 123‐type structure at 1100 °C in air. Cobalt ions completely fill the octahedrally coordinated positions in the structure of 123‐type Dy1.2Ba1.8Fe1.8Co1.2O8‐δ, while iron together with excess Co is in the pyramidal oxygen coordination. The oxygen content at room temperature of 7.86 decreases with temperature. A slight increase in the slope of thermal expansion observed at T >200 °C. The electrical conductivity, carried out mainly by holes, increases non‐linearly with temperature, reaching a maximum value 14.8 S ⋅ cm−1 at 900 °C. Magnetic measurements allow assuming that Fe3+ are in low spin state, all Co2+ ions are in high spin, and Co3+ can be split into several states depending on coordination.

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Structure and properties of layered perovskites Ba1-Ln Fe1-Co O3-δ (Ln = Pr, Sm, Gd)

Cited by 17 publications

References 18 publications

Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

Improvement of La0.8Sr0.2MnO3−δ Cathode Material for Solid Oxide Fuel Cells by Addition of YFe0.5Co0.5O3

Synthesis, structure, oxygen content and properties of layered Dy_1.2Ba_1.8Fe_1.8Co_1.2O_8‐δ

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Structure and properties of layered perovskites Ba1-Ln Fe1-Co O3-δ (Ln = Pr, Sm, Gd)

Cited by 17 publications

References 18 publications

Phase equilibria in the Nd2O3–BaO–Fe2O3 system: Crystal structure, oxygen content, and properties of intermediate oxides

Phase equilibria in the Nd2O3–BaO–Fe2O3 system: Crystal structure, oxygen content, and properties of intermediate oxides

Improvement of La0.8Sr0.2MnO3−δ Cathode Material for Solid Oxide Fuel Cells by Addition of YFe0.5Co0.5O3

Synthesis, structure, oxygen content and properties of layered Dy1.2Ba1.8Fe1.8Co1.2O8‐δ

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Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

Phase equilibria in the Nd₂O₃–BaO–Fe₂O₃ system: Crystal structure, oxygen content, and properties of intermediate oxides

Synthesis, structure, oxygen content and properties of layered Dy_1.2Ba_1.8Fe_1.8Co_1.2O_8‐δ