Structural and mechanical properties of sol–gel prepared pyrochlore lanthanum niobates

Bruncková, Helena; Medvecký, Ľubomír; Hvizdoš, Pavol; Durisin, Juraj; Girman, Vladimír

doi:10.1007/s10853-015-9274-8

Cited by 9 publications

(5 citation statements)

References 35 publications

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“…On the other hand, the other bands of the outer modes show almost no specific variation, a phenomenon attributed to the compensating balance between the lanthanide contraction (which tends to increase the wavenumber as the ion radius decreases) and the mass effect of these specific modes (dominated by the mass of the NbO 4 unit rather than the RE mass) . The 300–1000 cm –1 band represents the external mode, mainly related to the Nb–O vibrations in the NbO 4 unit. − The highest frequency modes in the 800–820 cm –1 are attributed to nondegenerate symmetric stretching of Nb–O vibrations (ν 1 ), while the 630–700 cm –1 range encompasses modes associated with asymmetric stretching vibrations (ν 3 ). Likewise, the symmetric bending mode (ν 2 ) manifests around 330 cm –1 , and the asymmetric bending mode (ν 4 ) emerges within the 400–500 cm –1 interval.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Sun,

Wang,

Liu

et al. 2024

ACS Appl. Mater. Interfaces

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Next-generation high-temperature applications increasingly rely heavily on advanced thermistor materials with enhanced thermal stability and electrical performance. However, thus far, the great challenge of realizing high thermal stability and precision in a wide temperature range has become a key bottleneck restricting the high-temperature application. Here, we propose a high-entropy strategy to design novel high-temperature thermistor ceramics (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)NbO4. Differences in atomic size, mass, and electronegativity in this high-entropy system cause high lattice distortion, substantial grain boundaries, and high dislocation density. These enhance the charge carrier transport and reduce the grain boundary resistance, thus synergistically broadening the temperature range. Our samples maintain high precision and thermal stability over a wide temperature range from room temperature to 1523 K (ΔT = 1250 K) with an aging value as low as 0.42% after 1000 h at 1173 K, showing breakthrough progress in high-temperature thermistor ceramics. This study establishes an effective approach to enhancing the performance of high-temperature thermistor materials through high-entropy strategies.

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Section: Resultsmentioning

confidence: 99%

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Sun,

Wang,

Liu

et al. 2024

ACS Appl. Mater. Interfaces

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“… 41 The shoulder near 1743 cm −1 is contributed by C–O stretching mode in free carboxylic group. 42 The shoulder about 2921 cm −1 may correspond to the residual organic presence. 43 …”

Section: Resultsmentioning

confidence: 99%

Lumino-structural properties of Dy³⁺ activated Na₃Ba₂LaNb₁₀O₃₀ phosphors with enhanced internal quantum yield for w-LEDs

et al. 2023

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“…La-Nb-O compounds mainly contain La 3 NbO 7 , LaNbO 4 , LaNb 3 O 9 , LaNb 5 O 14 , La 2 Nb 12 O 33 , etc. [11,12] [13][14][15]. However, among niobium oxide compounds, the NbO 4 tetrahedron is rarely found, because the large Nb 5+ atom cannot fit into the oxygen-anion tetrahedron.…”

Section: Introductionmentioning

confidence: 99%

Active La–Nb–O compounds for fast lithium-ion energy storage

2019

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Searching for novel complex materials with enhanced lithium-ion battery performances is one of the most challenging efforts. Many kinds of transition metal oxides and polyanionic frameworks were developed with various structures, which can improve the energy density of lithium-ion batteries. In this work, we explored 4d and 4f transition metal La-Nb-O compounds as cathode materials for lithium-ion energy storage. Orthorhombic pyrochlore LaNb 5 O 14 , orthorhombic perovskite LaNb 3 O 9 , and monoclinic LaNbO 4 compounds with different metal cation coordination polyhedra were synthesized using solid-state reaction. The orthorhombic pyrochlore LaNb 5 O 14 compound showed the highest capacity among these La-Nb-O compounds owing to its quasi-2D network for Li-ion incorporation. According to the electronegativity theory and ionic size, La 3+ cations can form LaO 12 polyhedra and hexahedral LaO 8 units in different La-Nb-O compounds, which can stabilize octahedral NbO 6 and/or pentahedral NbO 7 and their assembled structures, resulting in easy lithium-ion diffusion. This work may provide some structure clues for the design of electrode materials for fast lithium storage.

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Structural and mechanical properties of sol–gel prepared pyrochlore lanthanum niobates

Cited by 9 publications

References 35 publications

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Lumino-structural properties of Dy³⁺ activated Na₃Ba₂LaNb₁₀O₃₀ phosphors with enhanced internal quantum yield for w-LEDs

Active La–Nb–O compounds for fast lithium-ion energy storage

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Structural and mechanical properties of sol–gel prepared pyrochlore lanthanum niobates

Cited by 9 publications

References 35 publications

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)NbO4 Ceramics

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)NbO4 Ceramics

Lumino-structural properties of Dy3+ activated Na3Ba2LaNb10O30 phosphors with enhanced internal quantum yield for w-LEDs

Active La–Nb–O compounds for fast lithium-ion energy storage

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Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Enhanced Thermal Stability and Broad Temperature Range in High-Entropy (La_0.2Ce_0.2Nd_0.2Sm_0.2Eu_0.2)NbO₄ Ceramics

Lumino-structural properties of Dy³⁺ activated Na₃Ba₂LaNb₁₀O₃₀ phosphors with enhanced internal quantum yield for w-LEDs