scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Cr-=SUB=-2-=/SUB=-(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2018 ◽  
Vol 60 (1) ◽  
pp. 25
Author(s):  
А.С. Ногай ◽  
С.Ю. Стефанович ◽  
А.А. Буш ◽  
Д.Е. Ускенбаев ◽  
А.А. Ногай
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Phase Transformations ◽  
Structural Changes ◽  
High Ionic Conductivity ◽  
Relaxation Polarization ◽  
Dipole Ordering

AbstractThe aspects of structure, dipole ordering, and ionic conductivity of the Na_3Cr_2(PO_4)_3 crystal with the four polymorphic phases (α, α', β, and γ) have been investigated. The features of the α-Na_3Cr_2(PO_4)_3 crystal structure and its dipole ordering and relaxation polarization in the low-temperature α and α' phases have been refined. The occurrence of Na_3Cr_2(PO_4)_3 dipole ordering in the α and α' phases and high ionic conductivity in the β and γ phases is attributed to the structural changes in the rhombohedral [ Me _2(PO_4)_3]^–3_3∞ crystal frame upon phase transformations α → α', α' → β, and β → γ. A model for explaining the dipole ordering and ionic conductivity phenomena in Na_3Cr_2(PO_4)_3 is proposed.

scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Sc-=SUB=-2-=/SUB=-(PO_4)-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (11) ◽  
pp. 2016
Author(s):  
А.С. Ногай ◽  
А.А. Ногай ◽  
С.Ю. Стефанович ◽  
Ж.М. Солиходжа ◽  
Д.Е. Ускенбаев
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Phase Transformations ◽  
Structural Changes ◽  
High Ionic Conductivity ◽  
Α Phase ◽  
Relaxation Polarization ◽  
Dipole Ordering

AbstractProblems of the dipole ordering and ionic conductivity of Na_3Sc_2(PO_4)_3 polycrystal that has three polymorphic phases—α, β, and γ—are studied. The features of the α-Na_3Sc_2(PO_4)_3 crystal structure and the dipole ordering and relaxation polarization in the α and β phases are specified. The origin of the dipole ordering in the α phase and the partial dipole disordering in the β-Na_3Sc_2(PO_4)_3, as well as the high ionic conductivity in the β and γ phases of the Na_3Sc_2(PO_4)_3 polycrystal are associated with phase transformations α → β, β → γ that result in structural changes of the rhombohedral {[Sc_2(PO_4)_3]^3–}_3∞ crystalline framework. A model explaining the emergence of the dipole ordering and the ionic conductivity phenomena in Na_3Sc_2(PO_4) is proposed.

scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Fe-=SUB=-2-=/SUB=-(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2020 ◽  
Vol 62 (8) ◽  
pp. 1216
Author(s):  
А.С. Ногай ◽  
А.А. Ногай ◽  
С.Ю. Стефанович ◽  
Ж.М. Солиходжа ◽  
Д.Е. Ускенбаев
Keyword(s):  
Phase Transitions ◽  
Ionic Conductivity ◽  
Single Crystals ◽  
Hot Pressing ◽  
Structural Changes ◽  
Structural Features ◽  
Polymorphic Transformations ◽  
Relaxation Polarization ◽  
Dipole Ordering

Abstract The problems of the structural features, the dielectric and conducting properties of Na_3Fe_2(PO_4)_3 polycrystals prepared by hot pressing have been studied. The Na_3Fe_2(PO_4)_3 polycrystals in the α and β phases are shown to have higher conducting properties than the α and β phases of the single crystals grown by the solution–melt method. The regularities of the appearance of the dipole ordering, the ionic and superionic conductivities related to phase transitions and structural changes in the {[Fe_2(PO_4)_3]^3–}_3∞ rhombohedral crystalline frame during polymorphic transformations are refined. The problems of the relaxation polarization in the α and β phases of Na_3Fe_2(PO_4)_3 are discussed. A model for explaining the dipole ordering and the ionic conductivity in Na_3Fe_2(PO_4)_3 is proposed.

scholarly journals Crystal structure, magneto-structural correlation, thermal and electrical studies of an imidazolium halometallate molten salt: (trimim)[FeCl4]

RSC Advances ◽  
2020 ◽  
Vol 10 (19) ◽  
pp. 11200-11209 ◽  
Author(s):  
Palmerina González-Izquierdo ◽  
Oscar Fabelo ◽  
Garikoitz Beobide ◽  
Israel Cano ◽  
Idoia Ruiz de Larramendi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Neutron Diffraction ◽  
Molten Salt ◽  
Magnetic Structure ◽  
Imidazolium Cation ◽  
X Ray ◽  
Electrical Studies ◽  
Structural Correlation

We present a novel halometallate molten salt based on imidazolium cation with two structural transitions from 100 to 400 K which has been studied by X-ray and neutron diffraction techniques. Furthermore, the magnetic structure at low temperature and the ionic conductivity is also described.

Investigation of the Cs x Rb1−x TiOAsO4 Series. I. Crystal Structure Analysis and Pseudo-symmetry

1998 ◽  
Vol 54 (5) ◽  
pp. 635-644 ◽  
Author(s):  
M. N. Womersley ◽  
P. A. Thomas ◽  
D. L. Corker
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Low Temperature ◽  
Room Temperature ◽  
Structural Changes ◽  
Crystal Structure Analysis ◽  
Orthorhombic Space Group ◽  
Acta Cryst ◽  
Space Group ◽  
Structural Framework

Refinements of five crystals in the Cs2x Rb2−2x Ti2O2As2O8 series, caesium rubidium titanyl arsenate, with x = 0.07, 0.31, 0.58, 0.71 and 0.86, which are compositional analogues of KTiOPO4 (KTP), have been completed at 293 K and two (x = 0.71, 0.86) at low temperature. All the structures are found to be orthorhombic (space group Pna21) and are isostructural with KTP, although there is evidence of some Cs disorder over additional sites in the framework, particularly at the Cs-rich end of the series, as discussed in Part II [Thomas & Womersley (1998). Acta Cryst. B54, 645–651]. Unusually large U 33 parameters for shared Cs/Rb sites are observed and are shown to be the result of the existence of separate sites for Cs and Rb within the structural framework, although the coordinates of these sites cannot be resolved convincingly. The structural changes in the TiO6/AsO4 framework required to accommodate an increasing fraction of the larger Cs cation across the series and under cooling to 120 K are elucidated. Finally, the deviations of the room-temperature and low-temperature structures from the high-temperature prototypic structure (space group Pnan) are examined and suggest that the phase-transition temperature should increase linearly from CsTiOAsO4 to RbTiOAsO4.

High ionic conductivity dysprosium and tantalum Co-doped bismuth oxide electrolyte for low-temperature SOFCs

Ionics ◽  
2020 ◽  
Vol 26 (9) ◽  
pp. 4579-4586 ◽  
Author(s):  
P. S. Cardenas-Terrazas ◽  
M. T. Ayala-Ayala ◽  
J. Muñoz-Saldaña ◽  
A. F. Fuentes ◽  
D. A. Leal-Chavez ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Low Temperature ◽  
Bismuth Oxide ◽  
High Ionic Conductivity ◽  
Oxide Electrolyte ◽  
Co Doped

scholarly journals High Performance Low-Temperature Solid Oxide Fuel Cells Based on Nanostructured Ceria-Based Electrolyte

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2231
Author(s):  
Jiamei Liu ◽  
Chengjun Zhu ◽  
Decai Zhu ◽  
Xin Jia ◽  
Yingbo Zhang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Nanocrystalline Structure ◽  
Solid Oxide ◽  
High Ionic Conductivity ◽  
Oxide Fuel ◽  
Pure Ceo2 ◽  
Co Doped

Ceria based electrolyte materials have shown potential application in low temperature solid oxide fuel cells (LT-SOFCs). In this paper, Sm3+ and Nd3+ co-doped CeO2 (SNDC) and pure CeO2 are synthesized via glycine-nitrate process (GNP) and the electro-chemical properties of the nanocrystalline structure electrolyte are investigated using complementary techniques. The result shows that Sm3+ and Nd3+ have been successfully doped into CeO2 lattice, and has the same cubic fluorite structure before, and after, doping. Sm3+ and Nd3+ co-doped causes the lattice distortion of CeO2 and generates more oxygen vacancies, which results in high ionic conductivity. The fuel cells with the nanocrystalline structure SNDC and CeO2 electrolytes have exhibited excellent electrochemical performances. At 450, 500 and 550 °C, the fuel cell for SNDC can achieve an extraordinary peak power densities of 406.25, 634.38, and 1070.31 mW·cm−2, which is, on average, about 1.26 times higher than those (309.38, 562.50 and 804.69 mW·cm−2) for pure CeO2 electrolyte. The outstanding performance of SNDC cell is closely related to the high ionic conductivity of SNDC electrolyte. Moreover, the encouraging findings suggest that the SNDC can be as potential candidate in LT-SOFCs application.

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