(β-NaFeO2)1−x(SiO2, GeO2)x solid solutions: A study by X-ray diffraction, IR spectroscopy, and ionic conductivity measurements

AbstractWe have synthesized Gd-doped ceria polycrystalline samples (5, 10, 15 %mol), having relative densities exceeding 95% and grain sizes between 30 and 160 nm after axial hot pressing (750 °C, 250 MPa). The samples were prepared by sintering nanopowders obtained by sol-gel chemistry methods having a very narrow size distribution centered at about 16 nm. SEM and X-ray diffraction were performed to characterize the sample microstructures and to assess their structures. We report ionic conductivity measurements using impedance spectroscopy. It is important to investigate the properties of these systems with sub-micrometric grains and as a function of their composition. Therefore, samples having micrometric and nanometric grain sizes (and different Gd content) were studied. Evidence of Gd segregation near the grain boundaries is given and the impact on the ionic conductivity, as a function of the grain size and Gd composition, is discussed and compared to microcrystalline samples.

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Ion-exchange properties of solid solutions based on hydrated forms of monovalent metals antimonate-tungstates

Butlerov Communications ◽

10.37952/roi-jbc-01/20-62-6-74 ◽

2020 ◽

Vol 62 (6) ◽

pp. 74-79

Author(s):

Olga A. Firsova ◽

◽

Elena M. Filonenko ◽

Yulia A. Lupitskaya ◽

Hurshid N. Bozorov ◽

...

Keyword(s):

Ir Spectroscopy ◽

Ion Exchange ◽

Solid Solutions ◽

Rietveld Method ◽

Type Structure ◽

Water Molecules ◽

X Ray Diffraction ◽

X Ray ◽

Pyrochlore Type ◽

Exchange Properties

The research of tungsten-antimony crystalline acid (TACA) structural transformations in the condition of ion-exchange and thermolysis of its substituted M+, H+-forms (M+ – Li, Na, K, Ag) were conducted. The data of thermogravimetric and qualitative X-ray phase analyses made it possible to conclude that the thermolysis of TACA and its derivatives proceeds in a wide temperature range from 300 to 1150 K being accompanied by the removal of crystalline water molecules with the formation of phases mixture containing complex antimony oxides of the ( -,  - Sb2O4) modification and WO3. It was shown that compounds based on hydrated forms of monovalent metal antimonates-tungstates are stable up to 1023 K with a pyrochlore-type structure. For pyrochlore-like phases, a monotonic dependence of unit cell parameter a on ion-exchange degree α and the ionic radius of metals r was revealed indicating the formation of solid solutions Мх(Н3О)1–хWSbO6 nН2О (M+ – Li, Na, K, Ag; 0.0≤х<1.0; 0.0≤n<2.0) with a limited range of solubility from the crystal chemistry point of view. Within the framework of the Fd-3m space group, based on the data of X-ray diffraction analysis (Rietveld method), the structural characteristics of TACA and its substituted M+, H+-forms were refined, and a model for populating the corresponding metal ions by crystallographic positions of the pyrochlore-type structure was proposed. Using a complex of physicochemical methods (thermogravimetric, X-ray diffraction analyses and IR spectroscopy), a correlation between the composition of the obtained compounds, structural disorder, and ion-exchange properties were determined. According to the data of thermogravimetry and IR spectroscopy, it follows that the degree of compounds hydration analyzed depends on the nature of the alkaline ion. This allows to conclude that lithium and sodium ions are located in 16d– positions, dragging neutral water molecules into the structure occupying 8b-positions. In this case, potassium ions can partially occupy both 16d- and 8b-positions of the structure.

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ChemInform Abstract: New Arsenates M(I)3Sc2(AsO4)3 (M(I): K or Rb): Synthesis and Study by X-Ray Diffraction, Vibrational Spectroscopy, and Ionic Conductivity Measurements.

ChemInform ◽

10.1002/chin.198910032 ◽

1989 ◽

Vol 20 (10) ◽

Author(s):

J.-M. WINAND ◽

P. TARTE

Keyword(s):

Ionic Conductivity ◽

Vibrational Spectroscopy ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

X Ray

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X-ray diffraction study on the distribution of lithium ions in ? spinel solid solutions

Solid State Ionics ◽

10.1016/s0167-2738(97)00156-2 ◽

1997 ◽

Vol 101-103 (1-2) ◽

pp. 527-531 ◽

Cited By ~ 1

Author(s):

E Wolska

Keyword(s):

Diffraction Study ◽

Solid Solutions ◽

X Ray Diffraction ◽

Lithium Ions ◽

X Ray ◽

Spinel Solid Solutions

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IR SPECTROSCOPY AND SINGLE CRYSTAL X-RAY DIFFRACTION STUDY OF 1,2-BIS(2-AMINOPHENOXY)-ETHANE, 1,5-BIS(2-AMINOPHENOXY)-3-OXAPENTANE, AND 1,8-BIS(2-AMINOPHENOXY)-3,6-DIOXAOCTANE

Журнал структурной химии ◽

10.15372/jsc20170106 ◽

2017 ◽

Keyword(s):

Ir Spectroscopy ◽

Single Crystal ◽

Diffraction Study ◽

X Ray Diffraction ◽

X Ray

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v2 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v1 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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Changing the Static and Dynamic Lattice Effects for the Improvement of the Ionic Transport Properties Within the Argyrodite Li6PS5-xSexI

10.26434/chemrxiv.9807770.v1 ◽

2019 ◽

Author(s):

Roman Schlem ◽

Michael Ghidiu ◽

Sean Culver ◽

Anna-Lena Hansen ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Activation Barrier ◽

Parent Compound ◽

Ionic Transport ◽

X Ray Diffraction ◽

X Ray ◽

Lattice Effects ◽

Solid State Batteries ◽

All Solid State Batteries ◽

Pulse Echo

The lithium argyrodites Li6PS5X (X = Cl, Br, I) have been gaining momentum as candidates for electrolytes in all-solid-state batteries. While these materials have been well-characterized structurally, the influences of the static and dynamic lattice properties are not fully understood. Recent improvements to the ionic conductivity of Li6PS5I (which as a parent compound is a poor ionic conductor) via elemental substitutions have shown that a multitude of influences affect the ionic transport in the lithium argyrodites, and that even poor conductors in this class have room left for improvement.Here we explore the influence of isoelectronic substitution of sulfur with selenium in Li6PS5-xSexI. Using a combination of X-ray diffraction, impedance spectroscopy, Raman spectroscopy, and pulse-echo speed of sound measurements,we explore the influence of the static and dynamic lattice on the ionic transport. The substitution of S2-with Se2- broadens the diffusion pathways and structural bottlenecks, as well as leading to a softer more polarizable lattice, all of which lower the activation barrier and lead to an increase in the ionic conductivity. This work sheds light on ways to systematically understand and improve the functional properties of this exciting material family.

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Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

Engineering and Technology Journal ◽

10.30684/etj.v38i4a.351 ◽

2020 ◽

Vol 38 (4A) ◽

pp. 491-500

Author(s):

Abeer F. Al-Attar ◽

Saad B. H. Farid ◽

Fadhil A. Hashim

Keyword(s):

Ionic Conductivity ◽

Electrochemical Impedance ◽

Structural Information ◽

Impedance Analysis ◽

High Energy ◽

Yttria Stabilized Zirconia ◽

X Ray Diffraction ◽

Stabilized Zirconia ◽

Powder Morphology ◽

X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

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X- ray diffraction and dielectric properties of PbSe thin films

Iraqi Journal of Physics (IJP) ◽

10.30723/ijp.v15i34.115 ◽

2019 ◽

Vol 15 (34) ◽

pp. 1-14

Author(s):

Bushra A. Hasan

Keyword(s):

Thin Films ◽

Thermal Activation ◽

Thermal Evaporation ◽

Thermal Activation Energy ◽

Dielectric Constants ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

Thermal Evaporation Method ◽

X Ray ◽

Glass Substrates

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.

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