scholarly journals Ionic Conductors: Effect of Temperature on Conductivity and Mechanical Properties and Their Interrelations

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1008
Author(s):  
Masaru Aniya ◽  
Haruhito Sadakuni ◽  
Eita Hirano
Keyword(s):  
Mechanical Properties ◽  
Ionic Conduction ◽  
Effect Of Temperature ◽  
Large Temperature ◽  
Grüneisen Parameter ◽  
Ionic Conductors ◽  
Gruneisen Parameter ◽  
Crystalline Materials ◽  
Intimate Relation ◽  
Ion Conducting

The ionic transport and the mechanical properties in solids are intimately related. However, few studies have been done to elucidate the background of that relation. With the objective to fill this gap and gain further understanding on the fundamental properties of ion conducting materials, we are studying systematically the mechanical properties of different materials. In the present study, after showing briefly our previous results obtained in crystalline materials, results regarding the relation between ionic conduction and mechanical properties in superionic glasses is presented. All these results indicate the intimate relation between the mechanical and ionic conduction. The results also indicate that the Grüneisen parameter and the Anderson–Grüneisen parameter of ionic conductors exhibit large temperature dependence and increase with temperature.

TEMPERATURE EFFECT ON VIBRATIONAL PROPERTIES OF La0.7Sr0.3MnO3

2009 ◽  
Vol 23 (23) ◽  
pp. 4767-4777
Author(s):  
MINA TALATI ◽  
PRAFULLA K. JHA
Keyword(s):  
Debye Temperature ◽  
Phonon Dispersion ◽  
Effect Of Temperature ◽  
Grüneisen Parameter ◽  
Phonon Modes ◽  
Gruneisen Parameter ◽  
Anharmonic Lattice ◽  
Different Temperatures ◽  
Dynamical Method ◽  
Distinct Features

Temperature dependence of phonons spectra and allied properties of rhombohedral La 0.7 Sr 0.3 MnO 3 are investigated by using the lattice dynamical method. A tendency of phonon mode to instability causing JT lattice distortion is reflected in a softening of the stretching mode in the phonon dispersion curve of La 0.7 Sr 0.3 MnO 3 at both 1.6 and 300 K. While the A1g mode softens because of gradual decrease in MnO 6 rotations, the stretching mode hardens upon reduction in temperature. The distinct features of phonon modes at different temperatures are also reflected in the calculated phonon density of states. Other thermal properties such as specific heat, the Debye temperature, and Grüneisen parameter are also presented. The decrease in the Debye temperature at 300 K indicates the effect of temperature in lattice softening. Anomalously high value of the Grüneisen parameter points out the presence of anharmonic lattice modes.

scholarly journals New Good Ionic Conductor: Ba-Deficient Ba3Y4O9 with Zr Substitution

2020 ◽  
Author(s):  
Katsuhiro Ueno ◽  
Naoyuki Hatada ◽  
Tetsuya Uda
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Ionic Conduction ◽  
Ionic Conductor ◽  
Electronic Conduction ◽  
Ionic Conductors ◽  
Conducting Phase ◽  
Conducting Oxides ◽  
Total Electrical Conductivity ◽  
Ion Conducting ◽  
New Good

<p>To lower operating temperatures of solid oxide fuel cells (SOFCs), the development of ion-conducting oxides with high conductivity and durability is desired. In this work, we investigated Zr-substituted “Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>” as an ionic conductor at intermediate temperatures and found that the Zr substitution for Y dramatically improves the phase stability in humidified atmospheres at 300-800 °C. The total electrical conductivity of 20 mol% Zr-substituted Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub> is about 1 mS/cm at 700 °C in dry H­<sub>2</sub> and O<sub>2</sub> atmospheres and the contribution of electronic conduction (both hole and electron) is relatively small compared with Y-doped BaZrO<sub>3</sub> (BZY) and Gd-doped CeO­­<sub>2</sub> (GDC) which are typical intermediate-temperature ionic conductors. Besides, in the Zr-substituted “Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>” samples, we observed that BaO-rich amorphous phase coexists with the main phase whose composition is estimated to be Ba:(Y+Zr) ~ 2:3. Therefore, the main conducting phase might be Ba-deficient Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>. The mechanism of the ionic conduction and the improvement of chemical stability has not been revealed yet due to the lack of crystallographic information about the Ba-deficient phase. While we are now working on further investigation, we promptly report the characteristic of the new compound.</p>

scholarly journals New Good Ionic Conductor: Ba-Deficient Ba3Y4O9 with Zr Substitution

2020 ◽  
Author(s):  
Katsuhiro Ueno ◽  
Naoyuki Hatada ◽  
Tetsuya Uda
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Ionic Conduction ◽  
Ionic Conductor ◽  
Electronic Conduction ◽  
Ionic Conductors ◽  
Conducting Phase ◽  
Conducting Oxides ◽  
Total Electrical Conductivity ◽  
Ion Conducting ◽  
New Good

<p>To lower operating temperatures of solid oxide fuel cells (SOFCs), the development of ion-conducting oxides with high conductivity and durability is desired. In this work, we investigated Zr-substituted “Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>” as an ionic conductor at intermediate temperatures and found that the Zr substitution for Y dramatically improves the phase stability in humidified atmospheres at 300-800 °C. The total electrical conductivity of 20 mol% Zr-substituted Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub> is about 1 mS/cm at 700 °C in dry H­<sub>2</sub> and O<sub>2</sub> atmospheres and the contribution of electronic conduction (both hole and electron) is relatively small compared with Y-doped BaZrO<sub>3</sub> (BZY) and Gd-doped CeO­­<sub>2</sub> (GDC) which are typical intermediate-temperature ionic conductors. Besides, in the Zr-substituted “Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>” samples, we observed that BaO-rich amorphous phase coexists with the main phase whose composition is estimated to be Ba:(Y+Zr) ~ 2:3. Therefore, the main conducting phase might be Ba-deficient Ba<sub>3</sub>Y<sub>4</sub>O<sub>9</sub>. The mechanism of the ionic conduction and the improvement of chemical stability has not been revealed yet due to the lack of crystallographic information about the Ba-deficient phase. While we are now working on further investigation, we promptly report the characteristic of the new compound.</p>

A transmission electron microscopic study of structural transitions in fast ionic conductors

1987 ◽  
Vol 45 ◽  
pp. 156-157
Author(s):  
R. B. Queenan ◽  
P. K. Davies
Keyword(s):  
Optical Properties ◽  
Ionic Conduction ◽  
Recent Observation ◽  
Ionic Conductivities ◽  
Sodium Aluminate ◽  
Two Dimensions ◽  
Ionic Conductors ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Trivalent Cations

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.

On the Properties of an Ion Conductive System Incorporated in Hybrid Films

2000 ◽  
Vol 628 ◽  
Author(s):  
G. González ◽  
P. J. Retuert ◽  
S. Fuentes
Keyword(s):  
Electrochemical Impedance ◽  
Ternary Phase Diagram ◽  
Lithium Perchlorate ◽  
Molar Ratio ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Poly Ethylene Oxide ◽  
Ion Conducting ◽  
Poly Ethylene ◽  
High Degree

ABSTRACTBlending the biopolymer chitosan (CHI) with poly (aminopropilsiloxane) oligomers (pAPS), and poly (ethylene oxide) (PEO) in the presence of lithium perchlorate lead to ion conducting products whose conductivity depends on the composition of the mixture. A ternary phase diagram for mixtures containing 0.2 M LiClO4 shows a zone in which the physical properties of the products - transparent, flexible, mechanically robust films - indicate a high degree of molecular compatibilization of the components. Comparison of these films with binary CHI-pAPS nanocomposites as well as the microscopic aspect, thermal behavior, and X-ray diffraction pattern of the product with the composition PEO/CHI/pAPS/LiClO4 1:0.5:0.6:0.2 molar ratio indicates that these films may be described as a layered nanocomposite. In this composite, lithium species coordinated by PEO and pAPS should be inserted into chitosan layers. Electrochemical impedance spectroscopy measurements indicate the films are pure ionic conductors with a maximal bulk conductivity of 1.7*10-5 Scm-1 at 40 °C and a sample-electrode interface capacitance of about 1.2*10-9 F.

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

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

<p>The sodium-ion conducting family of Na<sub>3</sub><i>Pn</i>S<sub>4</sub>, with <i>Pn</i> = 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 Na<sub>3</sub><i>Pn</i>S<sub>4</sub>, the solid solutions with WS<sub>4</sub><sup>2-</sup> introduction are explored. The influence of the substitution with WS<sub>4</sub><sup>2-</sup> for PS<sub>4</sub><sup>3-</sup> and SbS<sub>4</sub><sup>3-</sup>, 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<sup>-1</sup> for Na<sub>2.9</sub>P<sub>0.9</sub>W<sub>0.1</sub>S<sub>4</sub> and 41 ± 8 mS·cm<sup>-1</sup> for Na<sub>2.9</sub>Sb<sub>0.9</sub>W<sub>0.1</sub>S<sub>4</sub> can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.</p>

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

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

<p>The sodium-ion conducting family of Na<sub>3</sub><i>Pn</i>S<sub>4</sub>, with <i>Pn</i> = 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 Na<sub>3</sub><i>Pn</i>S<sub>4</sub>, the solid solutions with WS<sub>4</sub><sup>2-</sup> introduction are explored. The influence of the substitution with WS<sub>4</sub><sup>2-</sup> for PS<sub>4</sub><sup>3-</sup> and SbS<sub>4</sub><sup>3-</sup>, 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<sup>-1</sup> for Na<sub>2.9</sub>P<sub>0.9</sub>W<sub>0.1</sub>S<sub>4</sub> and 41 ± 8 mS·cm<sup>-1</sup> for Na<sub>2.9</sub>Sb<sub>0.9</sub>W<sub>0.1</sub>S<sub>4</sub> can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.</p>

Effect of nickel on formation of transition layer during liquid-phase aluminizing of titanium

2020 ◽  
pp. 313-317
Author(s):  
A.I. Kovtunov ◽  
Yu.Yu. Khokhlov ◽  
S.V. Myamin
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Intermetallic Layer ◽  
Reaction Diffusion ◽  
Strength Properties ◽  
Effect Of Temperature ◽  
Nickel Concentration ◽  
Aluminum Melt ◽  
Titanium Aluminum ◽  
Titanium Foam

Titanium—aluminum, titanium—foam aluminum composites and bimetals obtained by liquid-phase methods, are increasingly used in industry. At the liquid-phase methods as result of the reaction diffusion of titanium and aluminum is formed transitional intermetallic layer at the phase boundary of the composite, which reduces the mechanical properties of titanium and composite. To reduce the growth rate of the intermetallic layer between the layers of the composite and increase its mechanical properties, it is proposed to alloy aluminum melt with nickel. The studies of the interaction of titanium and molten aluminum alloyed with nickel made it possible to establish the effect of temperature and aluminizing time on the thickness, chemical and phase compositions of the transition intermetallic layer. The tests showed the effect of the temperature of the aluminum melt, the nickel concentration on the strength properties of titanium—aluminum bimetal.

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