The Effect of the Multi-doping Strategy on Stabilization of the Cubic δ-phase in the Bi2O3-based Solid Electrolyte Systems in Terms of the SOFC Applications

Abstract In this study, the effects of multi-doping strategy on phase stabilization and electrical conductivity for the doped Bi 2 O 3 system were investigated. All solid mixtures were created by solid state reactions according to a certain stoichiometric ratio in atmospheric conditions. The structural, electrical, thermal and surface characterizations of the created samples were performed by x-ray diffraction method (XRD), four point-probe technique (4-PPT), differential thermal analysis/thermo gravimetric analysis (DTA/TGA) and scanning electron microscope (SEM), respectively. From XRD results, it was seen that the fcc δ-phase could be stabilized by using only 1:1:1:2 or 2:2:2:1 dopant content ratio (in here, “1:” is corresponds to” 5%” mole). The other compounds prepared out of this ratios were mixed phase because of the containing both α-phase peaks and δ-phase peaks on their XRD pattern. When the all samples were compared in terms of electrical conductivity at 750 °C, it was observed that the fcc δ-phase stabilized samples exhibited higher conductivity than that of other compounds as expected. The highest electrical conductivity was for the sample, dopant content ratios of which are 1: 1: 1: 2, with 0.014 S.cm -1 at 750 °C and also it had the lowest activation energy (0.51 eV) among all samples. On the other hand, according to the thermal analysis results, it was concluded that phase transition occurred only on the DTA curve of the sample given with dopant content ratios 1:1:1:1 due to presence of endothermic peak on its DTA curve at 729°C during the heating process. Also, for this sample, it was clearly predicted from the electrical conductivity graphs depending on temperature that the phase transition occurred at just that temperature (729 °C) due to the sudden increase in conductivity by indicating phase transition from the α-phase to the cubic δ-phase. The SEM analysis pointed out that grain size decreased as total dopant ratio increased and also the grain boundary changed sharply with the increase in the total dopant ratio.

Download Full-text

Composition-induced phase transition in a [Ag2HgI4:0.2AgI] mixed composite system doped with CuI

Open Chemistry ◽

10.2478/s11532-010-0098-8 ◽

2010 ◽

Vol 8 (6) ◽

pp. 1227-1235 ◽

Cited By ~ 3

Author(s):

◽

Afaq Ahmad

Keyword(s):

Phase Transition ◽

Composite System ◽

Thermo Gravimetric Analysis ◽

Mixed System ◽

Gravimetric Analysis ◽

Scanning Calorimetry ◽

Thermo Gravimetric ◽

Thermally Activated ◽

Α Phase ◽

Superionic System

AbstractA novel composite superionic system, [Ag2HgI4:0.2AgI]:xCuI, (x = 0.2, 0.4, 0.6 mol. wt.%), was prepared and [Ag2HgI4:0.2AgI] mixed system was used as the host. Electrical conductivity was measured to study the transition behavior at frequencies of 100 Hz, 120 Hz, 1 kHz, and 10 kHz in the temperature range 90°–170°C by a Gen Rad 1659 RLC Digibridge. Sharp increase in conductivity was observed for β-α phase transitions. As a result of increase in the dopant-to-host ratio, the conductivity of the system exhibited Arrhenius (thermally activated)-type behavior. X-ray powder diffraction, differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) studies confirmed the doping effect on the transition in the host, the phase transition temperature increased with an increase in the dopant concentration. Activation energies for the system in eV both for the pretransition and post-transition phase transformations are reported. The addition of CuI to [Ag2HgI4:0.2AgI] shifted the phase transition of the host [Ag2HgI4:0.2AgI], due to an interaction between [Ag2HgI4:0.2AgI] and CuI.

Download Full-text

Comparative study of polymorphic phase transition by differential thermal analysis, high temperature x-ray diffraction and temperature programmed electrical conductivity measurements: case study of mixed iron and cobalt molybdate

The Journal of Physical Chemistry ◽

10.1021/j100202a073 ◽

1992 ◽

Vol 96 (23) ◽

pp. 9466-9469 ◽

Cited By ~ 3

Author(s):

H. Ponceblanc ◽

J. M. M. Millet ◽

G. Thomas ◽

J. M. Herrmann ◽

J. C. Vedrine

Keyword(s):

Phase Transition ◽

Thermal Analysis ◽

Electrical Conductivity ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

Polymorphic Phase Transition ◽

X Ray ◽

Cobalt Molybdate ◽

Temperature Programmed

Download Full-text

Phase Behavior of La1-xMnO3-1.5x with Trivalent Manganese Ion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.741 ◽

2004 ◽

Vol 449-452 ◽

pp. 741-744 ◽

Cited By ~ 2

Author(s):

M. Kobayashi ◽

Hirohisa Sato ◽

Naoki Kamegashira

Keyword(s):

Phase Transition ◽

Thermal Analysis ◽

Electrical Conductivity ◽

High Temperature ◽

Thermal Diffusivity ◽

Room Temperature ◽

Orthorhombic Phase ◽

Ceramic Method ◽

X Ray ◽

Manganese Ion

Defect perovskite, La1-xMnO3-1.5x (x=0.00-0.10), was synthesized by conventional ceramic method and phase transition was measured by X-ray diffractometry, electrical conductivity, thermal diffusivity and thermal analysis. La1-xMnO3-1.5x (x=0.00-0.09) have single orthorhombic phase corresponding to GdFeO3 type perovskite structure at room temperature, while have rhombohedral structural at high temperature. The transition temperatures observed from electric conductivity, DSC, thermal diffusivity were mostly in agreement and they slightly decrease with increasing x.

Download Full-text

Electrical conductivity of the ionic conductor tetragonal (Bi2O3)1-x(Eu2O3)x

Cerâmica ◽

10.1590/s0366-69132011000200009 ◽

2011 ◽

Vol 57 (342) ◽

pp. 185-192 ◽

Cited By ~ 22

Author(s):

S. Yilmaz ◽

O. Turkoglu ◽

M. Ari ◽

I. Belenli

Keyword(s):

Phase Transition ◽

Thermal Analysis ◽

Electrical Conductivity ◽

Differential Thermal Analysis ◽

Doping Concentration ◽

Binary Systems ◽

Ionic Conductor ◽

Probe Technique ◽

Β Phase ◽

Concentration Dependences

Electrical conductivity of tetragonal β-phase (Bi2O3)1-x(Eu2O3)x (0.01 ≤ x ≤ 0.10 %mol) ceramic systems were investigated. The temperature and doping concentration dependences of the electrical conductivity were studied by four-point probe technique. The electrical conductivity increases with the increasing doping concentration and temperature. The highest value of the electrical conductivity is 0.013 Ω-1cm-1 (x = 0.05, 750 ºC) for the β-phase at 670 ºC and 0.57 Ω-1cm-1 (x=0.05, 800 ºC) in binary systems at 690 ºC. The phase transition which manifests itself by the jump in the conductivity curves was seen and verified by differential thermal analysis measurements. The activation energies of the samples were found to be about 0.71-1.57 eV.

Download Full-text

Effect of CdI2 on electrical conductivity and phase transition behavior in AgI

Canadian Journal of Chemistry ◽

10.1139/v81-386 ◽

1981 ◽

Vol 59 (18) ◽

pp. 2685-2688 ◽

Cited By ~ 8

Author(s):

Mahadeva Natarajan ◽

Etalo A. Secco

Keyword(s):

Phase Transition ◽

Thermal Analysis ◽

Electrical Conductivity ◽

Differential Thermal Analysis ◽

Phase Transitions ◽

Phase Transition Behavior ◽

Polymorphic Behavior ◽

X Ray ◽

Transition Behavior ◽

Low Concentrations

The phase transitions occurring in AgI containing dissolved CdI2 have been examined by differential thermal analysis (DTA), electrical conductivity technique, and X-ray diffractometry. The electrical conductivity and polymorphic behavior of AgI is significantly modified by low concentrations of CdI2. The results are interpreted in terms of substitutional Cd2+ and Ag+ vacancies in AgI sublattice.

Download Full-text

127I-NQR, 119 Sn Mössbauer Effect, and Electrical Conductivity of MSnI3 (M = K, NH4 , Rb, Cs, and CH3NH3 )

Zeitschrift für Naturforschung A ◽

10.1515/zna-1990-3-416 ◽

1990 ◽

Vol 45 (3-4) ◽

pp. 307-312 ◽

Cited By ~ 13

Author(s):

Koji Yamada ◽

Takashi Matsui ◽

Tomoko Tsuritani ◽

Tsutomu Okuda ◽

Sumio Ichiba

Keyword(s):

Phase Transition ◽

Electrical Conductivity ◽

Structural Change ◽

Mössbauer Effect ◽

The Other ◽

X Ray Diffraction ◽

Mossbauer Effect ◽

X Ray ◽

Regular Octahedron ◽

Other Hand

Abstract In a series of MSnI3 compounds (M = K, NH4 , Rb, Cs, CH3NH3) two types of coordination around the central Sn(II) were found by 127I-NQR and powder X-ray diffraction techniques. They are square pyramidal (for M = NH4 , Rb) and octahedral (for M = CH3NH3). CsSnI3 , on the other hand, showed a drastic structural change of the anion at 425 K from a square pyramid to a regular octahedron. Associated with this phase transition, the electrical conductivity increased from 4 x 10-3 S cm-1 to about 102 S cm-1 . This metallic modification was characterized by 127I-NQR and 119Sn Mössbauer spectroscopy.

Download Full-text

SCENARIOS FOR AN EXPANDING DEMAND OF TOURISM ON THE COASTS OF CUBA

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.21610/conferencearticle_58b43153a41e9 ◽

2017 ◽

Author(s):

Oscar Gutiérrez-Bolívar ◽

Pedro Fernández Carrasco ◽

Pedro Fernández Carrasco

Keyword(s):

United States ◽

The Other ◽

Sudden Increase ◽

Tourist Destination ◽

Other Hand ◽

The Usa ◽

The Impact

The opening of relationships between United States and Cuba could be a drive for a huge increase in the affluence of tourism to Cuba and especially to the coast areas. Cuba has been for many years an important tourist destination for people from many countries, but almost forbidden for US citizens. The proximity of the USA, its amount of population as well as their great acquisition power will increase in a very substantial way the demand for accommodation and other uses in the proximity of the coasts. There will be a need to implement a package of measures that reduce the impact of such sudden increase in the coastal line. On the other hand that augment in tourism could be an opportunity to improve the standard of life of Cubans. The consideration of different possibilities of such development, the analysis of the damages that each one could cause as well as the measures that could avoid, ameliorate or compensate such effects are the goals that are going to be presented in this paper.

Download Full-text

A model calculation for the α-α' phase transition in metal-hydrogen systems

Journal of Physics C Solid State Physics ◽

10.1088/0022-3719/7/18/014 ◽

1974 ◽

Vol 7 (18) ◽

pp. 3305-3325 ◽

Cited By ~ 138

Author(s):

H Horner ◽

H Wagner

Keyword(s):

Phase Transition ◽

Model Calculation ◽

Α Phase ◽

Hydrogen Systems

Download Full-text

Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽

10.3390/cryst11070746 ◽

2021 ◽

Vol 11 (7) ◽

pp. 746

Author(s):

Meiling Hong ◽

Lidong Dai ◽

Haiying Hu ◽

Xinyu Zhang

Keyword(s):

Phase Transition ◽

Electrical Conductivity ◽

High Pressure ◽

Phase Transformation ◽

Transport Properties ◽

Electrical Transport ◽

Structural Phase ◽

Structure Evolution ◽

Systematic Research ◽

Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

Download Full-text