Improvement of Fluorite Structures in M203-CeO2 (M=Sm, La) System Based on a Novel Effective Index

1998 ◽  
Vol 548 ◽  
Author(s):  
Toshiyuki Mori ◽  
Takayasu Ikegami ◽  
Hiroshi Yamamura
Keyword(s):  
Ionic Conductivity ◽  
Solid Solutions ◽  
Ionic Conduction ◽  
Fluorite Structure ◽  
Effective Index ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Ionic Radii ◽  
Order Of Magnitude ◽  
Oxide Ionic Conductivity

ABSTRACTM2O3-CeO2(M=Sm, La) system is one of the most interesting of fluorite oxides since the oxide ionic conductivity of it is higher than that of yttria-stabilized zirconia. In this study, the effective index for the improvement of ionic conductivity in CeO2 systems was defined using information regarding ionic radii and the level of oxygen vacancies from the perspective of crystallography. It is assumed that the M2O3 CeO2 based oxides approach the ideal fluorite structure for fast ionic conduction when the effective index increases toward 1. A small amount of alkali- or alkali-earth doped M2O3-CeO2 (M=Sm, La) solid solutions were prepared based on this effective index. The oxide ionic conductivity increased with an increase of this effective index. (La0.75Sr0.2Ba0.05)0.175 Ce0.825 O1.89 that had high effective index, showed high oxide ionic conductivity over the order of magnitude in comparison with 8mol% yttria-stabilized zirconia. Moreover, the oxygen partial pressure dependence of oxide ionic conductivity of M2O3-CeO2(M=Sm, La) solid solutions was improved by the increasing effective index. The utility of this effective index, for improvement of the electrical properties in fluorite CeO2 based materials, was investigated.

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

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.

scholarly journals Fluorite-Type Solid Solutions in the System Y-Ta-O-N: A Nitrogen-Rich Analogue to Yttria-Stabilized Zirconia (YSZ)

2006 ◽  
Vol 61 (6) ◽  
pp. 660-664 ◽  
Author(s):  
H. Schilling ◽  
H. Wolff ◽  
R. Dronskowski ◽  
M. Lerch
Keyword(s):  
Fuel Cells ◽  
Solid Electrolyte ◽  
Solid Solutions ◽  
Vacancy Concentration ◽  
Anion Vacancy ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Fluorite Type

Fluorite-type phases in the system Y-Ta-O-N have been prepared by ammonolysis of Y-Ta-O precursors. X-ray powder patterns show unusual asymmetrical reflection profiles explained by DFT and MD methods. The anion vacancy concentration of some of these oxynitrides is similar to that of yttria-doped zirconia, commercially used as solid electrolyte in fuel cells. Hence, these compounds are interesting candidates for mixed oxygen-nitrogen superion conductors

Preparation and Characterization of Epoxidized-30% Poly(methyl methacrylate)-grafted Natural Rubber Polymer Electrolyte

2014 ◽  
Vol 28 ◽  
pp. 163-170 ◽  
Author(s):  
Khuzaimah Nazir ◽  
Siti Fadzilah Ayub ◽  
Ahmad Fairoz Aziz ◽  
Ab Malik Marwan Ali ◽  
Muhd Zu Azhan Yahya
Keyword(s):  
Ionic Conductivity ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Room Temperature ◽  
Ionic Conduction ◽  
Lithium Triflate ◽  
Poly Methyl Methacrylate ◽  
Order Of Magnitude ◽  
Cast Technique

In this study, a freestanding thin film composed of lithium triflate (LiTf) salt (30-40 wt.%) and epoxidized-30% poly (methyl methacrylate)-grafted natural rubber (EMG30) (50, 54.6, 62.3 mol %) were prepared by a solvent cast technique. The EMG30 were found to increase the ionic conductivity of EMG30-LiTf by one order of magnitude compared to MG30-LiTf. The highest ionic conductivity achieved was 5.584 x10-3Scm-1at room temperature when 40 wt.% of LiTf salts were introduced into 62.3 mol % EMG30. The ionic conduction mechanisms in EMG30-LiTf electrolytes obey Arrhenius rule in which the ion transport in these materials is thermally assisted.

Study on Preparation and Properties of Yttria Stabilized Zirconia Solid State Electrolyte

2013 ◽  
Vol 544 ◽  
pp. 64-67
Author(s):  
Wei Liu ◽  
Ge Ming Liu ◽  
Niu Sheng Peng ◽  
Da Zhi Sun
Keyword(s):  
Solid State ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Methods ◽  
Stabilized Zirconia ◽  
Solid State Electrolyte ◽  
Spectroscopy Measurement ◽  
Basic Performance

Abstract. Currently, Yttria-stabilized zirconia solid state electrolyte are widely used in various fields . The basic performance of Yttria-stabilized zirconia (5YSZ) prepared by different synthesis methods and sintering temperatures are studied in this paper ,their phase compositions and microstructure are studied with XRD and SEM. The ionic conductivity of 5YSZ sintered at different temperature are studied with A.C. impedance spectroscopy measurement.

A Multiphysics Modeling Study of (Pr0.7Sr0.3)MnO3±δ∕8mol% Yttria-Stabilized Zirconia Composite Cathodes for Solid Oxide Fuel Cells

2004 ◽  
Vol 2 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ke An ◽  
Kenneth L. Reifsnider
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Solid Oxide Fuel Cells ◽  
Current Density ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Oxide Fuel ◽  
Stabilized Zirconia ◽  
Before And After

Solid oxide fuel cells (SOFCs) are expected to be a future power source. Simulation analyses of SOFCs can help to understand well the interactive functions among the multiphysics phenomena in the SOFC system. A three-dimensional multiphysics finite-element model was used to simulate the performance of a half-cell SOFC with (Pr0.7Sr0.3)MnO3±δ∕8mol% yttria-stabilized zirconia (8YSZ) composite cathode on one side of the 8YSZ electrolyte before and after aging. Multiphysics phenomena in the SOFC were considered in the modeling. The current/voltage curves simulated matched the experimental data before and after aging. The average current density was found to have a linear relationship to the logarithm of the effective exchange current density. The effect of the effective ionic conductivity of the composite cathode was more apparent for small total effective ionic conductivity values than for large ones.

Ionic Conductivity in Uniaxial Micro Strain/Stress Fields of Yttria-Stabilized Zirconia

2011 ◽  
Vol 50 (5R) ◽  
pp. 055803 ◽  
Author(s):  
Kazuhisa Sato ◽  
Ken Suzuki ◽  
Ryo Narumi ◽  
Keiji Yashiro ◽  
Toshiyuki Hashida ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Yttria Stabilized Zirconia ◽  
Stress Fields ◽  
Stabilized Zirconia ◽  
Strain Stress
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