Effect of Preparation and Impurities on The Size and Shape of The Crystallites and on The Crystal Symmetry of Superionic PbSnF4

1999 ◽  
Vol 580 ◽  
Author(s):  
Georges Dénès ◽  
M. Cecilia Madamba
Keyword(s):  
Local Structure ◽  
Strong Influence ◽  
Oxygen Sensor ◽  
Fluoride Ion ◽  
Crystal Shape ◽  
Oriented Sample ◽  
Ion Conductor ◽  
Preferred Direction ◽  
Polycrystalline Form ◽  
Crystalline Symmetry

AbstractThe highest performance fluoride ion conductor, PbSnF4, has been applied for the fabrication of an ambient temperature amperometric oxygen sensor, where it is used in the polycrystalline form. However, the structure of this material is highly anisotropic, thus one could expect polycrystalline samples to give a performance strongly dependent on crystallite direction. We have shown that the tin electronic structure has a very strong influence on the local structure, which determines the preferred direction of crystal growth, which is itself responsible for the crystal shape. This, in turn, determines the direction of preferred orientation, which can dramatically alter the properties relative to a randomly oriented sample. The effect of minor impurities on the size of the crystallites and on the crystalline symmetry has been studied.

High fluoride-ion conductivity and fluoride-ion conductor−insulator transition in fluorinated hexagonal boron nitride

2021 ◽  
Vol 21 ◽  
pp. 100523
Author(s):  
Tsuyoshi Takami ◽  
Takashi Saito ◽  
Takashi Kamiyama ◽  
Katsumi Kawahara ◽  
Toshiharu Fukunaga ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Insulator Transition ◽  
Ion Conductivity ◽  
Fluoride Ion ◽  
Ion Conductor ◽  
High Fluoride

scholarly journals Hexagonal perovskite related oxide ion conductor Ba3NbMoO8.5: phase transition, temperature evolution of the local structure and properties

2019 ◽  
Vol 7 (44) ◽  
pp. 25503-25510 ◽  
Author(s):  
Matthew S. Chambers ◽  
Kirstie S. McCombie ◽  
Josie E. Auckett ◽  
Abbie C. McLaughlin ◽  
John T. S. Irvine ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Local Structure ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Structure And Properties ◽  
Ion Conductor ◽  
Oxide Ion Conductor ◽  
Oxide Ion Conductivity ◽  
Reducing Conditions ◽  
Oxide Ion

Ba3NbMoO8.5 has recently been demonstrated to exhibit competitive oxide ion conductivity and to be stable under reducing conditions, making it an excellent potential electrolyte for solid oxide fuel cells.

Kinetics of Phase Transitions in Superionic Pbsnf4 Versus Temperature

1995 ◽  
Vol 398 ◽  
Author(s):  
Georges Denes ◽  
M. Cecilia Madamba ◽  
Galina Milova
Keyword(s):  
Phase Transitions ◽  
Chemical Sensors ◽  
Fluoride Ion ◽  
Prolonged Heating ◽  
Kinetics Of Phase Transitions ◽  
Ion Conductor ◽  
The Stability ◽  
Short Time ◽  
Kinetics Of ◽  
Time Evaluation

ABSTRACTPbSnF4 is the highest performance fluoride ion conductor known to date and is starting to be used for the fabrication of chemical sensors. Although several phase transitions have been reported, with conflicting results from different groups, the exact sequence of phase transitions versus temperature and the kinetics of the phase transformations remain unclear. We have prepared the three phases that can be stabilized at ambient temperature, i.e. o-, α- and β-PbSnF4, and studied the stability of each phase versus temperature. It appears that some of the phases transform very slowly to another under prolonged heating at constant temperature. This is very important since the conductivity is not necessarily the same for each phase, and therefore, a phase transition taking place slowly in the PbSnF4 used for the fabrication of a device, might not be detectable by a short time evaluation but, it could well alter its properties after prolonged use.

Neutron diffraction stufy of the high-fluoride-ion conductor, PbSnF4, prepared under an HF atmosphere

1994 ◽  
Vol 70-71 ◽  
pp. 253-258 ◽  
Author(s):  
R KANNO ◽  
K OHNO ◽  
H IZUMI ◽  
Y KAWAMOTO ◽  
T KAMIYAMA ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Fluoride Ion ◽  
Ion Conductor ◽  
High Fluoride

scholarly journals Correlation of Local Structure and Diffusion Pathways in the Modulated Anisotropic Oxide Ion Conductor CeNbO4.25

2016 ◽  
Vol 138 (4) ◽  
pp. 1273-1279 ◽  
Author(s):  
Stevin S. Pramana ◽  
Tom Baikie ◽  
Tao An ◽  
Matthew G. Tucker ◽  
Ji Wu ◽  
...  
Keyword(s):  
Local Structure ◽  
Ion Conductor ◽  
Oxide Ion Conductor ◽  
And Diffusion ◽  
Oxide Ion

Ionic Conductivity of the new Fluoride-Ion Conductor Casn2F6

2002 ◽  
Vol 756 ◽  
Author(s):  
Michael F. Bell ◽  
Georges DéNés ◽  
Zhimeng Zhu
Keyword(s):  
Solid Solution ◽  
Complex Impedance ◽  
Crystalline Material ◽  
Mixed Conductor ◽  
Impedance Method ◽  
Fluoride Ion ◽  
Ion Conductor ◽  
Covalently Bonded ◽  
Fluorite Type ◽  
First Time

ABSTRACTMetastable CaSn2F6 has been prepared for the first time and characterized. It is a well crystalline material that leaches SnF2 in water to give the microcrystalline fluorite-type Ca1-xSnxF2 solid solution. In both materials, tin(II) is covalently bonded to fluorine, and thus carries a stereoactive non-bonding electronic pair. The electrical conductivity of CaSn2F6 was measured by the complex impedance method. The CaSn2F6 material was found to be a mixed conductor (τi = 0.50), with a F- conductivity a little below that of α-SnF2. On heating to 250°C, it decomposes irreversibly to give SnF2 and probably amorphous CaF2 (undetected).

scholarly journals Mechanosynthesis of the Fast Fluoride Ion Conductor Ba1–xLaxF2+x: From the Fluorite to the Tysonite Structure

2014 ◽  
Vol 118 (13) ◽  
pp. 7117-7129 ◽  
Author(s):  
A. Düvel ◽  
J. Bednarcik ◽  
V. Šepelák ◽  
P. Heitjans
Keyword(s):  
Fluoride Ion ◽  
Ion Conductor ◽  
Tysonite Structure
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