Unusual Fast Cation Conduction in the High-Temperature Phase of Lithium Sodium Sulfate

2002 ◽  
Vol 756 ◽  
Author(s):  
H. Feldmann ◽  
R. E. Lechner ◽  
D. Wilmer
Keyword(s):  
High Temperature ◽  
Sodium Sulfate ◽  
Correlation Factor ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
60 Ghz ◽  
Tracer Transport ◽  
Ion Conductor ◽  
Fast Ion Conductor ◽  
A Charge

ABSTRACTLithium sodium sulfate (LiNaSO4) belongs to a group of simple inorganic salts exhibiting fast-cation conducting high-temperature phases with rotationally disordered anions. The analysis of a combination of quasielastic neutron scattering and high-frequency (10 MHz to 60 GHz) conductivity measurements in the high-temperature phase of LiNaSO4 reveals an unusual cation conduction mechanism: the Haven ratio, HR = D*/Dσ, turns out to be considerably larger than one. This behavior, to our knowledge detected for the first time in a typical fast ion conductor, can be traced back to a charge correlation factor clearly smaller than unity, indicating that charge transport is less effective than tracer transport in this material.

II. Electrical conductivity and phase transition studies on pure and doped (Cd2+, Gd3+)KNaSO4 and K3Na(SO4)2

1983 ◽  
Vol 61 (3) ◽  
pp. 599-601 ◽  
Author(s):  
M. Sunitha Kumari ◽  
Etalo A. Secco
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Conductivity Measurements ◽  
Ion Conductor ◽  
Fast Ion Conductor ◽  
Fast Ion ◽  
Transition Studies

Electrical conductivity measurements on pure and doped KNaSO4 and K3Na(SO4)2 reveal high ionic conductivity values in the high temperature phase. High conductivity values ascribed to Na+ resemble a superionic or fast-ion conductor.

Phase Transitions in Lead(II) Fluoride Upon Milling

1997 ◽  
Vol 481 ◽  
Author(s):  
Georges DÉnÉ ◽  
M. Cecilia Madamba
Keyword(s):  
Activation Energy ◽  
Phase Transitions ◽  
High Temperature ◽  
High Temperature Phase ◽  
Fluoride Ion ◽  
Temperature Phase ◽  
Ambient Conditions ◽  
Ion Conductor ◽  
Frenkel Defects ◽  
High Temperature Polymorph

ABSTRACTPbF2 is known to exist under two different polymorphic structures. Orthorhombic α-PbF 2 is stable at ambient temperature. It has the PbC12 structure. Cubic β-PbF2 is obtained by heating α-PbF2. It does not transform back to α-PbF2 on cooling, and it seems to be infinitely stable in the metastable state under ambient conditions. β-PbF2 crystallizes in the fluorite (CaF2) type. Owing to the large number of potential interstitial sites, many F- Frenkel defects can be formed, which make β-PbF2 the highest performance fluoride ion conductor among binary fluorides. In this work, both phases of PbF2 have been ball milled. Milling α-PbF2 results in a partial transformation to microcrystalline β-PbF2. The energy required for obtaining the high temperature phase is probably provided in the mechanical form. Milling β-PbF2 leads to partial amorphization and formation of α-PbF2. In this case, milling transforms the high temperature polymorph to the low temperature form, by providing the energy required to overcome the activation energy that keeps PbF2 trapped in the high temperature β-form after cooling.

Synthesis, Structure, and Ionic Conductivity of K3NdSi6O15

1990 ◽  
Vol 210 ◽  
Author(s):  
Sossina M. Haile ◽  
Theo Siegrist ◽  
Robert A. Laudise ◽  
Bernhardt J. Wuensch
Keyword(s):  
Preexponential Factor ◽  
High Temperature Phase ◽  
Thermal Vibration ◽  
Temperature Phase ◽  
Hydrothermal Conditions ◽  
Ion Conductor ◽  
Composition And Structure ◽  
Fast Ion Conductor ◽  
Fast Ion ◽  
Reversible Phase

AbstractA structure earlier reported for K3NdSi6O15 suggests the possibility for fast—ion conduction by virtue of K+ ions which not only reside in connected channels, but which also display very large thermal vibration amplitudes. No properties of the phase had heretofore been examined. Crystals up to 2mm inlength have been synthesized under a variety of hydrothermal conditions. Refinement of the structure with single crystal x-ray data to a residual of 8.3% confirms the composition and structure of our crystals and reveals a very high thermal vibration amplitude along c for K+ ions which reside in interconnected [001] channels.A reversible phase transformation has been discovered at 180ºC with a heat of transformation of 4J/g. Preliminary measurements of the conductivity of the high temperature phase yield a preexponential factor of 3.4/cm and an activation energy of 0.61ev along [001], indicating that this compound is not a particularly good fast—ion conductor.

Structural Study of TlH2PO4 and TlD2PO4 in the High Temperature Phase

1995 ◽  
Vol 5 (7) ◽  
pp. 763-769 ◽  
Author(s):  
S. Rios ◽  
W. Paulus ◽  
A. Cousson ◽  
M. Quilichini ◽  
G. Heger ◽  
...  
Keyword(s):  
High Temperature ◽  
Structural Study ◽  
High Temperature Phase ◽  
Temperature Phase

LATTICE DYNAMICS CALCULATIONS FOR SOLID BIPHENYL IN THE HIGH TEMPERATURE PHASE

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-599-C6-601 ◽  
Author(s):  
T. Wasiutynski ◽  
I. Natkaniec ◽  
A. I. Belushkin
Keyword(s):  
High Temperature ◽  
Lattice Dynamics ◽  
High Temperature Phase ◽  
Temperature Phase

High temperature phase transitions and proton conductivity in some kdp-family crystals

1989 ◽  
Vol 100 (1) ◽  
pp. 135-141 ◽  
Author(s):  
A. I. Baranov ◽  
V. P. Khiznichenko ◽  
L. A. Shuvalov
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
Proton Conductivity ◽  
High Temperature Phase ◽  
Temperature Phase

Review and characterisation of high-temperature phase change material candidates between 500 C and 700°C

2021 ◽  
Vol 150 ◽  
pp. 111528
Author(s):  
Ming Liu ◽  
Ehsan Shamil Omaraa ◽  
Jia Qi ◽  
Pegah Haseli ◽  
Jumal Ibrahim ◽  
...  
Keyword(s):  
High Temperature ◽  
Phase Change ◽  
Phase Change Material ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Change Material
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