Dielectric absorption and low-temperature ionic conduction in calcium fluoride doped with trivalent rare earths

1985 ◽  
Vol 18 (29) ◽  
pp. 5641-5649 ◽  
Author(s):  
H K Welsh
Keyword(s):  
Low Temperature ◽  
Rare Earths ◽  
Calcium Fluoride ◽  
Ionic Conduction ◽  
Dielectric Absorption

scholarly journals Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2277
Author(s):  
Zhengwen Tu ◽  
Yuanyuan Tian ◽  
Mingyang Liu ◽  
Bin Jin ◽  
Muhammad Akbar ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Ionic Conduction ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Open Circuit Voltages ◽  
Composite Samples

Recently, appreciable ionic conduction has been frequently observed in multifunctional semiconductors, pointing out an unconventional way to develop electrolytes for solid oxide fuel cells (SOFCs). Among them, ZnO and Li-doped ZnO (LZO) have shown great potential. In this study, to further improve the electrolyte capability of LZO, a typical ionic conductor Sm0.2Ce0.8O1.9 (SDC) is introduced to form semiconductor-ionic composites with LZO. The designed LZO-SDC composites with various mass ratios are successfully demonstrated in SOFCs at low operating temperatures, exhibiting a peak power density of 713 mW cm−2 and high open circuit voltages (OCVs) of 1.04 V at 550 °C by the best-performing sample 5LZO-5SDC, which is superior to that of simplex LZO electrolyte SOFC. Our electrochemical and electrical analysis reveals that the composite samples have attained enhanced ionic conduction as compared to pure LZO and SDC, reaching a remarkable ionic conductivity of 0.16 S cm−1 at 550 °C, and shows hybrid H+/O2− conducting capability with predominant H+ conduction. Further investigation in terms of interface inspection manifests that oxygen vacancies are enriched at the hetero-interface between LZO and SDC, which gives rise to the high ionic conductivity of 5LZO-5SDC. Our study thus suggests the tremendous potentials of semiconductor ionic materials and indicates an effective way to develop fast ionic transport in electrolytes for low-temperature SOFCs.

Crystallization Characteristics and Thermal Stability of Fluor-Hydroxyapatite Composites with Zirconia

2012 ◽  
Vol 182-183 ◽  
pp. 122-125
Author(s):  
Li Li Wang ◽  
Xiu Feng Wang ◽  
Cheng Long Yu ◽  
Hong Tao Jiang
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Solid State ◽  
Low Temperature ◽  
Solid Solutions ◽  
Tricalcium Phosphate ◽  
Solid State Reaction ◽  
Calcium Fluoride ◽  
Raw Materials ◽  
Thermal Stability Of

Hydroxyapatite (HA) was synthesized in presence of 20wt% m-ZrO2by solid state reaction between tricalcium phosphate(TCP) and Ca(OH)2at 1000 °C for 2h. Similarily, Fluorine hydroxyapatite(FA) was synthesized using tricalcium phosphate and calcium fluoride as raw materials at 1000 °Cfor 3h. The as-prepared HA was mixed with 10%,25%,45%,55%,70wt% FA and the mixture was sintered at 1000°C-1400°C for 2h. The main phase and bulk density was measured. The results show that when the relative amount of FA to HA increased, the decomposition of the composite is decreased gradually because of the formation of thermally stable FHA solid solutions. Low temperature would effect the exchange of ionic between FA and HA,while high temperature would impact synthesis of composites, because high temperature would lead to dissolution of HA ,which has to react with FA. Increase the content of HA would be advantage for synthesis FHA-ZrO2composite.

Study of low temperature luminescence and thermoluminescence in calcium fluoride crystals

1991 ◽  
Vol 48-49 ◽  
pp. 828-832 ◽  
Author(s):  
K. Chakrabarti ◽  
V.K. Mathur ◽  
R.J. Abbundi ◽  
N. Kristianpoller ◽  
W.F. Hornyak
Keyword(s):  
Low Temperature ◽  
Calcium Fluoride ◽  
Fluoride Crystals

scholarly journals Semiconductor-Ionic Nanocomposite La0.1Sr0.9MnO3−δ-Ce0.8Sm0.2O2−δ Functional Layer for High Performance Low Temperature SOFC

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1549 ◽  
Author(s):  
Zhaoqing Wang ◽  
Xunying Wang ◽  
Zhaoyun Xu ◽  
Hui Deng ◽  
Wenjing Dong ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Low Temperature ◽  
High Performance ◽  
Ionic Conduction ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Functional Layer ◽  
Rectification Effect ◽  
Electrochemical Impedance Spectroscopy Data ◽  
Low Temperature Sofc

A novel composite was synthesized by mixing La0.1Sr0.9MnO3−δ (LSM) with Ce0.8Sm0.2O2−δ (SDC) for the functional layer of low temperature solid oxide fuel cell (LT-SOFC). Though LSM, a highly electronic conducting semiconductor, was used in the functional layer, the fuel cell device could reach OCVs higher than 1.0 V without short-circuit problem. A typical diode or rectification effect was observed when an external electric force was supplied on the device under fuel cell atmosphere, which indicated the existence of a junction that prevented the device from short-circuit problem. The optimum ratio of LSM:SDC = 1:2 was found for the LT-SOFC to reach the highest power density of 742 mW·cm−2 under 550 °C The electrochemical impedance spectroscopy data highlighted that introducing LSM into SDC electrolyte layer not only decreased charge-transfer resistances from 0.66 Ω·cm2 for SDC to 0.47–0.49 Ω·cm2 for LSM-SDC composite, but also decreased the activation energy of ionic conduction from 0.55 to 0.20 eV.

The conformation and reorientation of enclathrated 1,2-dichloroethane

1979 ◽  
Vol 57 (6) ◽  
pp. 635-637 ◽  
Author(s):  
S. K. Garg ◽  
D. W. Davidson ◽  
S. R. Gough ◽  
J. A. Ripmeester
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dihedral Angle ◽  
Line Shape ◽  
Guest Molecule ◽  
Spectral Simulation ◽  
Rigid Lattice ◽  
Average Activation Energy ◽  
Dielectric Absorption

The rigid-lattice nmr line shape of the four-proton system in 1,2-dihaloethanes has been obtained by spectral simulation as a function of dihedral angle [Formula: see text] and used to show that 1,2-dichloroethane is encaged in the structure II hydrate in a gauche configuration with [Formula: see text] Very broad low-temperature dielectric absorption is associated with an average activation energy of 0.87 kcal/mol for guest-molecule reorientation.

Controlled-Atmosphere dc Arc for the Quantitative Determination of Rare Earths in Calcium Fluoride

1966 ◽  
Vol 20 (6) ◽  
pp. 392-394 ◽  
Author(s):  
D. L. Nash
Keyword(s):  
Quantitative Determination ◽  
Rare Earths ◽  
Calcium Fluoride ◽  
Controlled Atmosphere ◽  
Specific Technique ◽  
Limits Of Detection ◽  
Dc Arc

This paper discusses the investigation of optimum controlled-atmosphere conditions for the analysis of rare earths in calcium fluoride and describes the specific technique evolved for the determination of terbium and holmium. The limits of detection and precision of the method are given.

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