Electrical Conductivity in Praseodymium-Cerium Oxide

2002 ◽  
Vol 756 ◽  
Author(s):  
Todd S. Stefanik ◽  
Harry L. Tuller
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Cerium Oxide ◽  
Electronic Conductivity ◽  
Impurity Band ◽  
Defect Model ◽  
Valence States ◽  
Partial Pressures ◽  
Wide Range ◽  
Low Levels

ABSTRACTThe electrical conductivity of PrxCe1-xO2-δ (PCO) for 0 ≤ × ≤ 0.20 was examined over a wide range of temperatures and oxygen partial pressures. A defect model based on multiple Pr valence states was found to be qualitatively consistent with the observed data. A unique pO2-dependent ionic conductivity is observed at high pO2 values in compositions containing low levels of Pr (0 ≤ × ≤ 0.01). In compositions containing higher amounts of Pr (0.05 ≤ × ≤ 0.20), formation of a Pr induced impurity band results in a significant electronic conductivity at high pO2 values.

Coordination polymer-based conductive materials: ionic conductivity vs. electronic conductivity

2019 ◽  
Vol 7 (42) ◽  
pp. 24059-24091 ◽  
Author(s):  
Hai-Ning Wang ◽  
Xing Meng ◽  
Long-Zhang Dong ◽  
Yifa Chen ◽  
Shun-Li Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Coordination Polymer ◽  
Coordination Polymers ◽  
Electronic Conductivity ◽  
Structural Factors ◽  
Conductive Materials ◽  
Recent Developments

This review summarizes recent developments of coordination polymers and their derivatives for ionic and electrical conductivity with the discussion about synthetic strategies and possible mechanisms to identify the key structural factors.

scholarly journals Mixed Protonic-Electronic Conductivity of SrCe1-xPrxO3- δ

2021 ◽  
Author(s):  
Yevgeniy Ostrovskiy ◽  
Yi-Lin Huang ◽  
Christopher Pellegrinelli ◽  
Mohammed Hussain Abdul Jabbar ◽  
Mann Sakbodin ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electronic Conductivity ◽  
Proton Conductors ◽  
Separation Membranes ◽  
Reducing Conditions ◽  
Partial Pressures ◽  
Wide Range ◽  
Electrolysis Cells ◽  
P Type ◽  
Structurally Stable

Abstract Protonic conductors are gaining use in solid oxide fuel cells (SOFCs) and electrolysis cells (SOECs) as well as for H2 separation membranes. However, for SOFC/SOEC electrode and membrane applications their performance is limited by low electronic conductivity. One of the most promising classes of ceramic proton conductors, perovskites, have highly-tunable compositions allowing for the optimization of both ionic and electronic conductivity. In this work Pr-doped SrCeO3 was studied over a wide range of oxygen partial pressures (pO2’s) and temperatures to determine its defect properties and conductivity. Under reducing conditions Pr-doped SrCeO3 was found to be chemically and structurally stable, with an optimal Pr doping level of 10%. This composition shows greater conductivity compared to previously reported Eu-doped SrCeO3. Under low pO2 Pr-doped SrCeO3 exhibited n-type behavior as conductivity increased with decreasing pO2, suggesting that the electronic conductivity of SrCeO3 is significantly enhanced by Pr doping. Under high pO2 conditions, Pr-doped SrCeO3 exhibited p-type conductivity with higher conductivity in the presence of water affirming its protonic conductivity. This work validates the use of Pr as a means of enhancing electronic conductivity in proton conducting perovskites.

Electrical Conductivity Prediction in Langasite for Optimized Microbalance Performance at Elevated Temperatures

2002 ◽  
Vol 756 ◽  
Author(s):  
Huankiat Seh ◽  
Harry Tuller ◽  
Holger Fritze
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
High Temperatures ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Operating Conditions ◽  
Total Conductivity ◽  
Defect Model ◽  
Partial Pressures

ABSTRACTThe performance of the langasite-based crystal microbalance is limited due to reductions in its resistivity at high temperatures and reduced oxygen partial pressures. In this work, we utilize a recently developed defect model to predict the dependence of the ionic and electronic contributions to the total conductivity of langasite on temperature, oxygen partial pressure and acceptor and donor dopants. These results are used to select the type and concentrations of dopants expected to provide extended operating conditions for langasite-based gas sensors and crystal microbalances.

scholarly journals Comparison of the electrical conductivity of bulk and film Ce1–xZrxO2–δ in oxygen-depleted atmospheres at high temperatures

2021 ◽  
Author(s):  
Iurii Kogut ◽  
Carsten Steiner ◽  
Hendrik Wulfmeier ◽  
Alexander Wollbrink ◽  
Gunter Hagen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperatures ◽  
Ionic Conduction ◽  
Electronic Conductivity ◽  
Oxygen Storage ◽  
Coarse Grained ◽  
Reducing Conditions ◽  
Partial Pressures ◽  
Microstructural Effects ◽  
Defect Interactions

AbstractFeaturing high levels of achievable oxygen non-stoichiometry δ, Ce1−xZrxO2−δ solid solutions (CZO) are crucial for application as oxygen storage materials in, for example, automotive three-way catalytic converters (TWC). The use of CZO in form of films combined with simple manufacturing methods is beneficial in view of device miniaturization and reducing of TWC manufacturing costs. In this study, a comparative microstructural and electrochemical characterization of film and conventional bulk CZO is performed using X-ray diffractometry, scanning electron microscopy, and impedance spectroscopy. The films were composed of grains with dimensions of 100 nm or less, and the bulk samples had about 1 µm large grains. The electrical behavior of nanostructured films and coarse-grained bulk CZO (x > 0) was qualitatively similar at high temperatures and under reducing atmospheres. This is explained by dominating effect of Zr addition, which masks microstructural effects on electrical conductivity, enhances the reducibility, and favors strongly electronic conductivity of CZO at temperatures even 200 K lower than those for pure ceria. The nanostructured CeO2 films had much higher electrical conductivity with different trends in dependence on temperature and reducing atmospheres than their bulk counterparts. For the latter, the conductivity was dominantly electronic, and microstructural effects were significant at T < 700 °C. Nanostructural peculiarities of CeO2 films are assumed to induce their more pronounced ionic conduction at medium oxygen partial pressures and relatively low temperatures. The defect interactions in bulk and film CZO under reducing conditions are discussed in the framework of conventional defect models for ceria.

Space Charge Layers in Polycrystalline Cerium Oxide

2002 ◽  
Vol 756 ◽  
Author(s):  
Andreas Tschöpe
Keyword(s):  
Electrical Conductivity ◽  
Space Charge ◽  
Cerium Oxide ◽  
Oxygen Deficiency ◽  
Electronic Conductivity ◽  
Electrical Potential ◽  
Theoretical Models ◽  
Excess Charge ◽  
Two Phase ◽  
Space Charge Model

ABSTRACTThe effect of space charge layers in polycrystalline cerium oxide was analyzed by comparing experimental results of grain size-dependent electrical conductivity with theoretical models. Modeling included the calculation of space charge segregation of acceptor ions and of the effective electrical conductivity of polycrystalline cerium oxide in both the macroscopic and mesoscopic range of grain sizes. It is shown that an L-3 power law for the electronic conductivity in the nm-regime is characteristic for the equilibrium space charge model and different from the scaling behavior of alternative models. The origin of space charge potential was investigated by numerical calculation of the electrical potential in a two-phase model. It was found, that a positive excess charge at grain boundaries of cerium oxide is caused by an enhanced oxygen deficiency at the grain boundary core. The influence of acceptor ion doping in the dilute limit and of non-equilibrium distribution of acceptor ions on electrical conductivity was also studied.

Electrical Conductivity and Raman Studies of B2O3-Na2O-NaI Glass Systems

1994 ◽  
Vol 369 ◽  
Author(s):  
Byoung-Koo Choi ◽  
Kyoung-Hee Shin ◽  
Hyo-Kyoung Lee
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Raman Spectra ◽  
Glass Structure ◽  
Wide Range ◽  
Drastic Increase

AbstractGlasses of B2O3-Na2O-Na2I2 have been prepared over a wide range of compositions on the basis of a fixed O/B ratio and a fixed Na/B ratio, respectively. Raman spectra and the ionic conductivity have been measured to elucidate the role of the iodide. In the fixed O/B ratio, a drastic increase of the conductivity with the addition of iodide is observed. The conductivity results are found to be consistent with the Raman results. In the fixed Na/B ratio, the substitution of iodide does not influence significantly the glass structure as well as the ionic conductivity.

Electrical Conductivity of Ionic and Electronic Mixture

2001 ◽  
Vol 699 ◽  
Author(s):  
Gyeong Man Choi ◽  
Joon Hee Kim ◽  
Young Min Park
Keyword(s):  
Electrical Conductivity ◽  
Single Phase ◽  
Electronic Conductivity ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Total Conductivity ◽  
Mixed Conductivity ◽  
Emf Measurements ◽  
Wide Range ◽  
Mixed Ionic Electronic Conductors

AbstractMixed ionic-electronic conductors (MIECs) which have both ionic and electronic species as charge carriers have a wide range of applications, such as electrodes in fuel cells, electrocatalytic reactors, and gas separating membranes. They may have either electronic or ionic species as the majority charge carriers. In addition to the single-phase mixed conductors, they may be fabricated by mixing two different phases of materials. Although these composites have been less studied than the single phase MIECs, the combined properties are often superior to single phase MIECs, and properties not seen in an individual phase may appear in the composite phase.YSZ-based composite systems were chosen to test the effect of transition-metal-oxide (TMO) addition on the electronic conductivity of composite. To induce mixed conductivity, electronic-conducting TMOs such as NiO and Mn2O3 were added into YSZ above the solubility limit. While the solid solubility of NiO in YSZ is limited that of Mn2O3 is large.In this work, mixed conducting yttria (8 mol%) stabilized zirconia (YSZ) - TMO composites were prepared in full composition range and the electrical conductivity of the composites was measured by 4-probe d.c. conductivity. Electromotive force (emf) measurements of the galvanic cell, current-voltage (I-V) measurements in ion blocking condition and the oxygen-partial-pressure dependent conductivity have been used to determine the contribution of the ionic and electronic charge carriers on the conductivity. Thus the composition-dependent electrical properties were used to explain the percolation behavior of electronic charge carriers in ionic matrix.Although the total conductivity of dense YSZ-TMO composite was variable with TMO content, the partial-electronic conductivity increased and the ionic conductivity decreased. The composition-dependent conductivity was discussed.

Electrochemical Properties of Ag5Te2Cl0.8Br0.2, a Representative of the Solid Solutions Ag5Te2Cl1–xBrx

2008 ◽  
Vol 63 (9) ◽  
pp. 1083-1086 ◽  
Author(s):  
Melanie Bawohl ◽  
Tom Nilges
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Space ◽  
Ionic Conductivity ◽  
Phase Transition Temperature ◽  
Solid Solutions ◽  
Electronic Conductivity ◽  
Space Group ◽  
Disorder Phase Transition ◽  
Wide Range

Impedance spectroscopic investigations of Ag5Te2Cl0.8Br0.2, a selected representative of the solid solutions Ag5Te2Cl1−xBrx with x = 0 - 1, proved the mixed-conducting property of this class of materials. Two polymorphs are realized in the temperature range of 309 to 410 K, the monoclinic β - phase (space group P21/n) and the tetragonal α-phase (space group I4/mcm) with an order-disorder phase transition temperature of 336 K (DSC). A sharp increase of the total and ionic conductivity can be observed at 337 K, in good accordance with the phase transition temperature. The electronic conductivity exceeds the ionic conductivity by approximately one order of magnitude over a wide range of temperature. Conductivities are σion = 6.9×10−5 (309 K) and σtot = 4.80×10−4 Ω−1 cm−1 (310 K) for β -Ag5Te2Cl0.8Br0.2 and σion = 1.6×10−2 (395 K) and σtot = 1.73×10−1 Ω−1 cm−1 (394 K) for α-Ag5Te2Cl0.8Br0.2.

Experimental Study on Electrical Conductivity of FexO-CaO-SiO2-Al2O3 System at Various Oxygen Potentials

2018 ◽  
Vol 37 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Yan–Xiang Liu ◽  
Jun–Hao Liu ◽  
Guo–Hua Zhang ◽  
Jian–Liang Zhang ◽  
Kuo–Chih Chou
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Oxygen Potential ◽  
Electronic Conductivity ◽  
Transference Number ◽  
Free Oxygen ◽  
Total Electrical Conductivity ◽  
Oxygen Ion ◽  
Conductivity Increase ◽  
Temperature Dependences

AbstractThe electrical conductivity of FexO-CaO-SiO2-Al2O3 slags was measured by a four terminal method. The results show that the temperature dependences of total, electronic and ionic conductivity for different compositions obey the Arrhenius law and all of them increase as increasing the temperature. For all the studied slags, as increasing CO/CO2 ratio which is used to controlled the oxygen potential, both the total electrical conductivity and electronic conductivity increase, but the ionic conductivity decreases. It was also found that the electronic transference number exhibits a strong correlation with oxygen potential, but is independent of temperature. Under the condition of constant FexO content, the higher the basicity of slags is, the higher the total electrical conductivity and ionic/electronic conductivity will be, which is resulted from the increase of free oxygen ion.

scholarly journals Linking the Electrical Conductivity and Non-Stoichiometry of Thin Film Ce1−xZrxO2−δ by a Resonant Nanobalance Approach

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 748
Author(s):  
Iurii Kogut ◽  
Alexander Wollbrink ◽  
Carsten Steiner ◽  
Hendrik Wulfmeier ◽  
Fatima-Ezzahrae El Azzouzi ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Electronic Conductivity ◽  
Oxygen Storage ◽  
Partial Pressures ◽  
Maximum Conductivity ◽  
Defect Interactions

Bulk ceria-zirconia solid solutions (Ce1−xZrxO2−δ, CZO) are highly suited for application as oxygen storage materials in automotive three-way catalytic converters (TWC) due to the high levels of achievable oxygen non-stoichiometry δ. In thin film CZO, the oxygen storage properties are expected to be further enhanced. The present study addresses this aspect. CZO thin films with 0 ≤ x ≤ 1 were investigated. A unique nano-thermogravimetric method for thin films that is based on the resonant nanobalance approach for high-temperature characterization of oxygen non-stoichiometry in CZO was implemented. The high-temperature electrical conductivity and the non-stoichiometry δ of CZO were measured under oxygen partial pressures pO2 in the range of 10−24–0.2 bar. Markedly enhanced reducibility and electronic conductivity of CeO2-ZrO2 as compared to CeO2−δ and ZrO2 were observed. A comparison of temperature- and pO2-dependences of the non-stoichiometry of thin films with literature data for bulk Ce1−xZrxO2−δ shows enhanced reducibility in the former. The maximum conductivity was found for Ce0.8Zr0.2O2−δ, whereas Ce0.5Zr0.5O2-δ showed the highest non-stoichiometry, yielding δ = 0.16 at 900 °C and pO2 of 10−14 bar. The defect interactions in Ce1−xZrxO2−δ are analyzed in the framework of defect models for ceria and zirconia.

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