scholarly journals Mixed Ionic-Electronic Conductivity, Redox Behavior and Thermochemical Expansion of Mn-Substituted 5YSZ as an Interlayer Material for Reversible Solid Oxide Cells

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 641
Author(s):  
Alejandro Natoli ◽  
Blanca I. Arias-Serrano ◽  
Enrique Rodríguez-Castellón ◽  
Agnieszka Żurawska ◽  
Jorge R. Frade ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Oxygen Content ◽  
Electronic Transport ◽  
Photoelectron Spectroscopy ◽  
Electronic Conductivity ◽  
Fluorite Structure ◽  
Solid Oxide ◽  
Transference Numbers ◽  
X Ray ◽  
Dimensional Changes

Manganese-substituted 5 mol.% yttria-stabilized zirconia (5YSZ) was explored as a prospective material for protective interlayers between electrolyte and oxygen electrodes in reversible solid oxide fuel/electrolysis cells. [(ZrO2)0.95(Y2O3)0.05]1−x[MnOy]x (x = 0.05, 0.10 and 0.15) ceramics with cubic fluorite structure were sintered in air at 1600 °C. The characterization included X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetry and dilatometry in controlled atmospheres, electrical conductivity measurements, and determination of oxygen-ion transference numbers by the electromotive force (EMF) technique. Mn-substituted 5YSZ solid solutions exhibit variable oxygen nonstoichiometry with manganese cations in a mixed 2+/3+ oxidation state under oxidizing conditions. Substitution by manganese gradually increases the extent of oxygen content variation on thermal/redox cycling, chemical contribution to thermal expansion and dimensional changes on reduction. It also deteriorates oxygen-ionic conductivity and improves p-type electronic conductivity under oxidizing conditions, leading to a gradual transformation from predominantly ionic to prevailing electronic transport with increasing x. Mn2+/3+→Mn2+ transformation under reducing atmospheres is accompanied by the suppression of electronic transport and an increase in ionic conductivity. All Mn-substituted 5YSZ ceramics are solid electrolytes under reducing conditions. Prolonged treatments in reducing atmospheres, however, promote microstructural changes at the surface of bulk ceramics and Mn exsolution. Mn-substituted 5YSZ with 0.05 ≤ x < 0.10 is considered the most suitable for the interlayer application, due to the best combination of relevant factors, including oxygen content variations, levels of ionic/electronic conductivity and thermochemical expansion.

scholarly journals An in situ near-ambient pressure X-ray Photoelectron Spectroscopy study of Mn polarised anodically in a cell with solid oxide electrolyte

2015 ◽  
Vol 174 ◽  
pp. 532-541 ◽  
Author(s):  
Benedetto Bozzini ◽  
Matteo Amati ◽  
Patrizia Bocchetta ◽  
Simone Dal Zilio ◽  
Axel Knop-Gericke ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Solid Oxide ◽  
Spectroscopy Study ◽  
Solid Oxide Electrolyte ◽  
X Ray ◽  
A Cell ◽  
Oxide Electrolyte

Crystallization of Germanium-Carbon Alloys - Structure and Electronic Transport

1997 ◽  
Vol 467 ◽  
Author(s):  
T.-M. John ◽  
J. Bläsing ◽  
P. Veit ◽  
T. Drüsedau
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Electronic Transport ◽  
Cluster Formation ◽  
Electronic Conductivity ◽  
Rf Magnetron Sputtering ◽  
Cross Sectional ◽  
Structural Investigations ◽  
X Ray ◽  
Transmission Electron

ABSTRACTAmorphous Ge1-xCx alloys were deposited by rf-magnetron sputtering from a germanium target in methane-argon atmosphere. Structural investigations were performed by means of wide and small angle X-ray scattering, X-ray reflectometry and cross-sectional transmission electron microscopy. The electronic transport properties were characterized using Hall-measurements and temperature depended conductivity. The results of X-ray techniques together with the electron microscopy clearly proof the existence of a segregation of the components and cluster formation already during deposition. The temperature dependence of the electronic conductivity in the as-prepared films follows the Mott' T−1/4 law, indicating transport by a hopping process. After annealing at 870 K, samples with x≤0.4 show crystallization of the Ge-clusters with a crystallite size being a function of x. After Ge-crystallization, the conductivity increases by 4 to 5 orders of magnitude. Above room temperature, electronic transport is determined by a thermally activated process. For lower temperatures, the σ(T) curves show a behaviour which is determined by the crystallite size and the free carrier concentration, both depending on the carbon content.

Measuring fundamental properties in operating solid oxide electrochemical cells by using in situ X-ray photoelectron spectroscopy

2010 ◽  
Vol 9 (11) ◽  
pp. 944-949 ◽  
Author(s):  
Chunjuan Zhang ◽  
Michael E. Grass ◽  
Anthony H. McDaniel ◽  
Steven C. DeCaluwe ◽  
Farid El Gabaly ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solid Oxide ◽  
Electrochemical Cells ◽  
X Ray ◽  
Fundamental Properties

scholarly journals Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 74 ◽  
Author(s):  
Peter Staffeld ◽  
Martin Kaller ◽  
Philipp Ehni ◽  
Max Ebert ◽  
Sabine Laschat ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Crown Ether ◽  
Electronic Transport ◽  
Columnar Structure ◽  
Strong Increase ◽  
Temperature Dependent ◽  
X Ray ◽  
X Ray Scattering ◽  
Structural And Electronic Properties ◽  
The Stability

The Li+- and K+-complexes of new discotic mesogens, where two n-alkoxy-substituted triphenylene cores are connected by a central crown ether (12-crown-4 and 18-crown-6), provide interesting structural and electronic properties. The inter- and intra-columnar structure was investigated by small and wide angle X-ray scattering. The electronic and ionic transports were studied by temperature dependent photoconductivity and impedance spectroscopy, respectively. Besides a strong increase of the stability and the width of the columnar phases the presence of soft anions (iodide, thiocyanate, tetrafluoroborate) leads to an improved intra-columnar order. The hereby shortened stacking-distance of the triphenylene cores leads to a significant increase of the photoconductivity in the columnar mesophase. Furthermore, the ionic conductivity of the new materials was investigated on macroscopically aligned thin films. The existence of channels for fast cation transport formed by the stacked crown ether moieties in the centre of each column can be excluded. The cations are coordinated strongly and therefore contributing only little to the conductivity. The ionic conductivity is dominated by the anisotropic migration of the non-coordinated anions through the liquid, like side chains favouring the propagation parallel to the columns. Iodide migrates about 20 times faster than thiocyanate and 100 times faster than tetrafluoroborate.

Order-Disorder Transitions in Gadolinium Zirconate: A Potential Electrolyte Material in Solid Oxide Fuel Cells

1995 ◽  
Vol 393 ◽  
Author(s):  
Scott Meilicke ◽  
Sossina Haile
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Transition Temperature ◽  
Ionic Conductivity ◽  
Solid Oxide Fuel Cells ◽  
Low Temperatures ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Gadolinium Zirconate ◽  
X Ray

ABSTRACTRare-earth, yttrium, and calcium doped zirconates are the materials of choice for electrolytes in solid oxide fuel cells. The dopant in these materials serves not only to stabilized the cubic phase of zirconia, but also to introduce anion defects that presumably increase the ionic conductivity. In order to understand the relationships between anion defect distribution, thermal history and ionic conductivity, the structural properties of gadolinium zirconate, Gd2Zr207, have been examined via high-temperature x-ray powder diffraction. Gadolinium zirconate is an ideal material for such a structure-property-processing study: it shows ordering of defects at low temperatures, taking on a pyrochlore structure, and disordering at elevated temperature, taking on a defect fluorite structure. Diffraction experiments, performed as functions of time and temperature, confirmed the transition temperature to lie between 1500 and 1550 °C. They also revealed that the transformation takes place most rapidly just below the transition temperature, indicating that the ordering process is kinetically constrained at low temperatures. Moreover, x-ray data collected at room temperature from quenched samples were found to be as useful, if not more so, than those collected in situ at high temperature. The latter are affected by thermal scattering, severely compromising data quality.

Sintering and Electrical Properties of Ce0.8Sm0.2O1.9 Solid Electrolyte Modified by Addition of MnO2

2011 ◽  
Vol 197-198 ◽  
pp. 610-616 ◽  
Author(s):  
Yi Feng Zheng ◽  
Lu Cun Guo
Keyword(s):  
Ionic Conductivity ◽  
Boundary Behavior ◽  
Sintering Temperature ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
Marked Influence ◽  
X Ray ◽  
Lower Activation ◽  
Addition Amount ◽  
Lower Activation Energy

The effect of MnO2 addition (0–2.0 mol%) on the densification, crystal structure, and ionic conductivity of Ce0.8Sm0.2O1.9 (SDC) was studied. The addition of MnO2 promotes densification, reducing sintering temperature by ~150°C. X-ray diffraction analysis showed that all the samples exhibit a fluorite structure. Impedance spectroscopy measurements indicated that SDC with appropriate ratio of MnO2 addition has higher ionic conductivity and lower activation energy compared with that of SDC. As the addition amount of Mn increases up to 1.0 mol% [(Ce0.8Sm0.2O1.9)0.99+(MnO2)0.01], the sample attains the highest ionic conductivity, about 35% higher than that of SDC at 600°C. In addition, Mn addition has little effect on bulk conductivity, but a marked influence on grain boundary behavior is observed.

Plasma-Enhanced Metalorganic Chemical Vapor deposition of Lipon Thin Films

2011 ◽  
Vol 1313 ◽  
Author(s):  
Lamartine Meda
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Ionic Conductivity ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Metalorganic Chemical Vapor Deposition ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
X Ray ◽  
Metalorganic Chemical

ABSTRACTLithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasmaenhanced metalorganic chemical vapor deposition (PE-MOCVD) method using triethyl phosphate [(CH2CH3)3PO4] and lithium tert-butoxide [(LiOC(CH3)3] precursors. Growth rates were between 100 and 415 Å/min, and thicknesses ranged from 1 to 2.5 μm. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy revealed approximately 6.9 at.% carbon in the films. The ionic conductivity of Lipon was measured using electrochemical impedance spectroscopy (EIS) and approximately 1.02 μS/cm was obtained, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li3PO4 targets. An all-solid-state thin-film lithium microbattery such as Li/Lipon/LiCoO2/Au/substrate was successfully fabricated with Lipon deposited by PE-MOCVD. The battery has a capacity of ca. 22 μAh/cm2μm.

scholarly journals Green Synthesis of Nanostructure CeO2 Using Tea Extract: Characterization and Adsorption of Dye from Aqueous Phase

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chengshun Liu ◽  
Xiyao Liu ◽  
Yilin Wu ◽  
Zhuotong Chen ◽  
Zhuanrong Wu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fluorite Structure ◽  
Bulk Sample ◽  
Second Order ◽  
Raman Signal ◽  
Cerium Chloride ◽  
Adsorption Efficiency ◽  
Order Model ◽  
X Ray ◽  
Second Order Model

Nanostructure CeO2 powders were synthesized using tea waste extract as gel precursor. The as-prepared samples were characterized by thermogravimetric analyzer (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Based on the TGA/DTG analysis, the intermediates of cerium chloride hydrates (CeCl3.4H2O and CeCl3.H2O) and cerium anhydrous (CeCl3) were produced, and the formation temperature of CeO2 was estimated to be 773 K. The cubic fluorite structure of CeO2 was detected to be the predominant species and was completely formed at the calcination temperature of 773K–1073 K with a crystal size between 8.8 and 11.4 nm based on the XRD measurement. Moreover, the main chemical state of ceria on the surface of the synthesized samples was confirmed to be tetravalent ceria by XPS. All samples show a strong Raman signal at a well-defined chemical shift of 463 cm−1 and a significant symmetry feature was observed, suggesting that the tetravalent ceria is the dominant species throughout the bulk sample. All the synthesized CeO2 calcined at different temperatures showed higher adsorption efficiency for Congo red (CR) compared with commercial CeO2. The adsorption efficiency maintained a steady state of more than 95% when the concentration of CR and adsorption temperature were varied in this study. The kinetic analysis showed that the second-order model was the appropriate model to interpret the adsorption behavior of synthesized CeO2. The calculated adsorption capacity derived from the second-order model is in good agreement with the experimental data. The isotherm analysis revealed that the Freundlich and D-R models fit well for the synthesized CeO2 and represent physisorption with a multilayer mechanism. The thermodynamic parameters, including the changes in Gibb’s free energy, enthalpy, and entropy, suggested that the adsorption of CR on the synthesized CeO2 sample was a spontaneous and endothermic process.

Synthesis of Ce0.8Gd0.05Y0.15O1.9 Nanopowders

2007 ◽  
Vol 336-338 ◽  
pp. 2005-2007
Author(s):  
Xiang Feng Guan ◽  
Zhi Hui Liu ◽  
He Ping Zhou
Keyword(s):  
Electron Microscopy ◽  
Solid Oxide Fuel Cells ◽  
Single Phase ◽  
Fluorite Structure ◽  
Solid Oxide ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Mean Size ◽  
The Mean

Nanosized Ce0.8Gd0.05Y0.15O1.9 powders were synthesized using glycine nitrate process for use as the electrolyte of intermediate temperature solid oxide fuel cells. The powders were characterized by simultaneous thermogravimetry analysis (TGA) and differential thermal analysis (DTA), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD pattern indicated that the powders exhibited a single phase with cubic fluorite structure. The TEM studies showed that the calcined powders exhibited an almost spherical morphology and the mean size of the particles was 30nm, which is in agreement with the calculated result of XRD.

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