scholarly journals SmBa1-xCaxCo2O5+d Layered Perovskite Cathodes for Intermediate Temperature-operating Solid Oxide Fuel Cells

2021 ◽  
Vol 8 ◽  
Author(s):  
Kyeong Eun Song ◽  
Sung Hun Woo ◽  
Seung Wook Baek ◽  
Hyunil Kang ◽  
Won Seok Choi ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Single Phase ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Oxide Systems ◽  
Metal Insulator ◽  
A Value ◽  
Temperature Operating ◽  
Xrd Patterns

In SmBa1-xCaxCo2O5+d (x = 0.01, 0.03, 0.1, and 0.2, SBCCO) oxide systems calcined at 1100°C for 8 h, the XRD patterns of the SBCCO single phase were maintained in the cases of SmBa0.97Ca0.03Co2O5+d (SBCCO-0.97) and SmBa0.99Ca0.01Co2O5+d (SBCCO-0.99) compositions. In SmBa0.8Ca0.2Co2O5+d (SBCCO-0.8) and SmBa0.9Ca0.1Co2O5+d (SBCCO-0.9), CaCoSmO4 existed with the pattern SBCCO. SBCCO structures were identified as orthorhombic crystal structures because they showed splitting of the X-ray diffraction (XRD) peaks at 23.4°, 47.9°, and 59.1°.Typical metallic conduction behaviors were found in all measured compositions except SBCCO-0.8, which showed a metal-insulator transition (MIT) behavior. Compared to other SmBa1-xCaxCo2O5+d compositions, SBCCO-0.8 showed the highest electrical conductivity of 460 S/cm at 500°C. In particular, SBCCO-0.9 was found to have an excellent ASR characteristic of about 0.077 Ωcm2 at 700°C. The activation energy of SBCCO-0.9 was the lowest among SBCCO oxide systems with a value of 0.77 eV.

scholarly journals Enhanced Electrochemical Properties of Non-stoichiometric Layered Perovskites, Sm1−xBaCo2O5+d, for IT-SOFC Cathodes

2021 ◽  
Vol 9 ◽  
Author(s):  
Chan Gyu Kim ◽  
Sung Hun Woo ◽  
Kyeong Eun Song ◽  
Seung-Wook Baek ◽  
Hyunil Kang ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Properties ◽  
Single Phase ◽  
Specific Resistance ◽  
Stoichiometric Composition ◽  
Solid Oxide ◽  
Oxide Systems ◽  
Metal Insulator ◽  
Temperature Operating ◽  
Layered Perovskites

In this study, electrochemical properties of layered perovskites having non-stoichiometric compositions (Sm1−xBaCo2O5+d, x = 0, 0. 01, 0.02, 0.03, 0.04, 0.05, 0.10, and 0.15) were analyzed for the direct application of cathode materials for Intermediate Temperature-operating Solid Oxide Fuel Cells (IT-SOFC). From the Sm1−xBaCo2O5+d oxide systems calcined at 1,100°C for 8 h, single phase (SmBaCo2O5+d, SBCO_1) was maintained only in the case of the x = 0 composition. In the compositions of x = 0.05–0.10, BaCoO2.6 was mixed with the pattern of SBCO. In addition, in the composition of x = 0.15, it was confirmed that BaCoO2.6 and CoO phases coexisted with SBCO. In the compositions of Sm1−xBaCo2O5+d, the overall Area Specific Resistance (ASR) values decreased as the removal amount of Sm increased from x = 0–0.10; then, the values increased for compositions from x = 0.15. For example, the ASRs of SBCO_1, Sm0.95BaCo2O5+d (SBCO_0.95), Sm0.90BaCo2O5+d (SBCO_0.90), and Sm0.85BaCo2O5+d (SBCO_0.85) measured at 600°C were 0.301, 0.147, 0.119, and 0.179 Ω cm2, respectively. In particular, SBCO_0.90 was found to have an excellent ASR property of about 0.035 Ω cm2 at 700°C. Typical properties of the metal–insulator transition (MIT) electrical conductivity were shown in all measured compositions. The temperature at which MIT occurred increased as the non-stoichiometric composition increased.

scholarly journals Crystal structure and dielectric properties of layered perovskite-like solid solutions Bi3−xGdxTiNbO9 (x=0, 0.1, 0.2, 0.3) with high Curie temperature

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060002
Author(s):  
S. V. Zubkov
Keyword(s):  
Curie Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Aurivillius Phases ◽  
Lattice Space ◽  
Temperature Ranges ◽  
Curie Temperatures

The Aurivillius phases (APs) [Bi2O2][Formula: see text][[Formula: see text][Formula: see text]][Formula: see text] are well-known ferroelectrics with high Curie temperatures. High-temperature piezoceramics [Formula: see text]GdxTiNbO9(BiGdTiNb, [Formula: see text], 0.1, 0.2, 0.3) were prepared by a solid-state reaction method. The structural and electrophysical characteristics of BiGdTiNb ceramics have been studied. According to the data of powder X-ray diffraction, all the compounds are single-phase with the structures of two-layer APs ([Formula: see text]) with the orthorhombic crystal lattice (space group [Formula: see text]). The temperature dependence of the relative permittivity [Formula: see text] (T) of the compounds was measured and showed that the Curie temperature of perovskite-like oxides [Formula: see text]GdxTiNbO9 increases linearly with an increase in the substitution parameter [Formula: see text] to [Formula: see text]C. The activation energies of charge carriers have been found in different temperature ranges.

scholarly journals Pr- and Sm-Substituted Layered Perovskite Oxide Systems for IT-SOFC Cathodes

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6739
Author(s):  
Sung Hun Woo ◽  
Kyeong Eun Song ◽  
Seung-Wook Baek ◽  
Hyunil Kang ◽  
Wonseok Choi ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Ionic Radius ◽  
Perovskite Oxide ◽  
Layered Perovskite ◽  
Oxide Systems ◽  
Phase Synthesis ◽  
Small Ionic Radius ◽  
Temperature Operating ◽  
A Site ◽  
Layered Perovskites

In this study, the phase synthesis and electrochemical properties of A/A//A///B2O5+d (A/: Lanthanide, A//: Ba, and A//: Sr) layered perovskites in which Pr and Sm were substituted at the A/-site were investigated for cathode materials of Intermediate Temperature-Operating Solid Oxide Fuel cells (IT-SOFC). In the PrxSm1-xBa0.5Sr0.5Co2O5+d (x = 0.1–0.9) systems, tetragonal (x < 0.4) and orthorhombic (x ≥ 0.5) crystalline structures were confirmed according to the substitution amount of Pr, which has a relatively large ionic radius, and Sm, which has a small ionic radius. All of the layered perovskite oxide systems utilized in this study presented typical metallic conductivity behavior, with decreasing electrical conductivity as temperature increased. In addition, Pr0.5Sm0.5Ba0.5Sr0.5Co2O5+d (PSBSCO55), showing a tetragonal crystalline structure, had the lowest conductivity values. However, the Area-Specific Resistance (ASR) of PSBSCO55 was found to be 0.10 Ωcm2 at 700 °C, which is lower than those of the other compositions.

Structural and Magnetic Hysteresis Properties of Co-Zr Substituted Hexagonal Barium Ferrites

2015 ◽  
Vol 7 (1) ◽  
pp. 1346-1351
Author(s):  
Ch.Gopal Reddy ◽  
Ch. Venkateshwarlu ◽  
P. Vijaya Bhasker Reddy
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Grain Morphology ◽  
Hexagonal Structure ◽  
Ion Composition ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
Barium Ferrites ◽  
Xrd Patterns

Co-Zr substituted M-type hexagonal barium ferrites, with chemical formula BaCoxZrxFe12-2xO19 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), have been synthesized by double sintering ceramic method. The crystallographic properties, grain morphology and magnetic properties of these ferrites have been investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirm the single phase with hexagonal structure of prepared ferrites. The magnetic properties have been investigated as a function of Co and Zr ion composition at an applied field in the range of 20 KOe. These studies indicate that the saturation magnetization (Ms) in the samples increases initially up to the Co-Zr composition of x=0.6 and decreases thereafter. On the other hand, the coercivity (Hc) and Remanent magnetization (Mr) are found to decrease continuously with increasing Co-Zr content. This property is most useful in permanent magnetic recording. The observed results are explained on the basis of site occupation of Co and Zr ions in the samples.

scholarly journals Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Low Frequency ◽  
Solid State Reaction Method ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Frequency Regime ◽  
Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

Structural, Dielectric and Electrical Studies of Ba4CaRTi3Nb7O30 (R = Eu, Dy) Ferroelectric System

2013 ◽  
Vol 547 ◽  
pp. 41-48 ◽  
Author(s):  
Prasun Ganguly ◽  
A.M. Biradar ◽  
A.K. Jha
Keyword(s):  
Single Phase ◽  
Microstructural Analysis ◽  
Tungsten Bronze ◽  
Negative Temperature ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Paraelectric Phase Transition ◽  
Orthorhombic Crystal Structure

The polycrystalline samples of Ba4CaRTi3Nb7O30 (R = Eu, Dy), members of tungsten-bronze family, were prepared by high-temperature solid state reaction method and studied for their dielectric and electrical properties. X-ray diffraction (XRD) analysis reveals the formation of single-phase compounds having orthorhombic crystal structure at room temperature. Microstructural analysis by scanning electron microscope (SEM) shows that the compounds have well defined grains, which are distributed uniformly throughout the sample. Detailed dielectric properties of the compounds as a function of frequency and temperature show that the compounds undergo non-relaxor kind of ferroelectric-paraelectric phase transition of diffuse nature. Ferroelectric, piezoelectric and pyroelectric studies of the compounds have been discussed in this paper. The temperature dependence of dc conductivity of the compounds have been investigated. The conductivity study over a wide temperature range suggests that the compounds have negative temperature coefficient of resistance (NTCR) behaviour.

Analysis of Selected Area Diffraction Patterns With Winjade

1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey
Keyword(s):  
Single Phase ◽  
Xrd Analysis ◽  
Analysis Program ◽  
X Ray Diffraction ◽  
Program Module ◽  
Vast Number ◽  
One Dimensional ◽  
X Ray ◽  
Diffraction Patterns ◽  
Xrd Patterns

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.

scholarly journals Study of multiferroic properties of Bi2Fe2WO9 ceramic for device application

2016 ◽  
Vol 06 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Jyoshna Rout ◽  
R. N. P. Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Electrical Parameters ◽  
Orthorhombic Crystal ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Universal Power Law ◽  
Phase Compound ◽  
Comprehensive Study

The Bi2Fe2WO9 ceramic was prepared using a standard solid-state reaction technique. Preliminary analysis of X-ray diffraction pattern revealed the formation of single-phase compound with orthorhombic crystal symmetry. The surface morphology of the material captured using scanning electron microscope (SEM) exhibits formation of a densely packed microstructure. Comprehensive study of dielectric properties showed two anomalies at 200[Formula: see text]C and 450[Formula: see text]C: first one may be related to magnetic whereas second one may be related to ferroelectric phase transition. The field dependent magnetic study of the material shows the existence of small remnant magnetization ([Formula: see text]) of 0.052[Formula: see text]em[Formula: see text]/g at room temperature. The existence of magneto-electric (ME) coupling coefficient along with above properties confirms multi-ferroic characteristics of the compound. Selected range temperature and frequency dependent electrical parameters (impedance, modulus, conductivity) of the compound shows that electric properties are correlated to its microstructure. Detailed studies of frequency dependence of ac conductivity suggest that the material obeys Jonscher’s universal power law.

Structural and Electronic Properties of (CdTe)1−x(In2Te3)x Films Grown by Close-spaced vapor Transport Combined with Free Evaporation

2000 ◽  
Vol 15 (8) ◽  
pp. 1811-1815 ◽  
Author(s):  
M. Zapata-Torres ◽  
Y. P. Mascarenhas ◽  
M. A. Santana-Aranda ◽  
J. Luyo-Alvarado ◽  
M. Melé-Lirandez ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Single Phase ◽  
Vapor Transport ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Structural And Electronic Properties ◽  
Direct Band ◽  
Transmission Measurements

The structural and electronic properties of (CdTe)1−x(In2Te3)x thin films as a function of substrate temperature were studied using x-ray diffraction, energy dispersive x-ray analysis, and Raman, transmission, and modulated transmission spectroscopies. The films were grown by the close-spaced vapor transport technique combined with free evaporation; CdTe and In2Te3 were used as sources. From x-ray diffraction the presence of mixed phases and differences in composition were detected, and good correlation with Raman spectroscopy was found. Transmission spectroscopy suggested the possibility of a modulation of the band gap of the alloy from a value as low as 0.5 eV up to 1.5 eV. Single-phase films presented a direct band gap of around 1.15 eV, as obtained from modulated transmission measurements.

STUDY OF STRUCTURAL, ELECTRICAL TRANSPORT AND MAGNETIC PROPERTIES IN La1-xAgxMnO3 COMPOUNDS

2004 ◽  
Vol 18 (05n06) ◽  
pp. 221-231 ◽  
Author(s):  
MANORANJAN KAR ◽  
S. RAVI
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Single Phase ◽  
Ac Susceptibility ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Phase Form ◽  
X Ray ◽  
Maximum Value

X-ray diffraction, electrical resistivity and ac susceptibility measurements have been carried out on La 1-x Ag x MnO 3 compounds for x=0.05 to 0.30. These samples are found to be in single phase form with [Formula: see text] space group and with typical lattice parameters a=b=5.524Å and c=13.349Å for x=0.05 sample. The Mn–O–Mn bond angles and variance, σ2 are found to increase with doping. Metal-insulator transitions in the temperature range 254 to 259 K have been observed. These materials exhibit paramagnetic to ferromagnetic transitions in the vicinity of metal-insulator transition temperatures. The paramagnetic susceptibility could be analyzed using Curie–Weiss law. All the above samples exhibit colossal magneto-resistivity and its maximum value is found to be 73% for x=0.15 sample at 50 kOe magnetic field.

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