1,721,167 research outputs found
Comment on "Precursor morphology controlled formation of rutile VO2 nanorods and their self-assembled structure"
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Total scattering investigation of materials for clean energy applications: The importance of the local structure
No full textIn this Perspective article we give an account of the application of total scattering methods and pair
distribution function (PDF) analysis to the investigation of materials for clean energy applications such
as materials for solid oxide fuel cells and lithium batteries, in order to show the power of this technique
in providing new insights into the structure–property correlation in this class of materials
Electrochemical open circuit voltage (OCV) characterization of SOFC materials
No full textIn this paper, we are reporting an extensive characterization, by means of open circuit voltage measurements, of Ce0.8Gd0.2O2, La0.9Sr0.1Ga0.8Mg0.2O3, and La2Mo0.6W1.4O9 oxide-ions and BaCe0.8Y0.2O3 and BaCe0.55Zr0.3Y0.15O3 proton-conducting electrolyte materials for solid oxide fuel cell (SOFC) applications. This simple and common technique, well known for a long time in the electrochemical study of solid oxide fuel cells, has been here proposed for the electrical characterization of these ceramic materials, in order to define their ionic transport numbers, the maximum voltage performances, the thermal and chemical stability, and also to suggest the ideal temperature range for different applications, as in the electrochemical devices, sensors, and SOFC field. In the paper, controlled and reproducible working conditions have been applied in a wide range of temperature, by means of ultrapure gas (H2 and O2), under operational conditions found in real SOFC devices and, mainly, without the usual problems related to the chemical compatibility, the depolarization efficiency, and the high current density required to the electrode materials in the design of a more efficient SOFC device
Structure-properties correlations in Fe chalcogenide superconductors
Full text linkThe focus of this review article is on the PbO-type Fe chalcogenides that recently emerged as a
new class of superconductors. The fundamental correlations between structural details and
chemical compositions are discussed together with their influence on the electronic properties
Structural investigation of high-Tc superconductor EuBa2Cu3Oy by microRaman spectroscopy
No full textPolycrystalline EuBa2Cu3Oy (EuBCO) samples with various oxygen contents (y 6.25, 6.38 and 6.8) have been analysed by
means of microRaman spectroscopy. The usual Raman features of REBa2Cu3Oy high temperature superconductors (RE Y,
Eu, Sm, Er1⁄4) have been con®rmed also for EuBCO. A correlation between the crystal structure and the conductivity properties
as a function of the oxygen content has been established by studying in detail the features of the different Raman spectra. In
particular, the analysis of the peak pro®les of lattice vibrations involving oxygen atoms provides important information to
understand the anomalous superconducting properties found in the sample with y 6.38. In addition, the appearance in the
superconducting samples of a new mode centred at 223 cm21 may be correlated to ordering phenomena which have been called to justify the conductivity results
Correlation between thermal properties, electrical conductivity, and crystal structure in the BaCe0.80Y0.20O2.9 proton conductor
No full textIn this paper, we report an extensive neutron diffraction investigation at high temperature on the BaCe0.80Y0.20O2.9 proton conducting material. Our results precisely define the structural evolution of this compound as a function of temperature which evolves from the monoclinic structure found at room temperature to the orthorhombic symmetry (Imma space group) at 500 °C; then it adopts a rhombohedral structure from 600 to 700 °C and finally transforms into the more symmetric cubic structure at the highest investigated temperature (800 °C). This progressive increase in the symmetry of the system is not accompanied by any first order phase transition as also confirmed by thermal analysis. Finally, combined neutron data and TGA measurement shows that the oxygen content in the sample is stable up to about 700 °C. Above this temperature, the oxygen content reduces from the nominal content of about 2.9 to about 2.8
Local and average structures of the proton conducting Y-doped BaCeO3 from neutron diffraction and neutron pair distribution function analysis
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