共查询到20条相似文献,搜索用时 31 毫秒
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E. I. Get’man S. N. Loboda M. A. Sidorkina 《Russian Journal of Inorganic Chemistry》2009,54(3):346-349
The CaO-3 (1 + x)CuO-4TiO2 system was studied using powder X-ray diffraction in the concentration region near calcium copper titanate. A single-phase material is formed in this system only when x ~ 0. An excess or deficit of copper gives rise to extra phases: CuO or CaTiO3 and TiO2, respectively. Impurities increase the dielectric constant of CaCu3Ti4O12-based ceramics. An excess of copper oxide (x ~ 0.08) increases ? more than tenfold. 相似文献
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T. L. Lekanova Yu. I. Ryabkov O. A. Sevbo V. N. Filippov 《Russian Journal of Applied Chemistry》2005,78(8):1223-1228
Interactions in the Al2TiO5-Ti2O3 system were studied and the regions of existence of Al2?2xTi 2x 3+ Ti4+O5 solid solutions with a pseudobrookite structure were determined. 相似文献
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R. Sathiyamoorthi P. Santhosh P. Shakkthivel T. Vasudevan 《Journal of Solid State Electrochemistry》2007,11(12):1665-1669
Layered Ti-doped lithiated nickel cobaltate, LiNi0.8Co0.2 − xTixO2 (where x = 0.01, 0.03, and 0.05) nanopowders were prepared by wet-chemistry technique. The structural properties of synthesized materials
were characterized by X-ray diffraction (XRD) and thermo-gravimetric/differential thermal analysis (TG/DTA). The morphological
changes brought about by the changes in composition of LiNi0.8Co0.2 − xTixO2 particles were examined through surface examination techniques such as scanning electron microscopy (SEM) and transmission
electron microscopy (TEM) analyses. Electrochemical studies were carried out using 2016-type coin cell in the voltage range
of 3.0–4.5 V (vs carbon) using 1 M LiClO4 in ethylene carbonate and diethyl carbonate as the electrolyte. Among the various concentrations of Ti-doped lithiated nickel
cobaltate materials, C/LiNi0.8Co0.17Ti0.03O2 cell gives stable charge–discharge features. 相似文献
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Electrical conductivity in the monoclinic Li2TiO3, cubic Li1.33Ti1.67O4, and in their mixture has been studied by impedance spectroscopy in the temperature range 20–730 °C. Li2TiO3 shows low lithium ion conductivity, σ300≈10–6 S/cm at 300 °C, whereas Li1.33Ti1.67O4 has 3×10–8 at 20 °C and 3×10–4 S/cm at 300 °C. Structural properties are used to discuss the observed conductivity features. The conductivity dependences
on temperature in the coordinates of 1000/T versus loge(σT) are not linear, as the conductivity mechanism changes. Extrinsic and intrinsic conductivity regions are observed. The change
in the conductivity mechanism in Li2TiO3 at around 500–600 °C is observed and considered as an effect of the first-order phase transition, not reported before. Formation
of solid solutions of Li2–
x
Ti1+
x
O3 above 900 °C significantly increases the conductivity. Irradiation by high-energy (5 MeV) electrons causes defects and the
conductivity in Li2TiO3 increases exponentially. A dose of 144 MGy yields an increase in conductivity of about 100 times at room temperature.
Electronic Publication 相似文献
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Wataru Sakamoto Ken-ichi Mimura Takafumi Naka Tetsuo Shimura Toshinobu Yogo 《Journal of Sol-Gel Science and Technology》2007,42(3):213-220
Ba(Zr,Ti)O3/LaNiO3 layered thin films have been synthesized by chemical solution deposition (CSD) using metal-organic precursor solutions. Ba(Zr,Ti)O3 thin films with smooth surface morphology and excellent dielectric properties were prepared on Pt/TiO
x
/SiO2/Si substrates by controlling the Zr/Ti ratios in Ba(Zr,Ti)O3. Chemically derived LaNiO3 thin films crystallized into the perovskite single phase and their conductivity was sufficiently high as a thin-film electrode.
Ba(Zr,Ti)O3/LaNiO3 layered thin films of single phase perovskite were fabricated on SiO2/Si and fused silica substrates. The dielectric constant of a Ba(Zr0.2Ti0.8)O3 thin film prepared at 700°C on a LaNiO3/fused silica substrate was found to be approximately 830 with a dielectric loss of 5% at 1 kHz and room temperature. Although
the Ba(Zr0.2Ti0.8)O3 thin film on the LaNiO3/fused silica substrate showed a smaller dielectric constant than the Ba(Zr0.2Ti0.8)O3 thin film on Pt/TiO
x
/SiO2/Si, small temperature dependence of dielectric constant was achieved over a wide temperature range. Furthermore, the fabrication
of the Ba(Zr,Ti)O3/LaNiO3 films in alternate thin layers similar to a multilayer capacitor structure was performed by the same solution deposition
process. 相似文献
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V. Balek N. Todorova C. Trapalis V. Štengl E. Večerníková J. Šubrt Z. Malek G. Kordas 《Journal of Thermal Analysis and Calorimetry》2005,80(2):503-509
Summary Titania-based photocatalytic materials were prepared by sol-gel method using Fe3+ and polyethyleneglycol (PEG600) as additives. Thermogravimetry (TG), differential thermal analysis (DTA) and evolved gas analysis (EGA) with MS detection were used to elucidate processes that take place during heating of Fe3+ containing titania gels. The microstructure development of the Fe2O3/TiO2 gel samples with and without PEG600 admixtures was characterized by emanation thermal analysis (ETA) under in situ heating in air. A mathematical model was used for the evaluation of ETA results. Surface area and porosity measurements of the samples dried at 120°C and the samples preheated for 1 h to 300 and 500°C were compared. From the XRD measurements it was confirmed that the crystallization of anatase took place after thermal heating up to 600°C. 相似文献
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Izabella Dascalu Cristian Hornoiu Jose Maria Calderon-Moreno Madalin Enache Daniela Culita Simona Somacescu 《Journal of Sol-Gel Science and Technology》2018,86(1):151-161
The aim of this work was an investigation of structural and electrical properties of ZnO/Zn2-xFexTiO4 (x?=?0.7, 1, 1.4) powders. The compounds obtained by sol-gel method are characterized by several techniques: X-ray diffraction (XRD), N2 adsorption–desorption isotherms, scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), electrical and dielectrical measurements. The XRD, SEM and XPS analysis confirmed the formation of ZnFeTiO4 inverse spinel structure. The electrical and dielectrical properties of ZnO/Zn2-xFexTiO4 (x?=?0.7, 1, 1.4) were measured by impedance spectroscopy, revealing a decrease in the electrical conductivity and the dielectric constant with Fe content. 相似文献
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Differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) were used to study the thermal behaviour of (50-x)Na2O-xTiO2-50P2O5 and 45Na2O-yTiO2-(55-y)P2O5 glasses. The addition of TiO2 to the starting glasses (x=0 and y=5 mol% TiO2) resulted in a nonlinear increase of glass transition temperature and dilatation softening temperature, whereas the thermal
expansion coefficient decreased. All prepared glasses crystallize under heating within the temperature range of 300–610°C.
The contribution of the surface crystallization mechanism over the internal one increases with increasing TiO2 content. With increasing TiO2 content the temperature of maximum nucleation rate is also gradually shifted from a value close to the glass transition temperature
towards the crystallization temperature. X-ray diffraction measurements showed that the major compounds formed by glass crystallization
were NaPO3, TiP2O7 and NaTi2(PO4)3. The chemical durability of the glasses without titanium oxide is very poor, but with the replacement of Na2O or P2O5 by TiO2, it increases sharply. 相似文献
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L. T. Denisova A. D. Izotov L. A. Irtyugo Yu. F. Kargin V. V. Beletskii V. M. Denisov 《Doklady Physical Chemistry》2017,472(1):10-12
Erbium stannate Er2Sn2O7 and thulium stannate Tm2Sn2O7 with a pyrochlore-type structure were produced by solid-phase synthesis by calcining stoichiometric mixtures of the respective oxides in air at 1473 K for 240 and 200 h. The high-temperature heat capacity of Er2Sn2O7 and Tm2Sn2O7 was studied by differential thermal calorimetry at 353–1000 K. From the experimental dependences C P = f(T), the thermodynamic functions (enthalpy change, entropy change, and reduced Gibbs free energy) of oxide compounds were calculated. 相似文献
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Lin Zhou Jing Liu Lisi Huang Na Jiang Qiaoji Zheng Dunmin Lin 《Journal of Solid State Electrochemistry》2017,21(12):3467-3477
Sn-doped Li-rich layered oxides of Li1.2Mn0.54-x Ni0.13Co0.13Sn x O2 have been synthesized via a sol-gel method, and their microstructure and electrochemical performance have been studied. The addition of Sn4+ ions has no distinct influence on the crystal structure of the materials. After doped with an appropriate amount of Sn4+, the electrochemical performance of Li1.2Mn0.54-x Ni0.13Co0.13Sn x O2 cathode materials is significantly enhanced. The optimal electrochemical performance is obtained at x = 0.01. The Li1.2Mn0.53Ni0.13Co0.13Sn0.01O2 electrode delivers a high initial discharge capacity of 268.9 mAh g?1 with an initial coulombic efficiency of 76.5% and a reversible capacity of 199.8 mAh g?1 at 0.1 C with capacity retention of 75.2% after 100 cycles. In addition, the Li1.2Mn0.53Ni0.13Co0.13Sn0.01O2 electrode exhibits the superior rate capability with discharge capacities of 239.8, 198.6, 164.4, 133.4, and 88.8 mAh g?1 at 0.2, 0.5, 1, 2, and 5 C, respectively, which are much higher than those of Li1.2Mn0.54Ni0.13Co0.13O2 (196.2, 153.5, 117.5, 92.7, and 43.8 mAh g?1 at 0.2, 0.5, 1, 2, and 5 C, respectively). The substitution of Sn4+ for Mn4+ enlarges the Li+ diffusion channels due to its larger ionic radius compared to Mn4+ and enhances the structural stability of Li-rich oxides, leading to the improved electrochemical performance in the Sn-doped Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials. 相似文献
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Ba(Ti1−x
Sn
x
)O3 (x = 0.10 or 0.15) thin films were deposited on Si(100) and Pt(111)/TiO
x
/SiO2/Si(100) substrates via sol–gel spin-coating. Crack-free thin films could be obtained by single-step deposition, where the
thickness was about 0.46 and 0.29 μm at 1000 and 2000 rpm, respectively. Circular delaminated parts 100 μm in diameter, however,
tended to appear in thicker films deposited at 1000 rpm. On both kinds of substrates, the films were crystallized between
500 and 600 °C, where the perovskite phase emerged as the primary phase, and the formation of single-phase perovskite was
basically achieved between 700–800 °C. The films deposited on Pt(111)/TiO
x
/SiO2/Si(100) substrates, however, tended to have small SnO2 and BaCO3 diffraction peaks, which decreased with increasing spinning rate. The dielectric properties were evaluated on the films deposited
on Pt(111)/TiO
x
/SiO2/Si(100) substrates at 2000 rpm. The films prepared by single-step depositions had dielectric constants of 350 and 230, and
dielectric loss of 0.30 and 0.10 at x = 0.1 and 0.15, respectively. The films prepared by two time deposition had dielectric constants of 450 and 250, and dielectric
loss of 0.21 and 0.19 at x = 0.10 and 0.15, respectively. 相似文献
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G. B. Kunshina I. V. Bocharova V. I. Ivanenko 《Russian Journal of Applied Chemistry》2016,89(6):909-915
Compatibility of the lithium-titanium spinel Li4Ti5O12 in contact with precursors of lithium-conducting solid electrolytes of composition Li1.3Al0.3Ti1.7(PO4)3 (LATP), Li1.5Al0.5Ge1.5(PO4)3 (LAGP), Li0.5La0.5TiO3 (LLT) was studied. It was found that, in sintering of Li4Ti5O12 brought in contact with LATP and LAGP, a solid-phase reaction occurs to give nonconducting phases (TiO2 and Li3PO4). The conductivity of the stable composite Li4Ti5O12/LLT (10%) is higher than that of the starting Li4Ti5O12, which makes it possible to regard the composite as a promising anode material for lithium-ion batteries. 相似文献