Antimony-doped tin oxide films were prepared by sol-gel technique from an ethanolic solution of SnCl4.5H2O and SbCl3. The effect of the addition of acetylacetone as a hydrolysis modifier was investigated. Structural, ...
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ISBN:
(纸本)9781632660008
Antimony-doped tin oxide films were prepared by sol-gel technique from an ethanolic solution of SnCl4.5H2O and SbCl3. The effect of the addition of acetylacetone as a hydrolysis modifier was investigated. Structural, optical and electrical properties of the films were studied by XRD, FESEM, TEM, FTIR, UV-vis, TG and Hall effect measurements. TEM results showed that antimony-doped tin oxide films consist of well-crystallized grains ranging from 5 to 10 nm. It was found that the addition of the acetylacetone influences positively the film properties. The appropriate addition of acetylacetone allowed for the preparation of films with an optical transmittance as high as 97% in the visible region and 47% at 200 nm. Highly transparent films prepared in this study exhibit an electrical resistivity of 10-3 Ω cm which make them attractive for photovoltaic cell applications.
To investigate the quantitative relationship between the electromagnetic-shielding property of composites and the distribution of inclusions, a scheme for predicting the shielding effectiveness of composites containin...
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To investigate the quantitative relationship between the electromagnetic-shielding property of composites and the distribution of inclusions, a scheme for predicting the shielding effectiveness of composites containing variously-distributed flaky inclusions is proposed. The scheme is based on equivalent parameters of homogeneous comparison materials and the plane-wave shielding theory. It leads to expli- cit formulas for the shielding effectiveness of multi-layered composites in terms of microstructural parameters that characterize the shape, distribution and orientation of the inclusions. For single layer composite that contains random and aligned flaky silver-coated carbonyl-iron particles with fractions of different volume, the predicted shielding effectiveness agrees well with the experimental data. As for composites containing aligned flaky particles,the shielding effectiveness obtained by the proposed scheme and experiment data is higher than that the random case, e.g. about 20 dB higher at 750 MHz. The proposed scheme is a straightforward method for optimizing future composite de- signs.
In recent years, self-assembly nanoparticles into well-ordered structures possess quite important position in spectroscopy, magnetism, catalysis and *** all of the nanoparticles, magnetic nanoparticles promises an unp...
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In recent years, self-assembly nanoparticles into well-ordered structures possess quite important position in spectroscopy, magnetism, catalysis and *** all of the nanoparticles, magnetic nanoparticles promises an unparalleled opportunity for self-assembly as they can be controlled to form directional arrangements according to the external magnetic fields.
One-dimensional nanomaterialshave attracted significant attention for a wide range of energy-related applications due to such unique advantages as short Li-ion insertion/extraction distance, facile strain relaxation u...
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One-dimensional nanomaterialshave attracted significant attention for a wide range of energy-related applications due to such unique advantages as short Li-ion insertion/extraction distance, facile strain relaxation upon electrochemical cycling, enhanced electron transport, and very large surface to volume ratio. We designed the single nanowire electrode devices as a unique platform for in situ probing the direct relationship between electrical transport, structure, and electrochemical properties of the single nanowire electrode to understand intrinsic reason of capacity fading. It demonstrates that during the electrochemical reaction conductivity of the nanowire electrode decreased, which limits the cycle life of the devices. Then, the prelithiation and Langmuir-Blodgett technique have been used to improve the cycling stability of nanowire electrode. Recently, we have synthesized SVO/PANI triaxial nanowires and fabricated hierarchical MnMoO 4 /CoMoO 4 heterostructured nanowires by combining "oriented attachment" and "self-assembly". The asymmetric supercapacitors based on the hierarchical heterostructured nanowires showed a high specific capacitance and good reversibility with a cycling efficiency of 98% after 1,000 cycles. Furthermore, we fabricated Li-air battery based on hierarchical mesoporous LSCO nanowires and nonaqueous electrolytes, which exhibits ultrahigh capacity over 11000 mAh g –1 , with the improvement of one order of magnitude than LSCO nanoparticles. We also designed and synthesized novel cucumber-like MnO 2 nanoparticles-enriched V 2 O 5 /PEDOT coaxial nanowires by layer-by-layer assembly with enhanced electrochemical performance. Recently we designed a nanoscroll buffered hybrid nanostructural VO 2 (B) composed of nanobelts and nanowires with greatly improved cycle life and rate capability. It is expected that our study may extend effective and helpful methods in directions that will solve the challenge of property degradation in energy storage an
Lithium-ion batteries (LIBs) are receiving considerable attention as storage devices in the renewable and sustainable energy developments. However, facile fabrication of long-life and high-rate cathode materials for...
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Lithium-ion batteries (LIBs) are receiving considerable attention as storage devices in the renewable and sustainable energy developments. However, facile fabrication of long-life and high-rate cathode materials for LIBs is required to facilitate practical application. Among the candidate materials for high power LIBs, sodium super ionic conductor (NASICON) structured polyanion-based orthophosphate Li 3 V 2 (PO 4 ) 3 exhibits high energy and power density, and has been regarded as a prospective alternative cathode material in high power facilities such as electric vehicles, hybrid electric vehicles, and other power-supply equipment. Nevertheless, Li 3 V 2 (PO 4 ) 3 still faces some challenges such as low electronic conductivity and capacity fading during cycling. Here we propose a rationally controllable synthesis of highly crystalline Li 3 V 2 (PO 4 ) 3 nanospheres with a uniform carbon coating layer to restrain structure degradation during cycling. Additionally, acetylene black was used as the reducing agent and the template for particle growth, as well as a three-dimensional conductive and flexible network to provide a continuous electron pathway in the electrode. The uniform carbon layer and the conductive carbon network have a synergetic effect to enhance not only the cycling stability but also rate performance of Li 3 V 2 (PO 4 ) 3 in the application for LIBs. The as-prepared cathode material has a discharge capacity of 142 mA h g -1 at 1 C rate, approaching its theoretical value (150 mA h g -1 ), and can even be cycled at a rate as high as 30 C without capacity fading. After 1000 cycles at a rate of 5 C, the as-prepared material has capacity retention of up to 83%, and can also tolerate 5000 cycles with a considerable capacity, demonstrating excellent cycling stability. Our work shows that this material has great potential for high-energy and high-power energy storage applications, and this rational method can be applied to synthesizing high-performance catho
Rechargeable lithium batteries have been widely used for consumer electronics and are desirable for the development of hybrid electric vehicles and electric vehicles, due to their high energy density and good environm...
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Rechargeable lithium batteries have been widely used for consumer electronics and are desirable for the development of hybrid electric vehicles and electric vehicles, due to their high energy density and good environment compatibility. The enhanced electrochemical performance of electrodes depends on not only the material intrinsic characteristics, but also the designed morphologies. One-dimensional (1D) nanostructures can offer large surface area and efficient electron transport pathway to achieving high capacity. As a functional nanostructure, nanoscroll with open ends/edges could provide easy radial expansion by interlayer sliding to buffer the swelling during lithiation/delithiation. Herein, we report a nanoscroll buffered hybrid nanostructural VO 2 (B) (HNS) composed of nanobelts and nanowires with greatly improved cycle life and rate capability. It is found that this unique HNS with buffered section provides facile strain relaxation to accommodate the volume variations during lithiation/delithiation, which greatly enhance the structural stability and cyclability. Further, the interior of nanoscrolls and the interconnected voids between the hybrid nanostructures could shorten the lithium ion diffusion pathway for fast charge/discharge. As a result, the HNS cathode exhibits long-life performance with capacity retention over 82% after 1,000 cycles at C (1,000 mA g -1 ), and high rate up to ~20 C (2,000 mA g -1 ). This unique HNS can be applied to the next-generation high-performance batteries for portable electronics and large-scale energy storage devices. Constructing the nanoscroll buffered hybrid nanostructure described in this paper is a facile and effective method to enhance the electrochemical performance of other electrode materials.
As an air-pollution-free and high efficient power generating device,proton exchange membrane fuel cell (PEMFC) has attracted a wide *** of the key components of PEMFC is catalyst,during while the support materials pla...
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As an air-pollution-free and high efficient power generating device,proton exchange membrane fuel cell (PEMFC) has attracted a wide *** of the key components of PEMFC is catalyst,during while the support materials play an important role in improving the electrochemical surface area (ECSA) of the catalysts loaded on them.
As a layered-structure semiconductor material with wide band gap, MoO 3 has been considered to be a promising candidate for application in gas sensor. Recently, gas sensor based on MoO 3 have been found to have a resp...
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As a layered-structure semiconductor material with wide band gap, MoO 3 has been considered to be a promising candidate for application in gas sensor. Recently, gas sensor based on MoO 3 have been found to have a response towards various gases such as H 2 S, NO 2 , NH 3 , trimethylamine, formaldehyde and H 2 in the temperature range of 300–600 °C. Although MoO 3 films and nanorods are not sensitive to ethanol gas, it is found that the ultralong MoO 3 nanobelts have a good sensitivity and selectivity to ethanol gas in our works. In the present work, the ultralong MoO 3 nanobelts are prepared by hydrothermal method using a molybdenum organic salt precursor. The nanobelts are flexible with an average length of 200-300μm and width of 500nm, which won’t be broken even after bended or distorted. The nanobelts are characterized by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectra. Gas sensor based on ultralong and flexibility MoO 3 nanobelts is then fabricated. The sensor shows a good sensitivity towards ethanol gas, while almost no response towards other reducing gases, such as ammonia and formaldehyde in the temperature range of 220–380 ℃, the detection limit to ethanol gas may reach to 5ppm at the temperature of 380℃, which indicates that this kind of sensor has a promising future for ethanol detection. In conclusion, a gas sensor has been fabricated based on ultralong and flexibility MoO 3 nanobelts, which are prepared by hydrothermal method using a molybdenum organic salt precursor, and it is sensitive to ethanol gas. The reason for the good sensitivity to ethanol may be due to the large specific surface area, axial electron transfer and the non-stoichiometry of MoO 3 nanobelts.
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