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The submicron single crystals of LiCoPO 4 with 500 nm diameter are prepared by solvothermal method. The carbon coated sample is obtained using sucrose as carbon source under 650 °C subsequently. It is investigated that the solvent composition has an effect on the morphology and the electrochemical performance of the cathode material. The as-prepared samples are characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopic, dynamic light scattering, and Fourier transform infrared spectra. The electrochemical performance is evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The LiCoPO 4 /C cathode can reach an initial discharge capacity of 123.8 mA h g −1 at 0.1C, with a retention of 83% after 100 cycles. A discharge capacity of 84.9 mA h g −1 is still attainable when the rate is up to 2C. The good cycling performance and rate capability are contributed to the decrease of particle size along with the lower antisite defect concentration in the LCP crystals, and uniform carbon coating. [ABSTRACT FROM AUTHOR]

Li4SiO4was obtained by using quartzpowder of different particle sizes (75–180 μm, 45–75μm, 38–45 μm, and <38 μm) and Li2CO3as raw materials through a solid-state reaction at720 °C. X-ray diffraction (XRD), scanning electron microscopy(SEM), and differential thermal analysis and thermogravimetry (DTA/TG)were used to examine the sintering behavior and properties of thesamples. The results indicated that when the particle size of thequartz powder decreased, the solid-state reaction performed more completely,the content of the Li4SiO4phase increased,and the size of the grain agglomerates decreased gradually. The enhancedchemical reactivity of the quartz powder with Li2CO3and the shortened diffusion distance as the quartz size decreasesare helpful to the formation of the Li4SiO4phase.The sorption analysis revealed that the samples synthesized usingthe quartz powder with smaller particle sizes experienced a more rapidabsorption–desorption process with a higher absorption efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The intercalation compounds of kaolinite/potassium acetate were prepared by grinding and aging mixtures of potassium acetate and kaolinite from coal measures. The techniques of XRD, ICP-AES, IR, DSC, SEM and particle-size distribution analysis were used to characterize the microstructure and stability of the as-obtained intercalation compounds. The basal spacing increased from 0.72nm for the raw kaolinite to 1.42nm for the intercalation compound. The intercalation compounds were very stable in the anhydrous ethanol at room temperature, whereas deintercalation occurred when the as-obtained intercalation compounds were treated with water or heated at 296°C. [ABSTRACT FROM AUTHOR]

Single-crystal nickel-high materials (ST-LNCMO) LiNi 0.6 Co 0.2 Mn 0.2 O 2 have been synthesized using a versatile hydrothermal method. The as-prepared samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and selected area electron diffraction (SAED). The results show that the sample annealed at an optimized temperature of 850 °C reveals uniform fine well-crystallized single-particles with diameters of ～800 nm. Electrochemical data demonstrate that the cell using this nickel-high material as the cathode exhibits excellent performance. The sample displays a high capacity of 183.7 mA h·g −1 at 36 mA·g −1 (0.2 C) and excellent cycling stability at different rates. It yields an initial discharge capacity of 153.6 mA h·g −1 at a rate of 10C-rate and a voltage of 2.8 V – 4.3 V. The sample also has an outstanding rate capacity at a high cut-off voltage (4.6 V). This superior performance is attributed to the merits of the single-crystal structure, which may be beneficial to the transportation of the Li + ion along the grain. [ABSTRACT FROM AUTHOR]

A novel hierarchical structure carbon/sulfur composite is presented based on carbon fiber matrices, which are synthesized by electrospinning. The fibers are constituted with hollow graphitized carbon spheres formed using catalytic Ni nano-particles as hard templates. Sulfur is loaded to the carbon substrates via thermal vaporization. The structure and composition of the hierarchical carbon fiber/S composite are characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and nitrogen adsorption isotherms. The electrochemical performance is evaluated by cyclic voltammetry and galvanostatic charge–discharge. The results exhibit an initial discharge capacity of 845 mA h g −1 at 0.25 C (420 mA g −1 ), with a retention of 77% after 100 cycles. A discharge capacity of 533 mA h g −1 is still attainable when the rate is up to 1.0 C. The good cycling performance and rate capability are contributed to the uniform dispersion of sulfur, the conductive network of carbon fibers and hollow graphitized carbon spheres. [ABSTRACT FROM AUTHOR]

Micro/nanostructured ZnSn(OH)6/ZnO composite architectures were synthesized through a simple one-step hydrothermal method. Phase structure and morphology of the products were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). ZnSn(OH)6 microcubes and ZnO nanorods with uniform size were interconnected to form the micro/nanostructured architectures. ZnO nanorods preferentially grow at edges and corners of the microcubes. Morphology of the products was susceptible to concentration of the reactants. With increasing reactant concentration, the ZnO nanorods grown on the surfaces of ZnSn(OH)6 microcubes disappeared. Meanwhile, the smooth surfaces of the ZnSn(OH)6 microcubes become coarsened and were etched to spherical outlines. Growth mechanism of the micro/nanostructured ZnSn(OH)6/ZnO composite architectures was discussed and thermal decomposition properties of the micro/nanostructured ZnSn(OH)6/ZnO composite architectures at high temperature were examined. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

ZnSn(OH)6 regular octahedrons were successfully synthesized through a simple hydrothermal method using an aqueous solution containing ZnO flower-like structures, SnCl4·5H2O, and NaOH. Phase structure, morphology and microstructure of the samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Parameters in preparation process such as the ratios of Sn4+/OH-, the molar ratio of Zn/Sn and reaction time were discussed. Results show that the obtained samples are comprised of ZnSn(OH)6 regular octahedrons with about 2 μm in side length and ZnSn(OH)6 urchins-like structures. ZnSn(OH)6 urchins-like structures preferentially grow on the edges and corners of regular octahedrons. Morphology of the products is susceptible to the ratios of Sn4+/OH-. A relatively low concentration of OH- is favored to obtain ZnSn(OH)6 regular octahedrons with urchins-like structures on the surface, while a high concentration of OH- results in a handful of regular octahedrons without urchins-like structures on the surface. When the molar ratio of Zn/Sn changes to 1:2 or 2:1, the edges and corners of regular octahedrons become coarse and urchins-like structures disappear from the surface. More urchins-like structures form on the surface of regular octahedrons and the edges and corners of regular octahedrons become coarsened with the increase of reaction time. Moreover, the possible mechanism for ZnSn(OH)6 regular octahedrons is discussed. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper was to provide a convincing experimental research to demonstrate a dissolution–reorganization mechanism for the formation of tungstate-based inorganic–organic hybrid nanobelts by comparatively investigating the reaction behaviors of H2WO4 and H2W2O7·xH2O with n-alkylamines (C m H2m+1NH2, m =4–10). The formation of tungstate-based hybrid nanobelts derived from the reactions between n-alkylamines and H2WO4 with single-octahedral W–O layers was investigated with a detailed comparison with those between n-alkylamines and H2W2O7·xH2O with double-octahedral W–O layers. H2WO4 and H2W2O7·xH2O reacted with n-alkylamines, respectively, in reverse-microemulsion-like media. The obtained products were characterized by XRD, FT-IR, TG–DTA and SEM. The results indicated that the products derived from H2WO4 and those from H2W2O7·xH2O were similar in compositions, microstructures and morphologies. The structural analysis indicated the products were tungstate-based inorganic–organic hybrid one-dimensional belts with highly ordered lamellar structures by alternately stacking organic n-alkylammonium bilayers and inorganic single-octahedral W–O layers. The n-alkyl chains in the above hybrid nanobelts from H2WO4 and H2W2O7·xH2O took on a bilayer arrangement with tilt angles of 65° and 74°, respectively. The similarities in the microstructures of the products from H2W2O7·xH2O and H2WO4 demonstrated that the double-octahedral W–O layers of H2W2O7·xH2O were decomposed during the reactions. The changes of inorganic W–O layers and the morphologic changes of the tungstic-acid precursors before and after the reactions corroborated the dissolution–reorganization mechanism. [Copyright &y& Elsevier]

Abstract: ZnO nanowhiskers were successfully fabricated using DC-field induced water-in-oil microemulsions method. Phase structure, morphology and microstructure of the product were investigated by X-ray diffraction and transmission electron microscopy. Parameters in preparation process such as electric field intensity and surfactant were discussed and the product formation mechanism was studied. XRD and TEM results showed that the obtained ZnO particle was hexagonal wurtzite-type with 1–3nm in diameter and 20–70nm in length, and morphology of the particles was shown to be correlated not only with the electric field intensity but also with the surfactant. There was a threshold when the electric field intensity was 80V/mm. The morphology of the particles was basically spherical before the threshold, while L/D increased with the raise of electric field intensity. ZnO nanowhiskers were obtained under mixed surfactants but spherical particles were got with a single surfactant. [ABSTRACT FROM AUTHOR]

Abstract: The paper described a novel approach toward WO3 nanocrystals by pyrolytically decomposing tungstate-based inorganic–organic hybrid nanobelts in air at 500–600°C for 2h. The above-mentioned hybrid nanobelts were derived via a reaction of layered H2W2O7·xH2O and n-octylamine in a reverse-micelle-like medium (H2W2O7·xH2O/n-octylamine/heptane). The as-obtained WO3 nanocrystals and their intermediate products were characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM & FE-SEM), thermoanalysis (TG–DSC), Fourier-transform infrared spectra (FT/IR), UV–vis absorption and X-ray photoelectron spectroscopy (XPS). The as-obtained WO3 nanocrystals had an apparent size of 20–50nm, and took on a loose-aggregate-like morphology. The WO3 nanocrystals derived via the pyrolytic decomposition process were almost separated from each other and could be redispersed readily, while the WO3 nanocrystals obtained by the conventional acid-precipitation process tightly agglomerated into large particles with apparent sizes of several micrometers, without redispersibility even under an intense sonication treatment. [Copyright &y& Elsevier]