Advanced Materials Research Vols. 734-737

Abstract: The spinel LiMn₂O₄ was synthesized by high temperature solid-state reaction and modified by coating carbon nanotubes (CNTs) which was used as the carbon source. The effect of different coated quantity on the electrochemical performance of spinel cathode materials was discussed. The morphology and structure of the material was characterized by SEM and XRD. The results indicated that the crystal grew well and morphology displayed excellently. Based on electrochemical performance test, the conclusion could be drawn: at 0.5C1C2C rate, the initial discharge capacity of LiMn₂O₄ coated by 5%wt CNTs was 100.5113.1103.6mAh/g respectively. After 20 cycles, the capacity maintained at 115.5111.3101.1mAh/g, which displayed better capacity retention.

Abstract: Anatase/brookite mixtured TiO₂ nanoparticles have been synthesized by using a two-step process through a chimie douce technique. The as-prepared powders were characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and a nitrogen adsorption apparatus in multipoint Brunauer-Emmett-Teller (BET) method. The results indicated that the TiO₂ nanoparticles were composed of biphasial anatase/brookite mixtures, 38% anatase phase formed in quasi-spherical shape and 62% brookite phase formed in nanorod shape. The specific surface area, the average pore diameter, and the specific pore volume were 100.06 m²/g, 14.0 nm, and 0.561 cm³/g, respectively.

Abstract: Organic intermediate di (chloroethyl) phosphite was synthesized in this work. The influence of reaction temperature, reaction time and solvent on the yield of product was investigated with orthogonal method. The experiment results show that the optimal conditions were molar ration of 2-chloroethannol / phosphorus trichloride 4.0:1, reaction temperature 65~75 °C, reaction time 4h, solvent 60 mL, and the yield of the product reached 89.5%. The asprepared di (chloroethyl) phosphite samples were further characterized by FT-IR and NMR.

Abstract: The high-quality MCM-41 was synthesized from silica fume with Citric acid and cetyltrimethylammonium bromide (CTAB) as template agents. Silica fume entered into liquid system in silicate and matched with CTA⁺. Mesoporous phase formed with the help of Citric and PEG-6000 in an acidic process followed. The structure and morphology of mesoporous silica material so-prepared was investigated based on the analysis of X-ray diffraction (XRD), N₂ sorption/desorption (BET) and transmission electron microscopy (TEM). The results indicated that MCM-41 was successfully prepared by substituting silica fume for the traditional silica source of tetraethyl orthosilicate, and the MCM-41 displayed high quality with the pore sizes 4.3 nm, the BET areas 1058 m²/g, the total pore volume 0.862 cm³/g.

Abstract: The olivine LiFePO₄/C composite cathode materials for lithium-ion batteries were synthesized by solid state reduction method using mixed iron sources. The effects of different temperatures on the electrochemical performance of as-synthesized cathode materials were investigated and analyzed. The crystal structures and the electrochemical performances were characterized by SEM, galvanostatical charge-discharge testing and AC-impedance, respectively. The results demonstrated that the LiFePO₄/C composite cathode material synthesized at 710°C and with 1/2(FeC₂O₄·2H₂O/Fe₂O₃) molar ratio of mixed iron sources has the better electrochemical performance, it has a discharge capacity of 126.1mAh/g at 0.2C and the capacity is kept at 113.8mAh/g after 20 cycles.

Abstract: This study reports the successful preparation of Cu (In, Ga)Se₂ (CIGS) thin film solar cells by ion beam sputtering with a chalcopyrite CIGS quaternary target. The films were fabricated with different beam currents. The thin films were characterized with X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and hall effect-measurement system to study the microstructures, composition, surface morphology and electrical properties, respectively. Experimental results show that both the films are chalcopyrite structure, the Ga/(In+Ga) ratio, Cu/(In+Ga) ratio and Se/(Cu+In+Ga) ratio are decrease with the beam currents increase, the surfaces morphology of the films are dense, and the resistivity of the film deposited with the beam current of 40mA is 0.56Ωcm, with a carrier concentration of 4.11Χ10¹⁸cm^-3 and mobility of 2.73cm²V^-1s^-1. The resulting film exhibited p-type conductivity.

Abstract: The laboratory evaluation studied the matching relationship between different concentration polymer solution and the formation permeability,and also the matching relationship between different molecular weight polymer solution and the formation permeability. The influences on the solution viscoelasticity,which were caused by the polymer concentration and the molecular weights,were analysed by the laboratory evaluation tests on the viscoelasticity of the polymer solution.

Abstract: The title complex, [Co (ncpb)(μ-4,4'-bpy)(H₂O)₂](4,4'-bpy) (1) (4,4'-bpy = 4,4'-bipyridine, ncpb = 5-nitro-4-carboxylatophenylboronic acid), was synthesized from a hydrothermal reaction of CoCl₂·6H₂O, ncpb ligand and 4,4'-bpy, and characterized by single-crystal X-ray diffraction analysis. The complex 1 crystallizes in monoclinic space group C2/c with a = 27.104(2) Å, b = 11.3566(8) Å, c = 13.5065(10) Å, β = 113.0220(10)°. The structure of 1 is composed of discrete 4,4'-bpy moleculars and 1-D chains originating from terminal ncpb ligands and μ-4,4'-bpy molecules. The chains are further connected through rich intermolecular OH···O and OH···N hydrogen bonds to genenate a 3-D supramolecular architecture.

Abstract: Direct current magnetron co-sputtering was used to deposit zinc antimonide thin films on BK7 glass substrates at room-temperature. Then the films were annealed at 573 K to 673 K for 1 hour in Ar atmosphere. The results indicate that the Seebeck coefficient of the thin films increase from 30.5 μVK^-1to 132.5 μVK^-1 when the annealing temperature changed. The electrical conductivity of the thin films increases from 3.45×10³ to 6.86×10³ Sm^-1 and the Power Factor is enhanced greatly from 0.03×10^-4 to 0.99×10^-4 Wm^-1K^-2 when the annealing temperature reached 598 K. X-ray diffraction result shows that the major diffraction peaks of the thin films match those of β phase Zn₄Sb₃ and high crystalline thin films are achieved after annealing.

Abstract: The presence of the colloid will affect uranium heap leaching. The objective of this study was the examination of the ability of colloid retardation to uranium by irons hydroxide colloids simulated heap leaching process. Batch studies have been carried by observing the effects of pH, contact time, uranium concentration. Iron hydroxide colloids can exist stably at pH 1.5-3.0. The size of the colloid samples is between 20 nm and 1000 nm. The sorption equilibrium was attained at 24 h. The load uranium capacity on iron hydroxide colloids are between 2.43×10^-3 and 3.84×10^-3 mmol/mol. The colloid morphology of before and after loaded uranium were identified using S-4800 scanning electron microscopy (SEM/EDS). The load uranium capacity on iron hydroxide colloids is least at pH=2, it implies that the appropriate pH of uranium heap leach is 2.0 on the point of retardation of colloid to uranium migration.