Advanced Materials Research Vols. 785-786

Abstract: Yttrium iron garnet (YIG) glass ceramic was successfully synthesized by aqueous aolution-melt method. The as-prepared base glass was heat treated at different temperature and investigated by XRD and VSM. The annealed glass at 580°C shows the formation of magnetite structure with saturation magnetization of 10.6A·m²/kg.And the annealed glass heat treating at 850°C for 6h, show the formation of garnet structure with saturation magnetization of 18.2A·m²/kg.

Abstract: The hybrid guest-host nanocomposite films based on poly (ethylene oxide) (PEO) and molybdenum doped vanadium pentoxide (V_0.975Mo_0.025)₂O₅nH₂O were prepared by sol-gel and hydrothermal reaction via a two-part process. The electrical properties along and across V-O layers have been evaluated. The results indicate that the proper amount of PEO can increase the electrical conductivity of the films. The electrochromism of the films were investigated by cyclic voltammetry, the ex-situ transmission spectra and photographs. The films display a reversible multichromism (orangegreenbluebrown) upon Li⁺ ion insertion/extraction.

Abstract: This paper selected 10 kinds of fabrics of thermal underwear, which are the representatives on the market; carried out tests on the fabric properties (thickness, density, the gram per square meter, etc.) and the fabric wearability (permeability, water vapor permeability, wicking height, insulation and antistatic properties, etc.); analyzed these data by using SPSS, finding out the factors which effect the warmth, moisture permeability, air permeability, etc, as well as the relationship between these factors. This article evaluated fabric wearability comprehensively by using concentrated reflection method and function value evaluation method to select the proper fabrics of thermal underwear under different conditions. The results of this research can be a good reference of thermal underwear fabric selection for enterprises.

Abstract: A series of reduced graphene oxide/cobalt oxide composites (Co₃O₄/rGO)were fabricated via a chemical precipitation approach and subsequent calcination in Ar atmosphere. Experimental results show that Co₃O₄/rGO composite with 86 wt% of Co₃O₄ loading exhibits the optimum specific capacitance of 240 F g^-1 in 6.0 M KOH electrolyte at the current density of 0.8 A g^-1, excellent quick charge-discharge performance and outstanding cyclic stability with 2.3% of its specific capacitance increase after 2400 cycles at the current density of 8 A g^-1 in GCD test, exhibiting significant potential of Co₃O₄ /rGO composite in the application of supercapacitors.

Abstract: Graphene with different reduction degrees was prepared by fast thermally reduction of exfoliated graphite oxide (GO) at 200-700 °C. Structure and the electrochemical capacitive performance were characterized and measured. The results show that different thermal reduction temperatures can obtain reduced graphene oxide (rGO) with different reduction degrees and influence the electrochemical capacitive performance. The rGO-400 by thermal treat at 400 °C exhibits a significantly high specific capacitance of 407 F g^-1 in 6.0 M KOH electrolyte at a current density of 0.4 A g^-1 and outstanding cyclic stability with 96.1% of its origin specific capacitance maintained after 2000 cycles at the current density of 10 A g^-1 in GCD test.

Abstract: A facile process was developed to synthesize MoS₂ nanospheres by a simple PVP assisted hydrothermal method. The samples were characterized by XRD, SEM and Electrochemical tests. SEM demonstrates that the obtained MoS₂ has sphere-like morphology in the presence of surfactant PVP. Electrochemical measurements show that the initial discharge capacity of the MoS₂ nanospheres is 1915.1, 895.8 and 761.6 mAh g^-1 at current densities of 100, 400 and 800 mA g^-1, respectively. Meanwhile, it is found that the MoS₂ nanospheres have improved rate capacity and cycle stability.

Abstract: Layered manganese oxide nanostructures were synthesized by a facile hydrothermal method, using KMnO₄ and CH₃CH₂OH as the precursors. The structure, composition and morphology of the product are evaluated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and Infrared (IR) techniques. The results showed that crystalline birnessite-based manganese oxide was formed and the hydrothermal time and temperature had great influence on nanostructures of the products. The electrochemical results showed that birnessite nanowires exhibit excellent cyclic stability performance in the potential application window of 1.5~4.8 V.

Abstract: Spinel LiMn₂O₄ cathode material was rapidly prepared by solid-state combustion synthesis which used lithium carbonate and manganese carbonate as raw materials and β-cyclodextrin as a fuel. The effects of amount of β-cyclodextrin and calcination temperature on their structure and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge-discharge test and cyclic voltammetry (CV). The optimal synthesis conditions were found to be 5 wt% β-cyclodextrin. Under these conditions, high-purity spinel LiMn₂O₄ was obtained, and its discharge specific capacity was 110.5 mAh/g in the first cycle and still retained at 99.9 mAh/g after 40 cycles.

Abstract: The J-V curve measurment and AFM technology were applied to study the relationship between P3HT:PCBM heterojunction film solar cell devices photovoltics parameter and blend solution concentration and annealed time of this device. The Voc, Jsc, FF and PCE of device were obtained from the device prepared by three blend solution concentration respectively. Data show that with increasing solution concentration PCE of solar cell device do not always improve and it achieves maximum when concentration is 20 mg/mL. Result indicates that only when solar cell device has active layer with proper thickness its performance will achieve the best effect. Additionally, photovoltaic parameters from four sample prepared by different annealed time were obtained also. Results indicate that the device with proper annealed time of 20 min at 130°C can achieve the best effect.

Abstract: Polyacrylonitrile-based activated carbon fiber (PAN-ACF)/SnO₂ composites were synthesized by sol-gel and in-situ chemical synthesis method, respectively, and characterized by XRD, TGA, and SEM. The electrochemical properties of the resultant composites as negative electrodes in lithium-ion battery were also studied to investage the influence of different synthetic methods on the structure and electrochemical properties of the composites. The results show that the SnO₂ in the composites prepared by both methods has a tetragonal rutile structure but the structure and electrochemical properties are different. With the similar composition, the composites prepared by in-situ method have uniform distribution of SnO₂ particles, and exhibit better cyclic performance than those made by sol-gel method. The capacity of PAN-ACF/SnO₂ composites with SnO₂ content of 42.9% prepared by in-situ method remains 401.2 mAh g^-1 after 50 charge/discharge cycles at a current density of 50 mAh g^-1.