Advanced Materials Research Vols. 652-654

Abstract: Aiming at utilization status of China’s small particle oil shale, in the condition of laboratory, self-developed instrument of fluidized bed thermal cracking is used to conduct experimental researches on producing shale oil through thermal cracking of small-particle oil Shale. Through the orthogonal experiment, the optimal technological parameters on producing shale oil through thermal cracking are optimized. The experimental results have shown us that under the optimal technological conditions, oil productivity is at about 5%. Therefore, the technology of fluidized bed thermal cracking is an effective new method for producing oil through small-particle oil shale.

Abstract: In the paper, Li1+xMn2-xO4 are synthesized by ball-milling method and coprecipitation method. The phases of three compounds have been analyzed by X-ray diffraction to compare diffraction peak, crystal system and crystal lattice′ s size. Advisedly, the results show that a compound has more purity phase and better crystallinity. Synthetic method and reaction conditions of this compound are as follows: via coprecipitation method, heat the sample at 250°C for 4h in air, followed by heating at 750°C for 36h in air. This analysis provides a reasonable and valuable thinking for research of the structures of Li1+xMn2-xO4. And it is propitious to develop the positive material of lithium battery.

Abstract: The LiCrxMn2-xO4 material used for lithium ion battery cathode material was successfully prepared by a molten-salt flameless combustion synthesis method which used the LiNO3, LiAc•2H₂O, Mn(NO₃)₂, MnAc₂•4H₂O as raw materials and Cr(NO₃)₃•9H₂O as dopant. The results indicated that, the high-purity spinel LiCr_xMn_2-xO₄ was successfully prepared although including a little Mn3O4. The impurity peak intensity of Mn₃O₄ gradually weakened until it disappeared with the increase of the amount of Cr-doped. The product was monophasic LiCr_xMn_2-xO₄ when x (Cr) ≥ 0.1. It can be found that with Cr doped, the aggregation of the sample decreased. The structural stability, electrochemical activity and reversibility of LiCr_xMn_2-xO₄ was better than that of pristine LiMn₂O₄. The discharge capacity and capacity retention had been improved. The LiCr_0.02Mn_1.98O₄ had the highest initial capacity of 120.7 mAh•g^-1 and the capacity retention was 78.5% after 40 cycles.

Abstract: Effects of impurity (Fe, Si, Cu), temperature and Na2SnO3 on anodic behaviors of various grades of pure aluminum namely Al-1(99.999%),Al-2(99.99%),Al-3(99.82%) and Al-4(99.5%) in 4mol/L KOH solution have been examined by studying corrosion rate, polarization , open circuit potential (OCP, or Eocp), discharge performance and transfer resistance values (Rt) of EIS. The results indicate that aluminum has higher activation and more severe corrosion with the temperature increase. When impurities (Fe, Si, Cu) content increases, aluminum has higher corrosion and achieving stationary open current potential (OCP) needs longer time. However, Al-3 has lower polarization and higher current density(400mA/cm2,at 1.224V) than others at 50 °C. Meanwhile, for Al-3, the stationary OCP is about 120 mV more negative at 50 °C than at 25 °C. In order to achieve the stationary OCPs and avoid the appearance of tin oxidation peak, 20min is suitable soaking time for Al in 5mmol/LNa2SnO3 +4mol/LKOH solution. The optimal electrochemical behaviors of Al including corrosion-resistance, activation , OCP and shorter delay time of electrode potential, have been achieved by adding 5mmol/L SnO32+ into 4mol/LKOH solution.

Abstract: In order to enhance the dispersion property of Fe3O4 nanoparticles in Agarose-based magnetic polymer electrolytes for Dye-sensitized solar cell (DSSC), PEG200 was choosen to modify the magnetic polymer electrolytes. The electrochemical properties of polymer electrolytes with different content of PEG200 were studied by Electrochemical Impedance Spectroscopy (EIS). It was found that the electrolyte has an optimal conductivity of 2.88×10-3 Scm-1 when the mass fraction of PEG200 is 61.8wt% of Fe3O4 nanoparticles in the electrolyte. The electron lifetime of electron charges in photoanode increased and then decreased when the concentration of PEG200 increased. At the concentration of PEG200 of 68.3wt%, the cell reached the largest electron lifetime.

Abstract: Three kinds of carbon resources, poly(vinyl alcohol), phenol-formaldehyde resin and epoxy resin, were used to prepare the LiFePO₄/C composite (LFPC-1, LFPC-2, LFPC-3). XRD patterns show that the LFPC composites possess the typical olivine structure. The particle size and the reunited degree of LFPC-1 are smaller than those of LFPC-2 and LFPC-3. The discharge capacities of LFPC-1 at different C-rates are also much higher than those of the other two samples. Its discharge capacities at 0.1 C and 1 C are 158.8 mAh g^-1 and 136.20 mAh g^-1. Its discharge curve can maintain the stable potential platform of 3.3 V at the rate of 1 C. LFPC-1 possesses the highest electrical conductivity of 5.76×10^-2 S•cm^-1. This is because the ID/IG value of 1.20 in Raman spectra is much lower than that of LFPC-2 and LFPC-3. The selected area electron diffraction in the TEM of LFPC-1 shows directly that the graphitized carbon is formed on the cover surface of LFPC-1 composite.

Abstract: Low temperature oxidation of two different low rank coals was measured by in-situ FTIR. Curve-fitting analysis was employed to identify functional groups types of raw coals, and series technology was carried out on in-situ infrared spectrum of sample coals at low-temperature oxidation process to analyze the changes of main active functional groups with temperature. The results indicate that -CH3, -CH2, -OH, C=O, COOH are the main active functional groups in low rank coal. In the oxidation process, with temperature increasing, the methyl and methylene show the tendency of increase after decrease and then decrease, and all of hydroxyl, carboxyl and carbonyl group present the tendency of increase after decrease, there exists some differences among the main functional groups in the coal low-temperature process.

Abstract: A Fe-site doped lithium phosphate LiFe0.99La0.01PO4 as cathode material for lithium ion battery was synthesized by solid-state reaction. The crystalline structure, morphology of particles and electrochemical performances of the sample were investigated by X-ray diffraction, scanning electron microscopy, charge-discharge test and cyclic voltammetry. The results show that the small LiFe0.99La0.01PO4 particles are simple pure olive-type phase structure with uniformly distribution of gain size. The LiFe0.99La0.01PO4 obtained has proper electrochemical capacity, good cycle ability and rate performances. Such an excellent electrochemical characteristic should be partially related to the enhanced electronic conductivities and probably the better mobility of Li ion in the crystal of the doped sample.

Abstract: In this paper, (Ba,Ti)-doped lanthanum silicate nano-sized powders have been synthesized via microwave assisted sol-gel auto-combustion route by using TEOS and lanthanum nitrate as the starting materials, citric acid and glycol as chelators. Both the phase compositions and morphologies of the obtained powders have been characterized. The results indicated that: the synthesized nano powders were characterized as fluffy aggregates with the particle size ranging from 50 to 100nm. As the doping contents of Ba increased, the crystalline sizes decreased and the aggregation were deteriorated, while the particle size decreased from 120nm to 80nm and the aggregation between particles were halted as the doping contents of Ti increased.

Abstract: Ni-based Alloy C276 is a candidate material for the fuel cladding of super critical watered reactor (SCWR). In this paper, Alloy C276 was cut to a slice (thickness near to the fuel cladding) to investigate its creep character at 600-750oC with stress 130-240MPa. Scanning electron microscope (SEM) was used to analysis the microstructure of sheet-shape specimens (SS) and bar-shape specimens (BS). The result shows that SS have larger elongation and shorter lifetime than BS. By analyzing SEM images, we can infer that the different exfoliations made the different creep behavior of SS and BS.