Papers by Keyword: Spray Pyrolysis

Abstract: Spherical LiAl0.05Mn1.95O4 precursor powders were successfully prepared by spray pyrolysis. LiAl0.05Mn1.95O4 precursor powders were calcined by 800°C for 10hrs. The particles size, morphology, microstructure, crystal phases of the calcined powders were characterized by X-ray diffraction (XRD) and a scanning electron microscope (SEM). The XRD patterns showed that the crystal phases of the calcined powders were the same as spinel phase (space group: Fd3m). The particles exhibited a spherical morphology with a porous microstructure. The particle size of the primary particles was approximately 200nm. LiAl0.05Mn1.95O4 cathodes exhibited higher rechargeable capacity and cycle stability at high rates. The particle microstructure of LiAl0.05Mn1.95O4 powders was effective for the rechargeable capacity at high rates.

Abstract: La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) precursor particles were successfully prepared by ultrasonic spray pyrolysis. LSGM thin films were prepared by the electrophoretic deposition (EPD) technique using ethanol containing iodine. The LSGM films were obtained by sintering at 1300 °C for 10 h. The X-ray diffraction patterns revealed that the diffraction peak of LSGM thin films was in agreement with the perovskite structure. The LSGM films attained a uniform thickness of 10 μm.

Abstract: The present chapter deals with the difficult task of giving a brief survey of the synthetic routes employed to prepare materials with characteristic features on the nanometer scale. Definitions and general concepts regarding nanostructured and nanometer-sized materials are shortly tackled in the introductory part, which is followed by an overview of the most important approaches developed to synthesize such materials. No attempt is made to create a comprehensive and detailed synopsis of the experimental methods currently available. Rather, attention is focused on a selected number of general methodologies, the choice of which can be usually motivated by a mix of historical perspective, scientific significance and technological potential. So-called “top-down” approaches are discussed first, whereas the second part of the chapter is devoted to “bottom-up” ones. The former group includes mechanical processing, melt quenching, and de-vitrification methods. Sonochemistry, pulsed laser ablation, wet chemical synthesis, sol-gel processing, microwave processing, spray pyrolysis, flame synthesis, inert gas condensation, vapor deposition, and vapor-liquid-solid growth form instead the latter group.

Abstract: The effect of the pulsed – laser annealing on the parameters of CdS thin layers in the medium of oxygen was studied. The CdS thin layers were deposited by spray pyrolysis at different technological conditions. The changes of the layers’ characteristics were studied by SEM, XRD and XPS and electrical measurements were carried out. The results showed that a change in the morphology and the phase composition of the surface occurred; a by-surface layer consisted of CdО with high conductivity was formed in consequence of oxidation of CdS. The parameters of the CdS thin layers were retained in- depth after pulsed laser annealing. These results are discussed in the context of transparent layers in solar cells.

Abstract: Ag and Ni spherical fine powders were continuously produced by carrying out an aerosol process in a mass nanopowder production apparatus. The particles size, particle morphology, crystal phases and crystallinity of the as-prepared powders were characterized by a scanning electron microscope (SEM) and X-ray diffraction (XRD). The particles were nonaggregated and they exhibited a spherical morphology with a narrow size distribution. The average sizes of Ag and Ni particles were 500 nm and 700 nm, respectively. The crystallinity of the as-prepared powders was high. The XRD patterns showed that the crystal phases of the as-prepared powders were the same as those of their respective metals.

Abstract: Spherical C/LiFePO4 cathode materials were successfully prepared by spray pyrolysis. The saccharides such as monosaccharide and disaccharide or organic acid were used as carbon source. SEM observation showed that they had spherical morphology with particle size of about 1m. XRD analysis revealed that the olivine phase was obtained by heating at 700 °C under the atmosphere of argon/hydrogen (5 %). Electrochemical measurement revealed that the rechargeable capacity of LiFePO4 was significantly improved by the addition of carbon. The use of sucrose was most effective for the high rechargeable capacity and cycle stability.

Abstract: Spherical porous Mn2O3 powders were prepared by spray pyrolysis. Li and Al nitrate solution were immersed to porous Mn2O3 powders to obtain LiAlXMn2-XO4. Homogeneous LiAlXMn2-XO4 powders were formed by the calcination at 800°C. SEM observation showed that they had spherical morphology with particle size of about 1m. XRD revealed that the spinel phase was obtained by heating at 800°C. LiAlXMn2-XO4 cathode obtained by this method exhibited higher rechargeable capacity and cycle stability than that obtained by spray pyrolysis. The doping of Al ion was effective for the cycle stability at elevated temperature.

Abstract: Iron-Zinc oxide films were deposited by the well known ultrasonic spray pyrolysis method from an aqueous solution of iron nitrate and zinc acetate ([Zn]/[Fe] = 0.30). A Franklinite structure of these films turned out from XRD measurements. Additional basic characterization with UV-Vis and infrared spectroscopies and AFM was also performed. Electrical measurements under a small alternating current signal (15 mV RMS) were performed under dry air, humid air (53 % R:H.) and humid air plus propane. Frequency scans yielded sensitivities as high as 260% to humidity and  475% to propane at 30 °C. At 250 °C lower sensitivities were obtained, but in all cases the highest values came from the reactive response of the film. From dynamical response measurements, the response time was also assessed. The mechanisms of sensing are discussed as well.

Abstract: Ba(Mg1/3Ta2/3)O3 (BMT) powders were successfully prepared by ultrasonic spray pyrolysis from an aqueous solution of Ba, Mg and Ta. The particles characteristics of BMT nano-sized powders were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). As-prepared powder particles had a sub-micrometer size with a narrow distribution. Transmission electron microscopy (TEM) observation revealed that the average size of the BMT nano-particles was around 20 nm, and that these particles were aggregated. The dielectric constant (r) of 23.2 and the Q・f of 98,300 were obtained at 1550°C by a spray pyrolysis.

Abstract: LiNi1/3Co1/3Mn1/3O2 precursor powders were successfully prepared by internal combustion type spray pyrolysis. The production capacity of precursor powders was about 1 kg/h when the solution concentration was 0.5 mol/dm3. Particle size, morphology and crystal phase of LiNi1/3Co1/3Mn1/3O2 powders were characterized by XRD and SEM. XRD showed that a layered rock salt structure with a R3m space group was formed by calcination at 750 °C for 10 h. SEM showed that hollow powders with a particle size of 6 μm and irregular morphology were obtained. The discharge capacity of LiNi1/3Co1/3Mn1/3O2 was 130 mAh/g, which showed good cycle performance.