scholarly journals SYNTHESIS OF LiFePO4 NANOCRYSTALS IN THE ION-LIQUID MEDIUM USING MICROWAVE HEATING

2019 ◽  
Vol 85 (10) ◽  
pp. 78-82
Author(s):  
Vadym Galaguz ◽  
Eduard Panov ◽  
Sergiy Malovanyi
Keyword(s):  
Microwave Heating ◽  
Diethylene Glycol ◽  
Malic Acid ◽  
Carbon Coating ◽  
Choline Chloride ◽  
Phase Method ◽  
Thermal Synthesis ◽  
Organic Precursor ◽  
Liquid Phase Method ◽  
Annealed Powder

The liquid-phase method of synthesis of lithium iron(II) phosphate (LiFePO4) in the medium of choline chloride and diethylene glycol under the action of microwave heating is proposed. With a power of microwave radiation of 920 and 1150 W, a nanocrystalline LiFePO4 without impurities was obtained. Obtained samples of microwave processes contain amorphous phase and require long annealing resulting in nanocrystalline LiFePO4/C composites with small impurities Li3PO4, Li3Fe2(PO4)3, Fe2O3. For samples obtained in the choline chloride with diethylene glycol microwave heating characteristic is lamellar morphology – the same as for LiFePO4 obtained by thermal heating, but in the case of using microwave irradiation plates are smaller. This indicates that the reaction mechanism of LiFePO4 synthesis does not change in the microwave synthesis, but the reaction rate is significantly increased (up to 6 times faster than thermal synthesis). Using the Raman spectroscopy, the nature of the carbon coating on the crystal of LiFePO4 was studied. The Raman spectra of the LiFePO4/C composites obtained from an annealed powder with glucose and malic acid have pronounced D (~ 1340 cm-1) and G (~ 1600 cm-1) peaks, as well as two additional bands at ~ 1200 and ~ 1520 cm-1 obtained after the expansion of main peaks. The ratio of peak intensities of lines D and G (ID/IG) has a value of 1.06 for the material obtained after glucose carbonation and 1.01 for LiFePO4/C composites annealed with malic acid, which correlates with the results of other investigations of the carbon coating LiFePO4 (ID/IG  ~ 1-3) That means the choice of an organic precursor does not affect the nature of the carbon coating (ID/IG ~ 1). Capacity of cathode material based on LiFePO4/C composites is ~ 130 mAh/g for a current of 0.1C.

Synthesis and conformational investigation of β-turn forming tetra- and hexapeptides

1982 ◽  
Vol 47 (7) ◽  
pp. 1884-1892
Author(s):  
A. N. Abdel Rahman ◽  
S. Abdel Rahman
Keyword(s):  
Energy Transfer ◽  
Phase Method ◽  
Conformational Study ◽  
Poly Ethylene Glycol ◽  
High Solubility ◽  
Liquid Phase Method ◽  
Conformational Investigation ◽  
Transfer Method ◽  
Poly Ethylene ◽  
Good Agreement

Tetra- and hexapeptides containing Pro-Gly or Gly-Pro or Aib-Pro in their sequences were synthesized using the liquid-phase method. The high solubility of the poly(ethylene glycol) bound peptides in water and in organic solvents enables the application of the singlet-singlet energy transfer method for conformational investigation of these peptides. The conformational study in solid state by IR and in solution by CD were carried out in parallel to the energy transfer method. The qualitative results generated by IR and CD were found to be in good agreement with the quantitative end-to-end distances given by the energy transfer method.

The Research of Silica-Coated Chromium Oxide Green Pigment Prepared by Liquid Phase Method

2011 ◽  
Vol 84-85 ◽  
pp. 514-518
Author(s):  
Hong Yan Zhang ◽  
Jin Hua Wang ◽  
Li Fang Zhang ◽  
Li Li Wang
Keyword(s):  
Liquid Phase ◽  
Experimental Method ◽  
Chromium Oxide ◽  
Particle Surface ◽  
Tetraethyl Orthosilicate ◽  
Hydrolysis Reaction ◽  
Phase Method ◽  
Green Pigment ◽  
Coated Particle ◽  
Liquid Phase Method

This paper is researched on SiO2-coated Cr2O3 for the hydrolysis reaction of tetraethyl orthosilicate. The influences of precursors, solid contents of suspension and Si ratio of water on coated particle surface are investigated. The products are characterized and the conclusion shows that the experimental method is feasible.

Effect of crystal orientation and doping on the activation energy for GaAs oxide growth by liquid phase method

2000 ◽  
Vol 87 (5) ◽  
pp. 2629-2633 ◽  
Author(s):  
Hwei-Heng Wang ◽  
Dei-Wei Chou ◽  
Jau-Yi Wu ◽  
Yeong-Her Wang ◽  
Mau-Phon Houng
Keyword(s):  
Activation Energy ◽  
Liquid Phase ◽  
Crystal Orientation ◽  
Phase Method ◽  
Oxide Growth ◽  
Liquid Phase Method

scholarly journals Experimental investigation and modeling of thermophysical and extraction properties of choline chloride + DL-malic acid based deep eutectic solvent

2017 ◽  
Vol 82 (11) ◽  
pp. 1287-1302 ◽  
Author(s):  
Jelena Vuksanovic ◽  
Nina Todorovic ◽  
Mirjana Kijevcanin ◽  
Slobodan Serbanovic ◽  
Ivona Radovic
Keyword(s):  
Malic Acid ◽  
Atmospheric Pressure ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Ternary Mixtures ◽  
Extraction Ability ◽  
Experimental Phase ◽  
Liquid Liquid Extraction ◽  
Equilibrium Data ◽  
Extraction Properties

The ability of non-toxic and biodegradable deep eutectic solvent (DES) choline chloride + DL-malic acid in mole ratio 1:1, for the breaking of the azeotropes heptane + methanol and toluene + methanol by means of liquid? ?liquid extraction was evaluated. Ternary liquid?liquid equilibrium experiments were performed at 298.15 K and at atmospheric pressure. Densities, viscosities and refractive indices of DES + methanol and water + DES systems were experimentally determined over a wide temperature range and at atmospheric pressure. Additionally, the viscosities of DES + glycerol mixture were - determined at temperatures up to 363.15 K to check how much the addition of glycerol decreases high viscosities of DES. The results indicate that the addition of small amounts of water or glycerol as a third component significantly decreases the viscosity of the investigated deep eutectic solvent. Based on the selectivity and distribution ratio values, the extraction ability of the investigated deep eutectic solvent, in comparison with the conventionally used solvents, yields promising results. Non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models were satisfactorily applied for correlation of experimental phase equilibrium data for two ternary mixtures.

scholarly journals Cu Nanoparticles preparation by Laser Ablation in Liquid Phase method (LALP)

2019 ◽  
Vol 17 (42) ◽  
pp. 141-146
Author(s):  
Zaydoon Tariq Noori
Keyword(s):  
Aqueous Media ◽  
Laser Source ◽  
Phase Method ◽  
Laser Ablation In Liquid ◽  
Visible Absorption ◽  
Copper Target ◽  
Liquid Phase Method ◽  
Afm Analysis ◽  
532 Nm ◽  
Development Applications

Nanoparticle has pulled in expanding consideration with the developing enthusiasm for nanotechnology which hold potential as essential segments for development applications. In the present work, a copper nanoparticle is manufactured as a suspension in distilled water by beating a bulk copper target with laser source (532 nm wavelength, 10 ns pulse duration and 10 Hz repletion rate) via method. UV- visible absorption spectra and AFM analysis has been done to observe the effect of repetition rate for the pulsation of laser. Copper nanoparticles (Cu-NPs) were successfully synthesized with green color. The Cu- NPs have very high purity because the preparation was managed in aqueous media to eliminate ambient contaminations.  Absorption spectrum shows peaks at 450 nm- 700 nm µm due to the generation of Cu-NPs.  

Synthesis of Al – Fe/SiO2 and Al – Co/SiO2 catalysts by solid-phase method

2021 ◽  
Vol 2 ◽  
pp. 72-79
Author(s):  
V. A. Artyukh ◽  
◽  
V. N. Borshch ◽  
V. S. Yusupov ◽  
S. Ya. Zhuk ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Solid Phase ◽  
Iron Silicide ◽  
Phase Method ◽  
Thermal Synthesis ◽  
Annealing Conditions ◽  
Developed Surface ◽  
Solid Phase Method ◽  
Sio2 Support ◽  
Fe3al Intermetallic

Powders of catalysts from aluminides Fe and Co on a SiO2 support (33.3 wt. %) were obtained by mechano-thermal synthesis. The formation of large powder fractions (> 100 μm) was experimentally established. The fractions of these fractions for Fe – Al – SiO2 and Co – Al – SiO2 respectively amounted to ~ 43 % and ~ 55 %, which is a positive result for further catalytic studies. After annealing the powders at 700 and 900 °C in vacuum, the SiO2 support and compounds: Co27Al73 (close in composition to CoAl3, Co4Al13 type intermetallic compounds), Fe3Al intermetallic compound with iron silicide type Fe0.9Si0.1 and compound Al0,3Fe3Si0.7 in small volumes. On the synthesis of cobalt aluminides, a conclusion has been made about more efficient annealing at 900 °C than at 700 °C. For Fe – Al – SiO2 powders, it is advisable to anneal in the temperature range 700 – 750 °C with the assumption that the SiO2 support influences the thermosynthesis of iron aluminides. An experimental analysis of the morphology and elemental composition of the surface of the obtained samples is presented. It was found that the catalyst powders have medium sphericity and angularity. Fe – Al – SiO2 powders have a more developed surface than Co – Al – SiO2. Lower intermetallics are predominantly formed on the surface of the Co – Al – SiO2 sample. The correction of the mechanical alloying modes by means of the fragmentation of the process, changes in the intensity of its parameters, and various annealing conditions for Co – Al – SiO2 and Fe – Al – SiO2 are proposed.

Lithium storage properties of Li2MoO3 and its effect as a cathode additive in full cells

2021 ◽  
Author(s):  
Taolin Zhao ◽  
Shaokang Chen ◽  
Xingyue Gao ◽  
Yuxia Zhang
Keyword(s):  
Liquid Phase ◽  
Electrochemical Performance ◽  
Solid Phase ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Phase Method ◽  
Lithium Storage ◽  
Liquid Phase Method ◽  
Cathode Additive ◽  
Storage Properties

High-performance lithium–ion batteries (LIBs) are the main development direction of future energy storage devices. However, most LIBs still face a problem of high first irreversible capacity loss. Pre-lithiation technology can increase the content of active lithium source and compensate the loss of active lithium during the first cycle. Adding lithium supplement additive to the cathode provides an effective way to improve the electrochemical performance of LIBs. Here, Li2MoO3 has been investigated as a cathode additive in the full cells. In order to optimize its preparation, Li2MoO3 has been prepared by three different methods, including solid-phase method, liquid-phase method and ultrasonic method. Based on material characterization and electrochemical performance tests, Li2MoO3 material prepared by liquid-phase method shows the best lithium storage properties and chosen as a cathode additive in the LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2/SiO@C full cells. The addition of Li2MoO3 has successfully improved the electrochemical performance of the full cell. The first discharge specific capacity increases from 103.9 mAh g[Formula: see text] to 130.4 mAh g[Formula: see text]. In short, Li2MoO3 material is a promising cathode additive for LIBs.

Purification of SWNTs Using Microwave Heating

2001 ◽  
Vol 706 ◽  
Author(s):  
Avetik R. Harutyunyan ◽  
Bhabendra K. Pradhan ◽  
Gamini U. Sumanasekera ◽  
Jiping Chang ◽  
Gugang Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Heating ◽  
Acid Treatment ◽  
Carbon Coating ◽  
Single Wall Carbon Nanotubes ◽  
Metal Catalyst ◽  
Thermo Gravimetric ◽  
Mild Acid ◽  
Scanning Electron

AbstractA new method for purifying single wall carbon nanotubes (SWNTs) using microwave heating is developed. The microwaves couple to the residual metal catalyst, raising significantly the local temperature leading to both the oxidation and rupturing of the carbon passivation layer over the metal catalyst particles and sintering. With this protective carbon coating weakened or removed, a mild acid treatment in HCl is then sufficient to remove most of the metal in the sample, leaving the nanotubes in tact. Results from transmission and scanning electron microscopy (TEM & SEM), Raman spectroscopy and thermo-gravimetric studies are discussed.

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