scholarly journals Characterization of LiCo Nanopowders Produced by Sol-Gel Processing

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Sina Soltanmohammad ◽  
Sirous Asgari
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Gel Processing

LiCo nanopowders, one of the most important cathode materials for lithium-ion batteries, were synthesized via a modified sol-gel process assisted with triethanolamine (TEA) as a complexing agent. The influence of three different chelating agents including acrylic acid, citric acid, and oxalic acid on the size and morphology of particles was investigated. Structure and morphology of the synthesized powders were characterized by thermogravimetric/differential thermal analyses (TG/DTA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results indicate that the powder processed with TEA and calcinated at 800 had an excellent hexagonal ordering of -NaFe-type (space group Rm). Also, the other three complexing agents had a decisive influence on the particle size, shape, morphology, and degree of agglomeration of the resulting oxides. Based on the data presented in this work, it is proposed that the optimized size and distribution of LiCo powders may be achieved through sol-gel processing using TEA as a chelating agent.

STUDY ON SYNTHESIS AND EVOLUTION OF NANOCRYSTALLINE Mg4Ta2O9 BY AQUEOUS SOL–GEL PROCESS

2012 ◽  
Vol 19 (03) ◽  
pp. 1250024 ◽  
Author(s):  
H. T. WU ◽  
C. H. YANG ◽  
W. B. WU ◽  
Y. L. YUE
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Sol Gel ◽  
Phase Evolution ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
State Method ◽  
Size And Morphology

Nanosized and highly reactive Mg4Ta2O9 were successfully synthesized by aqueous sol–gel method compared with conventional solid-state method. Ta-Mg-citric acid solution was first formed and then evaporated resulting in a dry gel for calcination in the temperature ranging from 600°C to 800°C for crystallization in oxygen atmosphere. The crystallization process from the gel to crystalline Mg4Ta2O9 was identified by thermal analysis and phase evolution of powders was studied using X-ray diffraction (XRD) technique during calcinations. Particle size and morphology were examined by transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR-SEM). The results revealed that sol–gel process showed great advantages over conventional solid-state method and Mg4Ta2O9 nanopowders with the size of 20–30 nm were obtained at 800°C.

INFLUENCE OF THE INDEX METALLIC SALTS - COMPLEXING AGENT IN A SOL-GEL PROCESS TO OBTAIN NANOSCALED ZIRCONIUM SUBSTITUTED YTTRIUM (YSZ) TO ELECTROLYTE APPLICATION IN SOLID OXIDE FUEL CELL (SOFC)

2012 ◽  
Vol 1386 ◽  
Author(s):  
Rene Fabian Cienfuegos-Pelaes ◽  
Alejandro Ehécatl Correa ◽  
Ramona Alicia Salazar ◽  
L. Chávez-Guerrero ◽  
M. Hinojosa
Keyword(s):  
Low Cost ◽  
Sol Gel ◽  
Complexing Agents ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Crystalline Powder ◽  
Easy Method ◽  
X Ray ◽  
Metallic Salts ◽  
Sol Gel Process

ABSTRACTThe objective of the present study is to obtain the electrolyte material YSZ at low cost via sol gel, through exploration of the index rate between the complexing agents and the metallic salts (HMTA / metallic salts) from 1 to 5, prepared by a polymeric way in a sol gel process. We show an easy method that could be used in the industrial scale in order to obtain solid electrolyte material for its application in SOFC to operate at temperatures in the range of 700 800°C. This study has as reference the papers from Lenormand and Rieu about their synthesis of zirconium substituted to 8% of yttrium (CYSZ= 0.2 mol*L-1 metallic salts concentration-). The presence of the phase in the materials has been confirmed by X-ray diffraction assisted by thermal analysis tests, for indexes from 2 to 5 at a temperature of 1000°C for 5 hours at a calcination rate (from amorphous dust obtained at 400°C) of 1000°C per hour. The grain size mean for crystalline powder has an average near 50 nm and standard deviation close to 9 nm, it was confirmed by scanning electron microscope (SEM).

Study on Microstructure and Ferroelectricity of Strontium Barium Titanate Thin Films Prepared by Sol-Gel Processing

2013 ◽  
Vol 320 ◽  
pp. 202-207 ◽  
Author(s):  
Lian Wei Shan ◽  
Lai Guo Wang ◽  
Wei Li ◽  
Li Min Dong ◽  
Zhi Dong Han ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sol Gel ◽  
Chelating Agent ◽  
Frequency Dispersion ◽  
Bst Thin Films ◽  
Transmission Electron ◽  
Bst Thin Film ◽  
Inclined Angle ◽  
Gel Processing

Sr0.5Ba0.5-xBixTiO3 (SBT) thin films were fabricated on a Pt/SiO2/Si substrate by sol-gel method. The effects of chelating agent acetylacetone (HAcHAc) on the formation temperature and the microstructure of Sr0.5Ba0.5-xBixTiO3 (SBT) thin films were investigated in this paper. The microstructure of BST thin films was examined by XRD and TEM. It is found that Bi3+ doping decreases dielectric loss, improves frequency dispersion for BST thin films. The peak of temperature-dependence of dielectric constant of Bi3+-doped BST thin films is compressed and moves to a low-temperature region. An inclined angle of approximately 1.8o between the two different polarization vectors was observed for BST thin film from the results of high-resolution transmission electron microscopy (HRTEM). The Pr, Ps and Ec was 0.22μC/cm2, 0.72μC/cm2 and 60Kv/cm respectively for Sr0.5Ba0.485Bi0.015TiO3 thin film at 100Hz, 20V.

Properties and microstructure of thin LiNbO3 films prepared by a sol-gel process

1987 ◽  
Vol 2 (5) ◽  
pp. 595-605 ◽  
Author(s):  
D. P. Partlow ◽  
J. Greggi
Keyword(s):  
Sol Gel ◽  
Epitaxial Films ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Film Properties ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Oriented Polycrystalline ◽  
Diffraction Patterns ◽  
Gel Processing

Thin LiNbO3 films were prepared from polymerized sol-gel precursor solutions having various concentrations and water:alkoxide ratios in an effort to investigate the effects of these and other processing variables on the resultant film properties and microstructure. Films deposted on silicon substrates were mostly amorphous when pyrolyzed at 435°C for 30 min. Randomly oriented polycrystalline films having distinctive microstnietures were produced using longer heating times or higher temperatures. All of the films exhibited low refractive indices due to porosity, which was attributed to the low level of hydrolysis water required to produce stable polymeric precursor solutions. When single-crystal LiNbO4 was used as the substrate, epitaxial growth of the film resulted. This ideal case establishes the feasibility of producing epitaxial films via sol-gel processing. All films were characterized by transmission electron microscopy (TEM) and thin-film x-ray diffraction patterns.

GLYCINE-ASSISTED SOL–GEL SYNTHESIS OF LiFePO4/C CATHODE MATERIALS FOR LITHIUM-ION BATTERIES

2010 ◽  
Vol 03 (03) ◽  
pp. 217-221 ◽  
Author(s):  
SHIGUANG HU ◽  
TIANJING ZHANG ◽  
HUJUN CAO ◽  
HONGMEI ZHANG ◽  
ZHAOHUI LI ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Discharge Capacity ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Cyclic Voltammogram ◽  
Good Crystallinity ◽  
Sol Gel Process ◽  
Xrd Patterns ◽  
Sol Gel Synthesis

Glycine was firstly used as a chelating agent to prepare LiFePO4/C cathodes by the sol–gel process and sucrose as carbon source. The effects of calcination temperature on properties of LiFePO4/C cathode were investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic charge-discharge and cyclic voltammogram (CV) respectively. The XRD patterns indicate that all samples were of good crystallinity. The primary particle size increased with the calcination temperature from 600 to 750°C. The LiFePO4/C sample synthesized at 700°C has the best electrochemical performance with an initial discharge capacity of 162.6 mAh g-1 at 0.1 C and the discharge capacity remains at 154.6 mAh g-1 after 50 cycles.

Nuclear waste immobilization into structure of zirconolite by Complex Sol Gel Process

2014 ◽  
Vol 1683 ◽  
Author(s):  
Tomasz Smoliński ◽  
Andrzej Deptuła ◽  
W. Lada ◽  
Tadeusz Olczak ◽  
Andrzej G. Chmielewski ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Nuclear Waste ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

ABSTRACTZirconolite (CaZrTi2O7) is one of the components of Synroc materials, which are regarded throughout the world nuclear as the second generation of high-level nuclear waste forms. The zirconolite phase was synthesized by a sol-gel method, with one variant of the method making use of ascorbic acid as a strong complexing agent. Into the structure of the zirconolite was incorporated 10 mol% Sr. Undoped and doped samples were examined by thermal analyses and X-ray diffraction. Addition of ascorbic acid to the sols lowered the firing temperature and promoted formation of the zirconolite phase.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

scholarly journals Comparison of amorphous, pseudohexagonal and orthorhombic Nb2O5 for high-rate lithium ion insertion

CrystEngComm ◽  
2016 ◽  
Vol 18 (14) ◽  
pp. 2532-2540 ◽  
Author(s):  
Shuang Li ◽  
Qian Xu ◽  
Evan Uchaker ◽  
Xi Cao ◽  
Guozhong Cao
Keyword(s):  
Electrochemical Performance ◽  
Sol Gel ◽  
Lithium Ion ◽  
High Rate ◽  
Material Characteristics ◽  
Sol Gel Process ◽  
Ion Insertion

Amorphous, pseudohexagonal and orthorhombic Nb2O5 nanoparticles were synthesized by sol–gel process. The material characteristics and electrochemical performance of these polymorphs were compared.

Lithium ion conductivity of oriented Li0.33La0.56TiO3 solid electrolyte films prepared by a sol–gel process

2016 ◽  
Vol 284 ◽  
pp. 1-6 ◽  
Author(s):  
Takashi Teranishi ◽  
Yuki Ishii ◽  
Hidetaka Hayashi ◽  
Akira Kishimoto
Keyword(s):  
Solid Electrolyte ◽  
Sol Gel ◽  
Lithium Ion ◽  
Ion Conductivity ◽  
Sol Gel Process ◽  
Lithium Ion Conductivity

Electrochemical Performance Optimization of Li2NixFe1−xSiO4 Cathode Materials for Lithium-Ion Batteries

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Atef Y. Shenouda ◽  
M. M. S. Sanad
Keyword(s):  
Performance Optimization ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Sol Gel ◽  
Lithium Ion ◽  
Electrochemical Impedance Spectra ◽  
Cell Parameters ◽  
Sol Gel Process ◽  
Eis Measurements ◽  
And Function

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.

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