scholarly journals Kinetic and Thermodynamic Studies on Synthesis of Mg-Doped LiMn2O4 Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1409
Author(s):  
Aleksei Llusco ◽  
Mario Grageda ◽  
Svetlana Ushak
Keyword(s):  
Thermal Decomposition ◽  
Sol Gel ◽  
Thermal Inertia ◽  
Lithium Ion ◽  
Matrix Decomposition ◽  
State Theory ◽  
Nanocrystalline Powders ◽  
Decomposition Kinetic ◽  
Mg Doping ◽  
Mg Doped

In this work, a first study on kinetics and thermodynamics of thermal decomposition for synthesis of doped LiMn2O4 nanoparticles is presented. The effect of Mg doping concentration on thermal decomposition of synthesis precursors, prepared by ultrasound-assisted Pechini-type sol–gel process, and its significance on nucleation and growth of Mg-doped LiMn2O4 nanoparticles was studied through a method based on separation of multistage processes in single-stage reactions by deconvolution and transition state theory. Four zones of thermal decomposition were identified: Dehydration, polymeric matrix decomposition, carbonate decomposition and spinel formation, and spinel decomposition. Kinetic and thermodynamic analysis focused on the second zone. First-order Avrami-Erofeev equation was selected as reaction model representing the polymer matrix thermal decomposition. Kinetic and thermodynamic parameters revealed that Mg doping causes an increase in thermal inertia on conversion rate, and CO2 desorption was the limiting step for formation of thermodynamically stable spinel phases. Based on thermogravimetry experiments and the effect of Mg on thermal decomposition, an optimal two-stage heat treatment was determined for preparation of LiMgxMn2−xO4 (x = 0.00, 0.02, 0.05, 0.10) nanocrystalline powders as promising cathode materials for lithium-ion batteries. Crystalline structure, morphology, and stoichiometry of synthesized powders were characterized by XRD, FE-SEM, and AAS, respectively.

scholarly journals Synthesis and Characterization ofLiNi0.7–xMgxCo0.3O2(0≤x≤0.1) Cathode Materials for Lithium-Ion Batteries Prepared by a Sol-Gel Method

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hailang Zhang
Keyword(s):  
Cathode Materials ◽  
Sol Gel ◽  
Lithium Ion ◽  
Magnesium Content ◽  
Temperature Cycling ◽  
Structure Stability ◽  
Gel Method ◽  
Sol Gel Method ◽  
Mg Doping ◽  
Charge Discharge

Prospective cathode materialsLiNi0.7–xMgxCo0.3O2(0≤x≤0.1) for a lithium-ion secondary battery were synthesized using a sol-gel method. The structural and electrochemical properties were examined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry(CV), and charge-discharge tests. The results show that theLiNi0.7–xMgxCo0.3O2maintains theα-NaFeO2type layered structure regardless of the magnesium content in the rangex⩽0.1. On the other hand, Mg-doping improves the capacity retention well. Besides, the Mg-doping promotes the diffusion of Li+in LiNi0.7Co0.3O2. Moreover, Mg-doping suppresses the phase transitions that usually occur in LiNiO2during cycling and improves the charge-discharge reversibility of Li/LiNi0.7Co0.3O2. High temperature cycling performance of the cathode at 55.5°C is also improved by Mg-doping, which is possibly attributed to the total stronger metal-oxygen bonding and the enhanced structure stability of those delithiated Mg-doped cathodes during cycling.

scholarly journals Fabrication and Analysis of Near-Field Electrospun PVDF Fibers with Sol-Gel Coating for Lithium-Ion Battery Separator

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 186
Author(s):  
Mark D. Francisco ◽  
Cheng-Tang Pan ◽  
Bo-Hao Liao ◽  
Mao-Sung Wu ◽  
Ru-Yuan Yang ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Specific Capacitance ◽  
Near Field ◽  
Sol Gel ◽  
Lithium Ion ◽  
Nonwoven Fabric ◽  
Electrospun Fibers ◽  
Gel Method ◽  
Sol Gel Method ◽  
Microtensile Testing

Environmental and economic concerns are driving the demand for electric vehicles. However, their development for mass transportation hinges largely on improvements in the separators in lithium-ion batteries (LIBs), the preferred energy source. In this study, innovative separators for LIBs were fabricated by near-field electrospinning (NFES) and the sol-gel method. Using NFES, poly (vinylidene fluoride) (PVDF) fibers were fabricated. Then, PVDF membranes with pores of 220 nm and 450 nm were sandwiched between a monolayer and bilayer of the electrospun fibers. Nanoceramic material with organic resin, formed by the sol-gel method, was coated onto A4 paper, rice paper, nonwoven fabric, and carbon synthetic fabric. Properties of these separators were compared with those of a commercial polypropylene (PP) separator using a scanning electron microscope (SEM), microtensile testing, differential scanning calorimetry (DSC), ion-conductivity measurement, cyclic voltammetry (CV), and charge-discharge cycling. The results indicate that the 220 nm PVDF membrane sandwiched between a bilayer of electrospun fibers had excellent ionic conductivity (~0.57 mS/cm), a porosity of ~70%, an endothermic peak of ~175 °C, better specific capacitance (~356 mAh/g), a higher melting temperature (~160 °C), and a stable cycle performance. The sol-gel coated nonwoven fabric had ionic conductivity, porosity, and specific capacitance of ~0.96 mS/cm., ~64%, and ~220 mAh/g, respectively, and excellent thermal stability despite having a lower specific capacitance (65% of PP separator) and no peak below 270 °C. The present study provides a significant step toward the innovation of materials and processes for fabricating LIB separators.

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%.

THE EFFECTS OF CARBON NANO-COATING ON Li(Ni0.8Co0.15Al0.05)O2 CATHODE MATERIAL USING ORGANIC CARBON FOR Li-ION BATTERY

2010 ◽  
Vol 17 (01) ◽  
pp. 51-58 ◽  
Author(s):  
JEONG-HUN JU ◽  
YOUNG-MIN CHUNG ◽  
YU-RIM BAK ◽  
MOON-JIN HWANG ◽  
KWANG-SUN RYU
Keyword(s):  
Cathode Material ◽  
Coating Layer ◽  
Sol Gel ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Cyclic Voltammogram ◽  
Active Materials ◽  
Nano Coating ◽  
Primary Particles ◽  
Li Ion

Carbon nano-coated LiNi 0.8 Co 0.15 Al 0.05 O 2/ C (LNCAO/C) cathode-active materials were prepared by a sol–gel method and investigated as the cathode material for lithium ion batteries. Electrochemical properties including the galvanostatic charge–discharge ability and cyclic voltammogram behavior were measured. Cyclic voltammetry (2.7–4.8 V) showed that the carbon nano-coating improved the "formation" of the LNCAO electrode, which was related to the increased electronic conductivity between the primary particles. The carbon nano-coated LNCAO/C exhibited good electrochemical performance at high C -rate. Also, the thermal stability at a highly oxidized state of the carbon nano-coated LNCAO was remarkably enhanced. The carbon nano-coating layer can serve as a physical and/or (electro-)chemical protection shell for the underlying LNCAO, which is attributed to an increase of the grain connectivity (physical part) and also to the protection of metal oxide from chemical reactions (chemical part).

Nano MgFe2O4 synthesized by sol–gel auto-combustion method as anode materials for lithium ion batteries

2013 ◽  
Vol 66 (3) ◽  
pp. 540-543 ◽  
Author(s):  
Yanhong Yin ◽  
Bing Zhang ◽  
Xiaoting Zhang ◽  
Jingjing Xu ◽  
Shuting Yang
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Materials ◽  
Sol Gel ◽  
Lithium Ion ◽  
Combustion Method ◽  
Auto Combustion
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