Synthesis and Electrochemical Characteristics of Li3V2(PO4)3/C Cathode Materials for Li-Ion Batteries

2014 ◽  
Vol 912-914 ◽  
pp. 356-361
Author(s):  
Lu Zheng ◽  
Hony Yuan Peng ◽  
Jian Hua Wang ◽  
Yu Zhong Guo
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Carbon Sources ◽  
Particle Aggregation ◽  
High Rate ◽  
Electrochemical Performances ◽  
Electrochemical Characteristics ◽  
Preparation Conditions ◽  
Average Size ◽  
Charge Discharge

Li3V2(PO4)3/C composites were synthesized by sol-gel routine with citric acid as chelates and carbon sources at different preparation conditions , meanwhile saccharose has been used to separate the Li3V2(PO4)3/C particles When it dissolve out in the process of solvent volatilizing. The effects of different preparation conditions and the existence of saccharose on crystal structure and electrochemical performance were characterized by XRD, SEM and electrochemical workstation. The results shows that all the Li3 V2 (PO4)3 samples are pure monoclinic phase; The crystal structure and the lattice parameters remain unchanged in different conditions, but it has effects on their average size of particles. The existence of saccharose suppress the growth of particle size and particle aggregation, and then affect electrochemical performances indirectly. In addition , the cycling performances of all samples displayed well at 3.0~4.2V on low rate charge/discharge, but the rate performance become worse with the increasing of average size of particle and particle aggregation and the capacity reduces seriously on high rate charge/discharge.

Synthesis, Characterization and Charge-Discharge Profile of LiMn0.3Co0.3Ni0.3Fe0.1O2 Prepared via Sol-Gel Method

2012 ◽  
Vol 501 ◽  
pp. 56-60 ◽  
Author(s):  
Jaafar Mohd Hilmi ◽  
Mohamed Nor Sabirin ◽  
Rosiyah Yahya ◽  
Norlida Kamarulzaman
Keyword(s):  
Sol Gel ◽  
Layered Compounds ◽  
Electrochemical Characteristics ◽  
Voltage Range ◽  
Gel Method ◽  
Sol Gel Method ◽  
Cost Constraints ◽  
A Charge ◽  
Discharge Profile ◽  
Charge Discharge

LiCoO2 is a well established commercial Li-ion battery cathode. However, due to cost constraints and the toxicity of the metal, other layered compounds should be investigated. In this paper, layered LiMn0.3Co0.3Ni0.3Fe0.1O2 were prepared using sol-gel method with CH3COOLi•2H2O, (CH3CO2)2Mn•4H2O, (CH3CO2)2Co•4H2O, (CH3CO2)2Ni•4H2O and Fe (NO3)3•9H2O as starting materials. The sample was characterized by simultaneous thermogravimetric analysis, x-ray powder diffraction and scanning electron microscopy. The electrochemical characteristics were studied by a charge-discharge cycle done on the fabricated cell using a charge current of 1.0 mA and a discharge current 0.5 mA between 4.2 and 0.5 V. The XRD results showed that the layered LiMn0.3Co0.3Ni0.3Fe0.1O2 were of pure phase with discharge capacity of about 136 mAhg-1. The batteries were then subjected to a series of charge-discharge cycling in the voltage range of 2.5 to 4.2 V. The results showed there was little loss of capacity after 10 cycles.

scholarly journals Structural and Electrical Properties of Ca2+ Doped LaFeO3: The Effect of A-site Cation Size Mismatch

2020 ◽  
Vol 10 (2) ◽  
pp. 5538-5546
Author(s):  
A. E. Irmak
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Charge Ordering ◽  
Room Temperature Resistivity ◽  
Size Mismatch ◽  
Ca Doping ◽  
Average Size ◽  
A Site ◽  
Cation Size ◽  
Small Polarons

In this study, nanosized La1-xCaxFeO3 (0.00≤x≤0.40) compounds prepared via sol-gel method followed by heat treatment at 1100oC for 24 hours are studied. Crystal structure, microstructure, surface morphology and temperature-dependent resistivity of the samples are investigated. TEM investigation reveals nanoparticles with an average size of 35nm produced from the sol-gel process. The crystal structure of the compounds belongs to an orthorhombically distorted perovskite structure with Pbnm space group. Lattice distortion and cation size mismatch increase with an increase in Ca and particle and grain growth are suppressed by Ca doping. Electrical conduction is explained via thermally activated hopping of small polarons. Unit cell volume, charge ordering temperature, and activation energy for small polarons decrease linearly with an increase in cation size mismatch. Room temperature resistivity decreases with Ca doping and gets its minimum value for 30% Ca at which the orthorhombic distortion is maximum.

Synthesis and electrochemical properties of SrWO4/graphene composite as anode material for lithium-ion batteries

2014 ◽  
Vol 07 (02) ◽  
pp. 1450010 ◽  
Author(s):  
Linsen Zhang ◽  
Qingling Bai ◽  
Linzhen Wang ◽  
Aiqin Zhang ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Sol Gel ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycle Performance ◽  
Electrochemical Performances ◽  
Graphene Composite ◽  
Discharge Method ◽  
Charge Discharge

SrWO 4/graphene composite was synthesized via a sol–gel method. The morphology and structure of the products were analyzed by SEM, TEM and XRD. The electrochemical performances of SrWO 4/graphene composite were investigated by galvanostatic charge/discharge method, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the first cycle of the reversible specific capacity of SrWO 4/graphene composite can reach to 575.9 mAh g-1 at 50 mA g-1. The charge/discharge cycling study indicates that the SrWO 4/graphene composite was provided with excellent cycle performance and outstanding rate capability.

Effect of fuel content on formation of zinc aluminate nano and micro-particles synthesised by high rate sol–gel autoignition of glycine-nitrates

2016 ◽  
Vol 70 (3) ◽  
Author(s):  
Shiva Salem
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
High Rate ◽  
Zinc Aluminate ◽  
X Ray Diffraction ◽  
Micro Particles ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size ◽  
20 Nm

AbstractThe autoignition technique using glycine as fuel and related nitrate salts as an oxidiser is able to produce zinc aluminate spinel. The precursors were synthesised with lean and rich fuel at pH of 7.0 and the materials so obtained were calcined at various temperatures ranging from 600-1200°C. The autoignition process of precursors was studied by the simultaneous thermo-gravimetric and differential thermal analyses to determine the ignition mechanism. The calcined powders were characterised by X-ray diffraction, Brunauer-Emmett-Teller technique and transmission electron microscopy. The product contains nano-sized particles with an average size of approximately 20 nm. The XRD patterns showed the formation of ZnO in the powder obtained by the fuel-rich precursor and calcined at 600°C which disappears at 800°C due to solid-state reaction and proper crystallisation after heat treatment. The results presented here can be useful in manufacturing nano and micro-sized ZnAl

Sol-Gel Synthesis of LiFePO4/C Composite Cathode Material from FePO4/PANI

2013 ◽  
Vol 724-725 ◽  
pp. 1075-1078
Author(s):  
Zhong Yuan Cheng ◽  
Fu Xin Zhong ◽  
Ying Jiang ◽  
Peng Fei Yu ◽  
Yun Xia Jin ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
In Situ Polymerization ◽  
Sol Gel ◽  
Composite Cathode ◽  
Cycle Performance ◽  
Electrochemical Performances ◽  
Composite Cathode Material ◽  
Sol Gel Synthesis ◽  
Charge Discharge

Olivine structured LiFePO4 are prepared by sol-gel method from FePO4·H2O nanocrystallites, which are synthesized via in situ polymerization restriction technique. These composites are fully characterized using XRD, SEM, and the electrochemical performances have been shown by the charge/discharge capacity, rate property and cycle performance. The synthesized LiFePO4 samples show well-crystallized structures. Among those samples, the sample synthesized at 650°C presents the highest discharge capacity of 165.8 mAhg-1 at 0.2 C. This compares with a theoretical discharge capacity of 170 mAhg-1.

Fabrication and Properties of a New Type Micro Super-Capacitor

2013 ◽  
Vol 562-565 ◽  
pp. 102-107
Author(s):  
Ya Jiang Yin ◽  
Xiao Feng Wang ◽  
Wu Shuang Lu ◽  
Xiang Yu Li ◽  
Zheng You
Keyword(s):  
Layer Structure ◽  
Ruthenium Oxide ◽  
Impedance Analysis ◽  
Test System ◽  
High Rate ◽  
Electrochemical Characteristics ◽  
Super Capacitor ◽  
Discharge Performance ◽  
New Type ◽  
Charge Discharge

A new type of micro super-capacitor with high working voltage, high over loading, small bulk, and low impedance was fabricated by a new process. The hydrous ruthenium oxide powder was prepared in a solution of RuCl3·xH2O and NaHCO3. Different composites loaded with certain amount of carbon black were synthesized with this technique. Super-capacitor performance was assessed via cyclic voltammetry (CV), charge-discharge studies (DC), and impedance analysis (AC). The results show that the capacitance and resistivity of ruthenium oxide materials were dependent on the sample annealing temperature. The materials heated at 300°C exhibit the highest rate capacitance of 1080 F·g-1. Four to six cells of this capacitor was stacked up in series by conductive films in order to achieve higher working voltage. After packaged in resin, charge/discharge studies and impedance analysis were tested via the electrochemical test system. In the research, super-capacitors with a four-layer structure exhibited fine electrochemical characteristics with high working voltage over 5.5 V and low impedance under 1.5 ohm. Also, it had the ability of high-rate discharge performance and considerable large capacitance.

Impacts of Melt Spinning and Mn Replacement on Electrochemical Hydrogen Storage Performances of Nanocrystalline and Amorphous Mg2Ni-Type Alloys

2012 ◽  
Vol 251 ◽  
pp. 323-328
Author(s):  
Yang Huan Zhang ◽  
Ying Cai ◽  
Tai Yang ◽  
Zhong Hui Hou ◽  
Guo Fang Zhang ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
High Rate ◽  
Electrochemical Performances ◽  
Electrochemical Characteristics ◽  
Secondary Phases ◽  
Nanocrystalline And Amorphous ◽  
Electrochemical Hydrogen Storage ◽  
Rate Discharge

The Mg2Ni-type alloys with a nanocrystalline and amorphous structure have been confirmed possessing superior electrochemical hydrogen storage kinetics. The melt-spinning technique is used to preparing the nanocrystalline and amorphous Mg2Ni-type alloys with the nominal compositions of Mg20Ni10-xMnx (x = 0, 1, 2, 3, 4). The impacts of the melt spinning and the replacement of Ni by Mn on the structures and the electrochemical performances of the alloys are investigated systematically. The analysis of the structures by XRD and HRTEM reveals that the replacement of Ni by Mn facilitates the glass formation in the Mg2Ni-type alloy, and the amorphization degree of the as-spun alloys increases with the growing of the spinning rate. Furthermore, the replacement renders the formation of secondary phases MnNi and Mg instead of altering the Mg2Ni major phase in the alloys. The measurement of the electrochemical characteristics by an automatic galvanostatic system indicates that the discharge capacity and cycle stability of the alloys dramatically grow with the rising of the spinning rate and the amount of Mn replacement, with which the high rate discharge ability (HRD) of the alloys first augments and then falls.

Synthesis of LiFePO4/C by Carbon Thermal Reduction Method and its Electrochemical Properties

2011 ◽  
Vol 335-336 ◽  
pp. 1364-1367 ◽  
Author(s):  
Chao Chen ◽  
Yun Zhang ◽  
Fu Wang ◽  
Ji Zhou Zou
Keyword(s):  
Reduction Method ◽  
Carbon Sources ◽  
Thermal Reduction ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Good Cycling Stability ◽  
Charge Discharge ◽  
Discharge Test

LiFePO4/C were successfully synthesized by carbon thermal reduction method at sintering temperature of 650 °C for 12h, using Li2CO3, FePO4 and three organic carbon sources (citric acid, glucose and ascorbic acid) as starting materials. The crystal structure, morphology and electrochemical performances were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Charge/Discharge Test. The results showed that the sample using glucose as carbon source was shuttle type porous particles with bore diameter from 50 to 100 nm, charge/discharge test showed that the sample had not only high initial discharge capacity of 155.1mAh/g at 0.1C (17mA/g), and 144.8 mAh/g at 1C, but also excellent rate performance. Moreover, the capacities lose which was only 0.97% after 10 cycling number at 1C indicate its good cycling stability.

Effect of Acticarbon on the Electrochemical Characteristics of LiFePO4 Battery Powder by Microwave Hydrothermal

2012 ◽  
Vol 512-515 ◽  
pp. 199-202
Author(s):  
Ying Sun ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Discharge Capacity ◽  
Energy Dispersive Spectrometer ◽  
Hydrothermal Process ◽  
Composite Cathode ◽  
Electrochemical Performances ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
Microwave Hydrothermal ◽  
Charge Discharge

Olivine LiFePO4 and LiFePO4-C composite cathode materials were prepared by microwave hydrothermal process using FeC2O4·2H2O, NH4H2PO4, LiOH·H2O and acticarbon as source materials. The effect of acticarbon on the structure and charge-discharge property of LiFePO4 crystallites was investigated. The as-prepared battery powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer(EDS). The charge-discharge behavior was investigated for the characterization of the electrochemical performances of the powder. Results show that the introduction of acticarbon will not change the LiFePO4 crystal structure, but achieve more uniform and fine crystallites and result in better electrochemical performance. Initial discharge capacity of the as-prepared LiFePO4 is 103.4 mAh·g-1 at 0.1 C rate. The discharge capacity of LiFePO4-C is 136.1 mAh·g-1 at the first cycle and 133.9 mAh·g-1 after 30 cycles at 0.1 C rate.

scholarly journals Surface Chemistry, Crystal Structure, Size and Topography Role in the Albumin Adsorption Process on TiO2 Anatase Crystallographic Faces and Its 3D-Nanocrystal: A Molecular Dynamics Study

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Giuseppina Raffaini
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Surface Chemistry ◽  
Protein Adsorption ◽  
Adsorption Process ◽  
Sol Gel ◽  
Interaction Strength ◽  
Theoretical Work ◽  
Blood Protein ◽  
Tio2 Anatase

TiO2 is widely used in biomaterial implants. The topography, chemical and structural properties of titania surfaces are an important aspect to study. The size of TiO2 nanoparticles synthetized by sol–gel method can influence the responses in the biological environment, and by using appropriate heat treatments different contents of different polymorphs can be formed. Protein adsorption is a crucial step for the biological responses, involving, in particular, albumin, the most abundant blood protein. In this theoretical work, using molecular mechanics and molecular dynamics methods, the adsorption process of an albumin subdomain is reported both onto specific different crystallographic faces of TiO2 anatase and also on its ideal three-dimensional nanosized crystal, using the simulation protocol proposed in my previous theoretical studies about the adsorption process on hydrophobic ordered graphene-like or hydrophilic amorphous polymeric surfaces. The different surface chemistry of anatase crystalline faces and the nanocrystal topography influence the adsorption process, in particular the interaction strength and protein fragment conformation, then its biological activity. This theoretical study can be a useful tool to better understand how the surface chemistry, crystal structure, size and topography play a key role in protein adsorption process onto anatase surface so widely used as biomaterial.

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