Optimization of Synthesis Condition for LiFePO4/C Cathode Material

2011 ◽  
Vol 236-238 ◽  
pp. 698-702
Author(s):  
Ling Zhi Zhu ◽  
En Shan Han ◽  
Ji Lin Cao
Keyword(s):  
Citric Acid ◽  
Room Temperature ◽  
Specific Capacity ◽  
Carbon Coatings ◽  
Treatment Processes ◽  
Initial Discharge ◽  
Structure Morphology ◽  
Tap Density ◽  
Pre Treatment ◽  
Acid Coating

This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. Common and cheap organic matters (Glucose anhydrous, Citric acid, Vitamin C, Sucrose) were selected for carbon coatings on LiFePO4. The four pre-treatment processes were employed to optimize the carbon coating process, and through solid state-carbothermal reduction synthesis of LiFePO4/C composites. The structure, morphology and electrochemical performance of the material were studied by XRD, SEM and galvanostatic charge-discharge methods. It is observed that the tap density of citric acid coating material can reach 1.44 g/ml. Conductivity increased four orders of magnitude. At room temperature, the initial discharge specific capacity of the materials is as high as 89.6 mAh/g at 5.0 C (corresponding to 850 mA/g). After 30 cycles, the capacity is 83.9 mAh/g and decay only 2.0 %.

Preparation and Characterization of Nano-LiFePO4/C Using Two-Fluid Spray Dryer

2014 ◽  
Vol 563 ◽  
pp. 62-65 ◽  
Author(s):  
Lin Chen ◽  
Cheng Lu ◽  
Qi An Chen ◽  
Yi Jie Gu ◽  
Meng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Primary Particle ◽  
Raw Materials ◽  
Specific Capacity ◽  
Initial Discharge ◽  
Tap Density ◽  
Initial Charge ◽  
Discharge Efficiency ◽  
Two Fluid

Nano-LiFePO4/C materials were synthesized by two-fluid spray-drying using FePO4·2H2O, LiOH·H2O as raw materials. The morphology, physical and electrochemical properties of the LiFePO4/C were tested and analyzed. The morphology of the synthesis LiFePO4/C was spherical and its aggregated particle size was smaller than 10μm, primary particle size was smaller than 200nm, the tap density of the material up to 1.25g/cm3. The LiFePO4/C had an initial discharge specific capacity of 163.3mAh/g at 0.1C and its specific capacities were 147.7mAh/g and 121.8mAh/g at 1C and 5C, respectively. The initial charge/discharge efficiency reached 96.6%. Under low temperature 253K, the discharge capacity is 59.6% of that at 298K with 0.2C.

Study on the Electrochemical Performance of High Tap Density LiFePO4/C Synthesized by Spray-Drying

2014 ◽  
Vol 893 ◽  
pp. 60-63 ◽  
Author(s):  
Cheng Lu ◽  
Lin Chen ◽  
Yi Jie Gu ◽  
Yun Bo Chen ◽  
Meng Wang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
Red Blood Cells ◽  
Spray Drying ◽  
Blood Cells ◽  
Raw Materials ◽  
Specific Capacity ◽  
Conductive Additive ◽  
Initial Discharge ◽  
Tap Density

LiFePO4/C materials were synthesized by spray-drying using FePO4·2H2O, LiOH·H2O as raw materials, glucose as reducing agent and conductive additive. The morphology, structure and electrochemical properties of the LiFePO4/C were tested and analyzed. The morphology of the LiFePO4/C was biconcave and round looked similar to red blood cells, the tap density of the material up to 1.45g/cm3. The electrochemical performance of the material was excellent. The LiFePO4/C had an initial discharge specific capacity of 161.8mAh/g at rate of 0.1C and its specific capacities were 148.7, 120.9mAh/g at rates of 1, 5C rate, respectively. The discharge capacity remained at 95.8%, 81.7% after 500, 1000 cycles respectively at rate of 5C.

Preparation and Characterization of High-Density Li0.99W0.01FePO4/C Composite Cathodes

2012 ◽  
Vol 554-556 ◽  
pp. 399-403
Author(s):  
Mei E Zhong
Keyword(s):  
Low Cost ◽  
Specific Capacity ◽  
Rate Capability ◽  
Bimodal Distribution ◽  
Cycle Performance ◽  
Structure Morphology ◽  
Composite Cathodes ◽  
Tap Density ◽  
Current Densities

High tap-density Li0.99W0.01FePO4/C composite have been synthesized via a simple and low-cost solid state-carbothermal reduction method, using Fe2O3and citrate ferric as the Fe3+precursors and citric radical containing in citrate ferric as both carbon source and reducing agent. The structure, morphology, and physicochemical properties of Li0.99W0.01FePO4/C composite were characterized by XRD, SEM, laser diffraction and scattering measurement, and tap-density testing. It is observed the particle distribution of the Li0.99W0.01FePO4/C composite is bimodal distribution. Because of the smaller particles filling in the space between the larger particles, the Li0.99W0.01FePO4/C composite exhibits less vacancy, which resulted in a high tap density of 1.50 g•cm-3. The Li0.99W0.01FePO4/C composite also shows good rate capability and cycle performance. At current densities of 0.2, 0.5, 1.0 and 1.5 C, the composite material has initial discharge specific capacity of 141, 133, 130 and 125 mAh•g-1, respectively.

Structure, Morphology and Electrochemical Characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) as Cathode Materials for Na-Ion Batteries

2021 ◽  
Vol 105 (1) ◽  
pp. 199-207
Author(s):  
Yurii V. Shmatok ◽  
Vitalii A. Sirosh ◽  
Nataliya I. Globa
Keyword(s):  
Crystal Structure ◽  
Specific Capacity ◽  
Oxide Phase ◽  
Sodium Content ◽  
Electrolyte Composition ◽  
Electrochemical Characteristics ◽  
Initial Discharge Capacity ◽  
Initial Discharge ◽  
Structure Morphology ◽  
The Stability

The paper presents the results of the investigations of structural, morphological and electrochemical characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) .It is shown that the crystal structure of the resulting materials is determined by the sodium content and is tunnel in a case of Na0.44MnO2 and layered in a case of Na0.67MnO2 and Na0.8MnO2. In addition, the materials obtained are characterized by different morphology. The initial discharge capacity of the materials obtained increases with the increase of sodium content in oxide phase and is 117, 139 and 151 mAh/g for Na0.44MnO2, Na0.67MnO2 and Na0.8MnO2, respectively, however, at the same time the stability of the specific capacity decreases. Using Na0.44MnO2 as an example, the effect of the electrolyte composition, in particular the presence of FEC, on its electrochemical characteristics is shown.

scholarly journals Effect of nanostructured carbon coatings on the electrochemical performance of Li1.4Ni0.5Mn0.5O2+ x -based cathode materials

2016 ◽  
Vol 7 ◽  
pp. 1960-1970 ◽  
Author(s):  
Konstantin A Kurilenko ◽  
Oleg A Shlyakhtin ◽  
Oleg A Brylev ◽  
Dmitry I Petukhov ◽  
Alexey V Garshev
Keyword(s):  
Diffusion Coefficient ◽  
Charge Transfer ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Poly Vinyl Alcohol ◽  
Nanostructured Carbon ◽  
Transfer Resistance ◽  
Carbon Coatings ◽  
Lithium Diffusion Coefficient ◽  
Electrochemical Cycling

Nanocomposites of Li1.4Ni0.5Mn0.5O2+ x and amorphous carbon were obtained by the pyrolysis of linear and cross-linked poly(vinyl alcohol) (PVA) in presence of Li1.4Ni0.5Mn0.5O2+ x . In the case of linear PVA, the formation of nanostructured carbon coatings on Li1.4Ni0.5Mn0.5O2+ x particles is observed, while for cross-linked PVA islands of mesoporous carbon are located on the boundaries of Li1.4Ni0.5Mn0.5O2+ x particles. The presence of the carbon framework leads to a decrease of the polarization upon cycling and of the charge transfer resistance and to an increase in the apparent Li+ diffusion coefficient from 10−16 cm2·s−1 (pure Li1.4Ni0.5Mn0.5O2+ x ) to 10−13 cm2·s−1. The nanosized carbon coatings also reduce the deep electrochemical degradation of Li1.4Ni0.5Mn0.5O2+ x during electrochemical cycling. The nanocomposite obtained by the pyrolysis of linear PVA demonstrates higher values of the apparent lithium diffusion coefficient, a higher specific capacity and lower values of charge transfer resistance, which can be related to the more uniform carbon coatings and to the significant content of sp2-hybridized carbon detected by XPS and by Raman spectroscopy.

Prospects and problems of sludge pre-treatment processes

2001 ◽  
Vol 44 (10) ◽  
pp. 121-128 ◽  
Author(s):  
J.A. Müller
Keyword(s):  
Wastewater Treatment ◽  
Phase Changes ◽  
Ozone Treatment ◽  
Thermal Methods ◽  
Sludge Treatment ◽  
Freeze Thaw ◽  
Positive Effects ◽  
Treatment Processes ◽  
Stage Of Development ◽  
Pre Treatment

Pre-treatment processes have been developed in order to improve subsequent sludge treatment and disposal. Disintegration of sludge solids in the aqueous phase changes the sludge structure and solubilizes organic matter. This paper provides an overview of the applications of wet disintegration in wastewater and sludge treatment. Applied disintegration techniques such as mechanical, thermal, chemical and biological methods are briefly described. The methods are compared regarding energy consumption, operational reliability and stage of development for application on wastewater treatment plants. Mechanical and thermal methods appear to be most suitable at this stage. The effects of pre-treatment on subsequent sludge treatment processes and the wastewater treatment are described. The performance of various methods is assessed. For the improvement of stabilization, mechanical and ozone treatment as well as thermal treatment perform best. Dewatering can be enhanced by thermal and freeze/thaw treatment. All methods show positive effects in the reduction of the number of pathogens. Pre-treatment leads to secondary effects like the generation of recalcitrant compounds and odor, which is mainly a problem of thermal and ozone treatment. The evaluation of capital and operational costs is difficult, because of the lack of full-scale experience. Especially thermal, freeze/thaw and biological treatments can be realized at low costs if the conditions are appropriate. Nevertheless, the economic efficiency has to be investigated critically for each individual application.

Investigation and assessment of sludge pre-treatment processes

2004 ◽  
Vol 49 (10) ◽  
pp. 97-104 ◽  
Author(s):  
J.A. Müller ◽  
A. Winter ◽  
G. Strünkmann
Keyword(s):  
Fine Particles ◽  
Degradation Process ◽  
Solid Content ◽  
Ozone Treatment ◽  
Treatment Processes ◽  
Sludge Properties ◽  
Pre Treatment ◽  
The Cost ◽  
Degree Of Degradation ◽  
Cell Disintegration

The pre-treatment of sludges by disintegration will result in a number of changes in sludge properties. Floc destruction as well as cell disintegration will occur. This leads to an increase of soluble substances and fine particles. Furthermore, biochemical reactions may appear during or immediately after disintegration. The influence of disintegration of excess sludge on anaerobic digestion was studied in full scale. A stirred ball mill, an ultrasound disintegrator, a lysate centrifuge and ozone treatment were used. The results of the degradation process were compared to a reference system without pre-treatment. An enhancement of the degree of degradation of 7.4% to 20% was observed. The pollution of sludge water as well as the dewatering properties of the digested sludge were investigated. COD and ammonia in the sludge water were increased and a higher polymer demand was observed while the solid content after dewatering stayed almost unchanged. Based on these results the cost effectiveness has been assessed taking into account different conditions (size of WWTP, cost for disposal, etc.). Capital and energy costs are the main factors while the decrease in disposal costs due to the reduced amount of sludge is the main profit factor.

scholarly journals Study on printing wastewater treatment by decomposition reaction H2O2 catalyzed of complex between ion Ni2+ and citric acid

2020 ◽  
Vol 9 (4) ◽  
pp. 106-110
Author(s):  
Tue Nguyen Ngoc ◽  
Nghia Nguyen Trong ◽  
Thuong Nghiem Thi ◽  
Quang Tran Thuong ◽  
Trung Nguyen Duc
Keyword(s):  
Wastewater Treatment ◽  
Citric Acid ◽  
Industrial Wastewater ◽  
Room Temperature ◽  
Organic Pollutant ◽  
Decomposition Reaction ◽  
Efficient Treatment ◽  
Catalytic Role ◽  
Printing Processes

In this article, the results of the research on organic pollutant treatment in the wastewater of printing processes on fabric by H2O2 under the catalytic role of the complex between ion Ni2+ and Citric acid (H4L) were presented. The condition of pH, H4L/Ni2+, H2O2, Ni2+ concentration has been explored to get the optimal conditions for improving COD efficient treatment. The results provide the solutions of the homogeneous complex  catalysts in the industrial wastewater treatment at room temperature and atmosphere. 

Surface analytical study of uranium exposed to low pressures of hydrogen at ∼ 80°C

2012 ◽  
Vol 1444 ◽  
Author(s):  
Robert M. Harker ◽  
Afiya H. Chohollo
Keyword(s):  
Room Temperature ◽  
Analytical Study ◽  
Treatment Cycle ◽  
X Ray Diffraction ◽  
Standard Samples ◽  
X Ray ◽  
Surface Precipitation ◽  
Pre Treatment ◽  
Low Pressures ◽  
Scanning Electron

ABSTRACTIdentical samples of uranium coupons were prepared and each exposed to hydrogen for different times (where this time is significantly less than a classically understood ‘induction time’). Samples were prepared from rolled depleted uranium stock: as-received oxide was removed on all surfaces and two faces (~12x12 mm) were polished to a sub-micron standard. Samples were individually taken through a Vacuum Thermal Pre-Treatment cycle from room temperature to 200°C to the reaction temperature (80°C) over 40 hours and subsequently exposed to 10 mbar O2 for 24 hours. After O2 was removed, the samples were exposed to hydrogen for pre-determined times of up to 48 minutes. Examination of the samples by Scanning Electron Microscopy (SEM) has, as expected, identified small features protruding from the surface believed to have been caused by sub-surface precipitation of UH3. In general these features are circular and isolated from each other, have a diameter of less than 3μm and appear as either ‘flat-topped’ or ‘domed’ morphology. In addition, longer time exposure samples show a predominance of ‘area attack’ where coalesced sub-surface precipitation appears to be confined to particular metal grains. X-Ray Diffraction (XRD) data show an increase in the quantity of UH3 with time.

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