Electrolytic V2O5: Synthesis, Characterization and Lithium Insertion Behavior

1999 ◽  
Vol 575 ◽  
Author(s):  
E. Potiron ◽  
A. Le Galla Salle ◽  
A. Verbaere ◽  
Y Piffard ◽  
D. Guyomard
Keyword(s):  
Single Phase ◽  
Mixed Valence ◽  
Reversible Capacity ◽  
Layered Compounds ◽  
Lithium Insertion ◽  
Capacity Retention ◽  
Electrochemical Intercalation ◽  
Soluble Species ◽  
Water Contents ◽  
Better Than

ABSTRACTElectrolytic V2O5 materials were prepared by electrochemical oxidation of vanadyl ions in aqueous solution. The electrodeposition reaction includes two steps: an oxidation into soluble species followed by a precipitation. With the use of various electrodeposition conditions and subsequent heat treatment it is possible to obtain e-V2O5 compounds with different VIV and water contents.e-V2O5 compounds are mixed valence, hydrated vanadic acids and their formula can be written as H0.4V2O5.2−δ.nH2 with 0.04<8<0.22 and 0<n<1.8. These poorly crystallized layered compounds undergo a phase transformation into α-V2O5 starting at 240°C.The electrochemical intercalation of lithium into these compounds shows two main single phase phenomena at ≈3.2V/Li and ≈2.6V/Li. Their capacity retention is better than that of other V2O5 reference compounds, but the reversible capacity down to 2V is only ≈100Ah/kg at a rate faster than C/5, due to kinetic limitations.

A SYNTHESIS ROUTE FOR LITHIUM IRON PHOSPHATE PREPARED BY IMPROVED COPRECIPITATION

2010 ◽  
Vol 03 (03) ◽  
pp. 177-180 ◽  
Author(s):  
JUN-XI ZHANG ◽  
MING-YU XU ◽  
XIAO-WEI CAO ◽  
NA XU ◽  
CHUN-YAN LAI ◽  
...  
Keyword(s):  
Single Phase ◽  
Lithium Iron Phosphate ◽  
Molecular Level ◽  
Reversible Capacity ◽  
Iron Phosphate ◽  
Phosphoric Acid Solution ◽  
Crystalline Particle ◽  
Cycle Number ◽  
Coprecipitation Process ◽  
Better Than

Pure lithium iron phosphate and Mo -doped lithium iron phosphate were synthesized via improved coprecipitation, followed by spray dry processing and sintering at a high temperature for crystallization. The synthesis was based on a key step to promote the dissolution of Fe powder by the addition of Cu or CuO powder in phosphoric acid solution. The improved coprecipitation process could achieve homogeneous mixing of the reactants at the molecular level. The crystalline particle size of the LiFePO4 was between 20 and 70 nm. All the samples were pure single-phase indexed with orthorhombic Pnmb space group. The electrochemical performance of LiFe0.96Mo0.04PO4 , including its reversible capacity, cycle number and charge–discharge characteristics, were all better than those of pure LiFePO4 .

Sn and SnBi Foil as Anode Materials for Secondary Lithium Battery

2002 ◽  
Vol 756 ◽  
Author(s):  
Shoufeng Yang ◽  
Peter Y. Zavalij ◽  
M. Stanley Whittingham
Keyword(s):  
Anode Materials ◽  
Lithium Battery ◽  
Eutectic Composition ◽  
Capacity Fade ◽  
Lithium Insertion ◽  
Capacity Retention ◽  
Simple Systems ◽  
Stepwise Formation ◽  
Secondary Lithium Battery ◽  
Better Than

ABSTRACTIn order to better understand the cycling mechanism of metal alloy anodes, and to mitigate the capacity fade observed in lithium battery use a study of simple systems was initiated. Tin foil and tin-bismuth mixtures were chosen because there is no need for conductive diluents or binders so that the intrinsic behavior could be observed. A pure tin foil was found to react rapidly with lithium, ≥ 3 mA/cm2, and with no capacity fade for over 10 cycles. This is better than tin powder or electrodeposited tin. After the first cycle, the foil reacts with Li following a stepwise formation of different alloys as dictated by the thermodynamics. Incorporation of bismuth into the foil increased the capacity fade after the first few cycles, with the eutectic composition Sn0.57Bi0.43 having better capacity retention than the Sn0.5Bi0.5 composition. XRD and SEM-EDS shows that bismuth is rejected from the tin rich phase during lithium insertion and is not reincorporated on lithium removal, just as expected from the phase diagram.

Overlithiation of LiNi0.8Co0.2O2 for Increased Performance in Li-Ion Batteries

2014 ◽  
Vol 938 ◽  
pp. 253-256
Author(s):  
Hashlina Rusdi ◽  
Norlida Kamarulzaman ◽  
Rusdi Roshidah ◽  
Kelimah Elong ◽  
Abd Rahman Azilah
Keyword(s):  
Cathode Materials ◽  
Structural Instability ◽  
Cation Ordering ◽  
Capacity Fading ◽  
Capacity Retention ◽  
Battery Capacity ◽  
Li Ion ◽  
Battery Application ◽  
Charge Discharge ◽  
Better Than

Layered LiNi1-xCoxO2 is one of the promising cathode materials for Li-ion battery application. However, the Ni rich cathode materials exhibit low capacity and bad capacity retention. This is due to factors such as disorder and structural instability when Li is removed during charge-discharge. Overlithiation of cathode materials is expected to improve the cation ordering and structural stability. Good cation ordering will increase the battery capacity. During charge-discharge, the irreversible Li+ loss can be replaced to a certain extent by the interstitial Li+ ions in the lattice of the LixNi0.8Co0.2O2 material. This helps reduce capacity fading of the cathode materials. In this work the overlithiation of LiNi0.8Co0.2O2 is done by interstitially doping Li+ in the LiNi0.8Co0.2O2 materials producing Li1.05Ni0.8Co0.2O2 and Li1.1Ni0.8Co0.2O2. Results showthat the performance of the overlithiated LiNi0.8Co0.2O2 materials is better than pure LiNi0.8Co0.2O2.

Effect of Ferrite Volume Fraction on Mechanical Properties of X80 Pipeline Steel

2014 ◽  
Vol 989-994 ◽  
pp. 212-215
Author(s):  
J. Liu ◽  
G. Zhu ◽  
W. Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Single Phase ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
X80 Pipeline Steel ◽  
Hardening Behavior ◽  
Two Phases ◽  
Better Than

The effect of volume fraction of ferrite on the mechanical properties including strength, plasticity and wok hardening was systematically investigated in X80 pipeline steel in order to improve the plasticity. The microstructures with different volume fraction of ferrite and bainite were obtained by heat-treatment processing and the mechanical properties were tested. The work hardening behavior was analyzed by C-J method. The results show that the small amount of ferrite could effectively improve the plasticity. The work hardening ability and the ratio of yield/tensile strength with two phases of ferrite/bainite would be obviously better than that with single phase of bainite. The improvement of plasticity could be attributed to the ferrite in which more plastic deformation was afforded.

Effects of Aluminum Doping on The Phase Stability and Electrochemical Properties of LiCoO2 and LiMnO2

1997 ◽  
Vol 496 ◽  
Author(s):  
Y.-I. Jang ◽  
B. Huang ◽  
H. Wang ◽  
Y.-M. Chiang ◽  
D. R. Sadoway
Keyword(s):  
Single Phase ◽  
Low Cost ◽  
Reversible Capacity ◽  
Open Circuit ◽  
Teller Distortion ◽  
Al Content ◽  
Jahn Teller ◽  
Li Battery ◽  
Low Mass ◽  
Jahn Teller Distortion

ABSTRACTAluminum is of interest as a constituent for Li battery electrodes due to its low cost and low mass, and because ab initio calculations indicate that solid solution of LiAlO2 with LiMO2 (M = transition metal) in the α-NaFeO2 structure can increase intercalation voltage [1]. In this study, we investigated the effect of Al doping on LiCoO2 and LiMnO2. Single phase LiAlyCo1-yO2 has been synthesized up to y = 0.5 by firing homogenous hydroxide precursors. A systematic increase in the open circuit voltage is observed with Al content. In LiAlyMn1-yO2, the addition of LiAlO2 stabilizes LiMnO2 in the α-NaFeO2 structure under conditions where neither endmember is stable in the structure. High reversible capacity was obtained over both a 4 V and 3 V plateau, indicating that the compound transforms to a spinel-related structure during cycling, but that the cooperative Jahn-Teller distortion is suppressed.

scholarly journals High Accuracy Measurement of Total Losses in Fractional Horsepower Induction Motors

2015 ◽  
Vol 1 (2) ◽  
pp. 13
Author(s):  
Azzeddine Ferrah ◽  
Mounir Bouzguenda ◽  
Jehad M. Al-Khalaf Bani Younis
Keyword(s):  
Single Phase ◽  
Induction Motors ◽  
Data Acquisition System ◽  
High Accuracy ◽  
Industrial Applications ◽  
Motor Speed ◽  
Accuracy Measurement ◽  
Three Phase ◽  
Better Than ◽  
High Accuracy Measurement

Large and small single-phase and three-phase induction motors are commonly used in industrial applications. The present work represents an attempt towards the design of a high accuracy system for the measurement of fractional horsepower (FHP) induction motor losses and efficiency. The calorimeter designed and built is capable of measuring heat losses of up to 1 kW with an overall accuracy better than 3%. During all tests, ambient temperature, humidity, motor speed and motor frame temperature were recorded using precise digital instruments. The inlet, outlet temperatures and resulting losses were recorded automatically using a high accuracy 12-bit data acquisition system. The preliminary results obtained demonstrate the suitability of the designed calorimeter for the accurate measurement of losses in FHP induction motors.

Electrochemical Performance Research of Mg Ion Doped LiMnPO4/C

2012 ◽  
Vol 554-556 ◽  
pp. 365-368
Author(s):  
Zeng Fu Wei ◽  
Wei Su ◽  
Shi Nian Liu
Keyword(s):  
Single Phase ◽  
Phenolic Resin ◽  
Reversible Capacity ◽  
Electrochemical Kinetics ◽  
Cation Substitution ◽  
Rate Performance ◽  
Ionic Radii ◽  
Similar Morphology ◽  
Performance Research ◽  
Mg Substitution

LiMn1-xMgxPO4/C(x=0, 0.01, 0.04, 0.05, 0.1) were synthesized by using wet-ballmilling and solid-state calcining with phenolic resin as the carbon source. All samples are single phase with a similar morphology, but the cation substitution results in a crystal lattice shrink because of the smaller ionic radii of Mg2+, the particles are small and homogeneous. CV, EIS and charge/discharge measurement shows that the Mg substitution leads to a significantly increased reversible capacity due to the enhanced electrochemical kinetics. LiMn0.96Mg0.04PO4/C calcined at 600°C has a discharge capacity of 144mAh/g at 0.05C. When charging-discharging by CC-CV-CC mode at high rates, LiMn0.96Mg0.04PO4/C composite exhibits a good cycle and rate performance.

Synthesis, Characterization and Electrochemical Performance of Li2Mn0.7Fe0.3SiO4 Prepared from Solid-state Reaction

2009 ◽  
Vol 620-622 ◽  
pp. 17-20 ◽  
Author(s):  
Wen Gang Liu ◽  
Yun Hua Xu ◽  
Rong Yang
Keyword(s):  
Solid State ◽  
Electrochemical Performance ◽  
Cathode Material ◽  
Solid State Reaction ◽  
High Capacity ◽  
Reversible Capacity ◽  
Solid State Reaction Method ◽  
Cycle Life ◽  
Solution Route ◽  
Better Than

Li2MSiO4(M=Mn, Co, Ni) is a potential high capacity cathode material because of its outstanding properties that exchange of two electrons per transition metal atom is possible and the theoretical capacity of Li2MSiO4 can reach as high as 330 mAhg-1. In this family, the cathode performance of Li2MnSiO4 synthesized by solution route has been published recently. However, it seems that the cycle life of Li2MnSiO4 fell short of our expectation. In this work, the Li2Mn0.7Fe0.3SiO4 cathode material was synthesized by traditional solid-state reaction method. The prepared powder was consisted of majority of Li2Mn0.7Fe0.3SiO4 and minor impurities which were examined by XRD. FESEM morphology showed that the products of Li2Mn0.7Fe0.3SiO4 and Li2MnSiO4 have similar particle size (about 50-300 nm). The electrochemical performance of Li2Mn0.7Fe0.3SiO4, especially for reversible capacity and cycle life, exhibited better than those of Li2MnSiO4.

scholarly journals Compton scattering tomography for agricultural measurements

2006 ◽  
Vol 26 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Paulo E. Cruvinel ◽  
Fatai A. Balogun
Keyword(s):  
Compton Scattering ◽  
Linear Correlation ◽  
Imaging Technique ◽  
Reconstruction Algorithm ◽  
Transmission Tomography ◽  
Electronic Density ◽  
New Approach ◽  
Quantitative Results ◽  
Water Contents ◽  
Better Than

This paper presents a new approach in tomographic instrumentation for agriculture based on Compton scattering, which allows for the simultaneous measurements of density and moisture of soil samples. Compton tomography is a technique that can be used to obtain a spatial map of electronic density of samples. Quantitative results can be obtained by using a reconstruction algorithm that takes into account the absorption of incident and scattered radiation. Results show a coefficient of linear correlation better than 0.81, when comparison is made between soil density measurements based on this method and direct transmission tomography. For soil water contents, a coefficient of linear correlation better than 0.79 was found when compared with measurements obtained by time domain reflectrometry (TDR). In addition, a set of Compton scatter images are presented to illustrate the efficacy of this imaging technique, which makes possible improved spatial variability analysis of pre-established planes.

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