Effect of Niobium Doping on Electrochemical Properties of Microwave Synthesized Carbon Coated Nanolithium Iron Phosphate for High Rate Underwater Applications

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
A. Srinivas Kumar ◽  
T. V. S. L. Satyavani ◽  
M. Senthilkumar ◽  
P. S. V. Subba Rao
Keyword(s):  
Solid Solution ◽  
Lithium Iron Phosphate ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
High Rate ◽  
X Ray ◽  
Niobium Doping ◽  
Carbon Coated

Lithium iron phosphate (LiFePO4) for lithium-ion batteries is considered as perfect cathode material for various military applications, especially underwater combat vehicles. For deployment at high rate applications, the low conductivity of LiFePO4 needs to be improved. Cationic substitution of niobium in the native carbon coated LiFePO4 is one of the methods to enhance the conductivity. In the present work, how the niobium doped solid solution could be formed is studied. Nanopowders of LiFePO4/C and Li1−xNbxFePO4/C (x = 0.05, 0.1, 0.15, 0.16) are synthesized from precursors using microwave synthesis. The solid solution formation up to (x = 0.15) Li1−xNbxFePO4/C without impurity phases is confirmed by X-ray diffraction (XRD) pattern and Fourier transform infrared spectroscopic (FTIR) results. Particle distribution is obtained by scanning electron microscope from the synthesized powders. Energy dispersive X-ray spectrometer (EDS) results qualitatively confirmed the presence of niobium. Also, direct current (dc) conductivities are measured using sintered pellets and activation energies are calculated using Arrhenius equation. The dependence of conductivity and activation energy of LiFePO4/C on variation of niobium doping is investigated in this study. CR2032 type coin cells are fabricated with the synthesized materials and subjected to cyclic voltammetry studies, rate capability and cycle life studies. Diffusion coefficients are obtained from electrochemical impedance spectroscopy studies. It is observed that room temperature dc conductivity improved by niobium doping when compared to LiFePO4/C (0.379 × 10−2 S/cm) and is maximum for Li0.9Nb0.1FePO4/C (40.58 × 10−2 S/cm). It is also observed that diffusion coefficient of Li+ in Li0.9Nb0.1FePO4/C (13.306 × 10−9 cm2 s−1) improved by two orders of magnitude in comparison with the pure LiFePO4 (10 − 12 cm2 s−1) and carbon-coated nano LiFePO4/C (0.632 × 10−11 cm2 s−1). Cells with Li0.9Nb0.1FePO4/C are able to deliver useful capacity of around 104 mAh/g at 10 C rate. More than 500 cycles are achieved with Li0.9Nb0.1FePO4/C at 20 C rate.

Carbon-Coated, Bismuth-Substituted, Lithium Iron Phosphate as Cathode Material for Lithium Secondary Batteries

2013 ◽  
Vol 739 ◽  
pp. 21-25 ◽  
Author(s):  
Xiang Yin Mo ◽  
Xiao San Feng ◽  
Yi Ding ◽  
Cai Rong Kang
Keyword(s):  
Discharge Capacity ◽  
Carbon Coating ◽  
Lithium Iron Phosphate ◽  
Rate Capability ◽  
Iron Phosphate ◽  
Solid State Reaction Method ◽  
High Rate ◽  
High Discharge Capacity ◽  
Lithium Secondary Batteries ◽  
Carbon Coated

Carbon-coated, bismuth-doped, lithium iron phosphates, LiFe1xBixPO4(0x0.05), have been synthesized by a solid-state reaction method. From the optimization, the carbon-coated LiFe0.95Bi0.05PO4phase showed superior performances in terms of phase purity and high discharge capacity. The structural, morphological, and electrochemical properties were studied and compared to carbon-coated, LiFePO4. The Li/LiFe0.95Bi0.05PO4with carbon coating cell delivered an initial discharge capacity of 145 mAh/g and was 30 mAh/g higher than the Li/LiFePO4with carbon coating cell. Cyclic voltammetry revealed excellent reversibility of the LiFe0.95Bi0.05PO4with carbon coating material. High rate capability studies were also performed and showed a capacity retention over 93% during the cycling. It was concluded that substituted Bi ion play an important role in enhancing battery performance of the LiFePO4material through improving the kinetics of the lithium insertion/extraction reaction on the electrode.

In Situ Synthesis of Graphitized-Carbon Coated Li4Ti5O12/C Anode for High-Rate Lithium Ion Batteries

2015 ◽  
Vol 814 ◽  
pp. 358-364
Author(s):  
Peng Xiao Huang ◽  
Shui Hua Tang ◽  
Hui Peng ◽  
Xing Li
Keyword(s):  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
High Rate ◽  
Phase Method ◽  
Electrochemical Performances ◽  
Graphitized Carbon ◽  
Carbon Coated

Graphitized-Carbon coated Li4Ti5O12/C (Li4Ti5O12/GC) composites were prepared from Li2CO3, TiO2 and aromatic resorcinol via a facile rheological phase method. The microstructure and morphology of the samples were determined by XRD and SEM. The electrochemical performances of the samples were characterized by galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The results reveal that the coating of graphitized carbon could effectively enhance the charge/transfer kinetics of the Li4Ti5O12 electrode. The Li4Ti5O12/GC could deliver a discharge specific capacity of 166 mAh/g at 0.2 C, 148 mAh/g at 1.0 C, 142 mAh/g at 3.0 C, 138 mAh/g at 5.0 C and 127 mAh/g at 10.0 C, respectively, and it still could remain at 132 mAh/g after cycled at 5.0 C for 100 cycles. The excellent rate capability of the Li4Ti5O12/C makes it a promising anode material for high rate lithium ion batteries.

scholarly journals Structural and Electrochemical Characterization of PureLiFePO4and Nanocomposite C-LiFePO4Cathodes for Lithium Ion Rechargeable Batteries

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Arun Kumar ◽  
R. Thomas ◽  
N. K. Karan ◽  
J. J. Saavedra-Arias ◽  
M. K. Singh ◽  
...  
Keyword(s):  
Carbon Coating ◽  
Lithium Iron Phosphate ◽  
Rate Capability ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Rechargeable Batteries ◽  
Ex Situ ◽  
Cyclic Voltammograms ◽  
Carbon Coated ◽  
Olivine Structure

Pure lithium iron phosphate (LiFePO4) and carbon-coatedLiFePO4(C-LiFePO4) cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating onLiFePO4particles. Ex situ Raman spectrum of C-LiFePO4at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms ofLiFePO4and C-LiFePO4showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively forLiFePO4where as in case of C-LiFePO4that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pureLiFePO4was 69% after 25 cycles where as that of C-LiFePO4was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.

HIGH POWER PERFORMANCE OF MULTICOMPONENT OLIVINE CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

2011 ◽  
Vol 04 (03) ◽  
pp. 299-303 ◽  
Author(s):  
ZHUO TAN ◽  
PING GAO ◽  
FUQUAN CHENG ◽  
HONGJUN LUO ◽  
JITAO CHEN ◽  
...  
Keyword(s):  
Transition Metal ◽  
Cathode Material ◽  
High Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Coprecipitation Method ◽  
Homogeneous Distribution ◽  
Power Performance ◽  
X Ray ◽  
Carbon Coated

A multicomponent olivine cathode material, LiMn0.4Fe0.6PO4 , was synthesized via a novel coprecipitation method of the mixed transition metal oxalate. X-ray diffraction patterns indicate that carbon-coated LiMn0.4Fe0.6PO4 has been prepared successfully and that LiMn0.4Fe0.6PO4/C is crystallized in an orthorhombic structure without noticeable impurity. Homogeneous distribution of Mn and Fe in LiMn0.4Fe0.6PO4/C can be observed from the scanning electron microscopy (SEM) and the corresponding energy dispersive X-ray spectrometry (EDS) analysis. Hence, the electrochemical activity of each transition metal in the olivine synthesized via coprecipitation method was enhanced remarkably, as indicated by the galvanostatic charge/discharge measurement. The synthesized LiMn0.4Fe0.6PO4/C exhibits a high capacity of 158.6 ± 3 mAhg-1 at 0.1 C, delivering an excellent rate capability of 122.6 ± 3 mAhg-1 at 10 C and 114.9 ± 3 mAhg-1 at 20 C.

scholarly journals Material Characterization and Analysis on the Effect of Vibration and Nail Penetration on Lithium Ion Battery

2019 ◽  
Vol 10 (4) ◽  
pp. 69
Author(s):  
Ajeet Babu K. Parasumanna ◽  
Ujjwala S. Karle ◽  
Mangesh R. Saraf
Keyword(s):  
Surface Morphology ◽  
Lithium Iron Phosphate ◽  
Electrochemical Impedance ◽  
Dynamic Stiffness ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Internal Resistance ◽  
Chemical Degradation ◽  
Battery Pack ◽  
A Cell

Battery packaging in a vehicle depends on the cell chemistry being used and its behavior plays an important role in the safety of the entire battery pack. Chemical degradation of various parts of a cell such as the cathode or anode is a concern as it adversely affects performance and safety. A cell in its battery pack once assembled can have two different mechanical abuse condition. One is the vibration generated from the vehicle and the second is the intrusion of external elements in case of accident. In this paper, a commercially available 32,700 lithium ion cell with lithium iron phosphate (LFP) chemistry is studied for its response to both the abuse conditions at two different states of charge (SoC). The primary aim of this study is to understand their effect on the surface morphology of the cathode and the anode. The cells are also characterized to study impedance behavior before and after being abused mechanically. The cells tested for vibration were also analyzed for dynamic stiffness. A microscopy technique such as scanning electron microscopy (SEM) was used to study the surface morphology and electrochemical impedance spectroscopy (EIS) characterization was carried out to study the internal resistance of the cell. It was observed that there was a drop in internal resistance and increase in the stiffness after the cells subjected to mechanical abuse. The study also revealed different morphology at the center and at the corner of the cell subjected to nail penetration at 50% SoC.

scholarly journals High electrochemical performance of nanocrystallized carbon-coated LiFePO4 modified by tris(pentafluorophenyl) borane as a cathode material for lithium-ion batteries

RSC Advances ◽  
2018 ◽  
Vol 8 (51) ◽  
pp. 28978-28986 ◽  
Author(s):  
Yifang Wu ◽  
Shaokun Chong ◽  
Yongning Liu ◽  
ShengWu Guo ◽  
Pengwei Wang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Cathode Material ◽  
Lithium Ion Batteries ◽  
Rate Capability ◽  
Lithium Ion ◽  
High Rate ◽  
High Rate Capability ◽  
Carbon Coated ◽  
Boron Source

C18BF15 was first adopted as a boron source and has demonstrated its clear modification effects, as shown by the high rate capability.

Olivine electrode engineering impact on the electrochemical performance of lithium-ion batteries

2010 ◽  
Vol 25 (8) ◽  
pp. 1656-1660 ◽  
Author(s):  
Wenquan Lu ◽  
Andrew Jansen ◽  
Dennis Dees ◽  
Gary Henriksen
Keyword(s):  
Hybrid Electric Vehicle ◽  
Composite Electrode ◽  
Lithium Iron Phosphate ◽  
Electrochemical Impedance ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
High Energy ◽  
Discharge Performance ◽  
Energy And Power Density

High energy and power density lithium iron phosphate was studied for hybrid electric vehicle applications. This work addresses the effects of porosity in a composite electrode using a four-point probe resistivity analyzer, galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The four-point probe result indicates that the porosity of composite electrode affects the electronic conductivity significantly. This effect is also observed from the cell's pulse current discharge performance. Compared to the direct current (dc) methods used, the EIS data are more sensitive to electrode porosity, especially for electrodes with low porosity values.

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