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.

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.

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.

Iron Phosphates as Cathodes of Lithium-Ion Batteries

2006 ◽  
Vol 973 ◽  
Author(s):  
Shijun Wang ◽  
M. Stanley Whittingham
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Iron Phosphate ◽  
Low Cost ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Environmentally Benign ◽  
Iron Phosphates ◽  
Electrochemical Capacity ◽  
High Theoretical Capacity ◽  
Olivine Structure

ABSTRACTThis study focusses on optimizing the parameters of the hydrothermal synthesis to produce iron phosphates for lithium ion batteries, with an emphasis on pure LiFePO4 with the olivine structure and compounds containing a higher iron:phosphate ratio. Lithium iron phosphate (LiFePO4) is a promising cathode candidate for lithium ion batteries due to its high theoretical capacity, environmentally benign and the low cost of starting materials. Well crystallized LiFePO4 can be successfully synthesized at temperatures above 150 °C. The addition of a reducing agent, such as hydrazine, is essential to minimize the oxidation of ferrous (Fe2+) to ferric (Fe3+) in the final compound. The morphology of LiFePO4 is highly dependent on the pH of the initial solution. This study also investigated the lipscombite iron phosphates of formula Fe1.33PO4OH. This compound has a log-like structure formed by Fe-O octahedral chains. The chains are partially occupied by the Fe3+ sites, and these iron atoms and some of the vacancies can be substituted by other cations. Most of the protons can be ion-exchanged for lithium, and the electrochemical capacity is much increased.

Carbon-coated graphite for anode of lithium ion rechargeable batteries: Carbon coating conditions and precursors

2009 ◽  
Vol 194 (1) ◽  
pp. 486-493 ◽  
Author(s):  
Hidehiko Nozaki ◽  
Katsuhide Nagaoka ◽  
Kazuhito Hoshi ◽  
Naoto Ohta ◽  
Michio Inagaki
Keyword(s):  
Carbon Coating ◽  
Lithium Ion ◽  
Rechargeable Batteries ◽  
Carbon Coated

Properties of lithium iron phosphate prepared by biomass-derived carbon coating for flexible lithium ion batteries

2019 ◽  
Vol 300 ◽  
pp. 18-25 ◽  
Author(s):  
Hye-Jung Kim ◽  
Geun-Hyeong Bae ◽  
Sang-Min Lee ◽  
Jou-Hyeon Ahn ◽  
Jae-Kwang Kim
Keyword(s):  
Lithium Ion Batteries ◽  
Carbon Coating ◽  
Lithium Iron Phosphate ◽  
Lithium Ion ◽  
Iron Phosphate

scholarly journals An Overview of Lithium-Ion Battery Cathode Materials

2011 ◽  
Vol 1363 ◽  
Author(s):  
Yixu Wang ◽  
Hsiao-Ying Shadow Huang
Keyword(s):  
Energy Storage ◽  
Lithium Ion Battery ◽  
Cathode Materials ◽  
Lithium Iron Phosphate ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
High Energy ◽  
Rechargeable Batteries ◽  
Environmental Benefits ◽  
Energy Storage Devices

ABSTRACTThe need for the development and deployment of reliable and efficient energy storage devices, such as lithium-ion rechargeable batteries, is becoming increasingly important due to the scarcity of petroleum. In this work, we provide an overview of commercially available cathode materials for Li-ion rechargeable batteries and focus on characteristics that give rise to optimal energy storage systems for future transportation modes. The study shows that the development of lithium-iron-phosphate (LiFePO4) batteries promises an alternative to conventional lithiumion batteries, with their potential for high energy capacity and power density, improved safety, and reduced cost. This work contributes to the fundamental knowledge of lithium-ion battery cathode materials and helps with the design of better rechargeable batteries, and thus leads to economic and environmental benefits.

Effect of carbon coating methods on structural characteristics and electrochemical properties of carbon-coated lithium iron phosphate

2014 ◽  
Vol 262 ◽  
pp. 25-29 ◽  
Author(s):  
Jae-Kwang Kim ◽  
Dul-Sun Kim ◽  
Du-Hyun Lim ◽  
Aleksandar Matic ◽  
Ghanshyam S. Chauhan ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Carbon Coating ◽  
Lithium Iron Phosphate ◽  
Structural Characteristics ◽  
Iron Phosphate ◽  
Carbon Coated ◽  
Coating Methods

High-performance lithium iron phosphate with phosphorus-doped carbon layers for lithium ion batteries

2015 ◽  
Vol 3 (5) ◽  
pp. 2043-2049 ◽  
Author(s):  
Zhang Jinli ◽  
Wang Jiao ◽  
Liu Yuanyuan ◽  
Nie Ning ◽  
Gu Junjie ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lithium Ion Batteries ◽  
Hydrothermal Method ◽  
High Performance ◽  
Carbon Coating ◽  
Lithium Iron Phosphate ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Phosphorus Source ◽  
Phosphorus Doped

A novel composite of LiFePO4 with phosphorus-doped carbon layers has been prepared via a simple hydrothermal method using glucose as the carbon source to generate a carbon coating and triphenylphosphine as the phosphorus source.

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