Mössbauer study on LiFePO4 cathode material for lithium ion batteries (original) (raw)
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Characterization of LiFePO4/C Cathode for Lithium Ion Batteries
Industrial & Engineering Chemistry Research, 2011
LiFePO 4 /C was synthesized from a mixture of different precursors of Li, Fe, and C by solid-state reaction. The initial mixture obtained was heated in different calcination conditions under inert atmosphere. The precursor of LiFePO 4 doped with carbon was studied using different techniques such as thermal analysis, chemical and physical characterizations, and M€ osbauer spectroscopy. A calculation of the crystallinity of the final product with two different methods is also presented. The chemical analysis techniques used were IRTF, XRD, and SEM. This characterization confirmed that we obtained a well-crystallized LiFePO4/ C in all the operating conditions tested. The SEM showed aggregation and sintering during the calcination process, which were confirmed by the particle-size distribution measurements and by the physical characterizations. M€ osbauer spectroscopy was used to determine the quantity of Fe(II) and Fe(III) contained in the final product. Our calcination conditions did not significantly modify the quantity of the two oxidation states.
Advances in new cathode material LiFePO4 for lithium-ion batteries
Synthetic Metals, 2012
The cathode materials of lithium-ion batteries are developing towards the direction of high energy density, long cycle life, low cost and environment friendly. As a potential 'green' cathode material for lithium-ion power batteries in the 21st century, olivine-type lithium iron phosphate (LiFePO 4 ) become more attractive recently for its high theoretical capacity (170 mAh g −1 ), stable voltage plateau of 3.5 V vs. Li/Li + , good stability both at room temperature and high temperature, excellent cycling performance, high safety, low raw material cost, no pollution, and rich source of raw materials, etc. This paper introduces the research progress in recent years on the structure and performance, synthesizing methods, carboncoating, ion-doping and particle size control. Furthermore, the prospect of LiFePO 4 cathode material for the lithium-ion batteries is reviewed. (i) Preparation process of LiFePO 4 (including high temperature solid-phase method, sol-gel method, microwave method, hydrothermal method, carbothermal reduction method, spray pyrolysis method and other synthesis routes). (ii) Progress on modification of LiFePO 4 (three modification strategies including carbon coating, metal particle or ion doping and the optimization of the particle size and morphology). (iii) Finally, the trend of research and development of LiFePO 4 is also pointed out (the follow-up studies should be directed at the theoretical study and process improvement).
2011
CITATIONS 3 READS 69 4 authors, including: Some of the authors of this publication are also working on these related projects: Synthesis and studies on controlled porosity composite thin layers and systems for energy storage and conversion applications View project Research Cooperation Project: Synthesis and studies on controlled porosity composite thin layers and systems for energy storage and conversion applications (2014-2017) View project
A study on LiFePO 4 and its doped derivatives as cathode materials for lithium-ion batteries
Journal of Power Sources, 2006
LiFePO 4 , doped LiM x Fe 1−x PO 4 , and Li 1−x M x FePO 4 compounds have been prepared via a sol-gel synthesis method. The physical properties of the as-prepared lithium iron phosphates were characterised by X-ray diffraction, X-ray absorption near-edge spectroscopy (XANES), and magnetic susceptibility. The electrochemical properties lithium iron phosphates were tested by a variety of electrochemical techniques. Lithium iron phosphate electrodes demonstrated a stable discharge capacity of 160-165 mAh g −1 , almost approaching the theoretical capacity. The good electronic conductivity and nanocrystalline could contribute to the unique performance of lithium iron phosphate electrodes. Lithium iron phosphates have a significant potential to be used as a new cathode materials in Li-ion batteries.
Journal of Power Sources, 2007
In this paper technological aspects of a synthesis of phospho-olivine LiFePO 4 based composite cathode materials for lithium batteries are presented. An effective synthesis route yielding a highly conductive composite cathode material was developed. The structural, electrical and electrochemical properties of these materials were investigated. It was shown that the enhanced conductivity of the cathode material is due to the presence of a thin layer of the reduced material which has metallic properties, which is formed on the grain surfaces of the phospho-olivine. We propose a synthesis route yielding LiFePO 4 /Fe 2 P composite material.
Nanoscopic scale studies of LiFePO4 as cathode material in lithium-ion batteries for HEV application
Ionics, 2007
We present a review of the structural properties of LiFePO 4. Depending on the mode of preparation, different impurities can poison this material. These impurities are identified and a quantitative estimate of their concentrations is deduced from the combination of X-ray diffraction analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, and magnetic measurements. An optimized preparation provides samples with carbon-coated particles free of any impurity phase, insuring structural stability and electrochemical performance that justify the use of this material as a cathode element a new generation of lithium secondary batteries.
2012
Pure and carbon coated LiFePO 4 nanoparticles in the size ranging from 20-30 nm were synthesized by sol-gel technique. Three samples of C-LiFePO 4 were prepared by mixing 0.25M, 0.50M, and 1M lauric acid in the precursor solutions as a source of carbon to create carbon coating after carbonization. The samples were characterized by X-ray photoelectron spectroscopy (XPS), IR spectroscopy, SQUID magnetometery, and Fe 57 Mössbauer spectroscopy measurements in addition to X-ray diffraction (XRD) and Raman spectroscopy. All the samples were thoroughly investigated for their electrochemical properties. The XRD measurements showed all the samples are single phase materials with no impurity phase present. However, we identified at least three residual non crystalline impurity phases simultaneously using Fe 57 Mössbauer spectroscopy, XPS, and the magnetic measurements. IR spectroscopy did not show any phosphate type impurity phases. The elemental chemical states for Fe 2p, P 2p, and O 1s are analyzed using XPS for LiFePO 4 and compared with those of C-LiFePO 4 material. SQUID magnetometery measurements suggest an antiferromagnetic transition ~50 K in both pure LiFePO 4 and C-LiFePO 4 samples. The role of various phases, Fe 2 P, α-Fe and Fe 2 O 3 identified and analyzed by Fe 57 Mössbauer spectroscopy and XPS, have been discussed in relationship to the electrochemical properties of the cathode materials.
International Journal of Research in Engineering and Technology
Flame Spray Pyrolysis is a method used in the synthesis of LiFePO 4 with subsequent heat treatment in tubular furnace for Li-ion battery application as cathode material. The crystal structure, morphology of LiFePO 4 synthesized by Flame Spray Pyrolysis was studied by X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). From the Debye-Scherer equation, LiFePO 4 particles obtained by this method are pure, homogeneous and well-crystallized with size ranging from of 25-60nm. FESEM data reveal that the particles are in spherical morphology with primary particle size ranging from 15-75nm.
Electrochemical Properties of Zr4+ Doped LiFePO4 cathode Material for Li-Ion Battery
ECS Meeting Abstracts, 2019
Due to its thermal stability, low cost and high theoretical charge capacity, LiFePO4has emerged as one of the most promising cathode materials for large-scale lithium ion batteries. In this study, we systematically investigated the effect on structure and electrochemical properties brought by Zr doping on Fe site of LiFePO4. LiFe1−yZryPO4 (y = 0, 0.01, 0.02, 0.03, 0.05, 0.07, and 0.1) samples were prepared by using solid-state reaction. The phase and structure of as prepared powders were characterized by X-ray diffraction. Cycling charge and discharge measurement at various C-rates was employed to reveal the electrochemical properties. Results showed that the sample with 1% Zr doping was observed to have the highest charge capacity at various rates.