Morphological investigation of sub-micron FePO4 and LiFePO4 particles for rechargeable lithium batteries

Scaccia, Silvera; Carewska, Maria; Wiśniewski, P.; Prosini, Pier Paolo

doi:10.1016/s0025-5408(03)00110-7

Cited by 51 publications

(27 citation statements)

References 11 publications

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“…Thus far, triphylite has been the Li-bearing olivine-group phase most studied for application in rechargeable batteries (Andersson et al 2000, Chung et al 2002, Huang et al 2001, Padhi et al 1997a, b, Prosini et al 2001, Scaccia et al 2003, Yamada et al 2001a, b, Yang et al 2002. Critical properties for this application are its electrical and ion (Li) conductivity.…”

Section: Discussionmentioning

confidence: 99%

Structural Variation in the Lithiophilite-Triphylite Series and Other Olivine-Group Structures

Losey¹,

Rakovan²,

Hughes³

et al. 2004

The Canadian Mineralogist

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The crystal structures of five natural samples of the lithiophilite-triphylite series [Li(Mn,Fe)PO 4 ; Li = M1, (Mn,Fe) = M2] were refined to determine structural variation along the Mn (r = 0.83 Å) ⇔ Fe (r = 0.78 Å) solid-solution series, and to elucidate variations in the atomic arrangement of Pbnm olivine. The refinements converged to R ≤ 0.017. Bonds at the O3 site are fundamental in understanding the response of the atomic arrangement as Fe concentration increases. The M2-O3a bond shortens by more than 0.06 Å, and the M2-O3b bond shortens by ~0.02 Å over the series. This shift of the O3 oxygen toward the two coordinating M2 sites is commensurate with an increase in the M1-O3 bond length by approximately 0.03 Å, and an increase in the distortion of the M1 site. Much previous work has focused on polyhedron distortions in the olivine structure. The angle variance for the M1, M2, and T polyhedra were calculated for each phosphate sample in this study and published silicate and germanate olivine structures. In each case, the angle variance of the phosphate olivines was found to be smaller in the M1 octahedron, which is in contrast to the other olivine-structure phases examined in this study. However, if the size difference in the radius of the M1 and M2 site cations is ≥0.17 Å, the distortion is greater in the octahedral site that is occupied by the larger cation. The structural differences along the lithiophilite-triphylite solid-solution series may have significant effects on its solid electrolyte properties, including rates of lithium diffusion and activation energies, and thus are important in the development and design of Li-olivine storage cathodes.Keywords: lithiophilite, triphylite, olivine structure, crystal structure, lithium storage electrodes. SOMMAIRENous avons affiné la structure cristalline de cinq échantillons naturels faisant partie de la série lithiophilite-triphylite [Li(Mn,Fe)PO 4 ; Li = M1, (Mn,Fe) = M2] afin de déterminer la variation structurale le long de la série à mesure que le Mn (rayon 0.83 Å) remplace le Fe (rayon 0.78 Å), et pour élucider les agencements atomiques d'une olivine Pbnm. Les affinements ont convergé à un résidu R ≤ 0.017. Les liaisons impliquant le site O3 sont fondamentales pour expliquer la réponse de l'agencement atomique à mesure que la proportion de Fe augmente. La liaison M2-O3a est raccourcie de plus de 0.06 Å, et la liaison M2-O3b est raccourcie d'environ 0.02 Å le long de la série. Ces déplacements de l'atome O3 vers les deux sites M2 dans l'agencement sont conformes avec une augmentation de la longueur de M1-O3 d'environ 0.03 Å, et du degré de distorsion du site M1. Plusieurs travaux antérieurs ont porté sur les distorsions des polyèdres dans la structure d'une olivine. Nous avons calculé la variance des angles des polyèdres M1, M2, et T pour chaque échantillon de phosphate dans ce travail et pour les structures d'olivine parmi les compositions de silicates et de germanates. Dans chaque cas, la variance des angles dans les phosphates à structure d'oliv...

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Section: Discussionmentioning

confidence: 99%

Structural Variation in the Lithiophilite-Triphylite Series and Other Olivine-Group Structures

Losey¹,

Rakovan²,

Hughes³

et al. 2004

The Canadian Mineralogist

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“…We found that the addition of hydrochloric acid assisted in dissolving the ferric chloride and maintaining stability over the course of the reaction. The low pH also helped to prevent the undesired hydrolysis of Fe 3+ , which would precipitate into Fe(OH) x impurities [58]. Tribasic sodium phosphate was employed as the phosphate anion source.…”

Section: Mechanism Of Morphology-controlled Synthesis Of Amorphous Fementioning

confidence: 99%

“…These methods must effectively achieve two specific chemical goals: the reduction of Fe 3+ to Fe 2+ and the incorporation of Li + ions into the chemical structure. Thus far, the most popular reducing agent has been LiI, since it is cheaper and easier to handle than more powerful lithium-based reducing agents, such as n-butyl lithium [58]. Although LiI may not completely reduce Fe 3+ to Fe 2+ under simple wet chemistry conditions, likely due to hindered kinetics, materials synthesized through this technique have shown promising electrochemical performance [53,55,56,62].…”

Section: Conversion Of Amorphous Fepo 4 To Crystalline Lifepomentioning

confidence: 99%

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Ambient synthesis, characterization, and electrochemical activity of LiFePO4 nanomaterials derived from iron phosphate intermediates

et al. 2015

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LiFePO 4 materials have become increasingly popular as a cathode material due to the many benefits they possess including thermal stability, durability, low cost, and long life span. Nevertheless, to broaden the general appeal of this material for practical electrochemical applications, it would be useful to develop a relatively mild, reasonably simple synthesis method of this cathode material. Herein, we describe a generalizable, 2-step methodology of sustainably synthesizing LiFePO 4 by incorporating a template-based, ambient, surfactantless, seedless, U-tube protocol in order to generate size and morphologically tailored, crystalline, phase-pure nanowires. The purity, composition, crystallinity, and intrinsic quality of these wires were systematically assessed using transmission electron microscopy (TEM), high-resolution TEM (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), energy dispersive analysis of X-rays (EDAX), and high-resolution synchrotron XRD. From these techniques, we were able to determine that there is an absence of any obvious defects present in our wires, supporting the viability of our synthetic approach. Electrochemical analysis was also employed to assess their electrochemical activity. Although our nanowires do not contain any noticeable impurities, we attribute their less than optimal electrochemical rigor to differences in the chemical bonding between our LiFePO 4 nanowires and their bulk-like counterparts. Specifically, we demonstrate for the first time experimentally that the Fe-O3 chemical bond plays an important role in determining the overall conductivity of the material, an assertion which is further supported by recent "first-principles" calculations. Nonetheless, our ambient, solution-based synthesis technique is capable of generating highly crystalline and phase-pure energy-storage-relevant nanowires that can be tailored so as to fabricate different sized materials of reproducible, reliable morphology.

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“…Nevertheless, the crystalline peak intensities of the 400°C samples are less than those samples prepared at higher temperatures. The crystallization temperature of LiFePO 4 has been reported to be *567°C, based on a different thermal analysis study [26]. The spectrum of LiFe 0.9-Mg 0.1 PO 4 /C is almost the same as the spectrum of pure ordered orthorhombic olivine structured LiFePO 4 (Fig.…”

Section: Resultsmentioning

confidence: 96%

Preparation and electrochemical properties of spherical LiFePO4 and LiFe0.9Mg0.1PO4 cathode materials for lithium rechargeable batteries

2009

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The spherical LiFePO 4 /C and LiFe 0.9 Mg 0.1 PO 4 /C powders were successfully prepared from spherical FePO 4 via a simple uniform-phase precipitation method at normal pressure, using FeCl 3 and H 3 PO 4 as the reactants. The FePO 4 , LiFePO 4 /C, and LiFe 0.9 Mg 0.1 PO 4 /C powders were characterized by scanning electron microscopies (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), and tap-density testing. The uniform spherical particles produced are amorphous, but they were crystallized to FePO 4 after calcining above 400°C. Due to the homogeneity of the basic FePO 4 , the final products, LiFePO 4 /C and LiFe 0.9 Mg 0.1 PO 4 /C, are also significantly uniform and the particle size is of about 1 lm in diameter. The tap-density of the spherical LiFePO 4 /C and LiFe 0.9 Mg 0.1 PO 4 /C are 1.75 and 1.77 g cm -3 , respectively, which are remarkably higher than the nonspherical LiFePO 4 powders (the tap-density is 1.0-1.3 g cm -3 ). The excellent specific capacities of 148 and 157 mAh g -1 with a rate of 0.1 C are achieved for the LiFePO 4 /C and LiFe 0.9 Mg 0.1 PO 4 /C, respectively. Comparison of the cyclic voltammograms of LiFePO 4 /C and LiFe 0.9 Mg 0.1 PO 4 /C shows enhanced redox current and reversibility for the sample substituting Mg on the Fe site. LiFe 0.9 Mg 0.1 PO 4 /C exhibits better high-rate and cycle performances than the un-substituted LiFePO 4 /C.

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Morphological investigation of sub-micron FePO4 and LiFePO4 particles for rechargeable lithium batteries

Cited by 51 publications

References 11 publications

Structural Variation in the Lithiophilite-Triphylite Series and Other Olivine-Group Structures

Structural Variation in the Lithiophilite-Triphylite Series and Other Olivine-Group Structures

Ambient synthesis, characterization, and electrochemical activity of LiFePO4 nanomaterials derived from iron phosphate intermediates

Preparation and electrochemical properties of spherical LiFePO4 and LiFe0.9Mg0.1PO4 cathode materials for lithium rechargeable batteries

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