Silicon‐Doped LiFePO4 Single Crystals: Growth, Conductivity Behavior, and Diffusivity

Amin, Ruhul; Lin, C. T.; Peng, Jubo; Weichert, Katja; Acartürk, Tolga; Starke, Ulrich; Maier, Joachim

doi:10.1002/adfm.200801604

Cited by 75 publications

(48 citation statements)

References 29 publications

(64 reference statements)

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“…The reason for this opposite behavior is not clear [31]. In the case of Si substituting Fe, an increase of cell volume is also observed [35]. It also has to be noted that with combination of doping and 2 % vacant M 1 sites in LiFePO 4 will lead to a slight expansion of the cell volume [31].…”

Section: Electrochemical Characterizationsmentioning

confidence: 97%

“…Doping of LiFePO 4 has been widely investigated and controversially commented in the literature [31][32][33][34][35]. For instance, single element doping (Al, Ga, Zr, Ti, Nb, Ta), in M 1 or M 2 positions is thought to be impossible based on energetics considerations [34].…”

Section: Electrochemical Characterizationsmentioning

confidence: 99%

“…For instance, single element doping (Al, Ga, Zr, Ti, Nb, Ta), in M 1 or M 2 positions is thought to be impossible based on energetics considerations [34]. However, experimental observations point to effective doping of LiFePO 4 with supervalent cations of various oxidation states (Mg 2+ , Al 3+ , Zr 4+ , and Nb 5+ ) and Si in M 1 or M 2 occupations [31,33,[35][36][37]. The authors do not agree on the achievable dopant level though [32].…”

Section: Electrochemical Characterizationsmentioning

confidence: 99%

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LiFePO4 synthesized via melt synthesis using low-cost iron precursors

Talebi‐Esfandarani

Rousselot

Gauthier

et al. 2015

J Solid State Electrochem

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LiFePO 4 /C material has been prepared using fastmelt synthesis method followed by grinding and carbon coating. The low-cost iron ore concentrate (IOC) and purified iron ore concentrate (IOP) were used as iron precursors in the melt process to reduce significantly the cost of LiFePO 4 /C. The same product was also synthesized using pure Fe 2 O 3 under similar conditions as reference. The physical-chemical and electrochemical properties of samples were investigated. The X-ray Diffraction (XRD) results confirm the formation of an olivine structure of LiFePO 4 with a minor amount of Li 3 PO 4 and Li 4 P 2 O 7 impurities for all the samples but no Fe 2 P. The power performances of LiFePO 4 /C using low-cost iron precursors were close to the sample using pure Fe 2 O 3 precursor although capacity in mAh g −1 is somewhat lower. With the inherent presence of silicon and other metals species, multisubstitution may take place when using IOC as source of iron leading to a Li(Fe 1-y M y )(P 1-x Si x )O 4 general composition. Multi-substitution, however, allows a better cycling stability. Therefore, these iron precursors present a promising option in this field to reduce the cost of a large-scale synthesis of LiFePO 4 /C for Li-ion batteries application.

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Section: Electrochemical Characterizationsmentioning

confidence: 97%

Section: Electrochemical Characterizationsmentioning

confidence: 99%

Section: Electrochemical Characterizationsmentioning

confidence: 99%

See 1 more Smart Citation

LiFePO4 synthesized via melt synthesis using low-cost iron precursors

Talebi‐Esfandarani

Rousselot

Gauthier

et al. 2015

J Solid State Electrochem

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“…The conductivity values increased by increasing the amount of carbon in the LiFePO 4 /C composites [6]. There are many publications where conductivity of LiFePO 4 was investigated at low frequencies [4][5][6][7][8]. The O 1s, Fe 2p, P 2p core level XPS depends on the sputtering time of LiFePO 4 samples by Ar + [9].…”

Section: Introductionmentioning

confidence: 99%

SEM/EDX, XPS, and impedance spectroscopy of LiFePO4 and LiFePO4/C ceramics

Орлюкас

Fung²,

Venckutė

et al. 2014

Lith. J. Phys.

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The powders of LiFePO 4 compounds have been synthesized by the solid state reaction, and LiFePO 4 /C composites were sintered in argon gas. The ceramics of LiFePO 4 were sintered in air. The surfaces of the ceramics were investigated by a scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDX). The binding energies of the Fe 2p, P 2p, and O 1s core level of LiFePO 4 ceramic and LiFePO 4 /C composite surfaces were determined by X-ray photoelectron spectroscopy (XPS). The deconvolutions of Fe 2p core level XPS are associated with Fe 2+ and Fe 3+ valence states of the ceramics. Impedance spectroscopy of the ceramics has been performed in the frequency range of 10 Hz to 3 GHz by low frequency and microwave impedance spectrometers. Two-and four-probe methods were used for measurements at low frequencies. The LiFePO 4 /C composite was investigated in nitrogen gas, and the measurements of LiFePO 4 were conducted in air. The measurements of the electrical properties of the ceramics were carried out in the temperature interval of 300-500 K.

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“…3 Given the importance of the knowledge of equilibrium defect concentrations, there exists extensive literature on defect stability diagrams obtained from large sets of experimental data. 5,6,[14][15][16][17][18] Pioneering work in this direction was performed by Brouwer who proposed different scaling laws for oxygen defect (vacancy, interstitial) concentrations in terms of oxygen partial pressure. 5 These scaling laws were then matched with the experimental values of diffusivity and correspondingly the formation and migration energies of point defects were obtained.…”

mentioning

confidence: 99%

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

2012

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Point defects play a dominant role in determining the wide spectrum of electronic and physical properties of semiconducting materials that have vast technological applications. Using ab-initio simulations, a method to calculate equilibrium defect concentrations, Fermi energy and defect stability diagrams as functions of external parameters, such as temperature and pressure, is presented. Using SrTiO3 as a representative material, we report our analysis of the stability of oxygen vacancies and interstitials, in their different charge states, as a function of temperature, oxygen partial pressure and Fermi energy of the system. Further, by analyzing the defect chemistry at experimentally relevant temperatures, we find that at low oxygen partial pressure, neutral oxygen vacancies are most dominant and at intermediate and high oxygen partial pressure, doubly charged oxygen vacancies defects are dominant.

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Silicon‐Doped LiFePO₄ Single Crystals: Growth, Conductivity Behavior, and Diffusivity

Cited by 75 publications

References 29 publications

LiFePO4 synthesized via melt synthesis using low-cost iron precursors

LiFePO4 synthesized via melt synthesis using low-cost iron precursors

SEM/EDX, XPS, and impedance spectroscopy of LiFePO<sub>4</sub> and LiFePO<sub>4</sub>/C ceramics

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

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