Structure and electrochemical properties of mixed transition-metal pyrophosphates Li2Fe1−yMnyP2O7 (0≤y≤1)

Косова, Н. В.; Tsapina, Anna M.; Slobodyuk, A. B.; Petrov, Sergey A.

doi:10.1016/j.electacta.2015.06.070

Cited by 18 publications

(15 citation statements)

References 26 publications

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“…6) can be owing to a more effective redox couple, Fe 2+ / Fe 3+ participating in the redox process. Similar phenomenons have been occurred in Li 2 Fe 1-y Mn y P 2 O 7 [23] and Li x (Mn y Fe 1-y )PO 4 [24]. The remarkable difference between the oxidation and reduction peaks position, no matter in shape and voltage, suggests a large polarization in Li 2 Mn 1-x Fe x (PO 3 ) 4 /C system although the electrochemical capacities can be improved with increasing Fe-doping content (Fig.…”

Section: Resultssupporting

confidence: 62%

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Yan

Zhao

Dong

et al. 2015

J Solid State Electrochem

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Li 2 Mn 1-x Fe x (PO 3 ) 4 (x=0, 0.2, 0.4, 0.6, 0.7) solid solution phase has been successfully prepared via solid-state reaction. The Rietveld refinement results indicate that the Li 2 Mn 1-x Fe x (PO 3 ) 4 (x=0, 0.2, 0.4, 0.6, 0.7) solid solutions with orthorhombic structure can be obtained and the lattice parameters (including a, b, c, and V) decrease with the increasing of Fe concentration. Partial substitution of manganese with iron enhances the electrochemical performance; there, the discharge-specific capacity of the samples obviously increases from 21 mAh/g for x=0 to 59 mAh/g for x=0.7, which is 85 % capacity of that one lithium removal. The cyclic voltammetric (CV) curves present the Mn 2+ /Mn 3+ redox couple situated at 4.6 and 1.8 V and Fe 2+ /Fe 3+ redox couple located at 4.3 and 2.3 V, which can be observed in cathodic and anodic sweeps. Such a low discharge potential value for M 2+ / M 3+ redox couple may be attributed to the zigzag [(PO 3 ) 1− ] n chains in this structure.

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Section: Resultssupporting

confidence: 62%

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Yan

Zhao

Dong

et al. 2015

J Solid State Electrochem

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“…It should be noted that a rather large line-width (0.57 mm s −1 ) may imply the occurrence of the distorted local environment at the Fe1 site, which agrees with the XRD data and confirms the presence of larger amount of different Fe positions in its structure than in Na 2 [4] that is higher than that reported for Li 2 FeP 2 O 7 . 21,22 This implies the formation of the Na 2 CO 3 impurity phase which is X-ray amorphous. Figure 4 demonstrates the 23 Na MAS NMR spectrum of the pristine Na 1.56 Fe 1.22 P 2 O 7 .…”

Section: Resultsmentioning

confidence: 99%

“…4). 22 The difference in the character of the NMR spectra of Na 1 distinguished binding of the iron polyhedra either through corners or edges.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical and Chemical Na⁺/Li⁺Ion Exchange in Na-Based Cathode Materials: Na_1.56Fe_1.22P₂O₇and Na₃V₂(PO₄)₂F₃

Косова¹,

Rezepova²,

Petrov³

et al. 2016

J. Electrochem. Soc.

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In this work, XRD, EDX, Mössbauer and NMR spectroscopy were used to study chemical and electrochemical Na + /Li + ion exchange in the sodium iron pyrophosphate Na 1.56 Fe 1.22 P 2 O 7 with a triclinic symmetry, S. G. P-1, and sodium vanadium fluorophosphate Na 3 V 2 (PO 4 ) 2 F 3 with a tetragonal symmetry, S. G. P4 2 /mnm, cathode materials. Electrochemical Na + /Li + ion exchange was performed in hybrid-ion cells with Li metal anode and LiPF 6 -based electrolyte, while chemical ion exchange was realized in the solution of LiBr in acetonitrile. A facile electrochemical and chemical Na + /Li + ion exchange was observed for both cathode materials, resulting in the formation of the mixed Na-Li compositions: ∼Na Sodium-ion batteries have been considered as potential candidates for stationary energy storage, because of the low cost and wide availability of sodium sources. Sodium is more abundant and less expensive than lithium. However, Na-ion based systems have a lower energy density compared to Li-ion systems since a reduction potential of sodium metal vs. SHE is 0.3 V higher than that of lithium. Sodium has a larger ionic radius and bigger molecular weight. Therefore, sodium-based insertion materials are of interest for low-cost and large-scale Na-ion batteries. Substantial research efforts have been invested during the previous years to produce electrode materials for sodium batteries allowing facile intercalation of the Na ions at suitable potentials. Amongst the cathode materials investigated, various layered oxides (e.g. Na 0.6 CoO 2 , Na 2/3 Fe 1/3 Mn 2/3 O 2 , Na 2/3 Ni 1/3 Mn 2/3 O 2 , NaNi 1/3 Co 1/3 Mn 1/3 O 2 , etc.) and polyanionic compounds (e.g. NaFePO 4 , Na 2 FePO 4 F, Na 3 V 2 (PO 4 ) 3 , NaFeSO 4 F, etc.) are the most favorite cathode materials.1 To enhance the electrochemical performance of sodium-based cathode materials, Barker et al. first proposed a concept of a hybrid-ion battery whereby a non-lithium containing cathode material is used in conjunction with metallic Li, graphite, Li 4 Ti 5 O 12 , etc., and Li-based or mixed Li/Na electrolytes.2-5 The Na + /Li + ion exchange is an effective way to produce new metastable mixed Na/Li phases for Li-ion batteries without causing many structural changes to the pristine sodium-based materials. A new design concept of the simultaneously energy storage of multi-metal ions may overcome respective disadvantages of singlemetal ions and bring to a synergy effect. 6,7 Since the operation of hybrid-ion batteries depends on the reactivity of the selected electrodes in respect of Li + and Na + ions, two Na-based cathode materials, differing by crystal structure, triclinic Na 1.56 Fe 1.22 P 2 O 7 and tetragonal Na 3 V 2 (PO 4 ) 2 F 3 , were selected in this work to study electrochemical and chemical Na + /Li + ion exchange and their performance in hybridion cells.Sodium iron pyrophosphates 8,9 with a triclinic symmetry (S.G. P-1) and sodium vanadium fluorophosphates with tetragonal symmetry (S.G. P4 2 /mnm) [10][11][12] were recently examined and showed good e...

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“…Their identification was difficult due to the lack of accurate calculations of the hyperfine parameters. In several published papers only one doublet was ascribed to the combination of FeO 5 sites [8,13,26]. Taking into consideration the partial occupancy of the mixed-occupied sites established by the Rietveld refinement and the ratio of the relative areas of these two doublets (Table 3), we ascribed the doublet with the largest area, and also with a larger isomer shift and quadrupole splitting, to the Fe2 site.…”

Section: Accepted Manuscriptmentioning

confidence: 93%

“…So far, Li 2 FeP 2 O 7 or its composites with carbon have been synthesized in various ways, such as the conventional solid-state method [8][9][10][11][12], mechanochemically assisted solid state synthesis [13], combustion method [14], sol-gel method [15], spray pyrolysis [16], etc. The solid-state method is widely adopted in industry for the mass production of cathode materials due to its simplicity and low cost.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

Jugović

Mitrić

Milović

et al. 2019

Journal of Alloys and Compounds

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A new method involving the homogeneous dispersion of precursor compounds inside a methylcellulose matrix is used for the synthesis of a composite powder of Li 2 FeP 2 O 7 and carbon.The properties of carbon-containing and carbon-free powders are studied by X-ray powder diffraction (XRD) including Rietveld refinement, Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The structure of both powders is refined in a monoclinic framework (space group P2 1 /c). The structural refinement and Mössbauer spectroscopy reveal different degrees of partial occupancy of mixed-occupied sites

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Structure and electrochemical properties of mixed transition-metal pyrophosphates Li2Fe1−yMnyP2O7 (0≤y≤1)

Cited by 18 publications

References 26 publications

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Electrochemical and Chemical Na⁺/Li⁺Ion Exchange in Na-Based Cathode Materials: Na_1.56Fe_1.22P₂O₇and Na₃V₂(PO₄)₂F₃

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

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Structure and electrochemical properties of mixed transition-metal pyrophosphates Li2Fe1−yMnyP2O7 (0≤y≤1)

Cited by 18 publications

References 26 publications

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Electrochemical and Chemical Na+/Li+Ion Exchange in Na-Based Cathode Materials: Na1.56Fe1.22P2O7and Na3V2(PO4)2F3

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

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Electrochemical and Chemical Na⁺/Li⁺Ion Exchange in Na-Based Cathode Materials: Na_1.56Fe_1.22P₂O₇and Na₃V₂(PO₄)₂F₃