Spinel Solid Solutions in the Li–Fe–Mn–O System

Grygar, Tomáš Matys; Bezdička, Petr; Vorm, Petr; Jordanova, Neli; Krtil, Petr

doi:10.1006/jssc.2001.9310

Cited by 12 publications

(14 citation statements)

References 16 publications

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“…27 Previous studies showed the effects of the substitution of Mn for Fe in LiFe 5 O 8 , i.e., Li͑Fe,Mn͒ 5 O 8 with the ratio of Mn/͑Mn + Fe͒ Ͼ 0.7 on cation configuration and magnetic property. 28 In this Mn-Li ferrite system, tetrahedral sites are almost completely occupied by Fe and Li ions, and Mn ions are located at octahedral sites. As the Mn/͑Mn + Fe͒ ratio increases, the fraction of Li ions at the tetrahedral sites increases linearly, and the Curie temperature of the Mn-Li ferrite decreases linearly.…”

Section: Resultsmentioning

confidence: 99%

Formation and Disappearance of Spinel Nanograins in Li[sub 1.2−x]Mn[sub 0.4]Fe[sub 0.4]O[sub 2] (0≤x≤0.99) during Extraction and Insertion of Li Ions

Kikkawa

Akita

Tabuchi

et al. 2009

J. Electrochem. Soc.

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The authors investigated the changes in local structures and magnetic property of the Li 1.2 Mn 0.4 Fe 0.4 O 2 positive electrode material for lithium-ion batteries during the first charge-discharge cycle. Although Li 1.2 Mn 0.4 Fe 0.4 O 2 has a composite structure of the layered and disordered cubic rocksalt before the electrochemical testing, nanometer-sized grains with spinel structures are formed during the extraction of Li ions up to Li 1.2−x Mn 0.4 Fe 0.4 O 2 ͑0 Յ x Յ 0.99͒. The spinel nanograins have weak spontaneous magnetization ͑ca. 0.3 G cm 3 /g͒, which is associated with the movements of Fe ions from the octahedral to the tetrahedral sites in both the layered and disordered rocksalt structures. The fraction of spinel nanograins decreased after the subsequent insertion of Li ions.Lithiated transition-metal ͑TM͒ oxides are widely studied as positive electrodes of lithium-ion batteries. 1 LiAO 2 ͑A = Co, Ni, Mn, and combinations thereof͒ with a layered rocksalt structure, comprising alternative stacking of Li and TM layers between cubic close-packed oxygen arrays, has been most intensively studied to seek high energy and high power positive electrode materials. 2-5 A charge-discharge cycle of the battery is performed by reversible extraction/insertion of Li ions in both the positive and negative electrode materials. In practice, however, irreversible phase transitions during charge-discharge cycles which cause fatal capacity loss are an essential problem. Previous studies on LiCoO 2 and LiMnO 2 found that structural transformations from the layered rocksalt structure to the spinel structures deteriorate the battery performance. [6][7][8][9][10][11][12] It is believed that spinel phases simply accumulate and grow within an original layered rocksalt phase during charge-discharge cycling.Recently, Li 2 MnO 3 -LiAO 2 ͑A = Cr, Fe, Co, Ni, and combinations thereof͒ systems attract substantial interests as positive electrode materials due to potential high capacities ͑Ͼ200 mAh/g͒ for near-future electric vehicles. 13-20 Although one of the origins of the high capacity is abundant Li contents in the nominal formula Li 1+x A 1−x Ј O 2 ͑x Ͼ 0͒, charge-discharge mechanisms are not fully understood and an urgent issue to be addressed. A Li 2 MnO 3 -LiFeO 2 system is an attractive material because it contains cheap constituent TM elements and acts as a 3 V positive electrode, which is comparable to a Li 2 MnO 3 -LiCrO 2 system 13,14 in spite of the inactive bulk LiFeO 2 . Tabuchi et al. reported that ͑1 − x͒Li 2 MnO 3 -xLiFeO 2 shows high specific capacities for x between 0.3 and 0.5. 15 Typical charge-discharge voltage profiles of a Li 1.2 Mn 0.4 Fe 0.4 O 2 ͑calcinated at 850°C in air͒/Li cell 15 are shown in Fig. 1a. The first charge profile exhibits a specific high capacity of ca. 300 mAh/g although the large capacity fading occurs during the first cycle. After the 10th cycle, the charge-discharge profiles are basically reversible. Thus understanding the first charge-discharge mechanisms is most important for impr...

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Section: Resultsmentioning

confidence: 99%

Formation and Disappearance of Spinel Nanograins in Li[sub 1.2−x]Mn[sub 0.4]Fe[sub 0.4]O[sub 2] (0≤x≤0.99) during Extraction and Insertion of Li Ions

Kikkawa

Akita

Tabuchi

et al. 2009

J. Electrochem. Soc.

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“…The XRD patterns of the four powders are shown in Figure . All the patterns exhibit high‐intensity peaks indexed to a single phase of a cubic spinel structure (space group

italicFd \overset{3}{true} m

) of the lithium manganese iron oxide (ICSD 93818) . The high‐intensity peaks indicate that the powders are highly crystalline in nature.…”

Section: Resultsmentioning

confidence: 99%

Crystallite size and lattice strain of lithiated spinel material for rechargeable battery by X-ray diffraction peak-broadening analysis

et al. 2019

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Summary High‐energy ball milling is performed on Li1.1Mn1.95Fe0.05O4 spinel material, synthesized by sol‐gel method for lithium rechargeable battery, at different durations to obtain nanopowders of finite size distributions. The powders are investigated by means of scanning electron microscopy, particle size distribution, and X‐ray diffraction (XRD) measurements. The structural analysis of the powders is performed to investigate the effect of milling on the particle size, crystallite size, and lattice strain. The scanning electron micrographs and size distribution measurements show that the particle size decreases with the increase in milling duration. The XRD results show that the widths of the diffraction peaks increase with the decrease of particle size (increase of milling duration). This broadening is analyzed according to Scherrer, Williamson‐Hall, and Halder‐Wagner methods. Peak broadening is attributed to contributions of crystallite size and lattice strain. While reducing the particle and crystallite sizes is desirable to achieve higher specific capacity and energy density of the battery active material, lattice strain leads to material degradation and a reduced capacity retention. Thus, when performing mechanical milling, lattice strain should be taken seriously into consideration to optimize the milling parameters and to enhance the materials electrochemical performance.

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“…Although this phenomenon was reported already in the first papers dealing with this system 168 and since then it has been studied by numerous authors, the structural discontinuity in the solid solution LiMn 2 O 4 -λ-MnO 2 was proved by diffraction studies only in 1998 (refs 163,164 ). Similarly complex is the course of electrochemical Li + insertion/extraction in the system Li 1-x NiO 2 in which, at certain x, structural discontinuities due to Li ordering cause stepped discharge curves 165,166 .…”

Section: Solid Solutionsmentioning

confidence: 92%

“…Similarly complex is the course of electrochemical Li + insertion/extraction in the system Li 1-x NiO 2 in which, at certain x, structural discontinuities due to Li ordering cause stepped discharge curves 165,166 . Also in that case, voltammetry is more sensitive to structural discontinuities than for example XRD.…”

Section: Solid Solutionsmentioning

confidence: 99%

Electrochemical Analysis of Solids. A Review

Grygar

Marken

Schröder

et al. 2002

Collect. Czech. Chem. Commun.

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208

149

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The topic of the review is the electrochemical analysis of solids aimed to identify or determine their phase or elemental composition, analyse the composition of solid mixtures, characterise their electrochemistry-related properties and analyse the redox state of the constituent elements. The ways of the electrode preparation are discussed with a special attention paid to compact and composite electrodes including carbon-paste electrodes, and direct immobilisation of powders on a working electrode. Examples are given of simultaneous electrochemical measurements combined with X-ray diffraction, optical or atomic force microscopy, and mass measurement by quartz microbalance. The state-of-art of voltammetric analysis of inorganic and organic solids achieved in the last two decades is systematically reviewed with the aim to find cases, when electrochemistry can compete successfully with other analytical techniques as for sensitivity, specificity, and sample consumption. Electrochemical methods are shown to be a perspective tool for redox analysis of catalysts, combined elemental and phase analysis of inorganic pigments and minerals, characterisation of solid solutions, metalloorganic and organic solids. A review with 196 references.

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Spinel Solid Solutions in the Li–Fe–Mn–O System

Cited by 12 publications

References 16 publications

Formation and Disappearance of Spinel Nanograins in Li[sub 1.2−x]Mn[sub 0.4]Fe[sub 0.4]O[sub 2] (0≤x≤0.99) during Extraction and Insertion of Li Ions

Formation and Disappearance of Spinel Nanograins in Li[sub 1.2−x]Mn[sub 0.4]Fe[sub 0.4]O[sub 2] (0≤x≤0.99) during Extraction and Insertion of Li Ions

Crystallite size and lattice strain of lithiated spinel material for rechargeable battery by X-ray diffraction peak-broadening analysis

Electrochemical Analysis of Solids. A Review

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