X-ray absorption fine structure study on Li-Mn-O compounds: LiMn2O4, Li4Mn5O12 and Li2MnO3

Shinshu, Fumio; Kaida, Satoshi; Nagayama, M.; Nitta, Yoshiaki

doi:10.1016/s0378-7753(96)02591-8

Cited by 11 publications

(7 citation statements)

References 5 publications

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“…All of these suggest that phase transition takes place during cycling, and layered Li 2 MnO 3 phase at the near-surface region transforms into spinel LiMn 2 O 4 phase. 6,35 Indeed, similar observations have been reported by other research groups, 36 and two factors contributing to the atomistic kinetics and driving force for such transformation from layered structure to spinel phases upon electrochemical cycling have been proposed. First of all, there is an intrinsic structural correlation between layered and spinel patterns that makes TM ions' migration from TM layer to Li layer both thermodynamically and kinetically favorable at highly charged states.…”

Section: ■ Introductionsupporting

confidence: 81%

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Sun

Liu

et al. 2021

Nano Lett.

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Though low-cost and environmentally friendly, Li−Mn−O cathodes suffer from low energy density. Although synthesized Li 4 Mn 5 O 12 -like overlithiated spinel cathode with reversible hybrid anion-and cation-redox (HACR) activities has a high initial capacity, it degrades rapidly due to oxygen loss and side-reaction-induced electrolyte decomposition. Herein, we develop a two-step heat treatment to promote local decomposition as Li 4 Mn 5 O 12 → 2LiMn 2 O 4 + Li 2 MnO 3 + 1/2 O 2 ↑, which releases nearsurface reactive oxygen that is harmful to cycling stability. The produced nanocomposite delivers a high discharge capacity of 225 mAh/g and energy density of over 700 Wh/kg at active-material level at a current density of 100 mA/g between 1.8 to 4.7 V. Benefiting from suppressed oxygen loss and side reactions, 80% capacity retention is achieved after 214 cycles in half cells. With industrially acceptable electrolyte amount (6 g/Ah), full cells paired with Li 4 Ti 5 O 12 anode have a good retention over 100 cycles.

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Section: ■ Introductionsupporting

confidence: 81%

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Sun

Liu

et al. 2021

Nano Lett.

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“…It has been noted in the intercalation studies on powders that as soon as lithium intercalates to β-MnO 2 , manganese reduces from Mn 4+ to Mn 3+ . ,,,− The first intercalation site of lithium is sharing the edges of oxygen octahedron with the Mn 3+ ions. This intercalation site causes a strong repulsive force and pushes the oxide ions to the cubic close-packed structure, manganese cations to the octahedral 16d interstitial sites, and lithium into the 8a interstitial site, where it is tetrahedrally coordinated.…”

Section: Resultsmentioning

confidence: 99%

Intercalation of Lithium Ions from Gaseous Precursors into β-MnO₂ Thin Films Deposited by Atomic Layer Deposition

Nieminen¹,

Miikkulainen²,

Settipani³

et al. 2019

J. Phys. Chem. C

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LiMn2O4 is a promising candidate for a cathode material in lithium-ion batteries because of its ability to intercalate lithium ions reversibly through its three-dimensional manganese oxide network. One of the promising techniques for depositing LiMn2O4 thin-film cathodes is atomic layer deposition (ALD). Because of its unparalleled film thickness control and film conformality, ALD helps to fulfill the industry demands for smaller devices, nanostructured electrodes, and all-solid-state batteries. In this work, the intercalation mechanism of Li+ ions into an ALD-grown β-MnO2 thin film was studied. Samples were prepared by pulsing LiO t Bu and H2O for different cycle numbers onto about 100 nm thick MnO2 films at 225 °C and characterized with X-ray absorption spectroscopy, X-ray diffraction, X-ray reflectivity, time-of-flight elastic recoil detection analysis, and residual stress measurements. It is proposed that for <100 cycles of LiO t Bu/H2O, the Li+ ions penetrate only to the surface region of the β-MnO2 film, and the samples form a mixture of β-MnO2 and a lithium-deficient nonstoichiometric spinel phase Li x Mn2O4 (0 < x < 0.5). When the lithium concentration exceeds x ≈ 0.5 in Li x Mn2O4 (corresponding to 100 cycles of LiO t Bu/H2O), the crystalline phase of manganese oxide changes from the tetragonal pyrolusite to the cubic spinel, which enables the Li+ ions to migrate throughout the whole film. Annealing in N2 at 600 °C after the lithium incorporation seemed to convert the films completely to the pure cubic spinel LiMn2O4.

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“…X-ray and neutron diffraction experiments have been the methodology employed in most structural studies of the Li + -insertion reaction in LiMn 2 O 4 . These studies revealed that upon delithiation of LiMn 2 O 4 the lattice contracts while retaining the cubic structure, whereas lithiating LiMn 2 O 4 causes a first-order transformation of the cubic spinel (space group Fd 3̄ m ) into the tetragonal phase Li 2 Mn 2 O 4 (space group I 4 1 / amd ) with a c / a -axis ratio between 1.16 and 1.18. ,− Diffraction methods are sensitive to atomic structure, but the Li + -insertion reaction involves changes in electronic as well as atomic structure, according to the proposed reaction: 4 X-ray absorption near edge structure (XANES) spectra have been utilized in a number of experimental studies on transition-metal oxides to probe the local atomic and electronic structure surrounding the transition metal. − XAS studies during delithiation and relithiation of LiMn 2 O 4 were reported by Ammundsen et al for chemically prepared samples , and Shiraishi et al along with Shinshu et al for electrochemically prepared samples. Their findings supported the left-half of the proposed insertion reaction mechanism (1) and showed that delithiation is not accompanied by a large change in local structure.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure of Chemically-Prepared Li_xMn₂O₄ Determined by Mn X-ray Absorption and Emission Spectroscopies

et al. 2000

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We have performed Mn K-edge X-ray Absorption and Mn L-edge emission spectroscopies on LiMn 2 O 4 , its chemically delithiated and lithiated derivatives (λ-MnO 2 and Li 2 Mn 2 O 4 , respectively), and two Mn 3+ spinel model compounds. These experiments were undertaken to understand the associated changes in atomic and electronic structure occurring when LiMn 2 O 4 is used in a rechargeable lithium cell. Subtle changes in the Mn K-edge X-ray absorption near edge structure (XANES) occur upon delithiation that are consistent with literature reports of the oxidation of Mn 3+ to Mn 4+ , retention of the cubic phase, and contraction of the spinel lattice. Conversely, when LiMn 2 O 4 is lithiated, the XANES changes dramatically due to the concurrent transformation from a cubic to a tetragonal spinel. The spectrum is different from XANES of tetragonal Mn 3+ spinels possessing approximately the same degree of tetragonal distortion as Li 2 Mn 2 O 4 . This spectral difference is attributed to the inserted Li + imparting an increased degree of covalency within the Li 2 Mn 2 O 4 structure resulting in a 1s f 4p + LMCT (ligand to metal charge transfer) shakedown. This increase in covalency was confirmed through Mn L-edge X-ray Emission Spectroscopy measurements. The increased degree of covalency provides insight into the lower Li + diffusion coefficients reported in the literature and the electronic conduction mechanism for Li x Mn 2 O 4 when x > 1.

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X-ray absorption fine structure study on Li-Mn-O compounds: LiMn2O4, Li4Mn5O12 and Li2MnO3

Cited by 11 publications

References 5 publications

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Intercalation of Lithium Ions from Gaseous Precursors into β-MnO₂ Thin Films Deposited by Atomic Layer Deposition

Electronic Structure of Chemically-Prepared Li_xMn₂O₄ Determined by Mn X-ray Absorption and Emission Spectroscopies

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X-ray absorption fine structure study on Li-Mn-O compounds: LiMn2O4, Li4Mn5O12 and Li2MnO3

Cited by 11 publications

References 5 publications

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Thermally Aged Li–Mn–O Cathode with Stabilized Hybrid Cation and Anion Redox

Intercalation of Lithium Ions from Gaseous Precursors into β-MnO2 Thin Films Deposited by Atomic Layer Deposition

Electronic Structure of Chemically-Prepared LixMn2O4 Determined by Mn X-ray Absorption and Emission Spectroscopies

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Intercalation of Lithium Ions from Gaseous Precursors into β-MnO₂ Thin Films Deposited by Atomic Layer Deposition

Electronic Structure of Chemically-Prepared Li_xMn₂O₄ Determined by Mn X-ray Absorption and Emission Spectroscopies