Jahn–Teller instability in spinel Li–Mn–O

Yamada, Atsuo; Tanaka, Masahiro; Tanaka, Kōichi; Sekai, Koji

doi:10.1016/s0378-7753(99)00106-8

Cited by 131 publications

(72 citation statements)

References 30 publications

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“…A large theoretical capacity of 220 mAh/g is calculated based on the LiFeBO 3 chemical formula, which is much larger than the 170 mAh/g for LiFePO 4 . Furthermore, the true density of LiFeBO 3 is 3.46 g/cm 3 , which is close to that of LiFePO 4 and suitable for maximizing the volume energy density due to the minimum volume occupation of the planar triangle BO 3 oxyanion unit. Carefully prepared Li x FeBO 3 shows room temperature activity as a cathode with a capacity of >190 mAh/g at around 3 V versus Li.…”

Section: Lightening and Compaction Of Host Frameworkmentioning

confidence: 64%

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Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms

Yamada

2016

Electrochemistry

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"Abundance" is an important keyword in materials development. This is particularly the case for the energy storage sector, where materials themselves function as a storage host. The amount of materials is directly linked to the amount of energy stored in the device. In rechargeable batteries, transition metal elements are necessary to accommodate a large number of electrons/holes in a reversible redox reaction. Iron, as the fourth most abundant element in the earth's crust, is an ideal redox center, but practical storage electrodes with Fe redox have long been the "holy grail" of the lithium-ion battery since its commercialization in 1991. In this review article, the history of replacing Co with Mn and/or Fe in lithium battery electrodes is briefly reviewed followed by recent technical achievements toward more sustainable batteries using Na + as a guest ion, where the goal would be to discover a high voltage electrode material composed of Na and Fe without compromising the energy density. Further, our ultimate destination is set to high energy density aqueous lithium/sodium ion batteries, where the hydrate-melt electrolyte enables surprisingly high-voltage operation over 3 V. During materials identification and optimization, reaction mechanisms should be understood in a systematic way to provide a firm direction for strategic design. With this regards, important physicochemical properties of key materials will be introduced.

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Section: Lightening and Compaction Of Host Frameworkmentioning

confidence: 64%

“…3). 3 The replacement of the trivalent manganese ions by divalent (t 2g 3 e g 2 ) or tetravalent (t 2g 3 e g 0 ) manganese ions reduces the instability. Consequently, T t decreases and the magnitude of c/a decreases and approaches unity as the average manganese valence number increases from 3.0 to 3.5 (Fig.…”

Section: Jahn-teller Transitionmentioning

confidence: 99%

Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms

Yamada

2016

Electrochemistry

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“…An initial capacity of ~280 mA h g −1 was obtained, but rapidly faded. EXAFS spectra indicated partial collapse of the tunnel structure, which is brought about by dissolution of Mn into the electrolyte and Jahn-Teller distortion of octahedral containing Mn 3+ [233]. Rasul et al [220] prepared a composite of α-MnO 2 / acetylene black hydrothermally, which showed higher capacity than pristine α-MnO 2 obtained from a sol-gel route (210 and 85 mA h g −1 , respectively) [222].…”

Section: Reviewmentioning

confidence: 99%

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

2015

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to develop and install renewable energy harvesting technologies [3]. However, their successful implementation will be dependent on reliable and robust storage devices since harvesting solar and wind energy is inherently intermittent and the majority of consumption targets cannot be readily tethered to the grid.As energy storage devices, batteries possess high portability, high energy density, high Coulombic efficiency, and long cycle life. They are ideal power sources for portable devices, automobiles, and backup power supplies; accordingly, batteries power nearly all of our mobile electronics and are used to improve the efficiency of hybrid electric vehicles [4,5]. Unfortunately, considerable improvements in performance are still required in order to meet the demands of advanced portable devices and achieve energy sustainability (e.g., through smart grid and electric vehicle technologies) [6]. These enduring needs have driven intensive research investments. While efforts have been successful, there is still significant room for improvement regarding the development and understanding of electrode materials [7]. The overall capacity and potential cycling window of many electrode materials are limited to prevent degradation over long term cycling. In addition to exploring new electrode materials, there have been strong efforts to improve those that are already utilized. Expense reduction is a priority as approximately 23% and 8% of the overall battery pack costs stem from the respective cathode and anode active materials alone [8].An alkali-ion battery consists of several electrochemical cells connected in parallel and/or in series to provide a designated current or voltage. Each electrochemical cell has two electrodes separated by an electrolyte that is electrically insulating but ionically conductive. During discharge, when the alkali-ion battery operates as a galvanic cell, alkali ions exit the negative electrode (typically carbon) and insert themselves into the positive electrode while electronsThe need for economical and sustainable energy storage drives battery research today. While Li-ion batteries are the most mature technology, scalable electrochemical energy storage applications benefit from reductions in cost and improved safety. Sodium-and magnesium-ion batteries are two technologies that may prove to be viable alternatives. Both metals are cheaper and more abundant than Li, and have better safety characteristics, while divalent magnesium has the added bonus of passing twice as much charge per atom. On the other hand, both are still emerging fields of research with challenges to overcome. For example, electrodes incorporating Na + are often pulverized under the repeated strain of shuttling the relatively large ion, while insertion and transport of Mg 2+ is often kinetically slow, which stems from larger electrostatic forces. This review provides an overview of cathode and anode materials for sodium-ion batteries, and a comprehensive summary of research on cathodes for magnesium-ion batteries. In additi...

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“…The difference in amplitude is evident for k 3 of Mn 3ϩ , the significant damping suggests the enhancement of local disorder by the Jahn-Teller effect of Mn 3ϩ . [20][21][22][23][24] In addition, the spectrum shapes 3 , ͉F(r)͉, shows a radial atomic distribution-like function in real space about the emitting metal ions ͑Fig. 6͒.…”

Section: Samples With Large Mn Content (Y у 08)-thementioning

confidence: 99%

Phase Diagram of Li[sub x](Mn[sub y]Fe[sub 1−y])PO[sub 4] (0≤x, y≤1)

Yamada

Kudo²,

Liu³

2001

J. Electrochem. Soc.

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340

381

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The room temperature ͑x, y͒ two-dimensional phase diagram of the olivine-type solid-solution, Li x (Mn y Fe 1Ϫy )PO 4 (0 р x, y р 1, orthorhombic, D 2h 16 : Pmnb), is determined. The x-dependent changes in the unit cell dimensions at various fixed Mn contents y are analyzed in detail. The manganese substitution for iron in the octahedral 4c sites induces 1, the two-phase Mn . The conversion, 2, is complete at around y ϭ 0.6. The phase instability, 3, makes the Mn-rich phase (y Ͼ 0.8) unsuitable for battery applications. The local lattice deformation around Mn 3ϩ is severe enough to induce significant selective damping in the extended X-ray absorption fine structure for Mn The oxidation ͑charge͒ of LiM 2ϩ PO 4 to M 3ϩ PO 4 induces a reduction in the unit cell volume. This shrinkage compensates for the volume expansion of the carbon anodes in the charge process and contributes to efficient use of volume in a practical lithium-ion cell. The opposite movement of lithium ions and electrons occurs during the discharge process, while the transition metal M is reduced from trivalent to divalent.The LiMPO 4 crystal has an orthorhombic unit cell (D 2h 16 , space group Pmnb,) which accommodates four units of LiMPO 4 .11 As a typical example, LiFePO 4 has unit-cell dimensions of a ϭ 6.008(1) Å, b ϭ 10.324(2) Å, and c ϭ 4.694(1) Å. Graphic representations of the crystal structure have been given in many references. 1,3,4,11 Both the Li and M atoms are in octahedral sites with Li located in the 4a and M in the 4c positions. The oxygen atoms are nearly hexagonal closed-packed and the M atoms occupy zigzag chains of corner-shared octahedra running parallel to the c axis in alternate a-c planes. These chains are bridged by corner-and edge-sharing (PO 4 ͒ 3Ϫ polyanions to form a host structure with strong three-dimensional bonding. The Li ϩ ions in 4a sites form continuous linear chains of edge-shared octahedra running parallel to the c axis in the other a-c planes, which makes two-dimensional motion possible.The charge-discharge reaction of the presently used materials, such as the layered rock salt systems, LiCoO 2 , LiNiO 2 ͑space group, R3 m), and a spinel framework system Li 0.5 MnO 2 ͑space groups: Fd3m) are all based on the M 4ϩ /M 3ϩ couple in edge-shared MO 6 octahedra in the closed-packed oxygen array which generates ca. 4 V '' 1,6 The stable nature of the olivine-type structure having a (PO 4 ͒ 3Ϫ polyanion with a strong P-O covalent bond provides not only excellent cycle-life but also a safe system. When the battery is fully charged, the reactivity to the combustion reaction with the organic electrolyte is low.6 Safety issues are of paramount importance in the design of consumer batteries, and this makes olivinetype materials particularly attractive as cathodes for lithium-ion battery systems.The energy density of olivine-type LiMPO 4 is equal to that of presently used materials, based on the theoretical charge-discharge capacity of ca. 170 mAh/g obtained from the M 3ϩ /M 2ϩ one-electron redox reaction of Li x MPO ...

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Jahn–Teller instability in spinel Li–Mn–O

Cited by 131 publications

References 30 publications

Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms

Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

Phase Diagram of Li[sub x](Mn[sub y]Fe[sub 1−y])PO[sub 4] (0≤x, y≤1)

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Jahn–Teller instability in spinel Li–Mn–O

Cited by 131 publications

References 30 publications

Systematic Studies on &ldquo;Abundant&rdquo; Battery Materials: Identification and Reaction Mechanisms

Systematic Studies on &ldquo;Abundant&rdquo; Battery Materials: Identification and Reaction Mechanisms

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

Phase Diagram of Li[sub x](Mn[sub y]Fe[sub 1−y])PO[sub 4] (0≤x, y≤1)

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Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms

Systematic Studies on “Abundant” Battery Materials: Identification and Reaction Mechanisms