Impact of the crystalline phase of binary silicide on its lithiation and delithiation properties

Domi, Yasuhiro; Usui, Hiroyuki; Ando, Tomohiro; Sakaguchi, Hiroki

doi:10.1039/d2ma00171c

Cited by 5 publications

(3 citation statements)

References 44 publications

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“…We reported that pure silicide electrodes exhibited higher lithiation-delithiation plateaus and/or slopes than Si electrodes. [51][52][53] However, the silicide phase in the composite electrode hardly stored Li (although it may have functioned as a Li-diffusion path). 13,54 Table S1 lists Li + diffusion coefficients (D Li+ ) of Si and certain silicides estimated using a galvanostatic intermittent titration technique.…”

Section: Resultsmentioning

confidence: 99%

Silicon-Based Nanocomposite Anodes with Excellent Cycle Life for Lithium-Ion Batteries Achieved by the Synergistic Effect of Two Silicides

Domi,

Usui,

Okasaka

et al. 2024

J. Electrochem. Soc.

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Nanocomposite electrodes comprising LaSi2 and Si exhibit satisfactory charge–discharge cycling performances but their capacity is degraded after repeated cycles. A metallographic structure, in which the Si phase was finely dispersed in the LaSi2 matrix phase, was formed before cycling. The elastic LaSi2 relieved Si-generated stress and suppressed electrode disintegration. Contrarily, the LaSi2 phase in the metallographic structure was surrounded by the Si matrix phase after cycling. The positional relationship between the two phases was reversed, and LaSi2 could not relieve the stress. For a nanocomposite electrode containing CrSi2, which exhibits stiffness to withstand the Si-generated stress, the structural changes were suppressed after cycling, resulting in good cycling stability. Here, we considered that the addition of stiff silicides as a third phase to the LaSi2/Si composite could improve the cycle life. Thus, this study prepared nanocomposite electrodes containing elastic LaSi2, stiff MSi2 (where M = Cr, Mo, Nb, Ta, Ti, or W), and elemental Si and investigated their electrochemical performances. Reaction behaviors, such as the metallographic structure, electrode thickness, and phase transition, were also clarified. The LaSi2/NbSi2/Si electrode exhibited the best cycle life without changes in its metallographic structure owing to the synergistic effect of stiff and elastic silicides.

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Section: Resultsmentioning

confidence: 99%

Silicon-Based Nanocomposite Anodes with Excellent Cycle Life for Lithium-Ion Batteries Achieved by the Synergistic Effect of Two Silicides

Domi,

Usui,

Okasaka

et al. 2024

J. Electrochem. Soc.

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“…We focused on silicides as active anode materials because they exhibit unique metal-like ductility, malleability, and high electron conductivity. 14,15 In particular, A-FeSi 2 has a tetragonal crystal structure and it has been applied in various fields such as solar cells, optical sensors, thermoelectric conversion devices, thermal conductivity materials, and semiconductor devices, owing to its semiconductor properties, optical attributes, and thermal conductivity. 16 The versatility of A-FeSi 2 , which can be tailored to specific applications, is of particular significance in energy-related technologies.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Anode Behavior of α-FeSi<sub>2</sub> Co-Sintered with Solid Electrolyte

KAWANO,

KATO,

DOMI

et al. 2024

Electrochemistry

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It is essential in the production of the next generation of rechargeable batteries to elucidate the reaction phases formed after co-sintering in allsolid-state batteries with oxide solid electrolytes and silicon materials and their electrochemical behavior. Herein, we explore the presence or absence of reaction phases and the charge/discharge behavior after co-sintering with the solid electrolyte Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) and various silicon active anode materials. In the co-sintering investigation of LAGP and silicon active anode materials, α-FeSi 2 do not react with LAGP and the electronic conductivity of α-FeSi 2 is maintained even after sintering. In addition, using a mixed sintered sheet consisting of α-FeSi 2 , solid electrolyte LAGP, and carbon additive vapor-grown carbon fiber, a charge/discharge test is performed at 105 °C for the cell with a Li metal counter electrode and polymer electrolyte. The results of X-ray diffraction measurements of the disassembled test cell after charging/discharging confirm that the reduction decomposition reaction proceeding and disappearing of LAGP phase completely when Li is inserted into the active anode material for the first time. However, when Li is further inserted, Li alloy phases, Li 22 Si 5 , and Li 22 Ge 5 appear, and they show reversible charge/discharge behavior of 400 mA h g −1 . This is presumed to be owing to the partial reduction of α-FeSi 2 to Si and the reduction decomposition of LAGP to produce Ge during the Li insertion process, followed by the formation of Li alloy phases with Li and Si or Ge. Furthermore, while the solid electrolyte LAGP disappear during the first Li insertion, the formation of a Li 4 SiO 4 phase with a broad peak is observed, suggesting that the Li 4 SiO 4 phase might function as a Li conductor.

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“…[ 22–23 ] Other Si‐based alloy anodes such as Fe–Si, Cu–Si, and Ni–Si systems also display improved cycling stability. [ 24–28 ] Domi et al. reported that by combining Si with Cu or Fe, the cycling stability could be greatly improved.…”

Section: Introductionmentioning

confidence: 99%

Si‐Based High‐Entropy Anode for Lithium‐Ion Batteries

Lei,

Wang,

Wang

et al. 2023

Small Methods

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Up to now, only a small portion of Si has been utilized in the anode for commercial lithium‐ion batteries (LIBs) despite its high energy density. The main challenge of using micron‐sized Si anode is the particle crack and pulverization due to the volume expansion during cycling. This work proposes a type of Si‐based high‐entropy alloy (HEA) materials with high structural stability for the LIB anode. Micron‐sized HEA‐Si anode can deliver a capacity of 971 mAhg−1 and retains 93.5% of its capacity after 100 cycles. In contrast, the silicon–germanium anode only retains 15% of its capacity after 20 cycles. This study has discovered that including HEA elements in Si‐based anode can decrease its anisotropic stress and consequently enhance ductility at discharged state. By utilizing in situ X‐ray diffraction and transmission electron microscopy analyses, a high‐entropy transition metal doped Lix(Si/Ge) phase is found at lithiated anode, which returns to the pristine HEA phase after delithiation. The reversible lithiation and delithiation process between the HEA phases leads to intrinsic stability during cycling. These findings suggest that incorporating high‐entropy modification is a promising approach in designing anode materials toward high‐energy density LIBs.

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Impact of the crystalline phase of binary silicide on its lithiation and delithiation properties

Abstract: The reversible capacity is not dependent on the amount of Si included in the silicide; the capacity was found to be independent on the composition of silicide even in the case of a given transition metal making up the silicide.

Cited by 5 publications

References 44 publications

Silicon-Based Nanocomposite Anodes with Excellent Cycle Life for Lithium-Ion Batteries Achieved by the Synergistic Effect of Two Silicides

Silicon-Based Nanocomposite Anodes with Excellent Cycle Life for Lithium-Ion Batteries Achieved by the Synergistic Effect of Two Silicides

Electrochemical Anode Behavior of α-FeSi<sub>2</sub> Co-Sintered with Solid Electrolyte

Si‐Based High‐Entropy Anode for Lithium‐Ion Batteries

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