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Li-rich Li-Si alloy as a lithium-containing negative electrode material towards high energy lithium-ion batteries.

Iwamura S, Nishihara H, Ono Y, Morito H, Yamane H, Nara H, Osaka T, Kyotani T - Sci Rep (2015)

Bottom Line: Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si.The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode.Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell.

View Article: PubMed Central - PubMed

Affiliation: 1] Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan [2] Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan.

ABSTRACT
Lithium-ion batteries (LIBs) are generally constructed by lithium-including positive electrode materials, such as LiCoO2, and lithium-free negative electrode materials, such as graphite. Recently, lithium-free positive electrode materials, such as sulfur, are gathering great attention from their very high capacities, thereby significantly increasing the energy density of LIBs. Though the lithium-free materials need to be combined with lithium-containing negative electrode materials, the latter has not been well developed yet. In this work, the feasibility of Li-rich Li-Si alloy is examined as a lithium-containing negative electrode material. Li-rich Li-Si alloy is prepared by the melt-solidification of Li and Si metals with the composition of Li21Si5. By repeating delithiation/lithiation cycles, Li-Si particles turn into porous structure, whereas the original particle size remains unchanged. Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si. The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode. Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell.

No MeSH data available.


Related in: MedlinePlus

Illustrations for the structure change of (a) Li-Si/Cu and (b) Si/Cu electrodes by delithiation and/or lithiation.
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f5: Illustrations for the structure change of (a) Li-Si/Cu and (b) Si/Cu electrodes by delithiation and/or lithiation.

Mentions: The structure change of the Li-Si/Cu pellet upon its delithiation/lithiation can be illustrated as Fig. 5a. In the first delithiation step, Li-Si particles become porous Si. In the subsequent lithiation step, the porous Si particles would turn into dense Li-Si alloy, but their particle sizes do not exceed the original sizes of Li-Si alloy. Then, lithiation/delithiation could be repeated in the following cycles without the destruction of Cu-supporting electrode disc. The transformation of Li-Si alloy into the sponge-like porous Si would be one of the essential reasons for the better cyclability, since the presence of pores around Si framework can buffer the stress generated by the expansion of Si upon lithiation. On the other hand, the Si particles significantly expand up to about 3–4 times larger than their original sizes especially upon the first lithiation and the Cu-supporting electrode disc is therefore totally destroyed (Fig. 5b).


Li-rich Li-Si alloy as a lithium-containing negative electrode material towards high energy lithium-ion batteries.

Iwamura S, Nishihara H, Ono Y, Morito H, Yamane H, Nara H, Osaka T, Kyotani T - Sci Rep (2015)

Illustrations for the structure change of (a) Li-Si/Cu and (b) Si/Cu electrodes by delithiation and/or lithiation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4308695&req=5

f5: Illustrations for the structure change of (a) Li-Si/Cu and (b) Si/Cu electrodes by delithiation and/or lithiation.
Mentions: The structure change of the Li-Si/Cu pellet upon its delithiation/lithiation can be illustrated as Fig. 5a. In the first delithiation step, Li-Si particles become porous Si. In the subsequent lithiation step, the porous Si particles would turn into dense Li-Si alloy, but their particle sizes do not exceed the original sizes of Li-Si alloy. Then, lithiation/delithiation could be repeated in the following cycles without the destruction of Cu-supporting electrode disc. The transformation of Li-Si alloy into the sponge-like porous Si would be one of the essential reasons for the better cyclability, since the presence of pores around Si framework can buffer the stress generated by the expansion of Si upon lithiation. On the other hand, the Si particles significantly expand up to about 3–4 times larger than their original sizes especially upon the first lithiation and the Cu-supporting electrode disc is therefore totally destroyed (Fig. 5b).

Bottom Line: Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si.The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode.Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell.

View Article: PubMed Central - PubMed

Affiliation: 1] Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan [2] Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan.

ABSTRACT
Lithium-ion batteries (LIBs) are generally constructed by lithium-including positive electrode materials, such as LiCoO2, and lithium-free negative electrode materials, such as graphite. Recently, lithium-free positive electrode materials, such as sulfur, are gathering great attention from their very high capacities, thereby significantly increasing the energy density of LIBs. Though the lithium-free materials need to be combined with lithium-containing negative electrode materials, the latter has not been well developed yet. In this work, the feasibility of Li-rich Li-Si alloy is examined as a lithium-containing negative electrode material. Li-rich Li-Si alloy is prepared by the melt-solidification of Li and Si metals with the composition of Li21Si5. By repeating delithiation/lithiation cycles, Li-Si particles turn into porous structure, whereas the original particle size remains unchanged. Since Li-Si is free from severe constriction/expansion upon delithiation/lithiation, it shows much better cyclability than Si. The feasibility of the Li-Si alloy is further examined by constructing a full-cell together with a lithium-free positive electrode. Though Li-Si alloy is too active to be mixed with binder polymers, the coating with carbon-black powder by physical mixing is found to prevent the undesirable reactions of Li-Si alloy with binder polymers, and thus enables the construction of a more practical electrochemical cell.

No MeSH data available.


Related in: MedlinePlus