Li-Rich Li-Si Alloy As A Lithium-Containing Negative Electrode Material Towards High Energy Lithium-Ion Batteries

Shinichiroh Iwamura, Hirotomo Nishihara, Yoshitaka Ono, Haruhiko Morito, Hisanori Yamane, Hiroki Nara, Tetsuya Osaka, Takashi Kyotani

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28 Citations (Scopus)

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 Li21 Si5. 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.

Original languageEnglish
Article number8085
JournalScientific Reports
Volume5
DOIs
Publication statusPublished - 2015 Jan 28

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