Elucidation of Reaction Mechanism of Silicon Negative-Electrodes for Lithium-Ion Batteries by In-Situ Raman Spectroscopy

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K21166
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic industrial materials; Device related chemistry
• Research Institution: Tottori University
• Principal Investigator: Domi Yasuhiro 鳥取大学, 工学(系)研究科(研究院), 助教 (50576717)
• Research Collaborator: SAKAGUCHI Hiroki ; USUI Hiroyuki
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: リチウム二次電池 / ケイ素負極 / ラマン分光 / その場測定 / 相変化

Outline of Final Research Achievements

Silicon (Si) is an attractive material for use as a negative electrode in next-generation LIBs due to its high theoretical capacity compared to that of graphite, which is used currently. In this study, a reaction mechanism of Si is elucidated using Raman spectroscopy. Crystalline Si (c-Si) has a triply degenerated Raman active mode at 520 cm-1. c-Si transforms into amorphous Si (a-Si) after charge-discharge cycles, and a-Si shows Raman peak at 490 cm-1. Utilizing this phenomena, a distribution of lithiation-delithiation reaction with Si was investigated. In organic electrolytes, c-Si that has not reacted with Li was unevenly distributed on the electrode; Li storage into the Si electrode proceeded locally in limited area. In ionic liquid electrolytes, on the other hand, the domain of a-Si was homogeneously distributed on the surface, which indicates that Li ion was uniformly stored into the entire Si electrode surface. There results were quantitatively confirmed at large area.

Free Research Field

電気化学