کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5150369 | 1498239 | 2017 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Investigation of carbon-coated SiO phase changes during charge/discharge by X-ray absorption fine structure
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
الکتروشیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
To improve the cycling performance of carbon-coated SiO (SiO-C) as a high-capacity negative electrode material, we have used X-ray absorption fine structure measurements to assess the electronic state of Si and investigate phase changes during charge/discharge cycles. The results suggest that Si4Â + continuously absorbs Li during the charging process, mainly forming Li4SiO4. Li silicates with a lower valence are also formed. Neutral Si and Si2Â + mainly contribute to Li insertion during the initial charging stage, whereas low-valence oxides like Si1Â + and Si2Â + form during the middle charging stage. The fully charged state contains all Si phase states. These results suggest that during the discharge process, Li is mainly released from composites with Si2Â +-oxidation state, and Li is partially released from Li4SiO4 at a higher voltage forming Si0. SiO composites with Si1Â +-Si3Â + reversibly shift to a higher valence state during cycling. We confirmed that Li4SiO4 readily releases Li after long-term cycling, and SiO composites at the end of the cycle change to a higher valence state. The results indicate that disproportionation is a primary factor decreasing cell cycle performance and confirm that it is possible to design LiB cells with improved cycling performance by controlling the disproportionation linked to the structural deterioration of SiO-C.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Ionics - Volume 304, June 2017, Pages 1-6
Journal: Solid State Ionics - Volume 304, June 2017, Pages 1-6
نویسندگان
Takakazu Hirose, Masanori Morishita, Hideya Yoshitake, Tetsuo Sakai,