Artificial Solid Electrolyte Interphase-Protected LixSi Nanoparticles: An Efficient and Stable Prelithiation Reagent for Lithium-Ion Batteries

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• 作者：Jie Zhao ; Zhenda Lu ; Haotian Wang ; Wei Liu ; Hyun-Wook Lee ; Kai Yan ; Denys Zhuo ; Dingchang Lin ; Nian Liu ; Yi Cui
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：July 8, 2015
• 年：2015
• 卷：137
• 期：26
• 页码：8372-8375
• 全文大小：302K
• ISSN：1520-5126

文摘

Prelithiation is an important strategy to compensate for lithium loss in lithium-ion batteries, particularly during the formation of the solid electrolyte interphase (SEI) from reduced electrolytes in the first charging cycle. We recently demonstrated that Li_xSi nanoparticles (NPs) synthesized by thermal alloying can serve as a high-capacity prelithiation reagent, although their chemical stability in the battery processing environment remained to be improved. Here we successfully developed a surface modification method to enhance the stability of Li_xSi NPs by exploiting the reduction of 1-fluorodecane on the Li_xSi surface to form a continuous and dense coating through a reaction process similar to SEI formation. The coating, consisting of LiF and lithium alkyl carbonate with long hydrophobic carbon chains, serves as an effective passivation layer in the ambient environment. Remarkably, artificial-SEI-protected Li_xSi NPs show a high prelithiation capacity of 2100 mA h g^鈥? with negligible capacity decay in dry air after 5 days and maintain a high capacity of 1600 mA h g^鈥? in humid air (鈭?0% relative humidity). Silicon, tin, and graphite were successfully prelithiated with these NPs to eliminate the irreversible first-cycle capacity loss. The use of prelithiation reagents offers a new approach to realize next-generation high-energy-density lithium-ion batteries.