Direct Determination of Solid-Electrolyte Interphase Thickness and Composition as a Function of State of Charge on a Silicon Anode

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• 作者：Gabriel M. Veith ; Mathieu Doucet ; J. Kevin Baldwin ; Robert L. Sacci ; Tyler M. Fears ; Yongqiang Wang ; James F. Browning
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 3, 2015
• 年：2015
• 卷：119
• 期：35
• 页码：20339-20349
• 全文大小：503K
• ISSN：1932-7455

文摘

With the use of neutron reflectometry, we have determined the thickness and chemistry of the solid-electrolyte interphase (SEI) layer grown on a silicon anode as a function of state of charge and during cycling. We show the chemistry of this SEI layer becomes more LiF like with increasing lithiation and more Li鈥揅鈥揙鈥揊 like with delithiation. More importantly, the SEI layer thickness appears to increase (about 250 脜) as the electrode becomes less lithiated and thins to 180 脜 with increasing Li content (Li_3.7Si). We attribute this 鈥渂reathing鈥?to the continual consumption of electrolyte with cycling.