Progression of Solid Electrolyte Interphase Formation on Hydrogenated Amorphous Silicon Anodes for Lithium-Ion Batteries

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• 作者：David E. Arreaga-Salas ; Amandeep K. Sra ; Katy Roodenko ; Yves J. Chabal ; Christopher L. Hinkle
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：April 26, 2012
• 年：2012
• 卷：116
• 期：16
• 页码：9072-9077
• 全文大小：439K
• 年卷期：v.116,no.16(April 26, 2012)
• ISSN：1932-7455

文摘

Silicon anodes based on an alloy reaction with lithium have a large theoretical specific capacity making them an appealing candidate for use in lithium-ion batteries. A major factor influencing the power cyclability and cycle life of the battery is the formation of the solid electrolyte interphase (SEI) layer. In this work, the progression of SEI formation on hydrogenated amorphous Si (a-Si:H) anodes is determined as a function of applied electrochemical potential during the first charging cycle by combining cyclic voltammetry measurements with detailed surface chemical analysis. During this first lithiation cycle, the SEI layer begins to form at 1.8 V by decomposition of the LiPF₆ electrolyte to LiF, Li_xPF_y, and PF_y. The SEI layer, with LiF as the major species, continues to form upon further charging and forms a nonuniform layer on the surface of the electrode. At 0.4 V the Li atoms begin to penetrate the a-Si:H network, and upon full charging at 0.0 V, the anode itself is comprised in part by Si鈥揕i, Si鈥揊, and a network of F鈥揝i鈥揕i_n. During the second lithiation cycle, Li causes significant scission of the Si鈥揝i bonds resulting in the formation of high concentrations of Li_xSi.