Stability of Solid Electrolyte Interphase Components on Lithium Metal and Reactive Anode Material Surfaces

详细信息    查看全文

• 作者：Kevin Leung ; Fernando Soto ; Kie Hankins ; Perla B. Balbuena ; Katharine L. Harrison
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 31, 2016
• 年：2016
• 卷：120
• 期：12
• 页码：6302-6313
• 全文大小：757K
• ISSN：1932-7455

文摘

Lithium ion batteries (LIB) can feature reactive anodes that operate at low potentials, such as lithium metal or silicon, passivated by solid electrolyte interphase (SEI) films. SEI is known to evolve over time as cycling proceeds. In this modeling work, we focus on the stability of two main SEI components, lithium carbonate (Li₂CO₃) and lithium ethylene dicarbonate (LEDC). Both components are electrochemically stable but thermodynamically unstable near the equilibrium Li⁺/Li(s) potential. Interfacial reactions represent one way to trigger the intrinsic thermodynamic instability. Both Li₂CO₃ and LEDC are predicted to exhibit exothermic reactions on lithium metal surfaces, and the barriers are sufficiently low to permit reactions on battery operation time scales. LEDC also readily decomposes on high Li-content Li_xSi surfaces. Our studies suggest that the innermost SEI layer on lithium metal surfaces should be a thin layer of Li₂O, the only thermodynamically and kinetically stable component (in the absence of a fluoride source). This work should also be relevant to inadvertent lithium plating during battery cycling and SEI evolution on Li_xSi surfaces.