In Situ Mass Spectrometric Determination of Molecular Structural Evolution at the Solid Electrolyte Interphase in Lithium-Ion Batteries

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• 作者：Zihua Zhu ; Yufan Zhou ; Pengfei Yan ; Rama Sesha Vemuri ; Wu Xu ; Rui Zhao ; Xuelin Wang ; Suntharampillai Thevuthasan ; Donald R. Baer ; Chong-Min Wang
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：September 9, 2015
• 年：2015
• 卷：15
• 期：9
• 页码：6170-6176
• 全文大小：459K
• ISSN：1530-6992

文摘

Dynamic structural and chemical evolution at solid鈥搇iquid electrolyte interface is always a mystery for a rechargeable battery due to the challenge to directly probe a solid鈥搇iquid interface under reaction conditions. We describe the creation and usage of in situ liquid secondary ion mass spectroscopy (SIMS) for the first time to directly observe the molecular structural evolution at the solid鈥搇iquid electrolyte interface for a lithium (Li)-ion battery under dynamic operating conditions. We have discovered that the deposition of Li metal on copper electrode leads to the condensation of solvent molecules around the electrode. Chemically, this layer of solvent condensate tends to be depleted of the salt anions and with reduced concentration of Li⁺ ions, essentially leading to the formation of a lean electrolyte layer adjacent to the electrode and therefore contributing to the overpotential of the cell. This observation provides unprecedented molecular level dynamic information on the initial formation of the solid electrolyte interphase (SEI) layer. The present work also ultimately opens new avenues for implanting the in situ liquid SIMS concept to probe the chemical reaction process that intimately involves solid鈥搇iquid interface, such as electrocatalysis, electrodeposition, biofuel conversion, biofilm, and biomineralization.