Composition analysis of the solid electrolyte interphase film on carbon electrode of lithium-ion battery based on lithium difluoro(oxalate)borate and sulfolane

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• 作者：Shiyou Li ; Xiaoli Xu ; Xinming Shi ; Bucheng Li ; Yangyu Zhao ; Hongming Zhang ; Yongli Li ; Wei Zhao ; Xiaoling Cui ; Liping Mao
• 关键词：Impedance ; Lithium difluoro(oxalate)borate ; Solid electrolyte interphase ; Sulfolane
• 刊名：Journal of Power Sources
• 出版年：2012
• 出版时间：1 November, 2012
• 年：2012
• 卷：217
• 期：Complete
• 页码：503-508
• 全文大小：738 K

文摘

As a promising salt for lithium-ion batteries, lithium difluoro(oxalate)borate (LiODFB) has become a research hotspot in recently. In this work, LiODFB-based electrolytes are studied. When used in Li/MCMB (mesophase carbon microbeads) cells, cell with 0.9?M LiODFB-ethyl methyl carbonate (EMC)/sulfolane (SL) (1:1, v/v) electrolyte shows lower impedance than ones with 0.9?M LiODFB-EMC/ethylene carbonate (EC) (1:1, v/v) electrolyte. Reduction of impedance mainly dues to the fitting nature of solid electrolyte interphase (SEI) film on carbon electrode of lithium-ion battery. The changing morphologies of SEI films with increased circulation numbers were analyzed by scanning electron microscope (SEM). And C₂H₅OLi, C₂H₅CO₃Li, Li₂CO₃, RSO₃Li, Li₂SO₃, LiF, C₂H₅F and some complicated mesh compounds based on >B-O- bond, were found in SEI film by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was believed that the root of impedance reduction benefits from both the rich existence of sulfurous compounds and the low content of LiF in SEI film.