A blank comparison group of lithium salt-free electrolyte system, replacing the lithium salt of electrolyte with a redox shuttle agent, is constructed to give targeted research on the single role of lithium bis(oxalate)borate (LiBOB) salt, especially of bis(oxalate)borate anions (BOB⁻) in the film-forming process. By combining and comparing all available studies, such as attenuated total reflectance (IR-ATR), X-Ray photoelectron diffraction spectrum (XPS), electrochemical impedance spectrum (EIS), scanning electron microscopy (SEM) tests and quantum chemical calculation, the formation mechanism of the solid electrolyte interphase (SEI) film is proposed. Results reveal that the prior reduction of BOB⁻ anions can postpone the reduction potential and hinder the decomposition rate of carbonate solvents, but promote the formation of a dense, conductive and effective SEI film. This work provides a novel way to investigate the film-forming mechanism and has guiding significance for revealing the effect of other kinds of lithium salts on the surface film formation.

构建空白的无锂盐电解质体系比较组，用氧化还原穿梭剂代替电解质的锂盐，以针对双（草酸）硼酸锂（LiBOB）盐，特别是双（草酸）硼酸根阴离子（BOB ^-在成膜工序）。通过合并和比较所有可用的研究，如衰减全反射率（IR-ATR），X射线光电子衍射谱（XPS），电化学阻抗谱（EIS），扫描电子显微镜（SEM）测试和量子化学计算，形成提出了固体电解质界面相（SEI）膜的机理。结果表明，BOB的先期降低^-阴离子可以推迟还原电位并阻碍碳酸盐溶剂的分解速率，但会促进形成致密，导电和有效的SEI膜。这项工作为研究成膜机理提供了一种新颖的方法，对于揭示其他种类的锂盐对表面成膜的影响具有指导意义。