Effective electrolyte compositions are of primary importance in raising the performance of lithium-ion batteries (LIBs). Recently, fluorinated cyclic phosphazenes in combination with fluoroethylene carbonate (FEC) have been introduced as promising electrolyte additives, which can decompose to form an effective dense, uniform, and thin protective layer on the surface of electrodes. Although the basic electrochemical aspects of cyclic fluorinated phosphazenes combined with FEC were introduced, it is still unclear how these two compounds interact constructively during operation. This study investigates the complementary effect of FEC and ethoxy(pentafluoro)cyclotriphosphazene (EtPFPN) in aprotic organic electrolyte in LiNi_0.5Co_0.2Mn_0.3O ∥ SiO_x/C full cells. The formation mechanism of lithium ethyl methyl carbonate (LEMC)-EtPFPN interphasial intermediate products and the reaction mechanism of lithium alkoxide with EtPFPN are proposed and supported by Density Functional Theory calculations. A novel property of FEC is also discussed here, called molecular-cling-effect (MCE). To the best knowledge, the MCE has not been reported in the literature, although FEC belongs to one of the most investigated electrolyte additives. The beneficial MCE of FEC toward the sub-sufficient solid-electrolyte interphase forming additive compound EtPFPN is investigated via gas chromatography-mass spectrometry, gas chromatography high resolution-accurate mass spectrometry, in situ shell-isolated nanoparticle-enhanced Raman spectroscopy, and scanning electron microscopy.

中文翻译：

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通过乙氧基（五氟）环三磷腈表征的氟乙烯碳酸酯对 SiOx/C 阳极材料的分子粘附效应——以前不足的 SEI 形成添加剂化合物的新视角

有效的电解质成分对于提高锂离子电池（LIB）的性能至关重要。最近，氟化环状磷腈与氟代碳酸亚乙酯（FEC）的组合被引入作为有前途的电解液添加剂，它可以分解在电极表面形成有效的致密、均匀和薄的保护层。尽管介绍了环状氟化磷腈与 FEC 结合的基本电化学方面，但仍不清楚这两种化合物在操作过程中如何相互作用。本研究研究了FEC和乙氧基（五氟）环三磷腈（EtPFPN）在LiNi 0.5 _Co 0.2 _Mn 0.3 _O ∥ SiO _x /C全电池中非质子有机电解质中的互补作用。提出了乙基甲基碳酸锂（LEMC）-EtPFPN 相间中间产物的形成机理以及醇锂与 EtPFPN 的反应机理，并得到密度泛函理论计算的支持。这里还讨论了 FEC 的一个新特性，称为分子粘附效应 (MCE)。据了解，尽管 FEC 属于研究最多的电解液添加剂之一，但 MCE 尚未在文献中报道。通过气相色谱-质谱、气相色谱高分辨率-精确质谱、原位壳隔离纳米颗粒增强拉曼光谱和扫描电子技术，研究了 FEC 对次充足固体电解质界面形成添加剂化合物 EtPFPN 的有益 MCE显微镜。