Film-forming additives have been studied as one of efficient choices to improve battery performance. However, the relationship among film-forming additives, interphase film and battery performance remain mysterious. A comparative study was conducted on the effects of four sulfur-containing cyclic additives, sulfolane (Sul), 1,2-Ethylene Sulfite (ES), 1,3-Propane sultone (PS), and 1,3,2-Dioxathiolan-2,2-oxide (DTD), on the properties of interphase film. Through time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) detection, an “effective interfacial functional group (EIFG)”, sulfonate (−O−SO2−), was discovered in the electrode/electrolyte interphase (EEI) film of cells containing PS or DTD added electrolytes. It can stabilize the interphase and inhibit the continued decomposition of the electrolyte, thereby improving the electrochemical performance of 4.48 V graphite/LiCoO2 full-cell and 4.55 V Li/LiCoO2 half-cell. The capacity retention of the full-cell after 200 cycles exceeds 87 %, and that of half-cell after 300 cycles is nearly 90 %. Based on differential electrochemical mass spectra (DEMS), XPS detection during formation process and theoretical calculation results, it can be revealed that the similar EIFG-containing components can be obtained through different reaction pathways even with additives containing different functional groups. This provides an important basis for the design of new additives/electrolytes.

中文翻译：

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含硫添加剂如何稳定高压石墨/LiCoO2 电池的电极/电解质界面


成膜添加剂已被研究为提高电池性能的有效选择之一。然而，成膜添加剂、相间膜和电池性能之间的关系仍然是一个谜。对四种含硫环状添加剂环环丁砜 （Sul）、1,2-亚硫酸乙烯酯 （ES）、1,3-丙烷磺内酯 （PS） 和 1,3,2-二氧杂硫醇-2,2-氧化物 （DTD） 对间相膜性能的影响进行了比较研究。通过飞行时间二次离子质谱 （TOF-SIMS） 和 X 射线光电子能谱 （XPS） 检测，在含有 PS 或 DTD 添加电解质的电池的电极/电解质界面 （EEI） 膜中发现了“有效界面官能团 （EIFG）”磺酸盐 （−O−SO2−）。它可以稳定界面并抑制电解质的持续分解，从而提高 4.48 V 石墨/LiCoO2 全电池和 4.55 V Li/LiCoO2 半电池的电化学性能。200 次循环后，全电池的容量保持率超过 87 %，半电池在 300 次循环后的容量保持率接近 90 %。基于差分电化学质谱 （DEMS）、形成过程中的 XPS 检测和理论计算结果，可以揭示即使使用含有不同官能团的添加剂，也可以通过不同的反应途径获得相似的含 EIFG 组分。这为新型添加剂/电解质的设计提供了重要基础。