Herein, a novel sulfone‐based compound, methyl 2,2‐difluoro‐2‐(fluorosulfonyl) acetate (MDFA) is studied for its effects in improving LiCoO₂/graphite pouch Li‐ion cell performance at high working voltage (4.45 V). Calculations based on density functional theory (DFT) and electrochemical tests reveal that MDFA can be reduced preferentially compared with the electrolyte solvent. It helps form a robust interface film with high lithium‐ion conductivity, which will greatly reduce the interfacial impedance of cells. The pouch cells containing 1 wt% MDFA show excellent discharge performance at low temperature (−10 °C) and such concentration of MDFA can also inhibit the deposition of lithium on the anode. Moreover, this additive can promote stability of cell cycling at high voltage. The overall results indicate that the MDFA is a low‐impedance additive that can be well applied to improve the property of high‐voltage lithium‐ion batteries.

中文翻译：

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2,2-二氟-2-（氟磺酰基）乙酸甲酯是新型用于高压LiCoO2 /石墨袋式锂离子电池的电解质添加剂

在本文中，研究了一种新型的砜基化合物，即2,2-二氟-2-（氟磺酰基）乙酸甲酯（MDFA）对改善LiCoO _2的作用/石墨袋锂离子电池在高工作电压（4.45 V）下的性能。基于密度泛函理论（DFT）和电化学测试的计算表明，与电解质溶剂相比，MDFA可以优先降低。它有助于形成具有高锂离子传导性的牢固的界面膜，这将大大降低电池的界面阻抗。含有1 wt％MDFA的袋式电池在低温（-10°C）下表现出出色的放电性能，并且MDFA的这种浓度还可以抑制锂在阳极上的沉积。此外，该添加剂可以促进高电压下电池循环的稳定性。总体结果表明，MDFA是一种低阻抗添加剂，可以很好地应用于改善高压锂离子电池的性能。