Most electrolytes in today's lithium‐ion batteries contain a large proportion of ethylene carbonate (EC) mixed with other alkyl carbonate‐based solvents. EC has, however, been shown to be unstable at the high potentials at which several novel cathode materials are electrochemically active. Here, different mixtures of sulfolane and DMC are investigated in this context. The electrochemical stability is explored in addition to galvanostatic cycling of LiNi_0.6Mn_0.2Co_0.2O₂‐Li₄Ti₅O₁₂ (NMC‐LTO) cells. The measurement of the ionic conductivity showed that mixing 25 % sulfolane into DMC improved the electrolyte properties as compared to pure DMC, making the conductivity similar to EC:DEC electrolytes and therefore fully functional. Moreover, the addition of sulfolane slightly enhanced the capacity retention, likely caused by formation of thinner and more stable surface layers on the LTO electrodes as determined by X‐ray photoelectron spectroscopy (XPS). The cycling performance is especially improved for sulfolane‐based electrolytes during cycling at sub‐zero temperatures.

中文翻译：

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LiNi0.6Mn0.2Co0.2O2-Li4Ti5O12电池的基于环丁砜的无碳酸亚乙酯电解质

当今锂离子电池中的大多数电解质都包含大量的碳酸亚乙酯（EC）和其他基于碳酸烷基酯的溶剂。然而，已表明EC在几种新型阴极材料具有电化学活性的高电势下不稳定。在此，在此背景下研究了环丁砜和DMC的不同混合物。除了LiNi _0.6 Mn _0.2 Co _0.2 O ₂ -Li ₄ Ti ₅ O _12的恒电流循环外，还探索了电化学稳定性。（NMC-LTO）细胞。离子电导率的测量结果表明，与纯DMC相比，将25％的环丁砜混入DMC可以改善电解质性能，从而使电导率类似于EC：DEC电解质，因此具有完全的功能。此外，环丁砜的添加略微增强了容量保持能力，这可能是由X射线光电子能谱（XPS）确定的LTO电极上更薄，更稳定的表面层形成所致。对于环丁砜类电解质，在低于零温度的循环过程中，其循环性能尤其得到改善。