Use of nonflammable methyl nonafluorobuyl ether (MFE) has been studied to develop an inherently safe electrolyte for lithium secondary batteries. A no flash point (NFP) solution was prepared by mixing a proper amount of MFE with a common electrolyte solvent such as dimethyl carbonate or ethyl methyl carbonate (EMC) and the NFP electrolyte was obtained by dissolving organic lithium salts (e.g., Li[SO 2 C 2 F 5 ] 2 : LiBETI) in the NFP solution. Cell capacities with NFP electrolyte of 1 mol dm -3 (M) LiBETIMFE/EMC (80:20 vol %) were limited by the charge-discharge process on the graphite anode. Electrolyte components were investigated in terms of modifying the solid electrolyte interface film to improve the charge-discharge performance and cycle life of NFP electrolyte. Adding cyclic carbonate (e.g., ethylene carbonate, EC) and LiPF 6 to the electrolyte reduced the interfacial resistance in a graphite/Li cell. A 18650 cylindrical cell with EC and LiPF 6 added to I M LiBETI-MFE/EMC (80:20) electrolyte discharged more than 90% of its capacity at a I C current rate (vs. the capacity at the 0.1 C) and kept more than 80% of its initial capacity after 560 cycles at the I C current rate and room temperature. Effects of these additives on charge-discharge capacities in a graphite/Li cell were also investigated in terms of electrochemical spectroscopy. X-ray photoelectron spectroscopy. solid-state 7 Li nuclear magnetic resonance, and attenuated total reflection infrared spectroscopy.

中文翻译：

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锂二次电池用电解液用不可燃甲基九氟丁基醚

已经研究了使用不可燃的甲基九氟丁基醚 (MFE) 来开发一种用于锂二次电池的本质安全的电解质。将适量的 MFE 与常用的电解质溶剂如碳酸二甲酯或碳酸甲乙酯 (EMC) 混合制备无闪点 (NFP) 溶液，通过溶解有机锂盐 (如 Li[SO 2 C 2 F 5 ] 2 : LiBETI) 在 NFP 溶液中。使用 1 mol dm -3 (M) LiBETIMFE/EMC (80:20 vol %) 的 NFP 电解质的电池容量受到石墨负极充放电过程的限制。电解质组分在改进固体电解质界面膜以提高NFP电解质的充放电性能和循环寿命方面进行了研究。添加环状碳酸酯（例如碳酸亚乙酯、EC)和LiPF 6 到电解质中降低了石墨/锂电池中的界面电阻。将 EC 和 LiPF 6 添加到 IM LiBETI-MFE/EMC (80:20) 电解液中的 18650 圆柱形电池在 IC 电流速率下放电超过其容量的 90%（与 0.1 C 时的容量相比）并保持超过在 IC 电流速率和室温下循环 560 次后，其初始容量的 80%。还根据电化学光谱研究了这些添加剂对石墨/锂电池中充放电容量的影响。X 射线光电子能谱。固态 7 Li 核磁共振和衰减全反射红外光谱。20) 电解液在 IC 电流速率下放电超过 90% 的容量（与 0.1 C 下的容量相比），并在 IC 电流速率和室温下循环 560 次后保持其初始容量的 80% 以上。还根据电化学光谱研究了这些添加剂对石墨/锂电池中充放电容量的影响。X 射线光电子能谱。固态 7 Li 核磁共振和衰减全反射红外光谱。20) 电解液在 IC 电流速率下放电超过 90% 的容量（与 0.1 C 下的容量相比），并在 IC 电流速率和室温下循环 560 次后保持其初始容量的 80% 以上。还根据电化学光谱研究了这些添加剂对石墨/锂电池中充放电容量的影响。X 射线光电子能谱。固态 7 Li 核磁共振和衰减全反射红外光谱。