高电压锂离子电池用环丁砜基高浓度电解液

本文介绍了一种含双(三氟甲烷磺酰)亚胺锂(Li TFSI)和环丁砜(TMS)的高浓度电解液。采用FT-IR对样品进行结构表征,通过线性扫描伏安法(LSV)和循环伏安法(CV)研究电解液的电化学性能。结果表明,高浓度TMS/Li TFSI(摩尔比2∶1)电解液的电化学和化学稳定性良好,电化学窗口拓宽至5. 02V,可以有效抑制Al箔腐蚀,适用于5V级的镍锰酸锂(Li Ni_(0.5)Mn1. 5O4)正极材料。室温下,基于TMS/Li TFSI高浓度电解液的Li Ni_(0.5)Mn1. 5O4半电池经过大倍率充放电后,0. 1C的比容量基本回复到原始状态;在0. 2C的倍率下实现良好的循环,前25圈的库仑效率大于92%。

Tetramethylene sulfone-Based Concentrated Electrolytes for High-Voltage Lithium-Ion batteries

A concentrated electrolyte containing lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and tetramethylene sulfone (TMS) was prepared. The electrolyte samples were characterized by Fourier transform infrared spectroscopy. The electrochemical properties of electrolytes were researched by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The TMS/LiTFSI (mole ratio 2:1) concentrated electrolyte displayed satisfactory electrochemical and chemical stability, extended electrochemical window to 5.02 V. In addition, The 2:1 concentrated electrolyte could effectively restrain Al foil corrosion. Notably, the concentrated electrolyte was suitable for 5 V-class LiNi0.5Mn1.5O4 cathode material. The LiNi0.5Mn1.5O4 half-cells based on TMS/LiTFSI concentrated electrolyte showed excellent rate capability and cycle performance. The half-cell returned to its original specific capacity at 0.1C after high power charge and discharge, meanwhile the coulombic efficiency of the half-cell was above 92% at 0.2C after the first 25th cycles.