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Ionic liquid has a series of characteristics superior to conventional organic electrolyte, most likely as a new generation of green electrolyte used in electrochemical devices, has become a research hotspot in recent years. However, despite the research and development of the ionic liquid electrolyte caused a great deal of attention in recent years, but the complexity of the relationship between chemical structure and properties of ionic liquids, has not yet found a clear pattern, but different electrochemical devices on the requirements of the ionic liquid electrolyte has its own characteristics. Therefore, and actively develop new ionic liquid electrolyte, grasp the electrochemical behavior of the ionic liquid electrolyte lithium secondary battery and its impact on the battery performance of great significance to further understand the relationship between the structure and properties of ionic liquids, . This paper summarizes previous work on the basis of low prices tetrahydrothiophene as a raw material to develop a series of by alkyl thiophene-cation and TFSI anion novel cyclic sulfonium cation ionic liquid electrolyte systems studied their physical and chemical properties and electrochemical properties, including the nature of the common solvent solubility, melting point, thermal stability, viscosity, conductivity and electrochemical window and discusses the structure and performance of the cyclic sulfonium cation ionic liquid cations between relationship. Two kinds of ionic liquids the T4TFSI and T5TFSI melting point of -60 ° C or below, room temperature conductivity were 2.10, and 1.46mS cm-1, the electrochemical window 4.1V and 4.5V. Cyclic sulfonium cation ionic liquid as the electrolyte used in lithium secondary battery, the applicability of seven different electrolyte additive cyclic sulfonium cation ionic liquid electrolyte system. 10 wt% of ethylene carbonate (EC), vinyl acetate (VA), gamma-butyrolactone (GBL), sulfurous acid vinyl ester (ES), diethyl sulfate (DES), and 2,2 - dimethoxy 0.4mol L-1 LiTFSI / T5TFSI ionic liquid electrolyte system, the actual effect of the oxy-propane (DP) additives the six having different structural characteristics, the most intensively with the current study, the effect is ideal organic film-forming additives vinylene carbonate (VC) in the same system, the practical effect of the comparison. It was found that VA DES and DP three additives can not make the the cyclic sulfonium cation ionic liquid electrolyte in Li/LiMn2O4 battery work properly. 0.1C rate found after 100 charge-discharge cycles, the EC and VC additives actual battery performance is poor; GBL and ES additives capacity retention and cycling stability than the VC additive better GBL additives not only the first discharge capacity and VC additives similar in capacity retention rate, charge and discharge cycle coulombic efficiency and Batteries magnification performance of three completely than VC additives.
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