Synthesis and Electrochemical properties of Rechargeable Battery Electrolyte Lithium Bis(heptafluoroisopropyl)tetrafluorophosphate

摘要

Lithium-ion secondary cell has high energy density, stable and high working voltage, wide working temperature and long working term. It is a safe and clean energy resource without pollution. At present, Lithium Hexafluorophosphate is used as conducting electrolyte lithium salt in lithium-ion secondary batteries. But Lithium Hexafluorophosphate as conducting electrolyte lithium salt has some disadvantages such as hydrolysis and instability. Lithium Bis(heptafluoroisopropyl)t -etrafluorophosphate Li[(C_3F_7)_2PF_4] was received by simons process from diisopropylchlorophosphane in this paper. As electrolyte of Li ion secondary cell, Li [(C_3F_7)_2PF_4] had lower vapor pressure than LiPF_6 in the solvent in the same temperature, comparable conductivity and oxidation stability in the same concentration in room temperature. It was worth mentioning that Li [(C_3F_7)_2PF_4] has excellent stability towards hydrolysis. The synthesis process is safe and easily controlled.