Lithium-ion secondary cell has a high energy desity,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 a 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） tetrafluorophosphate Li[（C3F7）2PF4] was received by Simons process from diisopropylchlorophosphane in this paper.As an electrolyte of Li ion secondary cell,Li[（C3F7）2PF4] had lower vapor pressure than LiPF6 in the solvent at the same temperature,comparable conductivity and oxidation stability in the same concentration at room temperature.It was worth mentioning that Li[（C3F7）2PF4] has an excellent stability towards hydrolysis.The synthesis process is safe and easily controlled.
