Abstract:A promising preparation method for lithium hexafluorophosphate (LiPF₆) was introduced. Phosphorus pentafluoride (PF₅) was first prepared using CaF₂ and P₂O₅ at 280 ℃ for 3 h. LiPF₆ was synthesized in acetonitrile solvent by LiF and PF₅ at room temperature (20−30 ℃) for 4 h. The synthesized LiPF₆ was characterized by infrared spectrometry and X-ray diffraction(XRD). Atomic absorption and ion chromatography results show that the purity of synthesized LiPF₆ reaches 99.98%. Thermal stability of self-synthesized LiPF₆ was analyzed by differential thermal analysis and thermogravimetry. The results indicate that the self-synthesized LiPF₆ has higher purity, lower impurity contents and better thermal stability than the commercial LiPF₆.

Key words: lithium-ion batteries; lithium hexafluorophosphate; phosphorus pentafluoride; acetonitrile