Preparation and characterization of lithium hexafluorophosphate for lithium-ion battery electrolyte
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
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