Abstract:

In order to explore the preparation method of lithium difluorophosphate（LiPO₂F₂） and its effects on the perfor mance of lithium ion batteries,LiPO₂F₂ was prepared by solid phase method using lithium hexafluorophosphate（LiPF₆） and lithium phosphate（Li₃PO₄） as raw materials.The material was then subjected to phase analysis and qualitative detection by nuclear magnetic resonance（NMR）,X-ray diffraction（XRD） and ion chromatography（IC）,and the effects of materials on battery performance were investigated by charge and discharge tests,cyclic voltammetry（CV） and electrochemical impedance（EIS）.The results showed that liPO₂F₂ could be obtained by using LiPF₆ and Li₃PO₄ as raw materials,the polarization of the battery electrode was weakened by adding LiPO₂F₂ as an additive to the electrolyte,the film-forming resistance of the positive and negative materials of the battery was significantly reduced,and the cycle stability and high-temperature storage performance of the battery were improved.

Key words: lithium difluorophosphate, lithium ion battery, electrolyte additive