二氟磷酸锂的制备及电化学性能研究

Preparation and electrochemical properties of lithium difluorophosphate

为探究二氟磷酸锂(LiPO_2F_2)的制备方法及其对锂离子电池性能的影响,尝试以六氟磷酸锂(LiPF_6)和磷酸锂(Li_3PO_4)为原料,采用固相法制备LiPO_2F_2,通过核磁共振(NMR)、X射线衍射(XRD)、离子色谱(IC)对材料做了物相研究和定性检测;通过充放电测试、循环伏安(CV)、电化学阻抗(EIS)研究了材料对电池性能的影响。测试结果表明,以LiPF6及Li_3PO_4为原料可制得LiPO_2F_2,LiPO_2F_2作为添加剂加入电解液中使得电池电极极化现象有所减弱,电池正负极材料的成膜电阻明显减小,同时提高了电池的循环稳定性及高温存储性能。

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.