Study And Application On The Analysis Of Lithium Hexafluorophosphate

Lithium hexafluorophosphate (LiPF₆) is a new kind of electrolyte material for Li-ion batteries. This kind of material has excellent specific energy and energy density, so it is very popular since the last century. The development, application, working principle and development of its electrolyte solution were introduced. The most popular electrolyte is lithium hexafluorophosphate, its preparation methods and analysis methods were also introduced. Based on this, the material structure, properties, primary content and some familiar index of lithium hexafluorophosphate were studied, with some new methods preliminarily discussed..The qualitative and quantitative measurements of lithium hexafluorophosphate covered as follows:1. Qualitative study of LiPF₆ were conducted using infrared spectrum, ¹9F, ¹3C nuclear magnetic resonance, and X-Ray spectrum. All three methods coincided well with each other. The results indicated that self-made lithium hexafluorophosphate is basicly accordant with the standard. Those experiments were proved compatible.2. Primary content analysis were carried out by gravimetric determination, spectrophotometric determination and amperometric titration. The relative standard deviation indices showed good accuracy and precision for the composition determination.3. Atom absorption spectrum was also deployed to determine lithium. Experiments showed that we could reduce the deviation and improve the accuracy through choosing the appropriate calculation methods.4. As an important index of electrolytes, moisture determination requires more accuracy. Karl-Fischer Titrimetry was utilized to determine the moisture content in Lithium Hexafluorophosphate. The result was good.5.Insoluble residues, as still another crucial index, which has direct influences on the function of electrolyte. Gravimetric assay results showed that the self-made lithium hexafluorophosphate.had passed muster.6. The self-made lithium hexafluorophosphate was assembled into a battery and tested on Arbin BT-2401 battery instrument to determine its capacity. The results manifested the self-made battery had good electrochemical function, thereby proving the electrolyte meets requirements.