LiBF_4 Electrolyte for Lithium-Ion Battery:Preparation and Characterization

A LiBF4 electrolyte was prepared by an acetonitrile solvent method. The preparation process includes the thermal decomposition of NaBF4 to produce BF3,the reaction of BF3 with LiF in acetonitrile solvent,and the product recovery by filtration,cooling and crystallization. The intermediate BF3 for the process was monitored by GC-MS (in Selected Ion Monitoring (SIM) mode) by heat treatment of NaBF4 at 500 ℃ for 3 h. The product after purification in organic solvent was characterized by FTIR,XRD,AAS,Ion chromatography(IC) and TG-DTG. The results indicate that the product obtained by the present method is with less impurity and better thermal stability than conventional LiPF6.