Physicochemical and Electrochemical Properties of the Organic Solvent Electrolyte with Lithium Bis(fluorosulfonyl)Imide (LiFSI) As Lithium-Ion Conducting Salt for Lithium-Ion Batteries

Tuesday, 7 October 2014
Expo Center, 1st Floor, Center and Right Foyers (Moon Palace Resort)
T. Takekawa (Nissan Motor Co., Ltd.), K. Kamiguchi, H. Imai (NISSAN ARC Ltd.), and M. Hatano (Nissan Motor Co.,ltd.)
The basic physicochemical and electrochemical properties for organic solvent electrolyte dissolving lithium bis(fluorosulfonyl)imide (LiFSI) was studied. Ionic conductivity of 1M LiFSI in EC/DEC (3/7, v/v) was 7.2 mScm-1 at 20 oC, it is almost same value of 1M LiPF6 in EC/DEC (3/7,v/v). At lower temperature, however, the ionic conductivity of LiFSI was higher than that of LiPF6. Degree of ionic disassociation of LiFSI-electrolyte was 0.42 (20 oC) and 0.35 (-20 oC). Then the concentration of Li-ion is lower than LiPF6-electrolyte. On the other hand, diffusion coefficient of Li-ion in LiFSI-electrolyte is 1.8 cm2s-1 that is 1.3 times larger value comparing to LiPF6. This ratio gradually becomes big when it was low temperature, and reaches double at -20oC. From these results, it is assumed that the ionic conductivity is strongly affected by diffusion behavior.