Fluorinated electrolytes for Li-ion battery: An FEC-based electrolyte for high voltage LiNi0.5Mn1.5O4/graphite couple

• FEC-based high-voltage electrolyte for LiNi0.5Mn1.5O4/graphite cell was studied.
• High-voltage electrolyte showed improved cycle performance at 55 °C.
• Post-analysis indicates the new electrolyte is stable on LiNi0.5Mn1.5O4 cathode.
• Flame test demonstrated its non-flammability under ambient conditions.

A new electrolyte based on fluorinated solvents was studied in a high voltage Li-ion cell using graphite as the anode and 5 V spinel LiNi0.5Mn1.5O4 as the cathode. The electrolyte shows significantly enhanced voltage stability compared with the conventional electrolytes at elevated temperature (55 °C). Post-test study of the harvested cathode using FT-IR and SEM indicated that the buildup of organic decomposition product on the cathode surface is negligible for the fluorinated electrolyte.