Lithium Difluorophosphate (LiPO2F2) is a white powder solid with a melting point of 340℃. It can easily absorb moisture in the air and exhibit acidity when exposed to air. It is used as an additive in electrolytes for lithium-ion batteries to enhance the cyclic performance, high-temperature storage performance, and lower the internal resistance of the battery.
Lithium Difluorophosphate, as an additive of electrolyte for rechargeable Lithium-ion battery, effectively reduces the resistance of SEI layer formed on the electrode under low temperature, and reduces self-discharge of the battery. Meanwhile,adding of Lithium Difluorophosphate can reduce the usage of Lithium Hexafluorophosphate(LiPF6).
In the closed steel reaction dad, respectively, P2O5, LiF and dry tetrachlorofuran were added to the reaction dad at room temperature, sealed and stirred, cooled down to -40 C, and replaced the kettle atmosphere three times with nitrogen, argon or helium with a water content of less than 1 ppm, after the moisture content in the kettle was less than 1 ppm, the temperature was raised to 100 C, the pressure was raised to 0.8 MPa, and the reaction was conducted for 5 hours with stirring. The reaction temperature was 100C and the reaction pressure was 0.8MPa; the molar ratio of P0F3 to P2O5 and LiF was 1:1.2:1.7; then the temperature of the reactor was lowered to room temperature, and the insoluble material was removed by filtration after depressurization to obtain a light yellow transparent filtrate, and the solvent was removed by distillation under reduced pressure, and the rest of the solids were recrystallized with freshly dried acetonitrile at low temperature, and the crystals were obtained by filtration and dried under vacuum at 40C to obtain LiF3, and the crystals were obtained by drying under vacuum at 40C to obtain LiF3. After vacuum drying at 40C, LiPO2F2 is obtained as white powder solid, moisture 10ppm, color 20, LiF% 0.02%, purity is 99.7%.
