An Electrolyte Additive for Use in High-Voltage Lithium-Ion Batteries

A new compound was successfully synthesized as an additive in electrolyte used for high-voltage lithium-ion batteries, owing to its unique structure with the sulfone group that can increase conductivity and broaden the electrochemical window of existing electrolyte. Its lowest unoccupied molecular orbital (LUMO) is-2.686 eV, respectively. The lower LUMO value results in formation of solid electrolyte interface (SEI) film on anode surface which is prior to other solvents and can impede the electrolyte composition. Through the electrochemical test, the electrolyte having this additive (0.2 wt%) showed wider voltage window, enduring the potential up to 5.5V higher than that of 4.8V performed by available commercial high-voltage electrolytes. The additive to electrolyte was effective not only for Li/Li3V2(PO4)3 cell but also for Li/LiMn2O4 cells with a cut-off range of 3.0-4.8 V.