Patent ID: 11824160

Abstract:
Improved battery systems have been developed for lithium-ion based batteries. The improved battery systems consist of two-additive mixtures in an electrolyte solvent. Such battery systems are prepared by assembling a positive electrode and a negative electrode in the sealed cell, removing residual water from the sealed cell, filling the sealed cell with a nonaqueous electrolyte under an inert atmosphere, vacuum-sealing the sealed cell, carrying out a formation process comprising charging and discharging the sealed cell until the sealed cell achieves an initial capacity. The nonaqueous electrolyte includes lithium ions, a first nonaqueous solvent comprising a carbonate solvent, a second nonaquaeous solvent comprising methyl acetate, and an additive mixture of a first operative additive of either vinylene carbonate or fluoroethylene carbonate and a second operative additive of 2-furanone. Gas formation is suppressed in the battery system during the formation process.