Patent ID: 7422827

Claim:
A nonaqueous electrolyte for a lithium-ion secondary battery which uses at least one of LiCoO 2 , LiMnO 2 , LiMn 2 O 4 , LiNiO 2 , or a composite compound, LiM 1x M 2y O 2 as an anodic active material, and crystalline or amorphous carbon or lithium as a cathodic active material, wherein M 1 and M 2 are a metal element; and x and y are a rational number from 0 to 2, the electrolyte comprising: a mixed solvent comprising at least one carbonate solvent, as a solvent; at least one lithium salt selected from LiPF 6 , LiBF 4 , LiClO 4 , LiN(SO 2 CF 3 ) 2 and LiN(SO 2 CF 2 CF 3 ) 2 , as an electrolytic salt; and 2-sulfobenzoic acid cyclic anhydride as an additive, represented by the formula 1: