Patent ID: 7790322

Claim:
An additive mixture for electrolyte of lithium ion secondary battery, wherein the additive mixture comprises biphenyl based compound 0.5-95.4 wt %, cyclohexyl benzene based compound 0.1-93.8 wt %, vinylene carbonate 0.4-93.2 wt %, t-alkyl benzene based compound 0.5-96.5 wt %, and phenyl vinyl sulfone 0.5-95.8% based on the total weight of the additive mixture, wherein the term “biphenyl based compound” refers to a compound comprising a biphenyl group, the term “cyclohexyl benzene based compound” refers to a compound comprising cyclohexyl phenyl group, and “the term t-alkyl benzene based compound” refers to a product resulting from substitution of one or more hydrogen atoms on a benzene ring by a tert-carbon atom-containing linear alkyl group.