NONAQUEOUS ELECTROLYTE SOLUTION FOR LITHIUM ION SECONDARY BATTERY

摘要

PURPOSE: Provided is a nonaqueous electrolyte solution for lithium ion secondary battery in which anhydrous maleic acid is added to inhibit collapse of solid electrolyte interface, thereby remarkably improving both charging/discharging efficiency and thermal stability of lithium ion secondary battery. CONSTITUTION: In the nonaqueous electrolyte solution for lithium ion secondary battery comprising organic solvents and lithium salts, it is characterized in that 0.1-10wt.% of hexafluorobenzene of chemical formula I is contained in the nonaqueous electrolyte solution. The organic solvent is at least one selected from the group consisting of ethylene carbonate, propylene carbonate, butyrolactone, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate. The lithium salts is at least one selected from the group consisting of LiPF6, LiClO4, LiAsF5, LiBF4, LiCF3SO3 and its concentration is between 0.7 and 2.0 mol.