RECHARGEABLE LITHIUM ELECTROCHEMICAL BATTERY

PURPOSE: A rechargeable lithium electrochemical battery is provided, to improve the stability in the case of overcharge by forming a passivation layer on a positive electrode. CONSTITUTION: The rechargeable lithium electrochemical battery comprises a positive electrode; a negative electrode containing a lithium storage material; and an electrolyte comprising a lithium salt and at least one saturated aprotic organic solvent, wherein the electrolyte comprises further 0.001-10 vol% of an additive based on the volume of the organic solvent. The additive is an organic compound containing at least one unsaturated carbon-carbon bond activated by the oxidation by an electron-donating alkyl group and can be oxidized at a positive electrode of the potential of 4.3 V or more based on Li/Li+. Preferably the additive is selected from the group consisting of 1,5-hexadiene, cyclohexene and 4-vinyl cyclohexene. Preferably the aprotic organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate.