Nonaqueous electrolyte and lithium secondary battery using the electrolyte

Abstract

The invention provides a non-aqueous electrolytic solution superior in overcharge preventing effect and high-temperature storage property and suitable for a lithium secondary battery. The non-aqueous electrolytic solution comprises a fluorine atom substitutional aromatic compound, an aromatic hydrocarbon compound consisting of carbon and hydrogen only, a non-aqueous solvent and a lithium contained electrolyte. The non-aqueous electrolytic solution contains the 0.1-20 wt% fluorine atom substitutional aromatic compound and the 0.1-3 wt% aromatic hydrocarbon compound. In the desirable embodiment of the electrolytic solution, the fluorine atom substitutional aromatic compound is fluorine atom substitutional naphthalenes, fluolenes or biphenyls and the aromatic hydrocarbon compound is alkyl group or cylohexyl group substitutional benzenes or biphenyls. The electrolytic solution has improved high-temperature storage property if vinylene carbonates, alkenyl ethylene carbonates, unsaturated hydrocarbon group contained sultons, aryl group contained sulfonate, saturated hydrocarbon group contained sultons, or sulfonic imide is added thereto.

Description

technical field [0001] The present invention relates to a non-aqueous electrolytic solution having an overcharge prevention effect and excellent high-temperature storage characteristics, and a lithium secondary battery having excellent safety during overcharging using the electrolytic solution. Background technique [0002] Batteries using non-aqueous electrolytes have high energy density at high voltages and high reliability due to storage properties, and are widely used as power sources for consumer electronics. [0003] Such a battery is manufactured as a secondary battery, a representative example of which is a lithium ion secondary battery. This type of battery consists of a negative electrode containing an active material that can absorb and release lithium, a positive electrode containing a composite oxide of lithium and a transition metal, and an electrolyte. In the electrolyte, use a mixed solvent of a carbonate solvent with a high dielectric constant such as propy...

AI Technical Summary

Problems solved by technology

However, it has been found by the present inventors that even if these additives are used in batteries using biphenyl as an overcharge preventing agent, they hardly contribute to the improvement of high-temperature storage characteristics.