Lithium secondary battery including non-aqueous electrolyte solution

Abstract

The present invention relates to a lithium secondary battery which includes a non-aqueous electrolyte solution including lithium bis(fluorosulfonyl)imide (LiFSI) and a fluorobiphenyl compound, a positive electrode including a lithium-nickel-manganese-cobalt-based oxide as a positive electrode active material, a negative electrode, and a separator.In the lithium secondary battery including a non-aqueous electrolyte solution for a lithium secondary battery of the present invention, since the non-aqueous electrolyte solution may form a robust solid electrolyte interface (SEI) on the negative electrode during initial charge and may prevent decomposition of the surface of the positive electrode and an oxidation reaction of the electrolyte solution during a high-temperature cycle, excellent low-temperature output characteristics as well as improved high-temperature storage characteristics and life characteristics may be achieved.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of Korean Patent Application No. 10-2015-0138029, filed on Sep. 30, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.TECHNICAL FIELDTechnical Field[0002]The present invention relates to a lithium secondary battery which includes a non-aqueous electrolyte solution including lithium bis(fluorosulfonyl)imide (LiFSI) and a fluorobiphenyl compound, a positive electrode including a lithium-nickel-manganese-cobalt-based oxide as a positive electrode active material, a negative electrode, and a separator.Background Art[0003]Demand for secondary batteries as an energy source has been significantly increased as technology development and demand with respect to mobile devices have increased. Among these secondary batteries, lithium secondary batteries having high energy density and high voltage have been commercialized and widely used.[00...

AI Technical Summary

Benefits of technology

[0010]In a lithium secondary battery including a non-aqueous electrolyte solution for a lithium secondary battery of the present invention, since the non-aqueous electrolyte solution may form a robust solid electrolyte interface (SEI) on a negative electrode during initial charge and may prevent decomposition of the surface of a positive electrode and an oxidation reaction of the electrolyte solution during a high-temperature cycle, excellent low-temperature output characteristics as well as improved high-temperature storage characteristics and life characteristics may be achieved.

Problems solved by technology

Conventionally, with respect to an electrolyte solution which does not include an electrolyte solution additive or includes an electrolyte solution additive having poor characteristics, it may he difficult to expect the improvement of low-temperature output characteristics due to the formation of a non-uniform SEI.

Also, since a decomposition reaction of the electrolyte solution occurs when the lithium secondary battery is stored at high temperature, high-temperature storage performance and life performance of the battery may be degraded.

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