Electrolyte and lithium ion battery using same

Abstract

The invention discloses an electrolyte and a lithium ion battery using the same. The invention provides an electrolyte, which comprises a compound represented by a formula I in the description, an additive, a lithium salt and a non-aqueous solvent. The electrolyte disclosed by the invention is beneficial to reducing the interface impedance of the lithium ion battery, particularly a ternary lithiumion battery in the cycle process and reducing gas production, so that the high-temperature cycle life of the lithium ion battery is prolonged, the high-temperature storage capacity retention and recovery rate is increased, the low-temperature discharge retention rate is increased, and the volume expansion during high-temperature storage is reduced.

Description

technical field [0001] Embodiments of the present invention relate to an electrolyte solution and a lithium ion battery using the same. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high capacity, and long life, and are ideal energy sources for electric vehicles. Lithium-ion batteries mainly include: positive electrode, negative electrode, electrolyte and separator. The electrolyte is filled between the positive and negative plates and is the carrier of ion transmission in the battery. The inventors found in the research that an interface reaction occurs between the positive electrode material and the electrolyte. Under high temperature and high pressure, the side reaction at the interface between the positive electrode and the electrolyte is intensified, which seriously affects the high temperature cycle and storage performance. [0003] In the prior art, nitrile electrolyte additives are often used or combined with other additiv...

AI Technical Summary

Problems solved by technology

The inventors found in the research that an interface reaction occurs between the positive electrode material and the electrolyte. Under high temperature and high pressure, the side reaction at the interface between the positive electrode and the electrolyte is intensified, which seriously affects the high temperature cycle and storage performance.

[0003] In the prior art, nitrile electrolyte additives are often used or combined with other additives to improve the high temperature performance of lithium cobalt oxide positive electrode lithium ion batteries. An invention patent application with the authorized announcement number CN102637894B discloses a Electrolyte secondary battery, the electrolyte contains three additives of adiponitrile, fluoroethylene carbonate, and 2,3-dimethylmaleic anhydride, which can synergistically improve the cycle performance and high-temperature storage performance of lithium cobaltate at high voltage and improving high-temperature flatulence, the inventors found in the research, but the application of such additives in ternary cathode material batteries not only fails to improve the high-temperature performance of the battery, but also seriously deteriorates the battery rate performance and low-temperature performance

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