Electrolyte and lithium ion battery using same

Abstract

The application discloses an electrolytic solution and a lithium ion battery using the same. In the present application, the electrolyte includes a non-aqueous solvent, lithium salt and additives, the additives include the compound represented by formula I, the non-aqueous solvent includes the compound represented by formula II and the compound represented by formula III, the compound represented by formula II and the compound represented by formula The mass ratio of the compounds represented by III is 1:1 to 1:5. The electrolyte described in the application has better compatibility with the lithium-ion battery of the ternary positive electrode system, which is beneficial to reduce the interfacial impedance of the lithium-ion battery, especially the cycle process of the ternary lithium-ion battery, and reduce gas production, thereby improving the performance of the battery. High temperature cycle life and high and low temperature storage capacity retention rate reduce volume expansion during high temperature storage.

Description

technical field [0001] Embodiments of the present invention relate to lithium-ion batteries, in particular to electrolytes and lithium-ion batteries 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, and 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 high-temperature storage performance. [0003] In the prior art, the use of nitrile electr...

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Problems solved by technology

The inventors found in the research that an interface reaction occurs between the positive electrode material and the electrolyte, and 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 high-temperature storage performance

[0003] In the prior art, the use of nitrile electrolyte additives in lithium cobalt oxide positive electrodes can significantly improve the high-temperature performance of batteries, but the application of such additives in ternary positive electrode materials not only fails to improve the high-temperature performance of batteries, but also seriously deteriorates the discharge of batteries at low temperatures. Therefore, in the field of ternary cathode material batteries, it is still necessary to develop a suitable electrolyte system to improve the high temperature performance and low temperature discharge performance of the battery

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