Lithium ion battery and electrolyte thereof

Abstract

The invention discloses lithium ion battery electrolyte. The lithium ion battery electrolyte comprises a solvent, lithium salt and additives; the methyl-containing chain carbonate ester in the solvent is less than or equal to 5 percent of the total mass of the solvent; and the additives comprise 2 to 4 percent of 1,3-propane sultone (PS). Compared with the prior art, the lithium ion battery electrolyte has the advantages that: the content of the methyl-containing chain carbonate ester with low stability in the solvent is controlled, and the additives, namely the 1,3-propane sultone, butanedinitrile, adiponitrile, vinylene carbonate (VC), fluoroethylene carbonate (FEC) and the like are added into the solvent, so that an interface of an electrode / the electrolyte can be improved, the decomposition of the solvent in the electrolyte is reduced, the quantity of gas generated in the battery is reduced, and the high temperature storage performance, the safety performance and the cycle performance of the battery under a high voltage are improved. Besides, the invention also provides a lithium ion battery employing the electrolyte.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to an electrolyte that can significantly improve the high-temperature storage performance and safety performance of the lithium-ion battery under high-voltage conditions and a lithium-ion battery using the electrolyte. Background technique [0002] In recent years, lithium-ion batteries have been widely used in small electronic devices such as digital cameras and notebook computers due to their high energy density, high voltage, low self-discharge rate, and light weight. With the deepening of the application of lithium-ion batteries, people put forward higher and higher requirements for their safety performance and energy density. [0003] The cut-off voltage of the current full charge of the lithium-ion battery is 4.2V. If the upper limit voltage of the lithium-ion battery can be increased, the energy density of the battery can be significantly improved. However, when lithium-...

AI Technical Summary

Problems solved by technology

However, under the high voltage state of lithium-ion batteries, the oxidation ability of the positive electrode is enhanced, and the electrolyte solvent is oxidized on the positive electrode in a high-temperature environment, thereby generating a large amount of gas, causing the thickness of the battery to expand, and increasing the safety risk of battery use.

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