Lithium ion battery non-aqueous electrolyte, lithium ion battery and preparation method of lithium ion battery non-aqueous electrolyte

Abstract

The invention discloses a non-aqueous electrolyte of a lithium ion battery and a manufacturing method of the non-aqueous electrolyte. The electrolyte provided by the invention is good in low-temperature performance, good in high-temperature cycle characteristic and less in gas production in high-temperature storage. Comprising an electrolyte lithium salt, a non-aqueous organic solvent and an additive, according to the mass percentage content in the non-aqueous electrolyte of the lithium ion battery, the additive comprises a component A, a component B and a component C, and the component A accounts for 0.1-3%; the content of the component B is 10%-80%; the content of the component C is 0.1%-3%; the component A can effectively inhibit cobalt element from being separated out of a lithium cobalt oxide positive electrode, and side reaction is reduced; the component B can improve the oxygenolysis potential of the electrolyte, can form a passive film on the surface of the negative electrode, and improves the cycle performance of the electrolyte; and the component C can form a sulfur-containing compound on the negative electrode to improve the morphology of the negative electrode passivation film and effectively reduce the impedance of the negative electrode passivation film.

Description

technical field [0001] The invention relates to the technical research field of lithium-ion batteries, in particular to a non-aqueous electrolyte solution for lithium-ion batteries, a lithium-ion battery and a preparation method thereof. Background technique [0002] With the development of mobile technology, people have higher requirements on the performance of consumer lithium-ion batteries, and it is necessary to develop higher-performance lithium-ion batteries. [0003] At present, in order to improve the performance of lithium-ion batteries, an effective method is to increase the working voltage of the battery to increase the energy density of the battery. However, the existing common commercial electrolytes are suitable for 4.4V-4.45V systems, such as carbonate electrolytes, and carbonate compounds are prone to oxidative decomposition when working at a voltage of 4.45V-4.5V. On the one hand, its Part of the product will be deposited on the electrode surface, increasin...

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Problems solved by technology

[0004] According to literature reports (Electrochemistry Communications 44(2014) 34–37), some fluorocarbonate solvents can significantly improve the high-temperature cycle performance of high-voltage lithium-ion batteries, but there are the following disadvantages, although the high-temperature performance of lithium-ion batteries using such solvents The cycle performance is improved, but the gas production is more serious when the battery is stored at a high temperature above 60 ° C, causing obvious safety hazards

[0005] Patent CN202110197027 discloses a method for adding tetracyano-containing nitrile ether electrolyte additives to make lithium-ion batteries have good cycle performance and high-temperature storage and low-temperature performance under high voltage, but there are the following disadvantages. Exacerbate battery expansion during high temperature storage, posing a safety risk

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