Lithium ion battery electrolyte and preparation method

Abstract

The invention relates to the technical field of a lithium ion battery, in particular to a lithium ion battery electrolyte and a preparation method thereof. The lithium ion battery electrolyte comprises a non-aqueous solvent, a lithium salt and an additive, wherein the additive comprises a first type of additive capable of water removal and acid reduction and a second type of additive capable of stabilizing color change of the electrolyte, the first type of additive is a silazane compound or a carbodiimide compound, and the second type of additive is a benzothiodiazole compound or a phosphite ester compound. Compared with the prior art, the lithium ion battery electrolyte has the advantages that by controlling an environmental temperature for configuring the electrolyte and with the first type of additive capable of water removal and acid reduction and the second type of additive capable of stabilizing the color change of the electrolyte, long-term control on moisture, acidity and chromaticity of the electrolyte can be simultaneously achieved, the storage time of the electrolyte is substantially prolonged, and the electrolyte quality is ensured. The lithium ion battery electrode is particularly and suitably used for an additive system which easily causes the chromaticity and the acidity of the electrolyte to change.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte and a preparation method thereof. Background technique [0002] Lithium-ion battery electrolyte is one of the four key materials of lithium batteries, and its quality is crucial to the performance of lithium batteries. Among them, moisture, acidity, and chroma are the most basic physical indicators for evaluating the quality of the electrolyte, but some moisture is inevitably brought in during the production process. At present, the commercial electrolyte lithium salt is mainly LiPF 6 , which is very sensitive to water, LiPF 6 Dissolving in the solvent process releases heat, and may produce PF with catalytic polymerization 5 、FOF 3 , making the acidity and chroma of the electrolyte gradually increase. The water in the electrolyte is gradually converted into acid in the later stage, and the increase of acidity plays a catalytic ...

AI Technical Summary

Problems solved by technology

In order to improve the performance of the electrolyte, a series of functional additives are often added into the electrolyte system. The variety and quantity of additives are rich, on the one hand, it solves the problem of the performance of the electrolyte, but on the other hand, some additives are found to be ineffective in experiments and production. It is easy to accelerate the change of electrolyte acidity and chromaticity by adding

For example, compounds such as vinyl sulfate and 4-methyl vinyl sulfate have excellent electrochemical properties and can improve the performance of the battery. However, this additive can easily cause the acidity and chroma of the electrolyte to increase.

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