A kind of lithium ion battery electrolyte and preparation method thereof

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte and a preparation method thereof. The lithium ion battery electrolyte is composed of a nonaqueous solvent, a lithium salt and an additive, and the additive includes a first A class of additives and a second class of additives with stable electrolyte chromaticity changes; the first class of additives are silazane compounds or carbodiimide compounds, and the second class of additives are thiocarboxylates compounds or phosphite compounds. Compared with the prior art, the present invention can simultaneously realize the improvement of electrolysis by controlling the environment temperature of the electrolyte configuration, and through the combined use of the first type of additives with dehydration and acid reduction and the second type of additives with stable electrolyte chromaticity changes. The long-term control of liquid moisture, acidity, and chroma greatly prolongs the storage time of the electrolyte and ensures the quality of the electrolyte. The invention is especially suitable for additive systems that easily cause changes in the chroma and acidity of the electrolyte.

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.

Images