Electrolyte as well as preparation method and application thereof

Abstract

The invention provides an electrolyte as well as a preparation method and application thereof. The electrolyte comprises a lithium salt, an additive and an organic solvent; the additive comprises a sultone compound with a structure as shown in a formula I. According to the electrolyte, components are designed, particularly, the sultone compound with a specific structure is adopted as the additive, so that a dense, stable and elastic SEI film is formed in the charging and discharging process of a battery, the lithium ion conductivity of the SEI film is improved, the impedance can be effectively reduced, side reactions are reduced; and the consumption and degradation of the electrolyte in the use process are reduced, so that the internal resistance of the battery is reduced, the capacity retention ratio of the battery is high, the normal-temperature and high-temperature cycle performance of the battery is remarkably improved, and the service life of the battery is prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrolytic solution and a preparation method and application thereof. Background technique [0002] With the continuous enhancement of public energy awareness, the development and efficient use of energy has gradually become a global focus, and various battery systems have emerged to meet the growing demand for electric vehicles and large-scale energy storage. Among portable electronic devices that have attracted much attention at present, lithium-ion batteries have become the first choice due to their advantages of high energy, high density, flexible and lightweight design, and longer life than similar batteries. One of the key issues in the rapid development of the industry. In order to improve the performance of lithium-ion batteries, a small amount of additives are usually added to the electrolyte to preferentially form a layer of organic insol...

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Problems solved by technology

[0004] Although the electrolyte additives in the above prior art improve the cycle performance of the battery from the film-forming properties of the SEI film and the impedance reduction, etc., the acidic substances (such as hydrogen) produced by side reactions in the electrolyte in the middle and late stages of the normal temperature cycle and in the high temperature cycle Hydrofluoric acid) will still destroy the structure of the SEI film, and the repair of the SEI film will also accelerate the consumption of the electrolyte, resulting in deterioration of cycle performance and other phenomena

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