Electrolyte additive, electrolyte and lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to an electrolyte additive. The structural formula I of the electrolyte additive is shown in the description. The electrolyte additive of the lithium ion battery can significantly improve the high-temperature storage and cycle performance of a high-voltage battery. The electrolyte additive is added andapplied to a battery electrolyte, and a compact and stable protective layer can be formed on the surfaces of positive and negative active substances at the same time, so that direct contact between asolvent and the active substances is blocked, side reactions are avoided, and the cycle performance of the lithium ion battery at the high temperature and high voltage is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrolyte additive, electrolyte and lithium ion batteries. Background technique [0002] Lithium-ion batteries have the advantages of light weight, small size, high working voltage, high energy density, high output power, high charging efficiency, no memory effect, and long cycle life. They are not only widely used in mobile phones, notebook computers and other digital products, It is also considered the best choice for electric vehicles and large energy storage devices. At present, digital electronic products such as smartphones and tablet computers have higher and higher requirements for battery energy density, and it is difficult for commercial lithium-ion batteries to meet the requirements. The most effective way to increase the energy density of lithium-ion batteries is to use high-capacity cathode materials or high-voltage cathode materials. ...

AI Technical Summary

Problems solved by technology

On the one hand, at high temperature, LiPF 6 It is relatively easy to decompose in the electrolyte, thereby producing HF acid, which corrodes the positive electrode, causes the dissolution of metal ions, destroys the structure of the positive electrode material, and causes capacity loss; on the other hand, under high pressure, the electrolyte easily Oxidation at the electrode makes the metal ions in the positive electrode active material easily reduced and dissolved in the electrolyte, thereby destroying the structure of the positive electrode material and causing capacity loss

At the same time, the metal ions dissolved in the electrolyte can easily reach the negative electrode and destroy the structure of the SEI film, continuously increasing the impedance of the negative electrode, strengthening the self-discharge of the battery, increasing the irreversible capacity, and causing performance deterioration

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