Lithium battery negative electrode and preparation method thereof, lithium battery and application

Abstract

The invention discloses a lithium battery negative electrode as well as a preparation method thereof, a lithium battery and application. The lithium battery negative electrode comprises a current collector, a negative active material layer which is connected onto the surface of the current collector, and protective layers which are respectively connected onto the surface of the negative active material layer and a porous wall of the negative active material layer. The contact between an electrolyte solvent and the surface of the negative electrode can be inhibited through the protective layers of the lithium battery negative electrode, so that the consumption of lithium ions can be reduced when an SEI (solid electrolyte interphase) membrane on the surface of the lithium battery negative electrode is formed and repaired, and the cycling performance of the lithium battery can be remarkably improved; the formation of the SEI membrane on the surface of the lithium battery negative electrode is inhibited, the heat production when the SEI membrane on the surface of the negative electrode is decomposed at high temperature and the exothermic reaction generated when the electrolyte is contacted with the negative electrode after the SEI membrane is decomposed can be avoided, and the safety of the lithium battery can be improved. The preparation method of the lithium battery negative electrode adopts a simple process and easily controlled conditions, is high in efficiency and applicable to industrialized production.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a negative electrode of a lithium battery, a preparation method thereof, a lithium battery and an application thereof. Background technique [0002] Compared with other batteries, lithium-ion batteries have the advantages of high energy density, long cycle life, small self-discharge, and no memory effect. They are widely used in mobile phones and portable notebook computers, and gradually replace nickel-metal hydride, nickel-cadmium, and lead-acid batteries. Entering the fields of electric vehicles and electric tools has become the focus of researchers in recent years. With the wide application of lithium-ion batteries, their safety performance has been paid more and more attention. [0003] During the use, storage, and transportation of lithium-ion batteries, accidents such as external short circuits will occur, and the batteries will overheat due to the impact of...

AI Technical Summary

Problems solved by technology

[0006] However, the method of adding film-forming additives has the following defects: since the SEI film needs to be reformed under high temperature conditions, it will still be damaged and affect cycle performance; sex brings hidden dangers

[0008] However, this method also has the following defects: this method will cause the volatilization of components such as the electrolyte solvent, and change the original formula of the electrolyte. Even if the high-temperature performance is optimized, other performances of the lithium battery may decline sharply, often The loss outweighs the gain

[0014] However, in actual work, it is found that the electrode modified with organic matter as the coating layer still has the following disadvantages: because the organic matter as the coating layer has unstable characteristics at high temperatures, it is because of this characteristic that it brings hidden dangers to battery safety.

[0016] 1) The SEI film formed on the surface of the negative electrode when the electrolyte decomposes decomposes and releases heat at a higher temperature, which is likely to cause safety problems;

[0017] 2) After the SEI film on the surface of the negative electrode is decomposed, the surface of the negative electrode is in direct contact with the electrolyte, a series of side reactions will occur, and a large amount of heat will be released, which will aggravate potential safety hazards;

[0018] 3) The continuous decomposition and repair of the SEI film on the surface of the negative electrode during the cycle consumes a large amount of lithium ions, resulting in a decrease in battery cycle performance

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