Negative active material and preparation method thereof

Abstract

The invention discloses a negative electrode active material and a preparation method thereof. The negative electrode active material comprises silicon-containing active substance particles and a polymer layer coating the silicon-containing active substance particles, and a metal compound is dispersed in the polymer layer. The preparation method of the negative electrode active material comprisesthe following steps: (1) preparing required raw materials, and dissolving a polymer monomer in a solvent to form a solution; (2) dispersing a metal compound into the solution to form a mixed solution;(3) dispersing the mixed solution on the surfaces of the active substance particles to obtain the negative electrode active material. According to the invention, a lithium ion channel on the surfaceof the negative electrode active material can be improved, the generation of lithium dendrites and byproducts is inhibited, and the electrical properties, stability and safety of the battery are improved; the preparation method of the negative electrode active material is simple in process, simple and convenient to operate, high in productivity and suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a negative electrode active material and a preparation method thereof. Background technique [0002] Among the existing types of secondary batteries, lithium-ion batteries have great advantages in terms of development space, service life and electrical performance, and are quite competitive. At present, the rapidly developing power battery market has put forward higher requirements for lithium-ion batteries: higher energy density, better cycle life, better high and low temperature charge and discharge performance and safety performance, etc. Therefore, as lithium-ion batteries It is an important part of the lithium-ion battery and a key factor affecting the electrical performance of the battery. The research on electrode materials for lithium-ion batteries still needs to be further deepened and perfected. [0003] As a new type of negative electrode active materi...

AI Technical Summary

Problems solved by technology

However, when silicon is used as an anode active material, there is a large volume effect in the charging and discharging process, which can easily lead to electrode fracture and pulverization, increased resistance, and a sudden drop in cycle performance, which seriously limits the utilization and commercialization of silicon anode materials.

[0004] At present, the research on silicon negative electrode active materials mainly includes the preparation of silicon-carbon composite materials by mixed pyrolysis of silicon powder and carbon source, and the simultaneous deposition of silicon and amorphous silicon dioxide by the vapor phase method, but the silicon negative electrode improved by the above method The initial charging and discharging efficiency of active materials is still low, they are still relatively sensitive to water, and their safety and stability have not been significantly improved.

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