Preparation method of silicon-based lithium ion battery negative electrode material

Abstract

The invention provides a preparation method of a silicon-based lithium ion battery negative electrode material. The method mainly comprises the steps of designing a nitrogen-doped graphene-coated silicon sphere three-dimensional network of which defect induced stress is arranged again; preparing spherical nanometer silicon by a thermal plasma method; preparing a nanometer silicon template by a mechanical method; and preparing the nitrogen-doped graphene-coated silicon-based lithium ion battery negative electrode material by the nanometer silicon template and by a chemical vapor deposition method. A stress concentration principle in elastic mechanics is applied to design of the material, kilometer-scale nanometer silicon powder is prepared by the thermal plasma technology, nitrogen-doped graphene-coated silicon is prepared by the chemical vapor deposition method, and industrial production on a large scale is achieved; the stress concentration principle is introduced, the nitrogen-dopedgraphene-coated silicon is designed and optimized and has more stable structure, and more stable circulation is achieved; and the nanometer silicon prepared by the method has the advantages of smallergrain size, relatively good dispersing performance, relatively high yield and the like.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing a negative electrode material of a silicon-based lithium ion battery. Background technique [0002] At present, throughout the world, lithium-ion battery negative electrodes have penetrated into communications, transportation, computers and other industries, providing countless conveniences for people's lives. Energy, environment, safety issues. The lithium-ion battery is expected to become a candidate for a new generation of clean energy. Lithium-ion batteries include three parts: positive electrode, negative electrode and electrolyte. The electrode materials of lithium-ion batteries are very important for improving electrochemical performance and reducing costs. [0003] Among them, traditional commercial lithium-ion batteries are mainly composed of graphite anodes, and the lithium storage capacity of traditional graphite anodes can only r...

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Problems solved by technology

[0011] The disadvantages of the preparation method of the nitrogen-doped graphene-wrapped micro-silicon composite material in the above-mentioned prior art are: the prepared silicon-carbon composite material, due to the mixing of raw materials, may easily cause particles to agglomerate during the heating process, resulting in uneven coating. It will affect the electrochemical performance of silicon-carbon composite materials; and graphene-coated silicon-based negative electrode materials, due to the different volume expansion coefficients of silicon and graphene, can easily cause graphene to rupture, and silicon and graphene to separate

The preparation process is complex and uncontrollable, making it difficult to achieve large-scale industrial production

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