Silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a silicon-carbon negative electrode material and a preparation method thereof.The preparation method of the silicon-carbon negative electrode material comprises the following steps that nanometer silicon and a dispersing agent are evenly mixed in a calcium chromate aqueous solution, and heating, filtering and drying are conducted to obtain a first intermediate product; uniformly mixing the first intermediate product with dopamine, and calcining in an inert atmosphere to obtain a second intermediate product; and putting the second intermediate product into a dilute sulfuric acid solution for reaction, filtering, cleaning and drying to obtain the silicon-carbon negative electrode material. The preparation method of the silicon-carbon negative electrode material is simple in operation process and convenient to operate, hydrofluoric acid does not need to be used, the manufacturing process is very environment-friendly, almost no potential safety hazard exists, and the silicon-carbon negative electrode material prepared by the preparation method has an egg yolk shell structure and is suitable for large-scale production. Enough passivation space can be provided for volume expansion of silicon, the conductivity is good, and the electrochemical performance of the lithium ion battery can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a silicon-carbon negative electrode material and a preparation method thereof. Background technique [0002] In recent years, with the rapid development of portable electronic devices, electric vehicles, and hybrid vehicles, lithium-ion batteries have attracted much attention. Silicon is the most promising next-generation anode material for lithium-ion batteries, and has attracted widespread attention because of its large theoretical capacity, low delithiation potential, and abundant resource reserves. However, the huge volume change of silicon in the process of lithium ion lithiation and delithiation and the poor conductivity of silicon greatly restrict the commercialization of this material. Carbon materials have the characteristics of good conductivity and good flexibility. Encapsulating silicon in carbon materials can effectively avoid the problems caused by th...

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Problems solved by technology

[0003] Traditional core-shell silicon-carbon composites cannot provide enough space to accommodate the inevitable volume expansion of silicon. The yolk-shell structure is based on the core-shell structure. Through certain technical means, a gap is introduced between the core and the shell to form a A Novel Nanoscale Multiphase Composite

However, the preparation process of most silicon-carbon composite materials with egg yolk shell structure is complicated, and it is inevitable to use hydrofluoric acid for etching. Hydrofluoric acid is not only harmful to the environment but also has great safety hazards.

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