Negative electrode composite material of lithium ion battery and preparation method thereof

Abstract

The invention relates to a negative electrode composite material of a lithium ion battery. The material comprises a core body, an intermediate layer that is coated outside the core body and has pores,and an outer layer coated outside the intermediate layer, wherein the core body is nano silicon, the intermediate layer is silicon monoxide compounded with graphite, and the outer layer is amorphouscarbon. According to the scheme of the invention, a negative electrode composite material with a novel structure is obtained through the improvement of a preparation method, the negative electrode composite material can control the volume expansion of silicon in a certain space, effectively prevent silicon electrodes from being pulverized, and improve the cycling stability, and can be used as a negative electrode material of a high-capacity lithium battery. The preparation method has a simple process and is suitable for industrial production.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode composite material and a preparation method thereof. Background technique [0002] As an important part of lithium-ion batteries, negative electrode materials have a variety of research objects, which can be summarized into two categories: the first category is carbon materials, including graphitized carbon materials and amorphous carbon materials; the second category is non-carbon materials. Materials mainly include silicon-based materials, tin-based materials, transition metal oxides, metal nitrides and other alloy anode materials. [0003] An ideal lithium-ion battery anode material should meet the following requirements: [0004] 1. It should have a lower oxidation-reduction potential to ensure a higher output voltage for lithium-ion batteries; [0005] 2. It can allow a large number of lithium ions to be reversibly intercalated and extracted, and has a high energy density; [000...

AI Technical Summary

Problems solved by technology

However, this solution has the following disadvantages: elemental silicon and silicon oxide are simply mixed physically, and the final particles are all in the micron size, and then mixed with graphite and then coated with amorphous carbon

Due to the large particles of the material itself, the volume expansion during charging and discharging will destroy the previous coating layer, resulting in electrode pulverization and poor cycle stability.

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