Nitrogen-doped carbon-coated silicon nanoparticle composite material, preparation method and application

Abstract

The invention discloses a nitrogen-doped carbon-coated silicon nanoparticle composite material and a preparation method thereof. The preparation method comprises the following steps that: S1: puttinga silicon nanoparticle of which the grain diameter is 30-50nm in Tris-HCl buffer solution of which the pH (Potential of Hydrogen) is 7.5, cleaning, and drying to obtain processed silicon nanoparticles; S2: adding dopamine hydrochloride into Tris-HCl buffer solution of which the pH is 8.5, and dissolving to obtain dopamine solution; S3: adding the silicon nanoparticle processed in S1 into the dopamine solution obtained in S2, evenly dispersing, carrying out stirring reaction at the room temperature for 1-8 days, and carrying out separation and drying to obtain reactant; and S4: under an inert atmosphere, calcinating the reactant obtained in S3 at a temperature of 700-900DEG C for 1-2h to obtain a composite material. The invention also discloses the application of the above composite material on a lithium battery negative electrode. The composite material synthesized by the preparation method has excellent cycling stability.

Description

technical field [0001] The invention belongs to the technical field of silicon nanoparticle modified composite materials, and specifically relates to a nitrogen-doped carbon-coated silicon nanoparticle composite material, a preparation method and an application. Background technique [0002] Anode materials are very important components of lithium-ion batteries, which directly affect the energy density and electrochemical performance of lithium-ion batteries. Excellent negative electrode materials can improve the reversible capacity, cycle performance, and rate performance of lithium-ion batteries; otherwise, it will cause the performance of lithium-ion to attenuate, or even fail to work. [0003] The theoretical specific capacity of the traditional graphite negative electrode material is 372mAh / g, and the actual application material capacity can reach 360mAh / g, and there is almost no room for improvement; in contrast, silicon has a very high mass specific capacity (4200mAh / ...

AI Technical Summary

Problems solved by technology

However, due to the large volume deformation caused by cyclic stress during the charging and discharging process of the battery, the discharge specific capacity rapidly decays and the cycle stability is poor.

At present, although there are some methods to improve the electrochemical performance of silicon-based materials, most of the operation methods are complex steps, harsh conditions, and high cost

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