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A kind of silicon negative electrode composite material and preparation method thereof

A technology of composite material and silicon negative electrode, which is applied in the field of silicon negative electrode composite material and its preparation, can solve the problems such as the decrease of battery cycle performance, and achieve the effects of easy operation, low pollution and low cost

Active Publication Date: 2017-02-08
SHANGHAI PUTAILAI NEW ENERGY TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, since the volume expansion rate of silicon can reach 400% during charging and discharging, no matter whether it is mixed with carbon, coated with carbon on the surface, or by adding a conductive polymer, it cannot solve the extrusion of the surrounding space due to the expansion of silicon. The problem that leads to the degradation of battery cycle performance

Method used

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  • A kind of silicon negative electrode composite material and preparation method thereof
  • A kind of silicon negative electrode composite material and preparation method thereof
  • A kind of silicon negative electrode composite material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0034]Add 5g of silicon nanoparticles with a particle size of 50nm into 50ml of ethanol and stir for 0.5 hours to disperse the silicon nanoparticles evenly; then add 0.5g of trimethoxysilylpropylethylenediamine and continue stirring for 1 hour to form a uniform dispersion solution; then add 0.5ml of 1mol / L ammonia water, and continue to stir for 4 hours at room temperature. Layer, composition is R-Si-O, R is 3-((2-aminoethyl) amino) propyl group-, forms mixed solution; Next, in the mixed solution that forms, add 1g methyl orthosilicate, in At room temperature, stirring was continued for 2 hours, and after hydrolysis of methyl orthosilicate, a layer of SiO was coated on the organic-inorganic hybrid layer. 2 The shell layer forms a sol system; add 0.05mol / L HF solution to the sol system, and keep stirring for 1 hour at room temperature, the organic-inorganic hybrid layer is corroded and removed, and the SiO 2 The shell layer is also corroded to have holes or cracks. The obtaine...

Embodiment 2

[0037] Add 5g of silicon nanoparticles with a particle size of 100nm into 50ml of methanol and stir for 0.5 hours to disperse the silicon nanoparticles evenly; then add 0.05g of γ-aminopropyltrimethoxysilane and continue stirring for 1 hour to form a uniform Dispersion liquid; then add 0.5ml of 1mol / L ammonia water and continue to stir for 4 hours at room temperature. Under the catalysis of ammonia water, γ-aminopropyltrimethoxysilane is hydrolyzed and coated with loose organic particles on silicon nanoparticles. Inorganic hybrid layer R-Si-O, R is γ-aminopropyl group to form a mixed solution; then, add 1g of methyl orthosilicate to the formed mixed solution, and keep stirring for 2 hours at room temperature, orthosilicate Coating a layer of SiO on the organic-inorganic hybrid layer after methyl ester hydrolysis 2 The shell layer forms a sol system; add 0.05mol / L HF solution to the sol system, and keep stirring for 1 hour at room temperature, the organic-inorganic hybrid layer...

Embodiment 3

[0039] Add 5g of silicon nanoparticles with a particle size of 500nm into 50ml of methanol and stir for 0.5 hours to disperse the silicon nanoparticles evenly; then add 1g of anilinomethyltriethoxysilane and continue stirring for 1 hour to form a uniform dispersion ; Then add 1ml of 1mol / L ammonia water, at room temperature, continue to stir for 4 hours, under the catalysis of ammonia water, anilinomethyltriethoxysilane is hydrolyzed and coated with a loose organic-inorganic hybrid layer on the silicon nanoparticles , the composition is R-Si-O, R is anilinomethyl, forming a mixed solution; then, add 0.05g tetrabutyl titanate to the formed mixed solution, and keep stirring for 2 hours at room temperature, tetrabutyl titanate After hydrolysis, a layer of TiO is coated on the organic-inorganic hybrid layer 2 The shell layer forms a sol system; add 0.05mol / L HF solution to the sol system, and keep stirring for 1 hour at room temperature, the organic-inorganic hybrid layer is corro...

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Abstract

The invention discloses a silicon negative electrode composite material. The silicon negative electrode composite material comprises silicon-based nano-particles and a wrapping layer, wherein the wrapping layer is used for wrapping the silicon-based nano-particles; a cavity is formed between the silicon-based nano-particles and the inner wall of the wrapping layer; the wrapping layer comprises oxide. In the silicon negative electrode composite material disclosed by the invention, silicon dioxide and other metal oxygen compounds form core-shell structures on the outer layer of the silicon-based nano-particles, so that the clustering of the silicon-based nano-particles during the cyclic charging and discharging process is effectively inhibited. Meanwhile, a larger space outside the silicon-based nano-particles can be used for expansion, so that extrusion to surrounding space is prevented, and falling of a binding agent and contact with graphite are also prevented, and thus the cycle life of the material can be greatly prolonged. According to the embodiment, the preparation method is simple, easy to operate, good in repeatability, low in cost and little in pollution to the environment, and is suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a silicon negative electrode composite material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used in various fields due to their excellent characteristics such as high energy density, high power density, good cycle performance, environmental friendliness, diverse structures, and low price. For the negative electrode of lithium ion battery, the theoretical capacity of silicon material is the highest, the lithium storage capacity of single crystal silicon is 3800mAh / g, lithium and silicon form alloy LixSi (0<x<4.4), when forming Li 4.4 The theoretical lithium storage capacity of Si compound is as high as 4200mAh / g, which is much larger than the theoretical lithium storage capacity of graphite (372mAh / g). However, during the charge and discharge process, that is, the process of lithium deintercalation, th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62
CPCH01M4/366H01M4/386H01M4/628H01M10/0525Y02E60/10
Inventor 方祺陈卫
Owner SHANGHAI PUTAILAI NEW ENERGY TECH CO LTD