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Three-dimensional dendritic silicon negative electrode material and preparation method

A technology of three-dimensional dendritic and electrode materials, which is applied in the direction of negative electrodes, battery electrodes, active material electrodes, etc., and can solve problems such as large-volume expansion that cannot be solved

Active Publication Date: 2017-03-15
梧州市同创新能源材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the volume expansion rate of silicon can reach 400% during charge and discharge, no matter whether it is mixed with carbon, coated with carbon on the surface, or compounded by adding conductive polymers or metal alloys, such a large volume expansion cannot be solved.

Method used

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  • Three-dimensional dendritic silicon negative electrode material and preparation method

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Effect test

Embodiment 1

[0019] A method for preparing a three-dimensional dendritic silicon negative electrode material, the specific steps of which are as follows:

[0020] ① Soak the nano-sized silicon particles in an intercalation agent composed of dimethyl sulfone, formamide, and polyethylene glycol for 48 hours to activate the silicon particles, take out the silicon particles and centrifugally dry them to obtain intercalated silicon particles; The pH of the intercalation agent is 7.7-8;

[0021] ② adding the intercalated silicon microparticles of step ① to the molten excessive sodium chloride to disperse;

[0022] ③Quick freezing the molten mixture obtained in step ② through liquid nitrogen to obtain a low-temperature mixture;

[0023] ④ The low-temperature mixture obtained in step ③ is rapidly heated by microwaves to cause the nano-silicon particles to burst, and then cleaned and filtered to obtain the product, namely silicon particles with three-dimensional dendritic cracks.

Embodiment 2

[0025] A method for preparing a three-dimensional dendritic silicon negative electrode material, the specific steps of which are as follows:

[0026] ① Soak the nano-sized silicon particles in an intercalation agent composed of dimethyl sulfone and formamide for 48 hours to activate the silicon particles, take out the silicon particles and centrifugally dry them to obtain intercalated silicon particles; the pH of the intercalation agent is 7.7-8;

[0027] 2. The intercalated silicon particles of step 1. are added to the molten excessive molten mixture composed of sodium chloride and magnesium chloride to disperse;

[0028] ③Quick freezing the molten mixture obtained in step ② through liquid nitrogen to obtain a low-temperature mixture;

[0029] ④ The low-temperature mixture obtained in step ③ is rapidly heated by microwaves to cause the nano-silicon particles to burst, and then cleaned and filtered to obtain the product, namely silicon particles with three-dimensional dendrit...

Embodiment 3

[0031] A method for preparing a three-dimensional dendritic silicon negative electrode material, the specific steps of which are as follows:

[0032] ① Soak the nano-sized silicon particles in a sufficient amount of intercalation agent for 48 hours to activate the silicon particles, take out the silicon particles and centrifugally dry them to obtain intercalated silicon particles; the pH of the intercalation agent is 7.7-8;

[0033] ② adding the intercalated silicon particles of step ① to the molten excess chloride salt to disperse;

[0034] ③Quick freezing the molten mixture obtained in step ② through liquid nitrogen to obtain a low-temperature mixture;

[0035] ④ The low-temperature mixture obtained in step ③ is rapidly heated by microwaves to cause the nano-silicon particles to burst, and then cleaned and filtered to obtain the product, namely silicon particles with three-dimensional dendritic cracks.

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Abstract

The invention relates to the technical field of silicon negative electrode materials, and discloses a three-dimensional dendritic silicon negative electrode material and a preparation method. Nano-silicon particles are fine particles with slit openings, a volume change of a silicon material is only generated in single nano-particle in entry and exit processes of lithium ions, and the volume change is buffered and counteracted by internal cracks. The whole electrode plate prepared from the silicon material does not generate obvious volume expansion. The problem of violent volume expansion of the silicon material as the negative electrode material of a lithium battery in lithium extraction and insertion processes is effectively solved. The preparation method comprises the steps of dispersing the nano-silicon particles through a dispersing agent; and then carrying out snap freezing through liquid nitrogen, carrying out quick heating through microwaves and making the nano-silicon particles crack to form the silicon particles with three-dimensional dendritic cracks.

Description

technical field [0001] The invention relates to the technical field of silicon negative electrode materials, in particular to a three-dimensional dendritic silicon negative electrode material and a preparation method thereof. Background technique [0002] Due to its large theoretical capacity and low manufacturing cost, silicon materials are considered to be very likely to replace graphite materials as anode materials for next-generation lithium batteries. Especially at present, battery capacity has become a bottleneck in the development of the lithium battery industry, and silicon anode materials have attracted attention due to their large capacity. The main technical problem it faces is that the volume of the silicon material expands violently during the process of lithium ions entering and exiting, resulting in cracking and pulverization, resulting in the consequence of material pulverization. [0003] At present, the influence of volume expansion on the electrochemical ...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/134H01M4/1395B82Y30/00
CPCB82Y30/00H01M4/134H01M4/1395H01M4/386H01M2004/021H01M2004/027Y02E60/10
Inventor 陈庆陈兵王镭迪曾军堂
Owner 梧州市同创新能源材料有限公司