Silicon-based composite material, preparation method thereof, negative electrode and lithium ion battery

A silicon-based composite material and powder technology, applied in the direction of negative electrodes, battery electrodes, secondary batteries, etc., can solve problems such as poor cycle performance, uncontrollable nano-silicon quantity, and increased production costs, so as to improve electrical conductivity and inhibit Effect of volume expansion and improvement of electrical conductivity

Active Publication Date: 2021-10-01
新疆硅基新材料创新中心有限公司
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  • Abstract
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  • Application Information

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Problems solved by technology

Although the silicon oxide composite material has a relatively high specific capacity (>1600mAh / g) and a high initial Coulombic efficiency (>80%), the method introduces a vapor deposition method for modification, and large-scale preparation in production will be difficult. The production cost is greatly increased, and the amount of nano-silicon deposited in the vapor phase cannot be controlled, which will cause a huge volume expansion during use due to the excessive amount of nano-silicon, resulting in poor cycle performance

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  • Silicon-based composite material, preparation method thereof, negative electrode and lithium ion battery
  • Silicon-based composite material, preparation method thereof, negative electrode and lithium ion battery
  • Silicon-based composite material, preparation method thereof, negative electrode and lithium ion battery

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preparation example Construction

[0050] In the prior art, the negative electrode materials of lithium ion batteries have problems such as poor electrical conductivity, large volume expansion effect, and poor cycle performance. Therefore the present invention provides a kind of preparation method of silicon-based negative electrode material of lithium ion battery, comprising,

[0051] S1, performing the first carbon coating treatment on silicon and silicon oxide to obtain the first powder;

[0052] S2, subjecting the first powder to a second carbon coating treatment to obtain a second powder;

[0053] S3, sieving and demagnetizing the second powder to obtain a silicon-based composite material.

[0054] Correspondingly, the present invention also provides a silicon-based composite material prepared according to the above method.

[0055] Correspondingly, the present invention also provides a negative electrode of a lithium-ion battery, comprising the above-mentioned silicon-based composite material.

[0056]...

Embodiment 1

[0058] This embodiment discloses a method for preparing a silicon-based composite material, including:

[0059] S1, performing the first carbon coating treatment on silicon powder and silicon oxide powder to obtain a first powder.

[0060] Specifically, first, silicon powder particles, silicon oxide powder particles, a first carbon source, and a first solvent are wet-grinded to obtain a first mixed liquid. Among them, the size of silicon powder particles is preferably 1-50 nm, and the size of silicon oxide powder particles is preferably 0.5-20 μm; the mass ratio of silicon powder to silicon oxide powder is preferably (1-20): 100; the powder of silicon oxide is preferably silicon oxide SiOx (wherein, x=0.8~1); the first carbon source can be citric acid, sucrose, glucose, maltose, pitch, phenolic resin, epoxy resin, polypyrrole, One or more polyanilines, the quality of the first carbon source is 5% to 15% of the powder mass of silicon oxide; the first solvent can be ethanol, isop...

Embodiment 2

[0073] This embodiment discloses a method for preparing a silicon-based composite material, including:

[0074] (1) Take 10g of silicon powder with D50 (also known as median diameter or median diameter, which refers to the corresponding particle diameter value when the cumulative distribution percentage reaches 50%) of 30nm, and 1000g of silicon oxide with D50 of 10μm, and place them in 3L In the absolute ethanol solution, add 46g of asphalt, and then place it in a sand mill with a speed of 3000rpm / min for grinding for 3 hours, wherein the grinding medium is imported high-purity grinding zirconium beads with a diameter of 1.0mm; after grinding, grind The final material was subjected to vacuum rotary evaporation treatment, and the obtained solid material was placed in a carbonization furnace filled with argon, and treated at 600° C. for 2 hours to obtain the first powder.

[0075] (2) Get above-mentioned first powder material, be placed in 3L dehydrated ethanol solution, simult...

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Abstract

The invention discloses a preparation method of a silicon-based composite material. The preparation method comprises the following steps: S1, carrying out primary carbon coating treatment on silicon powder and silicon oxide powder to obtain first powder; S2, performing secondary carbon coating treatment on the first powder to obtain second powder; and S3, screening and demagnetizing the second powder to obtain the silicon-based composite material. The invention also discloses the silicon-based composite material prepared by the method, a lithium ion battery negative electrode containing the silicon-based composite material and a lithium ion battery containing the negative electrode. The lithium ion battery has the advantages of high first coulombic efficiency, small volume expansion and the like.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery negative electrode materials, and in particular relates to a silicon-based composite material, a preparation method, a negative electrode and a lithium-ion battery. Background technique [0002] With the rapid development of the new energy industry, the market has a strong demand for lithium-ion batteries with high battery energy density. Elemental silicon has a theoretical capacity of 4200mAh / g, and silicon oxide has a theoretical capacity of 2043mAh / g, so silicon-based negative electrode materials are attracting more and more attention. [0003] However, silicon anode materials will experience volume expansion of 100% to 300% in the process of lithium intercalation and deintercalation, and the huge volume change will cause the active material to fall off from the current collector, resulting in a sharp decline in cycle performance. The silicon oxide negative electrode material, alth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525
CPCH01M4/364H01M4/386H01M4/625H01M4/587H01M10/0525H01M2004/027Y02E60/10
Inventor 李硕范协诚袁芳伟石佳光胡保平刘朗
Owner 新疆硅基新材料创新中心有限公司
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