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Negative electrode material for lithium batteries and preparation method thereof

A negative electrode material, lithium battery technology, applied in battery electrodes, negative electrodes, secondary batteries, etc., can solve the problems of battery production and processing, hindered ion transport, structural damage of negative electrode materials, etc., to achieve excellent electrochemical performance and stable cycle. Good performance and high specific capacity

Inactive Publication Date: 2020-12-25
深圳石墨烯创新中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, silicon also has a great disadvantage. Its volume changes significantly during the lithium ion deintercalation process, and its expansion degree is extremely large, which can reach more than 300%, which brings difficulties to the processing technology. At the same time, such an obvious expansion is very easy. It leads to the destruction of the structure of the negative electrode material, the obstruction of ion transmission, and the difficulty in forming a stable solid-liquid interface film, which increases the consumption of the electrolyte, resulting in a low first battery efficiency and continuous decline in the capacity of the cycle process; in addition, its conductivity and ion diffusion performance are far away. Far lower than graphite materials, which limits the capacity and rate of the battery, and also causes troubles for the production and processing of the battery

Method used

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  • Negative electrode material for lithium batteries and preparation method thereof
  • Negative electrode material for lithium batteries and preparation method thereof
  • Negative electrode material for lithium batteries and preparation method thereof

Examples

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Effect test

Embodiment 1

[0033] 1) Use 30-40μm massive oil-based needle coke as the graphite raw material, after being crushed by a crusher, grind for 1 hour with a ball mill to obtain a particle size D 50 Needle coke with small particles of 800nm, and then subjected to high-temperature graphitization treatment in a high-temperature graphitization furnace at 2600°C for 45 minutes to obtain highly graphitized artificial graphite.

[0034] 2) Put 5 μm bulk micron silicon powder in a sand mill, use isopropanol as a dispersant, and grind for 3 hours with a vertical closed sand mill to obtain a uniform dispersion with a particle size of D 50 It is 80nm amorphous nano-silicon dispersion liquid, wherein the selected grinding medium is zirconium dioxide, the ball diameter is 0.08mm, and then dried in nitrogen atmosphere to obtain amorphous nano-silicon powder.

[0035] 3) Mix the obtained artificial graphite and amorphous nano-silicon powder according to a mass ratio of 5:1, and ball mill for 30 minutes at a ...

Embodiment 2

[0040] 1), 60-80μm massive coal-based needle coke is used as graphite raw material, after being crushed by a crusher, it is ground by a ball mill for 2 hours to obtain a particle size D 50 Needle coke with small particles of 1 μm, and then high-temperature graphitization treatment in a high-temperature graphitization furnace at 2800 ° C for 1 hour to obtain highly graphitized artificial graphite.

[0041] 2) Put 10 μm bulk micron silicon powder in a sand mill, use propanol as a dispersant, and grind for 5 hours with a horizontal non-screen sand mill to obtain a uniform dispersion with a particle size of D 50It is a 50nm amorphous nano-silicon dispersion, wherein the selected grinding medium is zirconium dioxide with a ball diameter of 0.1mm, and then dried in a nitrogen atmosphere to obtain an amorphous nano-silicon powder.

[0042] 3), the obtained artificial graphite and amorphous nano-silicon powder are mixed according to the mass ratio of 8:1, ball milled at 100 rpm / min fo...

Embodiment 3

[0047] 1) Take 100-120μm lump coal-based and oil-based needle coke, wherein the mass ratio of coal-based and oil-based needle coke is 1:1, as graphite raw material, crushed by a crusher, and then ground for 10 hours with a ball mill , to get the particle size D 50 Needle coke with small particles of 600nm, and then high-temperature graphitization treatment in a high-temperature graphitization furnace at 3100°C for 75 minutes to obtain highly graphitized artificial graphite.

[0048] 2) Put the massive micro-silica powder in a sand mill, use isopropanol as a dispersant, and grind it with a horizontal non-screen sand mill for 5 hours to obtain a uniform dispersion with a particle size of D 50 It is a 100nm amorphous nano-silicon dispersion, wherein the selected grinding medium is zirconium dioxide with a ball diameter of 0.05mm, and then dried in a nitrogen atmosphere to obtain amorphous nano-silicon powder.

[0049] 3), the obtained artificial graphite and amorphous nano-silic...

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Abstract

The invention discloses a negative electrode material for lithium batteries and a preparation method thereof. The negative electrode material comprises graphite, silicon and an adhesive, and the adhesive is asphalt. The mass ratio of the graphite to the silicon is 3: 1 to 20: 1. The method comprises the following steps of: treating graphite particles of which the particle size D50 is less than orequal to 1 [mu]m at 2600-3200 DEG C for 30-120 minutes to obtain artificial graphite; adding micron silicon powder into a dispersing agent, grinding to form uniformly dispersed nano silicon dispersionliquid, and drying the nano silicon dispersion liquid in nitrogen to obtain amorphous nano silicon powder; and mixing the artificial graphite and the amorphous nano silicon powder according to the ratio of 3: 1 to 20: 1 to form an artificial graphite nano silicon mixture. The silicon-carbon composite material prepared by the method has good small-particle-size particle dynamic performance and relatively small material expansion stress, and the silicon-carbon composite material particles are good in isotropy and dispersion uniformity, so that the silicon-carbon negative electrode material is small in embedded volume expansion and good in capacity and cycle performance.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a lithium battery negative electrode material and a preparation method of the material. Background technique [0002] With the urgent demand for the mileage of electric vehicles, the improvement of the energy density of lithium-ion batteries has attracted more and more attention. Among the anode materials for commercial lithium-ion batteries, graphite anode still occupies the mainstream market position. As we all know, even through continuous process improvement and material preparation technology, graphite anode materials with a theoretical capacity of only 372mAh / g have been difficult to meet the needs of the high energy density market. [0003] The reserves of silicon in the universe rank eighth. In the earth's crust, it is the second most abundant element, constituting 26.4% of the total mass of the earth's crust, second only to the first oxygen (49.4%). In lithiu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/362H01M4/386H01M4/583H01M4/621H01M10/0525H01M2004/027Y02E60/10
Inventor 吴耀宇秦显营罗丹李宝华
Owner 深圳石墨烯创新中心有限公司
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