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Silicon-carbon negative electrode material and preparation method thereof

A technology of negative electrode material and silicon carbon, which is applied in the field of silicon carbon negative electrode material and its preparation, can solve the problems of complex process, high energy consumption and less than 80% initial efficiency.

Active Publication Date: 2017-04-26
深圳市金润能源材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the material prepared by this method improves the battery cycle, the reversible capacity is 650mAh / g, and the first-time efficiency is less than 80%.
This method fills the gaps in the particles by impregnating them with liquid phases such as pitch or resin, and prepares a material with a dense structure and high capacity. However, multiple sintering processes require complex procedures and high energy consumption.

Method used

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  • Silicon-carbon negative electrode material and preparation method thereof
  • Silicon-carbon negative electrode material and preparation method thereof
  • Silicon-carbon negative electrode material and preparation method thereof

Examples

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preparation example Construction

[0027] The preparation method of the silicon carbon negative electrode material provided by the invention comprises the following steps:

[0028] First, mix nano-silicon, flat graphite, binder and dispersant in a solvent to obtain a uniformly dispersed suspension.

[0029] Among them, the average particle diameter of nano-silicon D50≤100nm, D99≤200nm. In some embodiments, the average particle diameter D50 of nano-silicon is 50-100 nm, preferably 60-80 nm.

[0030] Flat graphite can be natural graphite or artificial graphite. The average particle size of the flat graphite is 1≤D50≤6μm. The tabular shape refers to particles having a major axis and a minor axis, that is, the shape is not ideally spherical. For example, such particles may include at least some of scale-like particles, flake-like particles, and lumpy particles.

[0031] The binder can be one or a combination of at least two of rosin-modified alkyd resin, phenolic resin, urea-formaldehyde resin and polyvinyl but...

Embodiment 1

[0050] The first step: Add 5g of polyvinylpyrrolidone into isopropanol, stir to dissolve, add 12.8g of phenolic resin, continue to stir and dissolve, then add 150g of silicon powder with an average particle size of 50nm, stir at high speed for 1h, and finally add an average particle size of 5.2 500 g of natural flake graphite of μm was stirred again at a high speed for 1 h to prepare a suspension with a solid content of 20%.

[0051] Step 2: Adjust the inlet temperature of the spray dryer to 220°C, the outlet temperature to 110°C, the rotation speed of the atomizer to 18000r / min, and the feed rate to 30mL / min, to spray dry the suspension and collect 652.8g of powder.

[0052] Step 3: Add the powder into the kneading pot heated to 160°C and knead for 0.5h, then add 218g of melted and softened asphalt, and continue kneading until the volatile content is 12%.

[0053] Step 4: Transfer the kneaded powder to a soft steel-coated mold for hot isostatic pressing, with a controlled pre...

Embodiment 2

[0056] Step 1: Add 4g of cetyltrimethylammonium bromide to ethanol, stir to dissolve, add 15.5g of polyvinyl butyral, continue to stir and dissolve at 600r / min, and then add silicon powder with an average particle size of 80nm 150g, stirred at 3000r / min for 1h, and finally added 350g of natural graphite with an average particle size of 2.4μm while stirring, and continued to stir at 3000r / min for 1h to prepare a suspension with a solid content of 25%.

[0057] Step 2: Adjust the inlet temperature of the spray dryer to 180°C, the outlet temperature to 90°C, the rotation speed of the atomizer to 20,000r / min, and the feed rate to 10mL / min, spray-dry the suspension, and collect 501.2g of powder.

[0058] Step 3: Add the powder into a kneading pot heated to 160°C and knead for 1 hour, then add 255 g of melted and softened asphalt, and continue kneading until the volatile content reaches 13%.

[0059] Step 4: Transfer the kneaded powder to a soft steel-coated mold for hot isostatic p...

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Abstract

The invention relates to a silicon-carbon negative electrode material and a preparation method thereof. The silicon-carbon negative electrode material comprises flat graphite, nano silicon and a pyrolytic carbon layer, wherein the nano silicon is covered and loaded on the surface of the flat graphite to form skeleton particles, the pyrolytic carbon layer covers outer surfaces of the skeleton particles and is filled in the gaps among the skeleton particles and among the surfaces of the flat graphite in the skeleton particles. The silicon-carbon negative electrode material mentioned above has the advantages of high conductivity, low expansion, high capacity, long cycle life, simple preparation method and low energy consumption.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to a silicon carbon negative electrode material and a preparation method thereof. Background technique [0002] Compared with the traditional graphite negative electrode, silicon has an ultra-high theoretical specific capacity (4200mAh / g) and a lower delithiation potential (<0.5V), and the voltage platform of silicon is slightly higher than that of graphite, which is difficult to cause surface decomposition during charging. Lithium has better safety performance. Silicon has become one of the potential choices for upgrading carbon-based anodes of lithium-ion batteries. Based on the current demand for high-energy-density batteries for portable electronic consumer products and pure electric vehicles, silicon materials with high capacity have received extensive attention. However, silicon also has disadvantages as an anode material for lithium-i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M10/0525
CPCH01M4/362H01M4/386H01M4/587H01M10/0525Y02E60/10
Inventor 吴云胜蒋勇明吴泽轶胡晓东何晓云石九菊曾勇
Owner 深圳市金润能源材料有限公司
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