A modified silicon oxide/carbon nanotube composite negative electrode material and its preparation method

A technology of carbon nanotube composite and silicon oxide, which is applied in the field of lithium-ion batteries, can solve the problems of difficult grafting, difficulty in uniform dispersion, and high surface energy, so as to improve cycle stability, improve structural stability, and inhibit volume expansion. Effect

Active Publication Date: 2022-08-05
CHENGDU GUIBAO SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The surface of silicon oxide is rich in hydroxyl groups, which makes it have a hydrophilic polar surface. It has a large surface area and high surface energy. Properties of Composite Materials
At present, the cycle performance and conductivity of electrode materials have not been significantly improved after grafting organic substances on the surface of silicon oxide.

Method used

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  • A modified silicon oxide/carbon nanotube composite negative electrode material and its preparation method
  • A modified silicon oxide/carbon nanotube composite negative electrode material and its preparation method
  • A modified silicon oxide/carbon nanotube composite negative electrode material and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Take a certain amount of deionized water in a beaker, add 3g of silane coupling agent KH-560 to the beaker, adjust the pH value to 6.5 with sodium hydroxide and acetic acid, and let it stand for 1 hour; The siliceous particles were placed in a beaker, and equal amounts of ethanol and water were added respectively, and ultrasonically dispersed for 30 minutes; the uniformly dispersed siliceous oxide and the hydrolyzed silane coupling agent KH-560 were mixed and poured into the reaction kettle, and then 0.3 g was added. The surfactant dodecyl dimethyl betaine, passed through N 2 , heated to 140°C, stirred at this temperature for 4h, suction filtered, washed with ethanol, and dried in a vacuum drying oven at 80°C to obtain modified silicon oxide.

[0036] Acidification of carbon nanotubes: Weigh 5g of carbon nanotubes (radius distribution 40-60nm, length distribution 4-6μm, purity 99%) into a 250ml round bottom flask, add 45ml concentrated HNO 3 , stir evenly, then slowly ...

Embodiment 2

[0042] Take a certain amount of deionized water in a beaker, add 1.5g of silane coupling agent KH-560 to the beaker, adjust the pH value to 6.5 with sodium hydroxide and acetic acid, and let stand for 1h; weigh 30g of 200nm particle size The silicon oxide particles were placed in a beaker, and equal amounts of ethanol and water were added respectively, and ultrasonically dispersed for 30 minutes; the uniformly dispersed silicon oxide and the hydrolyzed silane coupling agent KH-560 were mixed and poured into the reaction kettle, and then 0.3 g of the surfactant dodecyl dimethyl betaine, passed through N 2 , heated to 140°C, stirred at this temperature for 4h, suction filtered, washed with ethanol, and dried in a vacuum drying oven at 80°C to obtain modified silicon oxide.

[0043] The remaining steps are the same as in Example 1, and finally powder sample B is obtained.

[0044] The button battery was assembled with sample B as the negative active material, and the constant cu...

Embodiment 3

[0046] Take a certain amount of deionized water in a beaker, add 4.5g of silane coupling agent KH-560 to the beaker, adjust the pH value to 6.5 with sodium hydroxide and acetic acid, and let stand for 1h; weigh 30g of 200nm particle size The silicon oxide particles were placed in a beaker, and equal amounts of ethanol and water were added respectively, and ultrasonically dispersed for 30 minutes; the uniformly dispersed silicon oxide and the hydrolyzed silane coupling agent KH-560 were mixed and poured into the reaction kettle, and then 0.3 g of the surfactant dodecyl dimethyl betaine, passed through N 2 , heated to 140°C, stirred at this temperature for 4h, suction filtered, washed with ethanol, and dried in a vacuum drying oven at 80°C to obtain modified silicon oxide.

[0047] The remaining steps are the same as in Example 1, and finally powder sample C is obtained.

[0048] A button battery was assembled with sample C as the negative active material, and the constant curr...

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Abstract

The invention discloses a modified silicon oxide / carbon nanotube composite negative electrode material and a preparation method thereof. The silane coupling agent is pre-hydrolyzed, and the pre-hydrolyzed silane coupling agent, silicon oxide and surfactant are mixed in a solvent. Ultrasonic dispersion is used to obtain a dispersion liquid, and the dispersion liquid is heated and stirred in a reaction kettle under an inert atmosphere to obtain a modified silicon oxide solution. The modified silicon oxide solution is mixed with carbon nanotubes and dispersed ultrasonically, filtered, washed, and dried dry, adding into carbon source for compound coating, sintering and pulverizing to obtain modified silicon oxide / carbon nanotube composite negative electrode material. The invention modifies the surface of silicon oxide particles, adds an appropriate amount of carbon nanotubes to the negative electrode material of silicon oxide, and coats a layer of carbon source on the surface of the modified silicon oxide, thereby effectively improving the cycle performance of the negative electrode material.

Description

technical field [0001] The present invention relates to the field of lithium-ion batteries, and more specifically, the present invention relates to a modified silicon oxide / carbon nanotube composite negative electrode material and a preparation method thereof. Background technique [0002] The theoretical specific capacity of pure silicon is as high as 4200mAh.g -1 , The theoretical specific capacity of graphite is 372mAh.g-1, the difference between the two is more than 10 times. Moreover, the lithium alloying voltage of silicon is moderate, the surface is not prone to lithium precipitation reaction during charging, and the safety performance is better. Therefore, silicon-based materials have become one of the future research directions for lithium-ion battery anode materials. [0003] However, during the lithium alloying / dealloying process of silicon-based anode materials, Li + Continuously embedding / extruding, the volume changes dramatically, and the expansion rate is as...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/168C01B32/174C01B33/113H01M4/36H01M4/48H01M4/62H01M10/0525
CPCY02E60/10
Inventor 王有治张君玉黄强罗才坤贺金味
Owner CHENGDU GUIBAO SCI & TECH
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