Silicon-carbon-carbon nanotube composite negative electrode material and preparation method and application thereof

A carbon nanotube composite and negative electrode material technology, which is applied in the direction of carbon nanotubes, negative electrodes, nanocarbons, etc., can solve the problems of silicon negative electrode electrochemical activity and low volume expansion effect, so as to improve electrochemical activity and stability, realize Effect of high-volume preparation, good electrical conductivity and mechanical properties

Active Publication Date: 2021-12-31
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The present invention provides a silicon-carbon-carbon nanotube composite negative electrode material and its preparation method and application, which are used to overcome the low electrochemical activity of silicon negative electrodes in the prior art , volume expansion effect and other defects

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  • Silicon-carbon-carbon nanotube composite negative electrode material and preparation method and application thereof
  • Silicon-carbon-carbon nanotube composite negative electrode material and preparation method and application thereof

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preparation example Construction

[0020] The invention proposes a method for preparing a silicon-carbon-carbon nanotube composite negative electrode material, which is characterized in that it comprises the following steps:

[0021] S1: Add nano-silica powder into the mixed solution containing surfactant, stir and sonicate, then add resorcinol and formaldehyde solution in sequence, heat and stir, filter, wash and dry to obtain the precursor powder of phenolic-wrapped silicon; The mixed solution is composed of water, alcohol and ammonia water.

[0022] A surfactant is added to disperse the nano-silicon more uniformly, so that the coating of the phenolic resin is more uniform.

[0023] The mixed solution is composed of water, alcohol and ammonia water. Resorcinol and formaldehyde must react in this environment to form phenolic resin, which is slowly and evenly coated on the surface of nano-silicon.

[0024] Preferably, the mol ratio of described resorcinol and formaldehyde is 1:(1~2), reacts more evenly under t...

Embodiment 1

[0040] This embodiment provides a silicon-carbon-carbon nanotube composite negative electrode material, which is composed of carbon-wrapped nano-silicon and carbon nanotubes grown in situ, and has a three-dimensional network structure; the three-dimensional network structure is composed of carbon nanotubes grown in situ Nanotubes are built; carbon-wrapped nano-silicon is dispersed in the three-dimensional network structure. The particle size of the nano-silicon is 30-80nm, the diameter of the in-situ grown carbon nanotube is 10-50nm, and the length is 1-10μm.

[0041]This embodiment also provides a method for preparing the silicon-carbon-carbon nanotube composite negative electrode material described above, comprising the following steps:

[0042] (1) Add 0.50g of nano-silica powder (30-80nm in particle size) to a mixed solution containing 0.1g of dodecyltrimethylammonium bromide in 40ml of water, 360ml of ethanol and 4ml of ammonia and stir, and ultrasonically disperse evenly...

Embodiment 2

[0049] This embodiment provides a silicon-carbon-carbon nanotube composite negative electrode material, which is composed of carbon-wrapped nano-silicon and carbon nanotubes grown in situ, and has a three-dimensional network structure; the three-dimensional network structure is composed of carbon nanotubes grown in situ Nanotubes are built; carbon-wrapped nano-silicon is dispersed in the three-dimensional network structure. The particle size of the nano-silicon is 100-150nm, the diameter of the in-situ grown carbon nanotube is 50-200nm, and the length is 1-10 μm.

[0050] This embodiment also provides a method for preparing the silicon-carbon-carbon nanotube composite negative electrode material described above, comprising the following steps:

[0051] (1) Add 0.50g of nano-silica powder (100-150nm in particle size) to a mixed solution containing 0.02g of dodecyltrimethylammonium bromide in 80ml of water, 320ml of ethanol and 4ml of ammonia and stir, and ultrasonically dispers...

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Abstract

The invention discloses a silicon-carbon-carbon nanotube composite negative electrode material and a preparation method and application thereof. The preparation method comprises the steps: firstly, taking nanometer silicon powder, resorcinol, formaldehyde and the like as raw materials, performing reaction under heating and stirring to generate phenolic resin, and coating the surface of nanometer silicon with the phenolic resin; performing grinding or ball-milling mixing on the phenolic aldehyde coated silicon particles, high-boiling-point mineral oil, melamine, a cobalt salt solution and the like to form a muddy mixture, carrying out heat treatment in an inert atmosphere, carbonizing the phenolic aldehyde resin, the melamine and the high-boiling-point mineral oil at high temperature, performing heating in the inert atmosphere to reduce cobalt ions into metal cobalt, and growing carbon nanotubes in situ by carbon under the catalysis of metal cobalt; and finally, removing the nanometer metal cobalt through acid pickling to obtain a silicon-carbon-carbon nanotube composite material. The raw materials adopted in the preparation method are low in price and easy to obtain, the preparation process is simple, and large-scale preparation can be achieved. When the negative electrode material is used as a lithium ion battery negative electrode material, the electrochemical activity and the cycling stability can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a silicon-carbon-carbon nanotube composite negative electrode material and a preparation method and application thereof. Background technique [0002] As the anode material of lithium-ion batteries, silicon has the highest theoretical specific capacity of 4200mAh / g, and silicon has a low intercalation potential (<0.5V vs Li) and abundant reserves, so it is considered to be the most ideal anode material for next-generation lithium-ion batteries. However, silicon itself has extremely low electronic conductivity and poor electrochemical activity. Moreover, the volume expansion of the silicon negative electrode after lithium intercalation can reach 300%, and the huge volume expansion effect will generate greater stress, resulting in pulverization of the silicon negative electrode material, poor contact between active materials, and detachment from the current collector, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/16C01B32/15C01B33/02B82Y30/00H01M4/587H01M4/38H01M4/62H01M10/0525
CPCC01B32/16C01B32/15C01B33/02B82Y30/00H01M4/587H01M4/386H01M4/625H01M10/0525H01M2004/027C01B2202/34C01B2202/36C01B2202/22Y02E60/10
Inventor 刘双科许静郝紫勋李宇杰孙巍巍郑春满
Owner NAT UNIV OF DEFENSE TECH
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