Graphene-silicon-based composite negative electrode material for lithium ion battery and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of material conductivity, danger, and difficult material scale preparation, etc., to improve conductivity, ensure continuous performance, Effect of improving structural stability and cycle performance

Active Publication Date: 2019-06-11
SHAANXI COAL & CHEM TECH INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Concentrated sulfuric acid and potassium permanganate are used to expand the graphite of this material. There is a certain risk in the experiment, and it is difficult to realize the large-scale preparation of the material; the dispersion of silicon and graphite adopt

Method used

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  • Graphene-silicon-based composite negative electrode material for lithium ion battery and preparation method thereof

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preparation example Construction

[0025] The preparation method of the graphene-silicon-based composite negative electrode material for lithium ion batteries of the present invention comprises the following steps:

[0026] Step 1, adding nano-silicon, graphene, and graphite in a certain proportion to a ball-milling jar for ball-milling for a certain period of time to obtain a uniformly mixed material 1;

[0027] Step 2, add the material 1 and the organic carbon source into the organic solvent, stir and mix, and disperse evenly, then place in a water bath and heat to 70-90°C, heat and stir until the organic solvent evaporates to dryness, and vacuum dry at 60-100°C Overnight, material 2 was obtained.

[0028] In step 3, the obtained material 2 is extruded and granulated by a tablet machine, and then heated to 150-300 °C to maintain a constant temperature, and after the organic carbon source is completely melted, the temperature is raised to 700-950 °C for high-temperature carbonization to obtain organic cracked ...

Embodiment 1

[0037] A method for preparing a graphene-silicon-based composite negative electrode material of the present invention, comprising the following steps:

[0038] Nano-silicon, graphene, and artificial graphite with a particle size of less than 300 nm and a particle size of about 5 μm were added to the ball milling tank for 300 min in a certain proportion, wherein the ball-to-material ratio was 10:1, the rotational speed was 500 rpm, and the solid content was 50%. Then stir and mix with pitch in ethanol for 2 hours (wherein the residual carbon ratio of pitch is 41%, and the mass ratio of nano-silicon:graphene:graphite:pitch cracked carbon is 45.5:4.5:25:25), and heated to 70 in a water bath It was heated and stirred at ℃ until the ethanol was evaporated to dryness, and then vacuum-dried at 60 ℃ overnight. The mixture was extruded and pelletized with a tablet machine, heated to 200 °C to maintain a constant temperature for 2 hours, and the heating rate was 5 °C / min. After the asph...

Embodiment 2

[0041] A method for preparing a graphene-silicon-based composite negative electrode material of the present invention, comprising the following steps:

[0042]The nano-silicon, graphene, and artificial graphite with a particle size of less than 300 nm and a particle size of about 5 μm were added to the ball mill in a certain proportion for ball milling for 180 minutes, wherein the ball-to-material ratio was 6:1, the rotational speed was 500 rpm, and the solid content was 50%. Then stir and mix with pitch in ethanol for 2 hours (wherein the residual carbon ratio of pitch is 41%, and the mass ratio of nano-silicon:graphene:graphite:pitch cracked carbon is 45.5:4.5:25:25), and heated to 70 in a water bath It was heated and stirred at ℃ until the ethanol was evaporated to dryness, and then vacuum-dried at 60 ℃ overnight. The mixture was extruded and pelletized with a tablet machine, heated to 200 °C to maintain a constant temperature for 2 hours, and the heating rate was 5 °C / min....

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Abstract

The invention provides a graphene-silicon-based composite negative electrode material for a lithium ion battery and a preparation method thereof. The preparation method comprises the following steps:step 1, ball milling nano silicon, graphene and graphite to obtain a uniformly-mixed material 1; step 2, adding the material 1 and organic matter carbon source into an organic solvent, stirring, uniformly dispersing, heating to 70 to 90 DEG C, stirring until the organic solvent is dried, drying, and obtaining a material 2; and step 3, granulating the obtained material 2, heating to 150 to 300 DEGC, keeping the temperature constant, after the organic matter carbon source is completely molten, heating to 700 to 950 DEG C, carbonizing at a high temperature, and obtaining an organic matter pyrolytic carbon-coated graphene-silicon-based composite negative electrode material. The graphene-silicon-based composite negative electrode material is prepared from graphene, and the graphne is good in mechanical performance and flexibility, so that the deformation stress of silicon can be alleviated, and the excellent conductivity and heat conductivity can accelerate the electron transfer and heat dissipation.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a graphene-silicon-based composite negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries entered practical applications in the 1980s. Because of their high energy density, long life, and wide operating temperature range, they have been widely used in the market of portable electronic products, such as cameras, power tools, computers, mobile phones, etc. . With the continuous development of society and the continuous rise of the electric vehicle industry, it is particularly urgent to develop lithium-ion batteries with high energy density. [0003] At present, the theoretical specific capacity of graphite-based materials used in the negative electrode of commercial lithium-ion batteries is only 372 mAh / g, and its low capacity limits the further improvement of energy dens...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/62
CPCY02E60/10
Inventor 白杨芝田占元张大鹏曹新龙曹国林邵乐
Owner SHAANXI COAL & CHEM TECH INST
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