Preparation method of Si / graphite / C composite material for lithium ion battery

A technology for lithium-ion batteries and composite materials, which is applied in the field of preparation of Si/graphite/C composite materials for lithium-ion batteries, can solve problems such as the dispersion of silicon materials, the difficulty in realizing industrial production, and the complexity of the preparation process. Good electrochemical cycle performance, low cost, and simple operation

Inactive Publication Date: 2015-03-25
CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the preparation process of chemical/thermal vapor deposition is complicated, the yield is low, and it is difficult to realize industrial production.
The high temp

Method used

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  • Preparation method of Si / graphite / C composite material for lithium ion battery
  • Preparation method of Si / graphite / C composite material for lithium ion battery
  • Preparation method of Si / graphite / C composite material for lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The main raw materials used in this embodiment: nano-silicon particles, carbon negative electrode material (AGP-8), sucrose, absolute ethanol, etc.

[0038] (1) Accurately weigh 4.644g of nano-scale silicon particles, 7.12g of sucrose, and add them in turn to a 2000ml beaker, then add 1000ml of absolute ethanol, stir with a glass rod and add an ultrafine mill to disperse for 1 hour to obtain a nano-silicon material slurry;

[0039] (2) Accurately weigh 88.236g of carbon negative electrode material (AGP-8), add it to a 2000ml beaker, then add 250ml of absolute ethanol, stir it with a glass rod and add it to the silicon material slurry dispersed uniformly in step (1), Secondary grinding for 2 hours in ultra-fine grinding equipment to obtain composite emulsion;

[0040] (3) spray drying the composite emulsion obtained in step (2) to obtain the precursor powder;

[0041] (4) Put the precursor powder obtained in step (3) into a graphite crucible, put it into a well-type res...

Embodiment 2

[0045] The main raw materials used in this embodiment: nano-silicon particles, carbon negative electrode material (AGP-8), nano-carbon fiber (VGCF), sucrose, absolute ethanol, etc.

[0046] (1) Accurately weigh 4.644g of nano-scale silicon particles, 7.12g of sucrose, and add them in turn to a 2000ml beaker, then add 1000ml of absolute ethanol, stir with a glass rod and add an ultrafine mill to disperse for 1 hour to obtain a nano-silicon material slurry;

[0047] (2) Accurately weigh 83.824g of carbon anode material (AGP-8), 4.412g of nano-carbon fiber (VGCF), add it to a 2000ml beaker, then add 250ml of absolute ethanol, stir with a glass rod, and then add them together to step (1) In the uniformly dispersed silicon material slurry, grind for 2 hours in the ultra-fine grinding equipment to obtain a composite emulsion;

[0048] (3) spray drying the composite emulsion obtained in step (2) to obtain the precursor powder;

[0049] (4) Put the precursor powder obtained in step (...

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Abstract

A preparation method of a Si / graphite / C composite material for lithium ion batteries includes the steps of: loading a nano silicon material on a carbon anode material base, and pyrolyzing organic or inorganic carbon by a high temperature pyrolysis method to coat the nano silicon material, so as to obtain the required Si / graphite / C composite material. The content of the nano silicon material is 1-69 wt.%, the content of the carbon anode material is 30-98 wt.%, and the content of the amorphous carbon layer coated with the nano silicon material is 1-10 wt.%. The silicon material with high dispersion structure loaded on the carbon material can effectively overcome the self aggregation of the nano material, and give full play to the characteristics of the nano material; and the carbon coated nano silicon material can improve the conductivity of the silicon material, promote the formation of a stable SEI film on the on surface of the silicon material, buffer the volume expansion of the silicon material, enhance the bonding strength of the silicon material with the carbon base, and improve the conductivity of the whole silicon carbon composite material. The preparation method is low in cost, simple for operation and applicable to large-scale industrialization production.

Description

technical field [0001] The invention relates to a preparation method of a Si / graphite / C composite material for a lithium ion battery, belonging to the field of lithium ion battery negative electrode materials. Background technique [0002] In recent years, silicon-based materials have attracted much attention due to their huge lithium storage capacity (theoretical specific capacity 4200mAh / g), a slightly higher discharge platform than carbon materials, and abundant reserves in the earth's crust. Potential secondary lithium-ion battery anode materials. However, so far, lithium-ion batteries using silicon-based materials as negative electrodes have not entered the commercial market. The change will cause the destruction of the electrode structure, resulting in a sharp decline in the cycle performance of the electrode. [0003] Studies have confirmed that the use of nano-silicon materials can significantly improve the cycle performance of silicon-based materials. However, na...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/62B82Y30/00
CPCH01M4/386H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 杨娟玉李涛卢世刚
Owner CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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