Preparation method for coated silicon/carbon/graphite composite negative electrode material

A technology of negative electrode material and graphite, applied in the field of preparation of silicon/carbon/graphite composite negative electrode material, achieves the effects of high initial charge and discharge efficiency, high initial discharge capacity and stable structure

Active Publication Date: 2016-10-12
INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] CN102394287A obtains a silicon-carbon composite material by preparing precursor silicon powder, chemical vapor deposition, liquid-phase coating and roasting, crushing, and mixing, and the silicon-carbon composite material is deposited on the surface of nano silicon powder particles by carbon nanotubes and / or carbon nanofibers And / or embedded between nano-silicon powder particles to form a core, the surface of the core is coated with a carbon layer, the reversible specific capacity of the silicon-carbon composite negative electrode material is greater than 500mAh / g, the first cycle Coulombic efficiency is greater than 80%, and the discharge capacity is high Compared with commercial graphite anode materials, there is still room for improvement in its first charge and discharge efficiency

Method used

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  • Preparation method for coated silicon/carbon/graphite composite negative electrode material
  • Preparation method for coated silicon/carbon/graphite composite negative electrode material

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Effect test

Embodiment 1

[0018] Will D 50 Micron-sized silicon powder of 1.5 µm and citric acid of 1% by mass of the silicon powder are mixed, added to deionized water, and ball-milled in a high-energy ball mill for 4 hours to obtain a uniformly dispersed slurry; the mass ratio of silicon powder, artificial graphite and glucose is 1 :3:1, resin arabic accounted for 4% of the mass of the mixture, the D 50 Mix 8µm artificial graphite, glucose and Arabic resin, add it into deionized water, stir well, then mix with the aforementioned silicon slurry, continue stirring evenly; at the inlet air temperature of 350°C, the outlet air temperature of 150°C, the speed of the feed pump 25rpm, spray pressure 0.25MPa, spray dry the above mixed slurry to obtain the silicon / carbon / graphite precursor; place the silicon / carbon / graphite precursor in a tube furnace, under the protection of nitrogen, at a rate of 5°C / min Raise the temperature to 600°C, keep it warm for 6 hours, cool down to 300°C at a rate of 5°C / min, and ...

Embodiment 2

[0021] Will D 50 The micron silicon powder of 80nm and the citric acid of silicon powder quality 1% are mixed, add deionized water, ball mill 4h in the high-energy ball mill, obtain the evenly dispersed slurry; According to silicon powder, artificial graphite and glucose mass ratio is 1: 3:0.8, resin arabic accounted for 4% of the mass of the mixture, the D 50 Mix 8µm artificial graphite, glucose and Arabic resin, add it into deionized water, stir well, then mix with the aforementioned silicon slurry, continue stirring evenly; at the inlet air temperature of 350°C, the outlet air temperature of 150°C, the speed of the feed pump 25rpm, spray pressure 0.25MPa, spray dry the above mixed slurry to obtain the silicon / carbon / graphite precursor; place the silicon / carbon / graphite precursor in a tube furnace, under the protection of nitrogen, at a rate of 5°C / min Heat up to 1100°C, hold for 3 hours, cool down to 300°C at a rate of 5°C / min, and cool to room temperature with the furnace...

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Abstract

Disclosed is a preparation method for a coated silicon/carbon/graphite composite negative electrode material. The preparation method comprises the steps of adding silicon powder and a dispersing agent into deionized water, wherein the D50 of the silicon powder is 1.2-1.5[mu]m; performing ball milling for 2-10h, and screening 100-mesh slurry; adding graphite, an organic carbon source and a binder into the deionized water, stirring and mixing uniformly, and enabling the obtained mixture to be mixed with the slurry, and continuously to stir the mixture uniformly; performing spray drying to obtain a silicon/carbon/graphite precursor; performing thermolysis on the silicon/carbon/graphite precursor under the protection of nitrogen or argon; and after screening, mixing the precursor with a coating agent, and performing ball milling for 1-3h, and carrying out heat treatment at a temperature of 400-600 DEG C under the protection of nitrogen or argon for 2-6h to obtain the coated silicon/carbon/graphite composite negative electrode material. According to the preparation method for the coated silicon/carbon/graphite composite negative electrode material provided by the invention, the initial charge-discharge efficiency of the material can be improved.

Description

technical field [0001] The invention relates to a method for preparing a silicon / carbon / graphite composite negative electrode material, in particular to a method for preparing a coated silicon / carbon / graphite composite negative electrode material which improves the first charge and discharge efficiency of the silicon-carbon composite negative electrode material. Background technique [0002] In recent years, among many new battery anode materials, the theoretical discharge specific capacity of silicon-based materials can reach 4200mAh / g, which is much higher than the actual discharge specific capacity (372mAh / g) of various graphite anode materials for commercial lithium-ion power batteries. . At the same time, the lithium intercalation potential of silicon is relatively high. When discharged at a large rate, lithium dendrites will not be formed, and it has high safety. It has become a very potential anode material for the next generation of lithium-ion batteries. Therefore, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/587H01M4/625H01M10/0525Y02E60/10
Inventor 王英肖方明唐仁衡孙泰
Owner INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI
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