Preparation method of high-performance silicon carbon-graphite negative material

A graphite anode, high-performance technology, used in nanotechnology for materials and surface science, battery electrodes, electrical components, etc., can solve the problems of high expansion rate, poor cycle performance and rate performance, and reduce expansion, discharge The effect of stable voltage and good buffering effect

Inactive Publication Date: 2019-05-10
HUNAN SHINZOOM TECH
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Si / C anode materials prepared by traditional methods cannot effectively solve the problems of high expansion rate, poor cycle performance and rate performance.

Method used

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  • Preparation method of high-performance silicon carbon-graphite negative material
  • Preparation method of high-performance silicon carbon-graphite negative material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] ① Disperse silicon powder with a particle size of 5 μm and butyl titanate (1% butyl titanate mass fraction) in ethanol to prepare a slurry with a solid content of 30%, and pulverize it in a ball mill for 5 hours to obtain granules Nano-slurry with a diameter of 100nm; ② Disperse the nano-slurry and PVDF (the mass percentage of PVDF is 2%) in ethanol to prepare a suspension A with a solid content of 30%, and use a vacuum dryer with a condensing system in the Vacuum-dry the suspension A at a temperature of 90°C, and the vacuum negative pressure does not exceed 0.1Mpa to obtain a silicon-carbon precursor; ③ Add graphite, polymer compound, and silicon-carbon precursor to the Carry out carbonization treatment in an electric heating high-speed modification mixer, raise the temperature to 600°C under nitrogen protection, the heating rate is 1°C / min, keep it warm for 6 hours, then cool to room temperature, and sieve out the material with a median particle size of 5 μm , to obta...

Embodiment 2

[0030] ① Disperse silicon powder with a particle size of 10 μm and ethyl titanate (the mass fraction of ethyl titanate is 3%) in glycerol, prepare a slurry with a solid content of 20%, and pulverize it in a ball mill for 20 hours. Obtain a nano-slurry with a particle size of 108nm; ② disperse the nano-slurry and polyurethane (the mass percentage of polyurethane is 4%) in glycerol, and prepare a suspension with a solid content of 25%. Liquid A is vacuum-dried at an inlet temperature of 250°C and an outlet temperature of 110°C to obtain a silicon-carbon precursor; ③ Add graphite, polymer compounds, and the obtained silicon-carbon precursor to electric heating at a mass ratio of 45:1:4 Carry out carbonization treatment in a type high-speed modified mixer, heat up to 700°C under nitrogen protection, the heating rate is 5°C / min, keep warm for 3 hours, then cool to room temperature, sieve out the material with a median particle size of 13μm, and obtain The silicon-carbon composite n...

Embodiment 3

[0032]Disperse silicon powder with a particle size of 4 μm and titanium isopropoxide (the mass fraction of titanium isopropoxide is 5%) in ethanol, prepare a slurry with a solid content of 10%, and pulverize it in a ball mill for 15 hours to obtain the particle size 145nm nano-slurry; ② Disperse the nano-slurry and polyvinyl chloride resin (the mass percentage of polyvinyl chloride resin is 7%) in ethanol to prepare a suspension A with a solid content of 25%. Vacuum drying under the conditions to obtain the silicon carbon precursor; ③ According to the mass ratio of 87:2:11, graphite, polymer compound and the obtained silicon carbon precursor were added to the electric heating type high-speed modification mixer for carbonization treatment, and the Under protection, the temperature was raised to 900°C at a heating rate of 10°C / min, kept for 4 hours, then cooled to room temperature, and the material with a median particle size of 30 μm was screened out to obtain the silicon-carbon...

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Abstract

The invention provides a preparation method of a high-performance silicon carbon-graphite negative material. The preparation method comprises the following steps: taking silicon powder as a raw material, smashing titanium-containing compound and the silicon powder through ball-milling to obtain nanometer silicon slurry; mixing the nanometer silicon slurry and high-molecular compound and then performing vacuum-drying to obtain the silicon carbon precursor; performing dynamic carbonization and screening on the silicon carbon precursor, the high-molecular compound and the graphite, thereby obtaining the silicon carbon-graphite composite material. The problem that the conventional Si/C is bad in cycle performance and easy to expand is solved, and the cycle stabilization performance is improved.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a method for preparing a high-performance silicon carbon-graphite negative electrode material. Background technique [0002] Lithium-ion batteries are favored for their excellent properties such as high capacity, high voltage, high cycle stability, high energy density and no pollution to the environment. As a negative electrode material, silicon has the advantage of high specific capacity (3675mAh / g), but its significant disadvantage is that the volume expands after lithium ions are intercalated (up to 300%), and the mechanical force generated will gradually pulverize the material and cause the structure to collapse. Ultimately, the cycle performance of the battery is greatly reduced. In order to solve the problems existing in the application of silicon anode materials, researchers currently mainly use silicon nano-siliconization an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCY02E60/10
Inventor 唐唯皮涛王志勇肖志平黎建锋邵浩明
Owner HUNAN SHINZOOM TECH
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