Lithium ion battery silicon carbon composite negative electrode material and preparation method thereof

A lithium-ion battery, silicon-carbon composite technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as limited capacity, low high-rate charge and discharge capacity, and poor low-temperature performance, to solve safety problems and avoid environmental problems. and safety and hygiene issues, the effect of high specific surface energy

Inactive Publication Date: 2014-03-05
南京毕汉特威高分子材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, as many new applications of lithium batteries, carbon materials such as graphite have gradually exposed some disadvantages: limited capacity, low high-rate charge-discharge capability, poor low-temperature performance, etc.
However, it is difficult to find a common organic dispersion medium to form a uniform dispersion of silicon, graphite and asphalt by using asphalt as a binder to prepare the compound. The silicon, graphite and carbon composite prepared after drying, firing and carbonization It is difficult to achieve a uniform and controllable structure in the structure of the material, and the reproducibility of the material performance is poor
During the charge and discharge process of the electrode prepared with this material, silicon is easy to fall off, resulting in capacity decay or battery activity reduction
After the button battery made of this material circulates for 20 weeks, the discharge capacity retention rate is about 90%, and there is no longer cycle data in its embodiment

Method used

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  • Lithium ion battery silicon carbon composite negative electrode material and preparation method thereof
  • Lithium ion battery silicon carbon composite negative electrode material and preparation method thereof
  • Lithium ion battery silicon carbon composite negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Using 80 parts by weight of styrene and 20 parts by weight of polyethylene glycol dimethacrylate as the grinding solvent, in the presence of hydroquinone accounting for 0.01% of the grinding solvent, utilize the grinding machine to grind silicon, and in the grinding liquid of silicon Inside, add fumaric acid, control the pH value of the silicon grinding dispersion below 5.5, the content of silicon is 6% of the grinding solvent, and the average particle size of silicon particles in the silicon grinding liquid is 100nm.

[0052] The silicon dispersion is transferred to a container with a stirring inert gas protection, and the 3-methacryloxypropylmethyldiethoxysilane of the grinding solvent 10wt% is added to the ball-milled silicon dispersion, Stir at a speed of 1200 r / min for 60 min to obtain a hydrophobized silicon dispersion. Continue to add conductive carbon black of grinding solvent 1wt%, dibenzoyl peroxide of grinding solvent 5wt%, n-dodecyl mercaptan of grinding sol...

Embodiment 2

[0062]Use 80 parts by weight of styrene and 20 parts by weight of polyethylene glycol dimethacrylate as the grinding solvent, in the presence of 0.01% hydroquinone in the grinding solvent, use a grinding machine to grind silicon, and in the grinding liquid of silicon , add fumaric acid, control the pH value of the silicon grinding dispersion below 5.5, the content of silicon is 6% of the grinding solvent, and the average particle size of silicon particles in the silicon grinding liquid is 100nm.

[0063] The silicon dispersion is transferred to a container with a stirring inert gas protection, and the 3-methacryloxypropylmethyldiethoxysilane of the grinding solvent 10wt% is added to the ball-milled silicon dispersion, Stir at a speed of 1200 r / min for 60 min to obtain a hydrophobized silicon dispersion. Continue to add conductive carbon black of grinding solvent 1wt%, dibenzoyl peroxide of grinding solvent 5wt%, n-dodecyl mercaptan of grinding solvent 0.5wt%, stir with 1200r / m...

Embodiment 3

[0073] Use 80 parts by weight of styrene and 20 parts by weight of polyethylene glycol dimethacrylate as the grinding solvent, in the presence of a small amount of hydroquinone accounting for 0.01% of the grinding solvent, utilize a grinder to grind silicon, and in the grinding of silicon Add fumaric acid to the liquid to control the pH value of the silicon grinding dispersion below 5.5, and the silicon content is 6% of the grinding solvent. The average particle size of the silicon particles in the silicon polishing liquid is 100 nm.

[0074] The silicon dispersion is transferred to a container with a stirring inert gas protection, and the 3-methacryloxypropylmethyldiethoxysilane of the grinding solvent 10wt% is added to the ball-milled silicon dispersion, Stir at a speed of 1200 r / min for 60 min to obtain a hydrophobized silicon dispersion. Continue to add 5wt% dibenzoyl peroxide as a grinding solvent and 0.5wt% n-dodecylmercaptan as a grinding solvent to form an organic mon...

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Abstract

The invention relates to a lithium ion battery silicon carbon composite negative electrode material and a preparation method thereof. The method comprises the following steps: fixing nanometer silicon in a macromolecule microsphere by preparing a micromolecule / silicon / (carbon black) composite microsphere emulsion, then compounding the microsphere emulsion and graphite, asphalt and the like, and carrying out thermal treatment, thereby obtaining the lithium ion battery silicon carbon composite negative electrode material. The macromolecule microsphere in the material has the effects that the macromolecule microsphere not only is a fixer for stabilizing and inlaying the nanometer silicon, but also is a bonding agent between the nanometer silicon and the graphite after being subjected to high-temperature sintering treatment. The method solves the problems that the nanometer silicon is high in specific surface energy and easy to agglomerate because of small granularity. The lithium ion battery silicon carbon composite negative electrode material prepared by the preparation method disclosed by the invention achieves the synergistic effect of graphite, high-dispersion silicon and carbon, and presents an excellent battery performance.

Description

technical field [0001] The invention belongs to a lithium-ion battery silicon-carbon composite negative electrode material and a preparation method thereof, and relates to a composite technology and a preparation method of nano-silicon / polymer microspheres and graphite. Background technique [0002] At present, the widely used negative electrode of lithium ion battery is mainly graphite. The theoretical capacity of graphite is 372mAh / g. It has good platform performance and low potential during charge and discharge, so it is an ideal negative electrode material. It has had very good results in past applications. However, as many new applications of lithium batteries, carbon materials such as graphite have gradually exposed some disadvantages: limited capacity, low high-rate charge-discharge capability, and poor low-temperature performance. In particular, the performance of high-current charging is not good, because the voltage platform of graphite is low, and the potential d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/583H01M4/62
CPCH01M4/364H01M4/386H01M4/587H01M4/622H01M10/0525Y02E60/10
Inventor 刘祥
Owner 南京毕汉特威高分子材料有限公司
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