Carbon-silicon composite material with spherical nucleocapsid, and its preparing method and use

A composite material, core-shell structure technology, applied in structural parts, electrical components, battery electrodes, etc., can solve the problems of low reversible capacity, low Coulombic efficiency, and high delithiation potential

Active Publication Date: 2007-01-10
LIYANG TIANMU PILOT BATTERY MATERIAL TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of existing negative electrode active materials, such as poor cycle performance, low reversible capacity, high delithiation potential, or low Coulombic efficiency, thereby providing a carbon with a spherical core-shell structure. Silicon composite material, when it is used as the powder negative electrode active material of secondary lithium battery, it can make secondary lithium battery have higher charge and discharge capacity and charge and discharge efficiency, and has better cycle characteristics and safety

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  • Carbon-silicon composite material with spherical nucleocapsid, and its preparing method and use
  • Carbon-silicon composite material with spherical nucleocapsid, and its preparing method and use

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1, prepare the carbon-silicon composite material I of spherical core-shell structure

[0042] Firstly, commercial silicon powder (325 mesh, purity>99%) was ground for 8 hours by a planetary mill, and its average particle size was 1 micron. Dissolve 20 g of sucrose in a mixed solvent of 100 ml of ethanol and water (volume ratio 1:4) to form a sucrose solution. Put 10 grams of ball-milled silicon powder and 1 gram of carbon black (average particle size: 30 nm) into the sucrose solution and stir for one hour to form a uniform slurry. Then 30 grams of spherical graphite (with an average particle size of 10 micrometers) was added into the above slurry to continue stirring, and the slurry was dried at 120° C. for 8 hours to completely remove the solvent. The obtained product was heated at 600°C with high-purity N 2 Under the atmosphere, pyrolyze in a tube furnace for 8 hours, take it out after cooling, grind it, and pass through a 400 mesh sieve, then put the abo...

Embodiment 2

[0051] Embodiment 2, prepare the carbon-silicon composite material II of spherical core-shell structure

[0052] Firstly, commercial silicon powder (325 mesh, purity>99%) was ground for 2 hours by a planetary mill, and its average particle size was 4 microns. Dissolve 40 g of water-soluble starch in a mixed solvent of 100 ml of ethanol and water (volume ratio 1:4) to form a starch solution. Put 20 grams of ball-milled silicon powder and 2 grams of acetylene black (average particle size of 40 nm) into the starch solution and stir for one hour to form a uniform slurry. Then 30 grams of mesocarbon pellets (MCMB28, with an average particle size of 32 μm) were added to the above slurry and continued to stir, and the slurry was dried at 120° C. for 8 hours to completely remove the solvent. The obtained product was heated at 700°C with high-purity N 2 Under the atmosphere, pyrolyze in a tube furnace for 5 hours, take it out after cooling, grind it, and pass through a 400 mesh sieve...

Embodiment 3

[0055] Embodiment 3, prepare the carbon-silicon composite material III of spherical core-shell structure

[0056] Firstly, commercial silicon powder (325 mesh, purity>99%) was ground by a planetary mill for 12 hours, and its average particle size was 0.2 microns. Dissolve 20 g of dextrin in a mixed solvent of 100 ml of ethanol and water (volume ratio 1:4) to form a starch solution. Put 2 grams of ball-milled silicon powder into the dextrin solution and stir for one hour to form a uniform slurry. Then 30 grams of hard carbon spheres (HCS, treated at 1000° C., with an average particle size of 10 μm) were added to the slurry and continued to stir, and the slurry was dried at 120° C. for 8 hours to completely remove the solvent. The obtained product was heated at 700°C with high-purity N 2 Under the atmosphere, pyrolyze in a tube furnace for 5 hours, take it out after cooling, grind it, and pass through a 400 mesh sieve, then put the above pyrolysis product into a tube furnace w...

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Abstract

This invention relates to a kind of silicon&carbon composite material with a spherical appearance and core-shell structure in spherical particles with a mean diameter of 1.2~53 micron and a 'core-shell' structure, there are silicon particles 5~50wt% and carbon particles 50~95wt%, the core of which is spherical carbon particles with a mean diameter of 1~45 micron. The carbon particles are the mixture of one, two or three kinds of mesophase carbon graphite balls, hard carbon balls and spherical graphite ball. The thickness of the shell is 0.1~4 microns composed of carbon and silicon grains with the average size of 10 nm~4 micron. The carbon&silicon composite materials are achieved through thermal decomposition and chemical vapor deposition after the spherical carbon particles are coated with silicon and carbon composite ultrafine silica slurry.

Description

technical field [0001] The invention relates to a carbon-silicon composite material, in particular to a carbon-silicon composite material with a spherical appearance and a core-shell structure, its preparation method and application. Background technique [0002] Since Japan's SONY company applied for the use of carbon as the negative electrode active material in 1989, LiCoO 2 The patent of the secondary lithium battery used as the positive electrode active material, and after it was first commercialized in 1992, the secondary lithium battery began to develop rapidly. Various forms of carbon materials such as petroleum coke, carbon fiber, pyrolytic carbon, natural graphite, and artificial graphite are widely selected as negative electrode active materials for secondary lithium batteries. However, the theoretical specific capacity of carbon as the negative electrode active material is 372mAh / g. It cannot satisfy people's further pursuit of high energy density secondary batt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/52C04B35/628C04B35/622H01M4/38
CPCY02E60/10
Inventor 李泓黄学杰
Owner LIYANG TIANMU PILOT BATTERY MATERIAL TECH CO LTD
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