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Silicon-carbon composite negative pole material preparation method and lithium ion battery

A negative electrode material, silicon-carbon composite technology, applied in the direction of negative electrodes, battery electrodes, secondary batteries, etc., can solve the problems of difficult control of hollow inner diameter, brittle PVC coating layer, unfavorable long-term cycle, etc., to reduce the surface active points of particles , uniform dispersion, and the effect of improving cycle performance

Active Publication Date: 2016-12-28
浙江超恒动力科技有限公司
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  • Application Information

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Problems solved by technology

CN103531760 discloses a method for preparing porous silicon-carbon composite microspheres with egg yolk-eggshell structure. The preparation process is too complicated, and the control of the hollow inner diameter is too difficult. Although it can provide a certain expansion space for silicon, the tap density is not high and the conductivity is poor. And need to adopt hydrofluoric acid etching, serious to environmental pollution; CN103000901 discloses the preparation method of the amorphous carbon-coated silicon particle that adopts PVC-coated silicon powder to prepare, although the volume effect can be curbed to a certain extent, but the conductivity is relatively low. Poor, and the PVC coating is brittle and easily damaged, which is not conducive to long-term circulation

Method used

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  • Silicon-carbon composite negative pole material preparation method and lithium ion battery
  • Silicon-carbon composite negative pole material preparation method and lithium ion battery
  • Silicon-carbon composite negative pole material preparation method and lithium ion battery

Examples

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Effect test

Embodiment 1

[0030] A method for preparing a silicon-carbon composite negative electrode material, comprising the following steps:

[0031] A: Ultrasonic disperse 120g of spherical graphite in 100ml of absolute ethanol, then add 40g of nano-silicon into the graphite dispersion, use a planetary ball mill for 7 hours, the speed of the ball mill is 250r / min, and then place it in a vacuum drying oven at 80°C for vacuum drying 3h;

[0032] Before nano-silicon is ball-milled, first add silicon powder to 10 times its mass of sodium hydroxide solution with a concentration of 10wt%, and after the dispersion is uniform, heat it to 120°C under reduced pressure, keep warm and decompose for 7 hours; Add the powder to 10 times the mass of ethanol solution with a concentration of 75wt%, heat it to 85°C and keep it warm for 4h, filter again, beat until the pulp has a beating degree of 15°SR, and then refine to a pulp The degree of beating is 20°SR. After beating, the silicon powder obtained by washing wi...

Embodiment 2

[0036] A method for preparing a silicon-carbon composite negative electrode material, comprising the following steps:

[0037] A: Ultrasonic disperse 120g of spherical graphite in 100ml of absolute ethanol, then add 15g of silicon powder into the graphite dispersion, use a planetary ball mill for 7 hours, the speed of the ball mill is 250r / min, and then place it in a vacuum drying oven at 80°C for vacuum drying 3h; before the nano-silicon is ball-milled, add silicon powder to 12 times the mass of the sodium hydroxide solution with a concentration of 12wt%, and after the dispersion is uniform, heat it to 130°C under reduced pressure, keep warm and decompose for 8h; filter after decompression to obtain Add silicon powder to 12 times its mass in an ethanol solution with a concentration of 80wt%, heat it to 90°C and keep it warm for 5h, filter again, beat until the slurry has a beating degree of 16°SR, and then refine to The beating degree of the slurry is 22°SR. After beating, th...

Embodiment 3

[0041] A method for preparing a silicon-carbon composite negative electrode material, comprising the following steps:

[0042] A: Ultrasonic disperse 80g of spherical graphite in 100ml of absolute ethanol, then add 10g of silicon powder into the graphite dispersion, use a planetary ball mill for 3 hours, and the speed of the ball mill is 250r / min, and then place it in a vacuum drying oven at 80°C for vacuum drying 3h; before the nano-silicon is ball-milled, add silicon powder to 12 times the mass of the sodium hydroxide solution with a concentration of 12wt%, and after the dispersion is uniform, heat it to 130°C under reduced pressure, keep warm and decompose for 8h; filter after decompression to obtain Add silicon powder to 12 times its mass in an ethanol solution with a concentration of 80wt%, heat it to 90°C and keep it warm for 5h, filter again, beat until the slurry has a beating degree of 16°SR, and then refine to The beating degree of the slurry is 22°SR. After beating,...

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Abstract

The invention relates to a silicon-carbon composite negative pole material preparation method and a lithium ion battery. The preparation method comprises putting nanometer silicon and graphite micro-powder into a ball mill, carrying out ball milling uniform dispersion in an organic solvent environment, carrying out vacuum drying, putting the dried mixture and asphalt into a cone-type mixer, carrying out coarse mixing, putting the mixed powder subjected to coarse mixing into a mechanical fusion machine, carrying out mechanical fusion, carrying out heat treatment in an inert gas protective atmosphere and carrying out cooling to obtain the silicon-carbon composite negative pole material. The preparation method carries out asphalt softening coating on nanometer silicon so that silicon particle and electrolyte direct contact is avoided, a capacity reduction rate is delayed, a lithium ion diffusion path is shortened, an electrode material electron conduction loss is avoided, and first charge-discharge efficiency, a charge-discharge electric capacity and cycle performances are improved. Before coating, nanometer silicon is dispersed through graphite micro-powder so that it is avoided that in asphalt coating, nanometer silicon aggregation causes local capacity excess and nanometer silicon is uniformly dispersed.

Description

technical field [0001] The invention belongs to the field of negative electrode materials for lithium ion batteries, and in particular relates to a method for preparing a silicon-based composite negative electrode material with high initial coulombic efficiency, good cycle performance, high compaction density and stable electrode structure, and a lithium ion battery using the negative electrode material . Background technique [0002] Lithium-ion batteries are widely used in various portable electronic devices and electric vehicles due to their advantages such as large specific energy, high working voltage, long cycle life, small size, light weight, and environmental protection. At present, the commercial lithium-ion battery anode material is mainly graphite, including natural graphite, artificial graphite, etc., but its theoretical specific capacity is only 372mAh / g, which is difficult to meet the demand for high energy density power supply in the application field of lithi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M10/0525
CPCH01M4/366H01M4/386H01M10/0525H01M2004/027Y02E60/10
Inventor 王成云任宁孙延先李洪涛
Owner 浙江超恒动力科技有限公司
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