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Multi-core core-shell-structure silicon carbon composite negative pole material and preparation method thereof

A technology of negative electrode material and core-shell structure, which is applied in the field of lithium-ion battery composite negative electrode materials and its preparation, can solve the problems of electrode cycle performance degradation, limited commercial application, and material structure damage, and solve the problem of poor silicon conductivity and improve Capacity utilization rate and effect of improving tap density

Active Publication Date: 2013-05-08
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the severe volume expansion and contraction of silicon materials during the lithium ion intercalation and deintercalation cycle, resulting in the destruction of the material structure and mechanical crushing, resulting in the decline of electrode cycle performance, limiting its commercial application

Method used

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  • Multi-core core-shell-structure silicon carbon composite negative pole material and preparation method thereof
  • Multi-core core-shell-structure silicon carbon composite negative pole material and preparation method thereof
  • Multi-core core-shell-structure silicon carbon composite negative pole material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033](1) High-dispersion multi-nuclear porous balls: add thermosetting phenolic resin (according to the content of pyrolytic carbon in the spherical core material after sintering is 5wt%) into an appropriate amount of de-tetrahydrofuran, stir magnetically to form a solution with a certain viscosity, and then Add silicon powder (according to the mass ratio of silicon / carbon in the spherical core material after sintering: 1:19) and natural graphite (according to 80% of the total mass of the spherical composite material after sintering), then add 10wt% polyethylene glycol dispersant, and ball mill 5h, ultrasonic plus mechanical stirring for 1h, after the uniformly dispersed suspension was spray-dried at 120~200℃, the precursor of multi-nuclear porous spheres was obtained. The obtained powder was transferred into a protective atmosphere at a constant temperature of 500°C for 2 hours, and cooled with the furnace to obtain multi-nuclear porous balls.

[0034] (2) Preparation of hig...

Embodiment 2

[0038] (1) High-dispersion multi-nuclear porous balls: Add polyvinyl alcohol-124 (according to the content of pyrolytic carbon in the composite material after sintering is 15wt.%) into an appropriate amount of deionized water, and magnetically stir to form a solution with a certain viscosity , and then add nano silicon powder (Nano-Si, according to the mass ratio of silicon / carbon in the spherical core material after sintering: 1:10) and natural graphite (50wt.% according to the total mass of the spherical composite material after sintering, and then add 10wt.% Propylene glycol dispersant, ultrasonic plus mechanical stirring to disperse for 1 hour, after spraying and drying the uniformly dispersed suspension at 170~200°C, the precursor of multi-nuclear porous balls is obtained. The obtained powder is transferred to a protective atmosphere at 1000°C for 2 hours, Cooling, that is, polynuclear porous balls.

[0039] (2) Preparation of highly dispersed asphalt suspension: pre-crus...

Embodiment 3

[0043] (1) High-dispersion multi-nuclear porous ball: add urea-formaldehyde resin (according to the content of pyrolytic carbon in the spherical core material after sintering is 10wt.%) into an appropriate amount of deionized water, stir magnetically to form a solution with a certain viscosity, and then Add nano-silica powder and silicon oxide (Si:SiO=1:1, according to the mass ratio of silicon / carbon in the spherical core material after sintering: 2:5) and natural graphite (40wt.% according to the total mass of the spherical composite material after sintering), Then add 1wt.% polyvinyl acetate dispersant, ball mill for 1 hour, ultrasonically add mechanical stirring to disperse for 1 hour, and spray-dry the uniformly dispersed suspension at 170-200°C to obtain the precursor of polynuclear porous balls. The obtained powder was transferred to a protective atmosphere at a constant temperature of 500°C for 5 hours, and cooled with the furnace to obtain multi-nuclear porous balls. ...

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Abstract

The invention relates to a multi-core core-shell-structure silicon carbon composite negative pole material and a preparation method thereof. The preparation method comprises the following steps: 1. preparation method of high-dispersivity multi-core porous spheres; 2. preparation of high-dispersivity asphalt suspension; and 3. preparation of multi-core core-shell-structure silicon carbon composite negative pole material: adding the porous spheres prepared in the step 1 into the high-dispersivity asphalt suspension prepared in the step 2, carrying out ultrasonic dispersion, heating and drying by distillation while intensely stirring to remove the solvent, transferring the powder particles into a protective atmosphere, and holding at low temperature so that the asphalt liquid enters the inside of the porous spheres to enhance the binding strength between the silicon source and the conducting carbon mesh, carry out secondary coating on the silicon source, overcome the defects in the coating in the step 1 and enhance the capacity performance of the silicon; and carrying out high-heat treatment. The invention is simple and easy to implement, and has the advantage of high practicality. The prepared silicon carbon composite material has the advantages of high reversible capacity, designable capacity, favorable cycle performance, favorable heavy-current discharge capacity, high tap density and the like.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials and preparation methods thereof, and relates to a lithium ion battery composite negative electrode material and a preparation method thereof. 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, low self-discharge rate, small size, and light weight. The current commercial lithium-ion battery anode material is mainly graphite, but its theoretical capacity is only 372mAh g -1 , high rate charge and discharge capacity is low, poor low temperature performance and other reasons, can no longer meet the demand for high energy density power supply in the field of lithium ion battery applications. Therefore, it is extremely urgent to develop new anode materials for lithium-ion batteries with high specific capacity. [0003] As an anode materi...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/134H01M4/133H01M4/1395H01M4/1393
CPCY02E60/122Y02E60/10
Inventor 郭华军黄思林李新海王志兴苏明如甘雷胡启阳彭文杰张云河
Owner CENT SOUTH UNIV
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