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Silicon-carbon cathode material with artificial SEI layers, high specific volumetric capacity and cycle performance

A cycle performance and negative electrode material technology, which is applied in the field of lithium ion battery negative electrode materials and silicon-carbon composite lithium ion battery negative electrode materials, can solve the problems of poor stability of SEI film, low volume specific capacity, large volume change, etc., and achieve improved adhesion effect , improve the volume specific capacity, the effect of simple process

Active Publication Date: 2016-12-07
天津爱敏特电池材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of the deficiencies in the prior art, one of the technical problems to be solved by the present invention is to overcome the problems of poor cycle performance caused by the large volume change, poor stability and poor conductivity of the formed SEI film during the charging and discharging process of the existing silicon negative electrode materials, and at the same time solve the problem of The problem of low volume specific capacity provides a preparation method and application of a silicon-carbon composite negative electrode material containing a stable artificial SEI film with high volume specific capacity and cycle stability

Method used

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  • Silicon-carbon cathode material with artificial SEI layers, high specific volumetric capacity and cycle performance

Examples

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Embodiment 1

[0031] Example 1 Mesophase graphite microspheres with a median particle size of 60 μm were processed in a crushing and shaping device to have a median particle size of 7 μm and a specific surface area of ​​7.5 m 2 / g powder. Take 42.5g of the powder material and add it to the ball mill jar, and at the same time add 7.5g of silicon powder with a median particle size of 200nm and 500ml of absolute ethanol, and use zirconia balls in the ball mill at a speed of 450rpm for 10h. The slurry was transferred to a stirring tank, and 58 g of a 10% lithium acetate aqueous solution was added under stirring, and stirred for 1 h. Prepare 10% NH with deionized water 4 F aqueous solution, 22g of this NH 4 F aqueous solution was added dropwise into the complex solution of lithium acetate, graphite and silicon, and stirred for 30 min. The mixed solution was spray-dried on a spray-drying device at an exhaust air temperature of 105°C. The spray-dried material and PVDF were mixed and added to t...

Embodiment 2

[0032] Example 2 Mesophase graphite microspheres with a median particle size of 60 μm were processed in crushing and shaping equipment into a median particle size of 7 μm and a specific surface area of ​​7.5 m 2 / g powder. Take 42.5g of the powder material and add it to a ball mill jar. At the same time, add 7.5g of silicon with a median particle size of 200nm and 500ml of absolute ethanol in the ball mill with zirconia balls at a speed of 450rpm for 10h. The slurry was transferred to a stirring tank, and 29 g of a 10% lithium acetate aqueous solution was added under stirring, and stirred for 1 h. Prepare 10% NH with deionized water 4 F aqueous solution, 11g of this NH 4 F aqueous solution was added dropwise into the complex solution of lithium acetate, graphite and silicon, and stirred for 30 min. The mixed solution was spray-dried on a spray-drying device at an exhaust air temperature of 105°C. The spray-dried material and PVDF were mixed and added to the pan granulator ...

Embodiment 3

[0033] Example 3 Mesophase graphite microspheres with a median particle size of 60 μm were processed in a crushing and shaping device to have a median particle size of 7 μm and a specific surface area of ​​7.5 m 2 / g powder. Take 42.5g of the powder material and add it to a ball mill jar. At the same time, add 7.5g of silicon with a median particle size of 200nm and 500ml of absolute ethanol in the ball mill with zirconia balls at a speed of 450rpm for 10 hours. The slurry was transferred to a stirring tank, and 58 g of a 10% lithium acetate aqueous solution was added under stirring, and stirred for 1 h. Prepare 10% NH with deionized water 4 F aqueous solution, 22g of this NH 4 F aqueous solution was added dropwise into the complex solution of lithium acetate, graphite and silicon, and stirred for 30 min. The mixed solution was spray-dried on a spray-drying device at an exhaust air temperature of 105°C. The spray-dried material and PVDF were mixed and added to the pan granu...

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Abstract

The invention relates to a silicon-carbon cathode material with artificial SEI layers, high specific volumetric capacity and cycle performance and application of the silicon-carbon cathode material. The silicon-carbon cathode material is of an intermediate-phase graphite structure which is secondarily granulated, outer shell layers of the intermediate-phase graphite structure are amorphous carbon coating layers, inner shell layers of the intermediate-phase graphite structure are dense LiF membranes, and nanometer silicon is uniformly dispersed to form cores of the intermediate-phase graphite structure. A method for preparing the silicon-carbon cathode material includes steps of 1, crushing and shaping intermediate-phase graphite balls with large particle diameters to obtain intermediate-phase graphite micro-powder with median particle diameters of approximately 7 micrometers; 2, carrying out ball-milling dispersion on the nanometer silicon and the micro-powder obtained at the step 1; 3, uniformly mixing lithium acetate solution and materials obtained at the step 2 with one another; 4, carrying out dropwise addition reaction on NH4F solution and materials obtained at the step 3; 5, carrying out spray-drying on materials obtained at the step 4; 6, mixing PVDF (polyvinylidene fluoride) and materials obtained at the step 5 with one another to obtain mixtures and granulating and coating the mixtures; 7, immobilizing and carbonizing materials obtained at the step 6; 8, sieving materials obtained at the step 7. The silicon-carbon cathode material and the application have the advantages that the silicon-carbon composite cathode material is stable in cycle performance, high in specific volumetric capacity and easy to industrially produce; a lithium ion battery with a cathode which is processed from the silicon-carbon cathode material is high in specific volumetric capacity and excellent in cycle performance.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium ion batteries, in particular to the field of silicon carbon composite lithium ion battery negative electrode materials. The invention also relates to a lithium ion battery containing said material. Background technique [0002] Lithium-ion batteries have outstanding performance in commercial applications due to their outstanding energy density and cost performance. However, with the development of electric vehicles, the market's demand for energy density of lithium-ion batteries is getting higher and higher, especially for the stable energy density of negative electrode materials. [0003] Most commercially used lithium-ion battery anodes in the market use graphite as raw material. However, the theoretical capacity of graphite is only 372mAh / g, which is difficult to meet the higher requirements of the market. Silicon materials have a theoretical capacity of 4200mAh / g, low ...

Claims

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Application Information

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IPC IPC(8): H01M4/583H01M4/58H01M4/38H01M10/0525B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00H01M4/362H01M4/386H01M4/582H01M4/583H01M10/0525Y02E60/10
Inventor 胡成胜樊屹军其他发明人请求不公开姓名
Owner 天津爱敏特电池材料有限公司
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