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A kind of high-performance lithium-ion battery negative electrode material and preparation method thereof

A technology for lithium ion batteries and negative electrode materials, which is applied in the field of materials science, can solve the problems of deactivation of part of the electrode, low electrical conductivity, decreased battery cycle performance, etc., and achieves the effect of a simple and easy preparation method.

Active Publication Date: 2015-10-21
ZHEJIANG WELLY ENERGY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, elemental silicon has the following problems as the negative electrode active material of the battery: (1) During the lithium intercalation process, Li 22 Si 5 Alloy phase, the volume change of the material reaches more than 300%
The mechanical internal stress generated by such a huge volume effect will gradually peel off the electrode active material from the current collector, and the silicon active phase itself will also be pulverized, thereby losing electrical contact with the current collector, resulting in a rapid decline in battery cycle performance; (2 ) low conductivity
Silicon itself is a semiconductor material with a low conductivity of only 6.7×10 -4 S cm-1, a conductive agent needs to be added to improve the electronic conductivity of the silicon active material; (3) it is difficult to form a stable SEI film
During the charge and discharge process, the huge volume effect will lead to the continuous exposure of silicon to the electrolyte, making it difficult to form a stable SEI film, resulting in a rapid decline in the cycle performance of electroactive materials
[0005] In many patent applications for Si-C composite negative electrode materials, the lithium storage capacity of the negative electrode material is improved by methods such as mixing, coating, and doping of silicon and graphite, but the dispersion of nano-scale silicon powder has not been completely solved. Solved, resulting in deactivation of some areas of the electrode

Method used

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  • A kind of high-performance lithium-ion battery negative electrode material and preparation method thereof
  • A kind of high-performance lithium-ion battery negative electrode material and preparation method thereof
  • A kind of high-performance lithium-ion battery negative electrode material and preparation method thereof

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preparation example Construction

[0034] The preparation method of negative electrode material of the present invention, it comprises the steps:

[0035] (1) Mix high-purity silica fume, microsilica fume, ultrafine aluminum powder and dispersant in a certain proportion;

[0036] (2) Place the material in step (1) in a ball mill jar, add a certain proportion of zirconia balls, and perform high-energy ball milling;

[0037] (3) The product of step (2) is vacuum-dried;

[0038] (4) sintering the product of step (3) in a non-oxidizing atmosphere;

[0039] (5) pickling, filtering, and vacuum drying the product of step (4);

[0040] (6) High temperature oxidation of commercial C raw material in air atmosphere for a certain period of time;

[0041] (7) Mix the product of step (5) and the product of step (6) in an appropriate proportion, join in the pyrolytic carbon solution of a certain concentration added with carbon nanotubes, and disperse by low-speed secondary ball milling;

[0042] (8) heating the product of...

Embodiment 1

[0061] The components are as follows:

[0062] High-purity metal silicon powder: 11.0g (99.9%), with an average particle size of 1.0-2.5μm;

[0063] Micro silica fume: 4.8g (99%), average particle size 3-10μm;

[0064] Ultrafine metal aluminum powder: 2.2g (99%), average particle size 5-10μm;

[0065] Dilute HCl: 120g (10% mass concentration);

[0066] Carbon nanotube slurry: 40g (battery grade, 5% concentration in water system), with an average diameter of 20-30nm and an average aspect ratio of 8-12;

[0067] Natural graphite: 89g (spherical graphite, battery grade) with an average particle size of 6-12μm and an interlayer distance of d 002 0.3353~0.3354nm;

[0068] Sucrose: 25g (food grade).

[0069] The preparation method is as follows:

[0070] (1) Take high-purity metal silicon powder, micro-silica powder, and ultrafine aluminum powder, and use 100ml alcohol as a dispersant to ultrasonically disperse for 1 hour;

[0071] (2) Transfer the above dispersion system int...

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Abstract

The invention discloses a high-performance negative material of a lithium ion cell. The negative material comprises a Si-SiOx / C / DC composite system which comprises a C base, porous Si-SiOx adhered to the base, carbon nano tubes distributed in the base and the Si-SiOx, and an outermost pyrolytic carbon coating layer. The invention also discloses a preparation method of the negative material. The negative material is high in specific capacity and good in cycling stability, thus being suitable for a high-energy-density cell of a portable mobile terminal or a digital product.

Description

technical field [0001] The invention belongs to the field of materials science, and in particular relates to a silicon-carbon composite negative electrode material with high specific capacity for a lithium ion battery. Background of the invention [0002] Since the practical use of lithium-ion batteries in the 1990s, due to their outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge, and no memory effect, they have been widely used in mobile terminals, digital products and portable mobile phones. Equipment, electric vehicles and energy storage power stations and other fields. However, with the birth of smart mobile terminal electronic equipment, it is difficult for lithium-ion batteries to meet their long-term use requirements. Due to the limited size of mobile terminals, the development of high-energy battery products is imminent. [0003] Most of the currently commercialized lithium batteries use lithium cobalt oxid...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/134H01M4/133H01M4/36H01M4/1393H01M4/1395
CPCY02E60/122Y02E60/10
Inventor 吴清国权学军徐中领朱玉巧
Owner ZHEJIANG WELLY ENERGY CORP