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Silicon-carbon composite material, preparation method thereof, and lithium ion battery containing material

A silicon-carbon composite material and composite material technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as low cycle performance and low electrical conductivity, and achieve fast conduction, prolong cycle life, and eliminate pulverization and shedding. Effect

Active Publication Date: 2013-08-07
CHERY AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of low cycle performance and low conductivity of the existing silicon-carbon composite materials and lithium ion batteries prepared therefrom, and provide a method for preparing silicon-carbon composite materials with excellent cycle performance and conductivity

Method used

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  • Silicon-carbon composite material, preparation method thereof, and lithium ion battery containing material
  • Silicon-carbon composite material, preparation method thereof, and lithium ion battery containing material

Examples

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Embodiment 1

[0032] Such as figure 1 As shown, this embodiment provides a method for preparing a silicon-carbon composite material, which includes the following steps:

[0033] 1) Mixing steps:

[0034] Add silicon powder and graphene as a conductive carbon material to a sodium silicate solution with a mass concentration of 40% for ultrasonic dispersion for 2 hours to obtain a dispersed mixture, wherein the mass ratio of silicon powder to sodium silicate is 1:5, graphene The mass ratio of silicon powder to silicon powder is 1:15, and the average particle size of silicon powder is 0.1nm;

[0035] 2) Silica coating steps:

[0036] Under stirring, add excess hydrochloric acid with a concentration of 0.5M to the dispersed mixture obtained in step 1) to react for 2 hours, filter and wash to obtain a silicon dioxide-coated silicon-conductive carbon network composite material;

[0037] 3) Carbon coating step:

[0038] Add the silicon dioxide-coated silicon-conductive carbon network composite ...

Embodiment 2

[0046] This embodiment provides a method for preparing a silicon-carbon composite material, which includes the following steps:

[0047] 1) Mixing steps:

[0048] Add silicon powder, carbon nanotubes and graphite as conductive carbon materials (the mass ratio of the two is 1:1) to a sodium silicate solution with a mass concentration of 40% for ultrasonic dispersion for 1 hour to obtain a dispersed mixture, in which silicon powder The mass ratio of sodium silicate to sodium silicate is 1:7, the mass ratio of carbon nanotubes, graphite to silicon powder is 1:20, and the average particle size of silicon powder is 1nm;

[0049] 2) Silica coating steps:

[0050]Under stirring, add excess sulfuric acid with a concentration of 0.5M to the dispersed mixture obtained in step 1) to react for 2.5 hours, filter and wash to obtain a silicon dioxide-coated silicon-conductive carbon network composite material;

[0051] 3) Carbon coating step:

[0052] Add the silicon dioxide-coated silico...

Embodiment 3

[0059] This embodiment provides a method for preparing a silicon-carbon composite material, which includes the following steps:

[0060] 1) Mixing steps:

[0061] Add silicon powder and vapor-grown carbon fiber as a conductive carbon material to a sodium silicate solution with a mass concentration of 40% for ultrasonic dispersion for 4 hours to obtain a dispersed mixture, wherein the mass ratio of silicon powder to sodium silicate is 1:10, and the gas phase The mass ratio of growing carbon fiber to silicon powder is 1:10, and the average particle size of silicon powder is 100nm;

[0062] 2) Silica coating steps:

[0063] Under stirring, add excess hydrochloric acid with a concentration of 0.5M to the dispersed mixture obtained in step 1) to react for 3 hours, filter and wash to obtain a silicon dioxide-coated silicon-conductive carbon network composite material;

[0064] 3) Carbon coating step:

[0065] Add the silica-coated silicon-conductive carbon network composite obtai...

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Abstract

The invention provides a silicon-carbon composite material, a preparation method of the material, and a lithium ion battery containing the material, which belong to the technical field of lithium ion batteries, and can solve the problems that an existing silicon-carbon composite cathode material and a lithium ion battery prepared from the existing material are poor in cycle performance and conductivity performance. The preparation method of the composite material comprises the steps of mixing materials, coating silicon dioxide, coating carbon and taking a silicon dioxide layer off. The preparation method of the silicon-carbon composite material utilizes reserved holes to contain volume expansion during the course that silicon particles are embedded into lithium, and a conductive network carbon material is dispersed in the holes in advance, so that the conductivity of the silicon-carbon composite material is improved, the pulverization and dropping of an electrochemical active substance due to the volume expansion are alleviated and even eliminated, and the cycle life of the silicon-carbon composite material is prolonged effectively. The silicon-carbon composite material is prepared by the method; and the lithium ion battery contains the silicon-carbon composite material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery material, a preparation method thereof, and a lithium ion battery containing the material. Background technique [0002] At present, the lithium-ion batteries used in production mainly use graphitized carbon as the negative electrode material, but the lithium storage capacity of the material is not high. As far as graphite-based negative electrode materials are concerned, their large layered structure voids not only provide a place for lithium storage, but also determine the characteristics of the material's low theoretical specific capacity (about 372mAh / g). Therefore, the development of new high-capacity and high-rate anode materials has high research and application value. For a long time, lithium alloy has attracted much attention as an alternative negative electrode material. Silicon-based materials and tin-based materials are...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M10/0525
CPCY02E60/122Y02E60/10
Inventor 朱广燕赵志刚陈效华
Owner CHERY AUTOMOBILE CO LTD