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

A technology of silicon-carbon composite materials and composites, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as expensive raw materials and difficult large-scale production, and achieve the effects of enhancing electrical conductivity, saving costs, and shortening diffusion paths

Active Publication Date: 2013-03-13
CHERY AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The above method is very effective in overcoming the specific capacity fading problem of silicon-based negative electrode materials, but because the above method uses expensive raw materials (nano-silicon powder), it is difficult to produce on a large scale

Method used

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

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Embodiment 1

[0031] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0032] (1) Weigh fumed silica powder (particle size: 30nm) and calcium particles (particle size: 1mm), wherein the amount of calcium is 100% of the theoretical amount that can completely reduce the fumed silica powder. The two were mixed, toluene was added thereto, and steel balls were added, put into a planetary ball mill, and ball milled at 350 rpm for 6 hours to obtain a mixed slurry. Transfer the above mixed slurry into a crucible, then put the crucible into an atmosphere furnace, raise the temperature to 600°C at 5°C / min under the protection of argon, and keep it warm for 1 hour; then raise the temperature to 800°C at 5°C / min , and keep warm for 1 hour to obtain a composite of porous silicon-calcium oxide.

[0033] (2) Put the porous silicon-calcium oxide composite into a beaker, and add hydrochloric acid to it, wherein the amount of hydrochloric ...

Embodiment 2

[0042] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0043] (1) Weigh mesoporous silica powder (SBA-15, which is a kind of mesoporous molecular sieve), potassium (particle size 1mm), and the amount of potassium is such that the mesoporous silica powder can completely 80% of the theoretical amount of reduction. The two were mixed and cyclohexane was added thereto, and then steel balls were added, put into a planetary ball mill, and ball milled at 350 rpm for 8 hours to obtain a mixed slurry. Transfer the above mixed slurry into the crucible, then put the crucible into the atmosphere furnace, raise the temperature to 550°C under the protection of argon at 5°C / min, and keep it for 5 hours; then raise the temperature to 800°C at 5°C / min , and kept for 12 hours to obtain a composite of porous silicon-potassium oxide.

[0044] (2) Put the composite of porous silicon-potassium oxide into a beaker, and add acet...

Embodiment 3

[0048] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0049] (1) Weigh quartz sand and magnesium (particle size: 1mm), and the amount of magnesium is 110% of the theoretical amount that can completely reduce the quartz sand. The two were mixed and cyclohexane was added thereto, and then steel balls were added, put into a planetary ball mill, and ball milled at 300 rpm for 6 hours to obtain a mixed slurry. Transfer the above-mentioned mixed slurry into a crucible, then put the crucible into an atmosphere furnace, raise the temperature to 650°C at 5°C / min under the protection of argon, and keep it warm for 2 hours; then raise the temperature to 900°C at 5°C / min , kept for 3 hours to obtain a composite of porous silicon-magnesia.

[0050] (2) Put the porous silicon-magnesia composite into a beaker, and add a mixture of acetic acid and hydrochloric acid to it, wherein the amount of the mixture of acetic acid ...

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Abstract

The invention discloses a silicon-carbon composite material, a preparation method of the silicon-carbon composite material, and a lithium ion battery containing the silicon-carbon composite material. The preparation method comprises the following steps of: (1) reducing silicon dioxide by using metal with activity larger than that of silicon, so as to obtain a porous silicon-metal oxide composite; (2) corroding the metal oxide by acid, so as to obtain porous silicon; and (3) coating the surface of the porous silicon by carbon by taking a carbon source as a raw material, so as to obtain the silicon-carbon composite material. The silicon in the silicon-carbon composite material is prepared through using a metallothermic reduction method and porous silicon particles prepared through using the metallothermic reduction method are micron-sized and hardly agglomerate; the pore walls and the pore diameters in the porous silicon particles are nano-sized; compared with imporous micron-sized silicon powder, for the silicon-carbon composite material, the porous silicon particles have the characteristics that a diffusion path of a lithium ion in a silicon substrate is shortened, thus being beneficial to charging and discharging with large current, the pores can hold the volume expansion of silicon during silicon intercalation and the charging and discharging cycle life of the material is prolonged. The surfaces of the porous silicon particles are coated with a carbon layer with the certain pores and the conductivity of the silicon-carbon composite material is enhanced.

Description

technical field [0001] The invention belongs to the technical field of battery manufacturing, and in particular relates to a silicon-carbon composite material, a preparation method thereof, and a lithium ion battery containing the material. Background technique [0002] At present, lithium-ion batteries used in production mainly use graphite-based negative electrode materials, but the theoretical lithium intercalation capacity of graphite is 372mAh / g, and the actual use has reached 370mAh / g. Therefore, graphite-based negative electrode materials have almost no improvement in lithium storage capacity. space. [0003] In the past ten years, a variety of new high-capacity and high-rate negative electrode materials have been developed, among which silicon-based materials have become a research hotspot due to their high mass specific capacity (the theoretical specific capacity of silicon is 4200mAh / g). During the lithium intercalation and desorption process, the material is acco...

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 曾绍忠赵志刚阴山慧
Owner CHERY AUTOMOBILE CO LTD
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