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

A silicon-carbon composite material, composite material technology, applied in nanotechnology for materials and surface science, battery electrodes, secondary batteries, etc., can solve problems such as slow decay, achieve increased stability and conductivity, high cycle The effect of stability and good cycle performance

Active Publication Date: 2012-09-26
CHERY AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Wu Jishan et al. (Hongfa Xiang, Kai Zhang, Ge Ji, Jim Yang Lee, Changji Zou, Xiaodong Chen, Jishan Wu, CARBON 49 (2011) 1787 1796) reported the direct mixing of graphene and nano silicon powder to

Method used

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

Examples

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Embodiment 1

[0037] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0038] (1) Put silicon monoxide into a porcelain boat, raise the temperature to 1050°C under the protection of nitrogen, keep the temperature at this temperature for 24 hours, make disproportionation reaction of silicon monoxide at high temperature, and cool to room temperature to obtain a brown product. The tan product includes a composite material of silica-coated nano-silicon particles and partially incompletely reacted silicon monoxide, wherein the nano-silicon particles are uniformly dispersed in the silica matrix. Mix the resulting tan product, expanded graphite (50% of the mass of the tan product), and a hydrofluoric acid solution with a concentration of 13 wt%, wherein the molar ratio of hydrofluoric acid to silicon monoxide initially added is 6:1 , after stirring for 10 hours, ultrasonically dispersed for 120 minutes, wherein, the nano-silicon ...

Embodiment 2

[0045] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0046] (1) Put silicon monoxide into a porcelain boat, raise the temperature to 1200°C under the protection of nitrogen, keep the temperature at this temperature for 0.5h, make disproportionation reaction of silicon monoxide at high temperature, and cool to room temperature to obtain a brown product. Mix the obtained tan product with a hydrofluoric acid solution with a concentration of 20wt%, wherein the molar ratio of hydrofluoric acid to silicon monoxide added initially is 4:1, and after stirring for a period of time, add three times the mass of silicon monoxide Graphite, stirred for 30 hours, ultrasonically dispersed for 5 minutes, filtered to obtain a solid product after ultrasonic dispersion, washed with distilled water to remove hydrofluoric acid, fluosilicic acid, etc. A composite material of nano-silicon particles, wherein the particle size of n...

Embodiment 3

[0052] This embodiment provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0053] (1) Put silicon monoxide into a porcelain boat, raise the temperature to 800°C under the protection of nitrogen, keep the temperature at this temperature for 6 hours, make disproportionation reaction of silicon monoxide at high temperature, and cool to room temperature to obtain a brown product. The resulting tan product was mixed with carbon nanotubes (the mass of which was 10% of the brown product), and then a hydrofluoric acid solution with a concentration of 3 wt% was added, wherein the molar ratio of hydrofluoric acid to the initially added silicon monoxide was 10 : 1, after stirring for 0.5 hours, ultrasonically disperse for 80 minutes, filter to obtain a solid product after ultrasonic dispersion is completed, wash with distilled water to remove hydrofluoric acid, fluorosilicic acid, etc. on the surface of the solid product, and then dry at ...

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Abstract

The invention discloses a silicon-carbon composite material, a preparation method thereof and a lithium ion battery prepared by adopting the material. The preparation method of the silicon-carbon composite material comprises the following steps: (1) mixing a composite material (silica-coated nano-silicon) manufactured by silicon monoxide, a porous carbon-based material and excessive hydrofluoric acid solution to obtain another composite material in which nano-silicon particles are compounded in pores of the porous carbon-based material; and (2) heating a composite material in which nano-silicon particles are compounded in pores of a high polymer-coated porous carbon-based material under an inert atmosphere to obtain the silicon-carbon composite material coated by porous carbon spheres. The process raw materials are accessible and simple to prepare. The silicon-carbon composite material has electrochemical reversible embedded lithium removal performance, greatly relieves efflorescence and falling-off phenomena of active particles in the charge-discharge process and has the high lithium storage capacity characteristic of silicon materials and the high cycling stability of carbon materials, and a battery prepared by the silicon-carbon composite material has better cyclicity.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a silicon-carbon composite material, a preparation method thereof, and a lithium ion battery prepared by using the material. Background technique [0002] At present, the negative electrode of commercialized lithium-ion batteries uses graphitized carbon, such as mesocarbon microspheres (MCMB, CMS) materials. The volume expansion of these materials is basically below 9% during the process of intercalation and delithiation, showing high Coulombic efficiency and Excellent cycle stability. However, the theoretical lithium intercalation capacity of graphite is 372mAh / g, which has actually reached 370mAh / g. Therefore, the low theoretical lithium storage capacity of the graphite electrode itself makes it difficult to make breakthroughs. Researchers have been exploring a new type of high Specific capacity electrode materials to replace graphitized carbon materi...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/134H01M4/133H01M10/0525B82Y30/00
CPCY02E60/122Y02E60/10
Inventor 曾绍忠赵志刚屈耀辉阴山慧
Owner CHERY AUTOMOBILE CO LTD
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