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Method for preparing silicon/carbon composite material with magnesiothermic reduction process

A technology of silicon-carbon composite materials and composite materials, which is applied in the direction of structural parts, electrical components, battery electrodes, etc., can solve the problems of easily changing the morphology of porous silicon and affecting the excellent performance of composite materials, and achieve the best capacity to withstand volume strain, ion The effect of short diffusion path and simple process method

Inactive Publication Date: 2017-02-01
TIANNENG SAFT ENERGY JOINT CO
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In the actual research process, it is found that the morphology of porous silicon is easily changed due to the need for pickling and drying of the product after the magnesia thermal reduction reaction, which in turn affects the excellent performance of the carbon-coated composite material.

Method used

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  • Method for preparing silicon/carbon composite material with magnesiothermic reduction process
  • Method for preparing silicon/carbon composite material with magnesiothermic reduction process
  • Method for preparing silicon/carbon composite material with magnesiothermic reduction process

Examples

Experimental program
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Effect test

Embodiment 1

[0035] 1. Preparation of silicon-carbon composite materials

[0036] Use a planetary ball mill to mix diatomite, polyvinylidene fluoride and methylpyrrolidone solvent at a mass ratio of 4:1:1, the mass ratio of the ball to material is about 5:1, the speed is 400 rpm, and the ball milling time is 4 hours. A silica / polyvinylidene fluoride homogeneous material was obtained. The obtained silica / polyvinylidene fluoride homogenate material is placed in an oven for drying.

[0037] After taking it out, mix the composite material and magnesium powder according to the ratio of 1:1. The mixture was placed in a tube furnace, heated to 700 °C at a rate of 5 °C / min in an argon atmosphere, kept for 4 hours, and naturally cooled to room temperature; pickled with hydrochloric acid, then deionized water and ethanol were used to Washed 3 times, dried in a vacuum oven at 100° C. for 5 hours to obtain a silicon-carbon composite material.

[0038] The prepared silicon-carbon composite material ...

Embodiment 2

[0044] 1. Preparation of silicon-carbon composite materials

[0045] Use a planetary ball mill to evenly mix mesoporous silica, polypyrrole and pyridine solvent with a mass ratio of 6:1:1, the mass ratio of the ball to material is about 4:1, the speed is 700 rpm, and the ball milling time is 6 hours. A silica / polypyrrole homogeneous material was obtained. The obtained silica / polypyrrole homogenate material is dried in an oven.

[0046] After taking it out, mix the materials according to the ratio of composite material and magnesium powder at 1:1. The mixture was placed in a tube furnace, heated to 700°C at a heating rate of 5°C / min in a nitrogen atmosphere, kept for 5 hours, and cooled to room temperature naturally; pickled with hydrochloric acid, then washed with deionized water and ethanol respectively 3 times, and dried in a vacuum oven at 120° C. for 3 hours to obtain a silicon-carbon composite material.

[0047] 2. Preparation of silicon-carbon composite negative elect...

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Abstract

The invention discloses a method for preparing a silicon / carbon composite material with a magnesiothermic reduction process, and belongs to the technical field of composite material preparation. The method comprises the following steps: (1) mixing a silicon dioxide source, an organic carbon source and a solvent, carrying out ball-milling to prepare a uniformly pulpous mixture, and obtaining a silicon dioxide-carbon precursor composite material through drying; (2) mixing the silicon dioxide-carbon precursor composite material with magnesium powder to carry out a magnesiothermic reduction reaction, collecting products and carrying out acid pickling and washing, and drying to obtain the silicon / carbon composite material. According to the method, silicon dioxide reduction and high temperature carbonization are completed by using a one-step process, and the method has the advantages of simple technical process, low cost and large-scale production; the prepared composite material effectively maintains the appearance of porous silicon, so that the composite material has preferable capability for bearing volumetric strain; the porous composite material is applied to a lithium battery, so that the lithium-ion de-intercalation depth is small, the ion diffusion path is short, the reversible capacity and coulombic efficiency of the lithium battery are effectively improved, and the cycle life is prolonged.

Description

technical field [0001] The invention belongs to the technical field of composite material preparation, and in particular relates to a method for preparing a silicon-carbon composite material by using a magnesia thermal reduction method. Background technique [0002] Lithium-ion batteries are widely used in various portable electronic devices due to their high energy density and good cycle stability. The negative electrode material is the main lithium storage body of the lithium-ion battery, and it realizes the intercalation and extraction of lithium ions during the charging and discharging process. In recent years, due to the shortcomings of traditional carbon materials such as low specific capacity, low initial charge and discharge efficiency, and co-intercalation of organic solvents, people have begun to develop other non-carbon materials with high specific capacity. [0003] Silicon materials are rich in natural resources, cheap, and more importantly, silicon has a high ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M10/0525
CPCH01M4/364H01M10/0525Y02E60/10
Inventor 周敏李文余心亮施利勇
Owner TIANNENG SAFT ENERGY JOINT CO
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