Method for preparing porous silicon/carbon composite material by using diatomite as raw material and application

A carbon composite material, porous silicon technology, applied in electrical components, battery electrodes, circuits, etc., to achieve the effects of abundant raw materials, simple process and low price

Inactive Publication Date: 2011-10-05
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Most of these raw materials come from chemical synthesis, and there a...

Method used

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  • Method for preparing porous silicon/carbon composite material by using diatomite as raw material and application
  • Method for preparing porous silicon/carbon composite material by using diatomite as raw material and application
  • Method for preparing porous silicon/carbon composite material by using diatomite as raw material and application

Examples

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Embodiment 1

[0031] Grind diatomaceous earth and mix it with water at a mass ratio of 1:10 and impregnate it until it fully absorbs water, then add 10 ml of NaOH with a concentration of 0.01 mol / L as a dispersant, stir well and let it stand for 2 hours, suck out the upper layer of suspended mud . The mud is filtered and dried. Take 2.5 g of the dried solid and heat it up to 600 °C at 5 °C / min for 10 hours in an air atmosphere. Sulfuric acid with a mass fraction of 30% was prepared, diatomite with organic matter removed was added to the solution, stirred at 95 °C for 8 hours, cooled to room temperature, the solution was diluted and washed, and diatomite with high purity was obtained. Mix diatomaceous earth and magnesium powder in a mass ratio of 1:1, in N 2Under protective atmosphere, keep warm at 700 ℃ for 10 hours, after natural cooling, soak the solid mixture in 0.1 mol / L hydrochloric acid solution for 12 hours, dilute the solution, wash, filter and dry to obtain silicon with porous st...

Embodiment 2

[0034] Grind diatomaceous earth and mix it with water at a mass ratio of 1:15. After it fully absorbs water, add 15 ml of NaOH with a concentration of 0.01 mol / L as a dispersant, stir well and let it stand for 2 hours, suck out the upper layer of suspended mud. The mud is filtered and dried. Take 2.5 g of the dried solid and heat it up to 800 °C at 5 °C / min for 10 hours in an air atmosphere. A hydrochloric acid solution with a mass fraction of 50% was prepared, diatomite with organic matter removed was added to the solution, stirred at 95 °C for 8 hours, cooled to room temperature, the solution was diluted and washed, and diatomite with high purity was obtained. Mix diatomaceous earth and sodium powder at a mass ratio of 1:2, and keep warm at 97°C for 6 hours under a He protective atmosphere. After natural cooling, soak the solid mixture in 0.01 mol / L hydrochloric acid solution for 12 hours to dilute the solution. After washing, filtering and drying, silicon with a porous str...

Embodiment 3

[0037] Grind diatomaceous earth and mix it with water at a mass ratio of 1:10. After it fully absorbs water, add 30 ml of NaOH with a concentration of 0.01 mol / L as a dispersant, stir evenly and let it stand for 1 hour, suck out the upper layer of suspended mud. The mud is filtered and dried. Take 2.5 g of the dried solid and heat it up to 850 °C at 5 °C / min in an air atmosphere, and calcinate for 3 hours. Sulfuric acid with a mass fraction of 50% was prepared, diatomite with organic matter removed was added to the solution, stirred at 100 °C for 5 hours, cooled to room temperature, the solution was diluted and washed, and diatomite with high purity was obtained. After mixing diatomaceous earth and aluminum powder in a mass ratio of 1:2, under an Ar protective atmosphere, heat up to 650 °C and keep warm for 6 hours. After natural cooling, soak the solid mixture in 0.1 mol / L hydrochloric acid solution for 6 hours, dilute The solution was washed and filtered and then dried to o...

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Abstract

The invention provides a method for preparing a porous silicon/carbon composite material by using diatomite as the raw material, which is characterized by comprising the following steps of: with the diatomite as the raw material, performing simple refinement and purification processing to obtain silicon with a porous structure by means of metallothermic reduction; performing mechanical ball-milling with the carbon materials and/or precursors of carbon, hydro-thermal carbonization, pyrolytic carbonization or chemical vapor deposition to prepare the porous silicon/carbon composite material. Thecomposite material can be directly used as the cathode of the lithium ion battery, or can be mixed with other cathode materials to be used as the cathode materials of the lithium ion battery. Compared with a pure silicon material as the cathode material of the lithium ion battery, the porous silicon/carbon composite material has the advantages that the first reversible capacity and the circulation stability of the material are greatly improved. In the method, the inexpensive and accessible natural minerals are used as the raw materials, thus the cost is low and the preparation method is simple.

Description

technical field [0001] The invention relates to a porous silicon / carbon composite material prepared by using diatomite as a raw material and its application, in particular to a silicon / carbon lithium ion battery negative electrode material prepared from diatomite. Background technique [0002] With the rapid development of electronics and information industries, mobile communications, digital processors, and portable computers have been widely used. The development of space technology, the demand for national defense equipment, and the research and development of electric vehicles have promoted chemical energy, especially lithium-ion secondary energy. The rapid growth of batteries. The currently used secondary batteries mainly include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries and lithium-ion batteries. Lithium-ion batteries are currently the most widely used secondary batteries. Compared with traditional Ni-MH rechargeable batteries and ...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/139
CPCY02E60/12Y02E60/122Y02E60/10
Inventor 范丽珍王明珊陶华超
Owner UNIV OF SCI & TECH BEIJING
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