Silicon-containing composite material and its preparation method and application

A technology of silicon composite materials and silicon particles, which is applied in the direction of fibrous fillers, dyed polymer organic compounds, etc., can solve the problems of destroying the structure of graphite particles and affecting the electrochemical performance of composite materials, and achieve uniform structure, excellent conductivity, The effect of little environmental pollution

Active Publication Date: 2008-07-02
BYD CO LTD
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Problems solved by technology

This method uses the concentrated sulfuric acid dehydration method instead of the high-temperature carbonization method. Although it overcomes the industrial energy consumption problem caused by the high-temperature carbonization method, it also brings a lot of waste concentrated sulfuric acid or dilute sulfuric acid treatment problems.
In addition, this method uses high-energy ball milling to mix silicon powder and graphite to obtain silicon powder with a small particle size, but the ball mill destroys the graphite particle structure, thereby affecting the electrochemical performance of the composite material.

Method used

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  • Silicon-containing composite material and its preparation method and application
  • Silicon-containing composite material and its preparation method and application

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preparation example Construction

[0027] According to the preparation method of the silicon-containing composite material provided by the present invention, in order to make the polymerization reaction more uniform and to make the coating layer more uniformly cover the surface of the silicon particles, the method of making the conductive polymer coated on the surface of the silicon particles is included in In the presence of inorganic dopants and silicon particles, the solution of the organic polymer precursor is subjected to polymerization reaction under polymerization reaction conditions. The solution of the organic polymer precursor contains the organic polymer precursor and a solvent, and the concentration of the organic polymer precursor in the solution may be 0.5-25% by weight, preferably 1-10% by weight. The organic polymer precursor is a monomer substance capable of reacting with an inorganic dopant to form a conductive polymer after polymerization. The organic polymer precursor may be, for example, on...

Embodiment 1

[0040] This example is used to illustrate the silicon-containing composite material provided by the present invention and its preparation method.

[0041] Add 0.5 gram of silicon particles (the average particle diameter is 20-50 nanometers, purchased from Zhongzhang International Co., Ltd.) and 0.5 gram of polyvinyl alcohol into 100 milliliters of hydrochloric acid solution with a concentration of 1 mol / liter, and magnetically stir the silicon particles to disperse evenly . Then 0.5 g of aniline was added at room temperature and magnetic stirring was continued for 30 minutes. Then 50 milliliters of 1 mol / liter hydrochloric acid solution containing 1.32 grams of ammonium persulfate was added dropwise to the above mixed solution, and the addition was completed in 1 hour. After the dropwise addition was complete, stirring was continued for 3 hours. Then the mixed solution was filtered, washed, and dried at 80° C. to obtain the silicon-containing composite material S1 provided b...

Embodiment 2

[0043] This example is used to illustrate the silicon-containing composite material provided by the present invention and its preparation method.

[0044] 0.5 grams of silicon particles (average particle diameter D 50 0.45 μm) and 0.5 g of polyvinyl alcohol were added to 100 ml of lithium chloride solution with a concentration of 1 mol / L, and magnetically stirred to disperse the silicon particles evenly. Then 2.5 g of aniline was added and magnetic stirring was continued for 30 minutes. Then 50 milliliters of 1 mol / liter hydrochloric acid solution containing 1.32 grams of ammonium persulfate was added dropwise to the above mixed solution, and the addition was completed in 1 hour. After the dropwise addition was complete, stirring was continued for 3 hours. Then the mixture was filtered, washed, and dried at 80° C. to obtain the silicon-containing composite material S2 provided by the present invention. Measure the average particle diameter D with X100 particle size analyzer...

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Abstract

The invention provides a siliceous composite material, comprising silicon particles and a clad wrapped on the surface of silicon particles, wherein, the clad is conducting polymer. The siliceous composite material provided by the invention takes the conducting polymer as the clad; the polymer does not need to be transformed further into 'hard carbon', and the siliceous composite material is guaranteed to have excellent conductivity; meanwhile, the aggregation between silicon particles can be avoided. When the composite material is taken as negative active material of a lithium iron battery, the lithium iron battery is ensured to have high reversible capacity and good cycle performance. Therefore, the invention can be taken as the negative active material of the lithium iron battery. As the polymer does not need to be transformed further into the 'hard carbon' and the siliceous composite material has good conductivity in the preparation of the siliceous composite material provided by the invention, the manufacturing technique is simplified and the problem of huge energy consumption caused by the high temperature carbonization process in the prior art is solved.

Description

technical field [0001] The invention relates to a silicon-containing nanocomposite material and its preparation method and application. Background technique [0002] Most of the current commercialized lithium-ion batteries use lithium transition metal oxide / graphite system as the negative electrode active material. The capacity is only 372 mAh / g. Such a low capacity is currently difficult to meet the miniaturization development of various portable electronic devices and the demand for large-capacity and high-power chemical power sources for electric vehicles. Therefore, a new negative electrode active material with higher specific capacity is currently being studied to improve the performance of lithium-ion batteries and meet market demand. [0003] Studies on non-carbon negative electrode active materials have shown that there are many metals or alloys with high lithium storage performance that may be used as negative electrode active materials. Among them, silicon has a l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09C3/10C09C1/28C08L79/00C08L65/00C08K3/24
Inventor 梁善火沈菊林肖峰
Owner BYD CO LTD
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