Silicon-based composite material and preparation method thereof

A technology of silicon-based composite materials and composite materials, applied in the direction of active material electrodes, electrical components, electrochemical generators, etc., can solve the problems of inability to effectively improve cycle stability and rate performance, complex preparation process, and uneven coating thickness and other problems, to achieve the effect of improving the high charge transfer impedance, improving the low power output, and improving the rate performance

Inactive Publication Date: 2020-09-11
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above-mentioned coating materials still cannot effectively improve the cycle stability and rate performance, and the preparation method has disadvantages such as complicated process, low strength of the coating layer, and uneven coating thickness.

Method used

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  • Silicon-based composite material and preparation method thereof
  • Silicon-based composite material and preparation method thereof
  • Silicon-based composite material and preparation method thereof

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preparation example Construction

[0047]The present invention also provides a method for preparing the silicon-based composite material described in the above technical solution, comprising the following steps:

[0048] a) dissolving aluminum salt compound, lithium salt compound and silicon dioxide in a solvent and then sintering to obtain fast ion coating agent;

[0049] b) mixing the silicon-based substrate with the fast ion coating agent to obtain a precursor powder;

[0050] c) mixing the precursor powder, carbon source and liquid-phase coating agent, and sintering to obtain a silicon-based composite material.

[0051] Regarding step a):

[0052] In the present invention, the aluminum salt compound is preferably one or more of aluminum isopropoxide, aluminum sec-butoxide, aluminum sulfate and aluminum nitrate. The lithium salt compound is preferably one or more of lithium carbonate, lithium hydroxide, lithium acetate and lithium citrate. The particle size of the silica is preferably 0.5-2 μm, more prefe...

Embodiment 1

[0074] S1. Weigh 20g of aluminum sec-butoxide, 10g of lithium carbonate, and SiO 2 30g of powder was dissolved in 50mL of ethanol solution, stirred with a magnetic stirrer for 4h, after stirring evenly, dried at 80°C for 5h, and then the dried material was ground to obtain mixture A. Sintering is then carried out in an argon atmosphere at a heating rate of 5° C. / min, raised to 1000° C. and kept for 5 hours to obtain a fast ion coating agent.

[0075] S2, weigh silicon oxide SiO z (z is 0.9, particle size is 3 μm) 200g, fast ion coating agent 10g, put into a ball mill jar for ball milling at a speed of 400r / min, and ball mill for 2h to obtain a precursor powder.

[0076] S3. Add the precursor powder, asphalt and liquid phenolic resin into the fusion machine at a mass ratio of 90:5:5, stir at room temperature at a speed of 300 r / min, and mix for 30 minutes to obtain a mixture.

[0077] S4. Put the mixed material into a crucible, and sinter in an argon atmosphere at a heating r...

Embodiment 2

[0081] S1. Weigh 20g of aluminum sec-butoxide, 10g of lithium carbonate, and SiO 2 30g of powder was dissolved in 50mL of ethanol solution, stirred with a magnetic stirrer for 4h, after stirring evenly, dried at 80°C for 5h, and then the dried material was ground to obtain mixture A. Sintering is then carried out in an argon atmosphere at a heating rate of 5° C. / min, raised to 1000° C. and kept for 5 hours to obtain a fast ion coating agent.

[0082] S2, weigh silicon oxide SiO z (z is 0.9, particle size is 3 μm) 100 g, fast ion coating agent 10 g, put into a ball mill jar for ball milling at a speed of 400 r / min, and ball mill for 2 hours to obtain a precursor powder.

[0083] S3. Add the precursor powder, asphalt and liquid phenolic resin into the fusion machine at a mass ratio of 90:5:5, stir at room temperature at a speed of 300 r / min, and mix for 30 minutes to obtain a mixture.

[0084] S4. Put the mixed material into a crucible, and sinter in an argon atmosphere at a h...

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Abstract

The invention provides a silicon-based composite material and a preparation method thereof. The silicon-based composite material provided by the invention comprises a silicon-based matrix, a fast ionconductor layer coating the surface of the silicon-based matrix, and a carbon layer coating the surface of the fast ion conductor layer. A fast ion conductor of the fast ion conductor layer is LiAlSixOy, x is greater than or equal to 1, and y is greater than or equal to 1. According to the invention, the specific fast ion conductor layer LiAlSixOy and the carbon coating sequentially coat the surface of the silicon-based matrix, so that problems of relatively high charge transmission impedance and relatively low power output of the silicon-based negative electrode material are effectively improved, and the rate capability is improved; and meanwhile, the specific double coating layers are matched, so that the expansion of the silicon-based material is effectively relieved, and the cycle performance is improved.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a silicon-based composite material and a preparation method thereof. Background technique [0002] Over the past 20 years, lithium-ion batteries have dominated the market for portable electronics and have made huge strides in the electric vehicle industry. Graphite is the most commonly used anode material for lithium-ion batteries, with a theoretical capacity of 372mAh / g and an energy density below 150Wh / kg, which is far from meeting the requirement of an energy density of 350Wh / kg. Therefore, research on new anode materials for lithium-ion batteries is imminent. [0003] Due to its theoretical capacity as high as 3590mAh / g, high working platform voltage, environmental friendliness and abundant reserves, silicon anode material is considered the most promising alternative to graphite and will occupy a major position in the future anod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62H01M10/0525H01M10/42
CPCH01M4/386H01M4/624H01M4/625H01M4/628H01M10/0525H01M10/4235H01M2004/027Y02E60/10
Inventor 查晓娟刘兆平季晶晶王益郎庆安
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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