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

A negative electrode material, silicon-carbon composite technology, applied in nanotechnology for materials and surface science, battery electrodes, secondary batteries, etc., can solve problems affecting battery cycle life, increase side reactions, etc., to improve cycle performance, Effect of reduced volume expansion and high reversible capacity

Inactive Publication Date: 2014-10-15
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of this, the first aspect of the embodiment of the present invention provides a silicon-carbon composite negative electrode material, which is used to solve the problem of the interface between the electrode and the electrolyte due to the increase in the specific surface area after silicon nanometerization in the prior art. Increased reaction, and electrochemical agglomeration easily occurs after silicon nanometerization, which seriously affects the cycle life of the battery

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

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[0045] In the second aspect, an embodiment of the present invention provides a method for preparing a silicon-carbon composite negative electrode material, including:

[0046] (1) Dissolving the nitrogen-containing aromatic compound in an organic solvent and preparing a solution with a mass fraction of 1% to 10%; the nitrogen-containing aromatic compound is pyrene diimide, metal-free phthalocyanine or aminopyrene;

[0047] (2) Add silicon nanomaterials to the solution obtained above, the silicon nanomaterials are silicon nanosheets or silicon nanobelts with a length and width of 50-5000nm and a thickness of 10-500nm, stir evenly and ultrasonicate for 5-15 minutes , drying the solvent at 80-100° C. to obtain nitrogen-coated silicon nanomaterials;

[0048] (3) Dissolving the nitrogen-containing organic carbon source in a solvent to prepare a solution with a mass fraction of 1% to 10%; the nitrogen-containing organic carbon source is a polymer containing -CN and / or -CON groups; ...

Embodiment 1

[0066] A method for preparing a silicon-carbon composite negative electrode material, comprising:

[0067] (1) Weigh 7.7g of pyreneimide and place it in a 500mL beaker, add 250mL of acetone, and stir for 30 minutes to obtain a pyreneimide solution with a mass fraction of 3.0%;

[0068] (2) Weigh 5g of silicon nanosheets with a thickness of 20nm, a width of 50nm, and a length of about 500nm, and add them to the above solution, stir at 5000r / min for 20 minutes, then use an ultrasonic cell disruptor to sonicate for 10 minutes, and then place the obtained solution in a rotating Evaporate the solvent in an evaporator, and then place it in an oven and dry it at 80°C for 8 hours to remove the residual solvent and obtain a nitrogen-coated silicon nanomaterial;

[0069] (3) Dissolve 3.0g of polyacrylamide completely in 100g of deionized water, then add 12g of nitrogen-coated silicon nanomaterials, 2.2g of carbon nanotubes, and 20g of artificial graphite powder with a particle size of 3...

Embodiment 2

[0075] A method for preparing a silicon-carbon composite negative electrode material, comprising:

[0076] (1) Weigh 3.8g of metal-free phthalocyanine into a 500mL beaker, add 250mL of acetone, and stir for 30 minutes to obtain a metal-free phthalocyanine solution with a mass fraction of 1.5%;

[0077] (2) Weigh 5g of silicon nanosheets with a thickness of 30nm, a width of 40nm, and a length of about 1000nm, add them to the above solution, stir at 5000r / min for 20 minutes, then use an ultrasonic cell disruptor to sonicate for 10 minutes, and then place the obtained solution in Evaporate the solvent in a rotary evaporator, and then place it in an oven and dry it at 90°C for 10 hours to remove the residual solvent and obtain a nitrogen-coated silicon nanomaterial;

[0078] (3) Dissolve 3.0g of polyacrylamide completely in 100g of deionized water, then add 12g of nitrogen-coated silicon nanomaterials, 2.2g of carbon nanotubes, and 20g of natural graphite powder with a particle si...

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Abstract

An embodiment of the invention provides a silicon-carbon composite anode material which includes a shell and an active and conductive material which is accommodated in the shell. The active and conductive material includes a silicon nano-material, a graphite material and carbon nano-tubes, wherein the silicon nano-material, the graphite material and the carbon nano-tubes are blended according to a weight ratio of 10-30:15-35:1-5. The shell is a cracked carbon layer. The silicon nano-material is silicon nano-sheets or silicon nano-belts with a length-width size being 50-5000 nm and a thickness being 10-500 nm. Surfaces of the silicon nano-sheets or silicon nano-belts are provided with Si-N-Si composite layers and Si-N-C composite layer. The silicon-carbon composite anode material is high in reversible capacity, is high in first-time charging-discharging efficiency, is good in circulating performance, can finally increasing a system capacity of a lithium ion battery and prolongs a cyclic service life of the lithium ion battery. The embodiment of the invention also provides a preparation method of the silicon-carbon composite anode material and the lithium ion battery containing the silicon-carbon composite anode material.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a silicon-carbon composite negative electrode material, a preparation method thereof, and a lithium ion battery. Background technique [0002] In recent years, lithium-ion batteries have been widely used in various portable electronic devices, electric vehicles, and new energy storage due to their advantages such as large specific energy, high working voltage, high safety, and low environmental pollution. However, with the increasing demand for high-energy power sources, there is an urgent need for lithium-ion batteries with high energy density, fast and high-power charging and discharging. In recent years, a lot of research has been carried out on how to develop lithium-ion batteries with high energy density, fast and high-power charging and discharging. [0003] Generally speaking, the total specific capacity of a lithium-ion battery is determined by the components that ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/134H01M4/1393H01M4/1395H01M4/62H01M10/0525
CPCY02E60/122B82Y30/00B82Y40/00H01M4/364H01M4/386H01M4/587H01M10/0525Y02E60/10
Inventor 余翯
Owner HUAWEI TECH CO LTD
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