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Preparation method of silicon/carbon/graphite composite material for lithium ion battery cathode

A technology for lithium ion batteries and composite materials, which is applied in the field of preparation of silicon/carbon/graphite composite materials for negative electrodes of lithium ion batteries, can solve problems such as unfavorable large-scale preparation and application, and achieves improved high-rate discharge performance and improved stability. The effect of improving the stability of the structure

Pending Publication Date: 2019-07-23
内蒙古斯诺新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, a single modification method is difficult to make the electrochemical performance of silicon-based anode materials meet the requirements of commercial development, which is not conducive to large-scale preparation and application.

Method used

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  • Preparation method of silicon/carbon/graphite composite material for lithium ion battery cathode
  • Preparation method of silicon/carbon/graphite composite material for lithium ion battery cathode
  • Preparation method of silicon/carbon/graphite composite material for lithium ion battery cathode

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preparation example Construction

[0030] The invention provides a method for preparing a silicon / carbon / graphite composite material for a negative electrode of a lithium ion battery, which specifically comprises the following steps:

[0031] 1) Pretreatment and purification are carried out after drying the silicon-containing raw material to obtain a silicon source meeting the particle size requirements;

[0032] 2) Composite the silicon source, organic carbon source, and high-purity graphite in the following two different ways to obtain a silicon / carbon / graphite composite material.

[0033] A. Combining the silicon source and the organic carbon source in solid phase or liquid phase to obtain a precursor, then placing the precursor in an inert gas atmosphere for high-temperature pyrolysis to obtain a silicon-carbon material, and then combining the silicon The carbon material is mechanically mixed with the high-purity graphite to obtain the silicon / carbon / graphite composite material.

[0034] B. Mix the silicon...

Embodiment 1

[0043] (1) Weigh 500g of silicon-copper alloy and dry it, add 1000g of 2M hydrochloric acid, stir for 12h under magnetic stirring, pour out the supernatant after standing, add water and ethanol to wash repeatedly 3 times, test the pH value of the solution, if If it is acidic, then add sodium hydroxide solution to neutralize to neutral; finally add 500g of absolute ethanol (mass ratio of material: ethanol is 1:1), and then add 2500g of agate balls of different diameters (mass ratio of ball: material is 5 : 1) Carry out high-energy ball milling, wherein 1500g of agate balls with a diameter of 5mm, 750g of agate balls with a diameter of 8mm, and 250g of agate balls with a diameter of 1cm, mixed ball milling time 12h, rotating speed 250r / min, collect the product after ball milling and dry it for subsequent use, and test the product particle size, morphology or crystal form.

[0044] (2) Weigh 53.3g of citric acid and dissolve it in 2000ml of pure water to make a solution, take 200...

Embodiment 2

[0048] (1) Weigh 500g of silicon-copper alloy and dry it, add 1000g of 2M hydrochloric acid, stir for 12h under magnetic stirring, pour out the supernatant after standing, add water and ethanol to wash repeatedly 3 times, test the pH value of the solution, if If it is acidic, then add sodium hydroxide solution to neutralize to neutral; finally add 500g of absolute ethanol (mass ratio of material: ethanol is 1:1), and then add 2500g of agate balls of different diameters (mass ratio of ball: material is 5 : 1) carry out high-energy ball milling, wherein the agate ball 1500g of diameter 5mm, the agate ball 750g of diameter 8mm, the agate ball 250g of diameter 1cm, mixing ball milling time 12h, rotating speed 250r / min, the product drying after collecting ball milling is standby.

[0049] (2) Weigh 133g of polyvinylpyrrolidone and dissolve it in 4000ml of pure water to make a solution, take 200g of the product obtained in the above step (1) and add it to the above solution, stir for...

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Abstract

The invention provides a preparation method of a silicon / carbon / graphite composite material for a lithium ion battery cathode, which comprises the following steps: drying the silicon-containing raw material, and then carrying out pretreatment and purification to obtain a silicon source; compounding a silicon source, an organic carbon source and high-purity graphite in two different ways to preparethe silicon / carbon / graphite composite material: performing solid-phase or liquid-phase compounding on the silicon source and the organic carbon source to prepare a precursor, then placing the precursor in an inert gas atmosphere for high-temperature pyrolysis to obtain a silicon-carbon material, and then mechanically mixing the silicon-carbon material and high-purity graphite to obtain a silicon / carbon / graphite composite material; and mixing the silicon source, the organic carbon source and the high-purity graphite, adding a dispersing agent, uniformly dispersing, spray-drying, and placing inthe inert gas atmosphere for high-temperature pyrolysis to obtain the silicon / carbon / graphite composite material. The cathode material prepared by the invention can improve the conductivity, inhibitthe volume expansion of silicon, improve the cycle performance of the battery and is suitable for large-scale production.

Description

[0001] 【Technical field】 [0002] The invention belongs to the technical field of battery negative electrode materials, and in particular relates to a method for preparing a silicon / carbon / graphite composite material for lithium ion battery negative electrodes. [0003] 【Background technique】 [0004] Lithium-ion batteries have the advantages of high working voltage, large specific energy, long cycle life, no pollution, and no memory effect. Expand the field of high-power systems such as energy batteries. Lithium-ion battery anodes mainly use graphite-based anode materials, but their theoretical specific capacity is low (372mAh / g), and the first cycle efficiency is relatively low, which cannot meet the needs of high specific energy batteries. Looking for anode materials with higher specific capacity is currently the One of the important directions of lithium-ion battery research. At present, silicon-based anode materials have attracted much attention because of their high the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 杨建锋袁媛卢源明田东
Owner 内蒙古斯诺新材料科技有限公司