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Modified silicon carbon material and its preparation method and application

A carbon material and modified silicon technology, applied in the field of modified silicon carbon material and its preparation, can solve the problems of poor volume change conductivity, pulverization of pole pieces, falling off, etc., and achieve the effect of inhibiting volume expansion and ultra-long cycle life. , the effect of stabilizing the Coulomb efficiency

Active Publication Date: 2021-10-08
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its pure silicon material has a huge volume change and poor conductivity during the charging and discharging process of the battery. This huge volume change will lead to the pulverization and shedding of the prepared pole piece, resulting in the separation of the electrode active material and the current collector, thus seriously Affect the cycle performance and rate performance of the battery

Method used

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  • Modified silicon carbon material and its preparation method and application
  • Modified silicon carbon material and its preparation method and application
  • Modified silicon carbon material and its preparation method and application

Examples

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preparation example Construction

[0122] As one of the specific implementations, the preparation method of the modified silicon carbon material includes the following steps:

[0123] (1) placing the carbon source in the dispersion liquid to disperse to obtain the first suspension;

[0124] (2) adding a silicon source to the first suspension, and dispersing to obtain a second suspension;

[0125] (3) Spray-drying the second suspension to obtain a silicon-carbon precursor; then mixing the silicon-carbon precursor with a coated carbon source for carbonization to obtain silicon carbide carbon;

[0126] (4) Disperse the carbon fluoride material and / or the functional additive material in the dispersion to obtain the third suspension; (5) Mix the third suspension with silicon carbide carbon, and then dry it to obtain the modified Silicon carbon material;

[0127] or

[0128] (1) placing the carbon source in the dispersion liquid to disperse to obtain the first suspension;

[0129] (2) adding a silicon source to t...

Embodiment 1

[0135] Embodiment 1 prepares modified silicon carbon material by fluorinated carbon material (fluoride I)

[0136] Preparation of sample M1#:

[0137] (a) Take 100g of graphitized carbon and drop it into the mixed dispersion of 500ml ethanol and water (volume ratio 1:1) and stir evenly, then add 60g of nano-silicon material and mix evenly to obtain a silicon-carbon suspension, the silicon-carbon suspension Spray drying is carried out to obtain a silicon carbon precursor;

[0138] (b) Stir 150g of sucrose in a mixed dispersion of 500ml of ethanol and water (volume ratio 1:1), and add 310g of the silicon-carbon precursor in step (a), and then carbonize at 950°C for 4h to obtain silicon carbide carbon Precursor;

[0139] (c) Get graphene fluoride 5g and drop into the mixed dispersion liquid of the ethanol of 50ml and water (volume ratio 1:1) and stir evenly, make the first suspension;

[0140] (d) Mix the first suspension in step (c) with 100 g of the silicon carbide carbon pr...

Embodiment 2

[0151] Example 2 Preparation of Modified Silicon Carbon Material by Fluoride II

[0152] Preparation of sample M4#:

[0153] (a) Take 100g of graphitized carbon and drop it into the mixed dispersion of 500ml ethanol and water (volume ratio 1:1) and stir evenly, then add 60g of nano-silicon material and mix evenly to obtain a silicon-carbon suspension, the silicon-carbon suspension Spray drying is carried out to obtain a silicon carbon precursor;

[0154] (b) Stir 150g of sucrose in a mixed dispersion of 500ml of ethanol and water (volume ratio 1:1), and add 310g of the silicon-carbon precursor in step (a), and then carbonize at 950°C for 4h to obtain silicon carbide carbon Precursor;

[0155] (c) 5g of lithium fluoride was dropped into a mixed dispersion of 30ml of isopropanol and water (volume ratio 2:1) and stirred evenly to obtain a second suspension;

[0156] (d) mixing the second suspension in step (c) with 100 g of the silicon carbide carbon precursor in step (b), and...

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Abstract

The present application discloses a modified silicon carbon material, which includes a silicon carbon body and a carbon fluoride protective layer, and the carbon fluoride protective layer is coated on the surface of the silicon carbon body; the carbon fluoride protective layer is selected from At least one of the compounds of formula I. The modified material provided by this application has stable coulombic efficiency and long cycle life, and has high capacity retention rate at the same time.

Description

technical field [0001] The application relates to a modified silicon-carbon material and its preparation method and application, belonging to the technical field of lithium battery materials. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, small self-discharge capacity, and no memory effect. They have brought revolutionary changes to the field of energy storage and are widely used in various portable electronic devices and electric vehicles. However, as the market demand for high-energy-density lithium-ion batteries increases, lithium-ion battery anode materials are required to have higher mass and volumetric energy densities. At present, the marketed negative electrode materials are mainly graphite (theoretical capacity 372mAh / g), but its actual specific capacity is close to the theoretical capacity, and it is difficult to greatly increase it, thus limiting the improvement of the energy density of negativ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M4/38H01M4/58H01M10/0525
CPCH01M4/362H01M4/366H01M4/386H01M4/5815H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 刘孟王木钦任重民王德宇
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI