Preparation method of silicon carbon negative electrode precursor

A technology of precursor and negative electrode, applied in the field of preparation of silicon carbon negative electrode precursor, can solve the problems of poor controllability of composite structure and particle size, poor material capacity, and difficulty in commercial use, so as to ensure the activity of nano-silicon and improve the first effect. and cycle performance, the effect of improving stability

Active Publication Date: 2019-10-18
CHANGSHA RES INST OF MINING & METALLURGY
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  • Abstract
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Problems solved by technology

This material has good electrical conductivity, but the composite structure and particle size controllability of the material are poor, which eventually leads

Method used

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  • Preparation method of silicon carbon negative electrode precursor
  • Preparation method of silicon carbon negative electrode precursor
  • Preparation method of silicon carbon negative electrode precursor

Examples

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Example Embodiment

[0039] Example 1:

[0040] A preparation method of the silicon carbon negative electrode precursor of the present invention includes the following steps:

[0041] (1) Add nano silicon powder with particle size D50=120nm and artificial graphite powder with particle size D50=6μm into N-methylpyrrolidone (wherein, the mass ratio of nano silicon powder to artificial graphite powder is 20:100, powder The mass ratio to the solvent is 30:100), and then it is placed in a sand mill for dispersion (the grinding process is sealed and nitrogen is introduced for protection), the sanding speed is 1200rpm, and the sanding is 1h to prepare a uniformly dispersed nano-silicon slurry A;

[0042] (2) Dissolve stearic acid in N-methylpyrrolidine at a mass ratio of 40:100, mix and stir it thoroughly with a mechanical mixer at a speed of 1500 rpm for 30 minutes to prepare slurry B;

[0043] (3) Dissolve graphene in N-methylpyrrolidine chamber at a mass ratio of 2:100, and use an ultrasonic disperser to ult...

Example Embodiment

[0060] Example 2:

[0061] A preparation method of the silicon carbon negative electrode precursor of the present invention includes the following steps:

[0062] (1) Add nano silicon powder with particle size D50=100nm and mesophase carbon microspheres with particle size D50=8μm into absolute ethanol (the mass ratio of nano silicon powder to mesophase carbon microspheres is 25:100, powder The mass ratio to the solvent is 30:100), disperse and grind with a sand mill (protected by nitrogen), the speed of the sand mill is 1500 rpm, and the sanding time is 45 minutes to prepare slurry A with uniformly dispersed nano-silicon;

[0063] (2) Dissolve palmitic acid in absolute ethanol at a mass ratio of 50:100, thoroughly mix and stir the mixture with a mechanical mixer, rotate at 1500 rpm, and stir for 30 minutes to prepare slurry B;

[0064] (3) Dissolve the carbon nanotubes in absolute ethanol at a mass ratio of 5:100, and use an ultrasonic disperser to ultrasonically disperse the mixed li...

Example Embodiment

[0067] Example 3:

[0068] A preparation method of the silicon carbon negative electrode precursor of the present invention includes the following steps:

[0069] (1) Add nano silicon powder with particle diameter D50=100nm and natural graphite powder with particle diameter D50=6μm into acetone (the mass ratio of nanometer silicon powder to natural graphite powder is 20:100, the mass ratio of powder to solvent 25: 100), disperse with a planetary ball mill (nitrogen protection during the sanding process), the ball milling speed is 1800 rpm, and the ball milling time is 45 minutes, to obtain a uniformly dispersed nano-silicon slurry A;

[0070] (2) Dissolve sebacic acid in acetone at a mass ratio of 40:100, fully mix and stir with a mechanical stirrer at a speed of 1500 rpm for 30 minutes to prepare slurry B;

[0071] (3) Dissolve graphene in acetone at a mass ratio of 2:100, and perform ultrasonic dispersion with an ultrasonic disperser, frequency 10khz, power 5kw, ultrasonic 30min, to...

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Abstract

The invention discloses a preparation method of a silicon carbon negative electrode precursor. The preparation method comprises the steps of adding nanometer silicon powder and carbon micro powder into an organic solvent, and performing grinding and dispersion to form paste A; adding a nanometer carbon material into the organic solvent, and performing uniform dispersion to form paste B; adding a binding agent into the organic solvent, and performing uniform dispersion to form paste C; mixing and uniformly dispersing the paste A, the paste B and the paste C to form paste D; and performing spraydrying granulation on the paste D to obtain the silicon carbon negative electrode precursor. Multi-step dispersion is employed, the dispersion performance and the stability of the mixed paste are improved, the dispersion process time is reduced, the dispersion efficiency is improved, a relevant risk such as granulation plug is reduced, and subsequent application and mass production are facilitated; meanwhile, the carbon micro powder and the nanometer carbon material are introduced, on one hand, the problem of silicon conductivity is solved, the internal resistance is reduced, and the initialcoulombic efficiency and the rate performance are improved; and on the other hand, the volume expansion during the charge-discharge process of silicon is solved, the integral expansion rate of the material is reduced, the material pulverization is prevented, and the cycle property is improved.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a preparation method of a structurally stable silicon-carbon negative electrode precursor. Background technique [0002] Lithium-ion batteries have the characteristics of high working voltage, high energy density, light weight, and environmental friendliness, and are widely used in various portable electronic devices and electric vehicles. At present, the commercial lithium-ion battery anode materials are mainly graphite, but the low specific capacity (theoretical specific capacity is 372mAh / g) limits its further development in the energy density of lithium-ion batteries. As a representative of new high-capacity materials, silicon materials have the advantages of high lithium storage capacity (theoretical specific capacity 4200mAh / g), low discharge platform, and abundant reserves, which has become a breakthrough to solve the goal of 300Wh / kg. [0003] How...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/364H01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 汤刚彭青姣杨乐之涂飞跃陈涛余林遇史诗伟罗磊王艳华殷敖庄子龙刘志宽覃事彪
Owner CHANGSHA RES INST OF MINING & METALLURGY
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