Silicon-based negative electrode active material and its preparation method and application

A technology of active materials and silicon-based negative electrodes, applied in nanotechnology for materials and surface science, battery electrodes, final product manufacturing, etc., can solve the problem of loss of electrical contact between electrode active materials and current collectors, hindering the practical application of silicon negative electrode materials , reduce battery rate performance and other issues, to achieve the effect of large-scale industrial production, simple and efficient preparation method, and excellent rate performance

Active Publication Date: 2021-07-02
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] But there are two main problems hindering the practical application of silicon anode materials
First of all, silicon will have a severe volume effect in the process of inserting and removing lithium, and the mechanical force generated will pulverize and break the material, resulting in the loss of electrical contact between the electrode active material and the current collector, thereby greatly reducing the battery cycle performance.
And this drastic volume change makes it difficult for silicon to form a stable SEI film in the electrolyte, which intensifies the capacity fading of silicon.
In addition, silicon is a semiconductor material with low electrical conductivity, which reduces the rate performance of the battery

Method used

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  • Silicon-based negative electrode active material and its preparation method and application
  • Silicon-based negative electrode active material and its preparation method and application
  • Silicon-based negative electrode active material and its preparation method and application

Examples

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preparation example Construction

[0054] The present invention also provides a method for preparing a silicon-based negative electrode active material, the method comprising:

[0055] (1) In situ polymerizing aniline monomers on the surface of silicon nanoparticles to form a polyaniline crosslinked three-dimensional network structure to obtain a silicon / polyaniline composite material;

[0056] (2) molding the silicon / polyaniline composite material;

[0057] (3) Convert at least part of the surface layer of the formed silicon / polyaniline composite material into a carbonized layer by carbonization treatment.

[0058] According to the present invention, the particle size of the silicon nanoparticles is not particularly limited, for example, it may be 500 nm or less. From the perspective of facilitating the transport of lithium ions and suppressing the volume effect of the material, the particle size of the silicon nanoparticles is preferably within 300nm, more preferably within 200nm, for example, it can be 20-2...

Embodiment 1

[0076] (1) In-situ polymerization: 1.273g phytic acid, 0.419g aniline monomer and 4g silicon nanoparticles (particle size: 100nm) were mixed and recorded as solution A; 0.428g ammonium persulfate was dissolved in 15mL deionized water and recorded as Solution B: Mix solution A and solution B, stir (20h) and sonicate (100Hz, 30min) to obtain a silicon / polyaniline composite material with a three-dimensional porous network structure.

[0077] (2) Spray drying: the silicon / polyaniline composite material in step (1) is spray-dried to obtain silicon / polyaniline microspheres (average particle diameter is 10 μm), wherein the spray drying conditions include: air inlet temperature 180 ℃, air outlet temperature 60 ℃, peristaltic pump rate 8%, needle pass frequency 2 times per second.

[0078] (3) Surface carbonization: heat the silicon / polyaniline microspheres in step (2) at a temperature of 500° C. for 1 hour in a tube furnace fed with argon, and heat up at a rate of 5° C. / min to make th...

preparation example 1

[0088] The silicon-based negative electrode active materials of the above-mentioned examples and comparative examples were ground and evenly coated with conductive carbon black (Super P), sodium carboxymethylcellulose, and styrene-butadiene latex according to a weight ratio of 8:1:0.5:0.5. Copper foil current collector, and vacuum drying at 120 ° C to obtain a negative electrode sheet.

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Abstract

The invention relates to the field of lithium ion batteries, and discloses a silicon-based negative electrode active material, a preparation method and application thereof, a negative electrode sheet and a lithium ion battery. The silicon-based negative active material includes a core layer including polyaniline and silicon nanoparticles, and a carbonized layer formed on at least a portion of the core layer. The lithium ion battery prepared by the silicon-based negative electrode active material of the invention has good cycle stability and rate performance.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a silicon-based negative electrode active material, a preparation method and application thereof, a negative electrode sheet and a lithium-ion battery. Background technique [0002] With the growth of world population and the development of social technology, the demand for energy is also increasing day by day. Among all currently existing energy storage devices, high-performance lithium-ion batteries are indispensable energy storage devices, which are widely used in portable electronic equipment, such as mobile phones, notebook computers, and even in electronic transportation equipment, such as electric vehicles. applied. The traditional lithium-ion battery anode material is graphite anode material. However, the theoretical specific capacity of graphite is low (372mAh / g), which cannot meet today's demand for energy. The silicon negative electrode material has a theoretica...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/134H01M4/36H01M4/38H01M4/62H01M10/052H01M10/058B82Y30/00
CPCB82Y30/00H01M4/134H01M4/366H01M4/386H01M4/625H01M10/052H01M10/058Y02E60/10Y02P70/50
Inventor 吴伯荣穆道斌牟鸽丁泽鹏
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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