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Carbon-coated amorphous silicon/graphene composite negative electrode material and preparation method thereof and lithium ion battery

A graphene composite and amorphous silicon technology, which is applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of low composite degree of porous silicon and graphene, which is not conducive to alleviating the expansion of silicon materials, and the preparation process of porous silicon is complicated. , to achieve the effects of good expansion and self-digestion ability, good market application prospects and high energy density

Active Publication Date: 2021-05-18
余姚市海泰贸易有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Comparative document 1: CN105185956A discloses a method for preparing a spongy silicon graphene and carbon nanotube composite negative electrode material, which is mainly aimed at the composite of silicon, graphene and carbon nanotubes. This technology combines crystalline silicon with graphene and carbon nanotubes Disperse in a solvent to form a gel, and freeze-dry to obtain a spongy graphene carbon nanotube composite airgel material that absorbs silicon powder; the product obtained by this method has a low energy density, especially for the silicon material itself. The structure is relatively simple, which is not conducive to alleviating the expansion of the silicon material itself
[0007] Reference document 2: CN106611843A discloses a method for preparing a porous silicon / graphene composite lithium-ion battery negative electrode material. In this method, silicon and metal aluminum are alloyed, and the alloyed product is cut and pickled to obtain a porous Silicon, and finally the obtained porous silicon and graphene are dispersed in a solvent, suction filtered, dried, and roasted to obtain a porous silicon / graphene composite lithium-ion battery negative electrode material; the preparation process of porous silicon is complicated in this method, and porous silicon and graphene are composited The degree is low, the specific surface area of ​​the obtained product is larger, the first irreversible capacity is higher than that of silicon itself, and there is not much use value

Method used

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  • Carbon-coated amorphous silicon/graphene composite negative electrode material and preparation method thereof and lithium ion battery
  • Carbon-coated amorphous silicon/graphene composite negative electrode material and preparation method thereof and lithium ion battery
  • Carbon-coated amorphous silicon/graphene composite negative electrode material and preparation method thereof and lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0045] (1) Put 45g of monocrystalline silicon with a purity of 99.999% and 18g of metal lithium in a ball milling tank, add 12.6g of silicon carbide balls, pass in Ar gas protection, and ball mill at 400r / min for 40 hours to obtain precursor 1;

[0046] (2) Take 20g of precursor 1 and put it into 200ml of solvent 1. Solvent 1 is a mixed solution composed of ethanol with a volume ratio of 1:1: n-butanol. Heat it to 50°C under the protection of Ar gas atmosphere, treat for 5h, and the reaction is complete. After stirring for 5 hours, filter with suction, soak the filter residue in 1mol / L HCl solution for 5 hours, filter with suction, wash the filtrate with deionized water until the pH of the washed liquid is detected to be ≥ 6.5, and obtain amorphous silicon with a layered structure, that is, the precursor 2;

[0047] (3) Precursor 2 is dispersed in deionized water, and sand milled. The feeding speed of the sand mill is 15mL / min, and the frequency is 2000 revolutions. Shaped si...

Embodiment 2

[0052] (1) Put 50g of monocrystalline silicon with a purity of 99.999% and 25g of metallic lithium in a ball milling tank, add 25g of zirconia balls, pass in Ar gas protection, and ball mill at 450r / min for 40 hours to obtain precursor 1;

[0053] (2) Take 20g of precursor 1 and put it into 500ml of solvent 1. Solvent 1 is a mixed solution composed of ethanol with a volume ratio of 1:1: n-butanol. Heat it to 80°C under the protection of Ar gas atmosphere, treat for 5h, and the reaction is completed. After stirring for 5 hours, filter with suction, soak the filter residue in 1mol / L HCl solution for 5 hours, filter with suction, wash the filtrate with deionized water until the pH of the washed liquid is detected to be ≥ 6.5, and obtain amorphous silicon with a layered structure, that is, the precursor 2;

[0054] (3) Precursor 2 is dispersed in deionized water, and sand milled. The feeding speed of the sand mill is 20mL / min, and the frequency is 2300 revolutions. Shaped silicon...

Embodiment 3

[0059] (1) Put 40g of polysilicon with a purity of 99.999% and 60g of metal aluminum in a ball milling tank, add 30g of silicon carbide balls, pass through He gas protection, and ball mill at 800r / min for 30 hours to obtain the precursor 1;

[0060] (2) Take 30g of precursor 1 and put it into 600ml of solvent 1. Solvent 1 is a mixed solution composed of ethanol: ethylene glycol with a volume ratio of 1:1. Heat it to 100°C under the protection of nitrogen atmosphere and treat it for 10h. After the reaction is completed, Stir for 6 hours, filter with suction, soak the filter residue in 1mol / L HCl solution for 8 hours, filter with suction, wash the filtrate with deionized water until the pH of the washed liquid is detected to be ≥ 6.5, and obtain amorphous silicon with a layered structure, that is, the precursor 2;

[0061] (3) Precursor 2 is dispersed in deionized water, and sand milled. The feeding speed of the sand mill is 5mL / min, and the frequency is 2500 revolutions. Shape...

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Abstract

The invention provides a carbon-coated amorphous silicon / graphene composite negative electrode material and its preparation method and lithium ion battery. The preparation method is as follows: after mixing micron silicon, metal and ball milling agent in proportion and ball milling, heat treatment under an inert atmosphere to obtain Precursor 1; Precursor 1 was added to solvent 1, and heated under an inert atmosphere to obtain Precursor 2; Precursor 2 was dispersed in deionized water, sand-milled, classified, filtered, and dried to obtain Precursor 3; Precursor 3, Graphene oxide, surfactant, and carbon source 1 are dispersed in solvent 2 in proportion, and spray granulated to obtain precursor 4; precursor 4 and carbon source 2 are mixed and thermally fused in proportion to obtain precursor 5; precursor 5 is in an inert atmosphere High temperature sintering, that is. As a negative electrode material, the layered structure of amorphous silicon can alleviate the volume expansion of silicon materials during charging and discharging. The carbon-coated shell is conducive to the formation of a dense SEI film. The material has high reversible capacity, good cycle performance, and rate performance. excellent.

Description

technical field [0001] The invention relates to a composite negative electrode material and its preparation method and lithium ion battery, in particular to a carbon-coated amorphous silicon / graphene composite negative electrode material and its preparation method and lithium ion battery, belonging to the lithium ion battery negative electrode material preparation technology field. [0002] technical background [0003] Compared with traditional lead-acid, nickel-cadmium, nickel-metal hydride and other secondary batteries, lithium-ion secondary batteries have high working voltage, small size, light weight, high capacity density, no memory effect, no pollution, small self-discharge and good cycle life. Long life and other advantages. Since Sony successfully commercialized lithium-ion batteries in 1991, lithium-ion batteries have become the dominant power source for mobile phones, notebook computers and digital products, and are increasingly used in electric vehicles and energ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/628H01M10/0525Y02E60/10
Inventor 车欢张言齐士博陈小平
Owner 余姚市海泰贸易有限公司