Preparation method of nano silicon-based/carbon composite material

A carbon composite material, nano-silicon technology, applied in the direction of nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc. The effect of improving cycle stability

Active Publication Date: 2016-01-20
HUNAN SHINZOOM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the average particle size of commercially available nano-silica powder is basically above 50nm, so cracking and pulverization still occur

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] A preparation method of nano-silicon-based / carbon composite material, prepared according to the following steps:

[0016] Step (I) Preparation of carbon-coated nano-silicon: After dissolving the phenolic resin in absolute ethanol, add naphthalene to it at a ratio of 1:1 according to the molar ratio of the resin to the organic pore-forming agent naphthalene, and wait for the naphthalene to dissolve According to the ratio of phenolic resin to silicon mass ratio of 1:10, nano-silicon powder with a particle size D50 of 50nm was added to it, ultrasonically dispersed for 60min, and then vacuum-dried at 200°C. Under nitrogen atmosphere, the heating rate was 10°C / Min to 800 ° C for 360 min, naturally cooled to room temperature, and then pulverized;

[0017] Step (II) Preparation of silicon-carbon composite precursor: After dispersing cornstarch in water to form a suspension, add dry yeast powder according to the mass ratio of starch and dry yeast powder at 1:0.05, and then pre...

Embodiment 2

[0023] Basically the same method and steps as in Example 1, but there are the following differences:

[0024] 1. In the first step, the molar ratio of resin to organic pore-forming agent naphthalene is 1:0.1, the mass ratio of phenolic resin to silicon is 1:1, the particle size D50 of nano silicon powder is 10nm, and ultrasonically dispersed for 60min After vacuum drying at 200°C, under nitrogen atmosphere, heat preservation at 10°C / min to 800°C for 10 hours.

[0025] 2. In the second step, the mass ratio of starch to dry yeast powder is 1:0.01, and the mass ratio of starch to composite granules is 1:0.1.

[0026] 3. Step IV is not required.

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PUM

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Abstract

The invention provides a preparation method of a nano silicon-based / carbon composite material. The method comprises the following steps: firstly, coating a nano silicon surface with a micro-pore carbon layer by organic resin and a pore forming material in a liquid phase; and then adopting fermented starch as a carbon source, and carrying out coating and high-temperature carbonization to prepare the nano silicon-based / carbon composite material. The nano silicon-based / carbon composite material with pomegranate-type structure characteristics can be prepared by the method provided by the invention. When the nano silicon-based / carbon composite material is applied to a preparation of a lithium-ion battery anode material, the problems of a rapid volume expansion in a lithium intercalation process and grain breakage, pulverization and falling in a circulating process can be effectively solved; the specific capacity of the material can be up to 450-950mAh / g; and the capacity retention ratio is 85%-92% after circulating charge and discharge for 500 cycles.

Description

technical field [0001] The invention relates to a preparation method of a nano silicon material, in particular to a preparation method of a nano silicon base / carbon composite material. Background technique [0002] The theoretical specific capacity of graphite-based carbon negative electrode materials widely used in lithium-ion batteries is only 372mAh / g, which limits the application of lithium-ion batteries in the direction of high energy density. Due to its high lithium intercalation capacity and high lithium ion diffusion capacity, silicon-based materials have become the first choice for carbon replacement materials for lithium-ion battery anode materials. However, due to the complex phase transition of Si in the process of electrochemical lithium intercalation, accompanied by a huge volume change, the volume change of silicon-based materials is as high as more than 300% in the process of intercalation and delithiation, which makes it rupture during charging and dischargi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/587B82Y30/00
CPCB82Y30/00H01M4/362H01M4/386H01M4/587Y02E60/10
Inventor 肖志平皮涛黄越华黎建峰邵浩明
Owner HUNAN SHINZOOM TECH
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