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Carbon-silicon composite secondary particle and preparation method thereof

A secondary particle, carbon-silicon composite technology, applied in the preparation/purification of carbon, secondary batteries, silicon, etc., can solve the problems of material disintegration, poor cycle performance, large volume change, etc., and achieve the effect of improving electrical conductivity

Pending Publication Date: 2022-03-18
BEIJING TU CREATIVE CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it has the problems of large volume change during charging and discharging, material disintegration after cycling, and poor cycle performance.

Method used

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  • Carbon-silicon composite secondary particle and preparation method thereof
  • Carbon-silicon composite secondary particle and preparation method thereof
  • Carbon-silicon composite secondary particle and preparation method thereof

Examples

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preparation example Construction

[0041] According to an embodiment of the present disclosure, such as figure 2 As shown, a method for preparing carbon-silicon composite secondary particles is provided, wherein the method comprises the following steps:

[0042] S1: Mixing the carbon precursor and nano hollow silicon material by high-speed stirring to obtain nano hollow silicon-carbon precursor embedded particles;

[0043] Wherein, relative to the total weight of the carbon precursor and the nano hollow silicon material, the amount of the carbon precursor is 5%-40%;

[0044] S2: heating the nano hollow silicon-carbon precursor embedding particles to 600-1000° C. to prepare carbon-silicon composite secondary particles.

[0045] The preparation method of the present disclosure adopts a relatively simple preparation method, and obtains a silicon-carbon fusion integrated structure in the case of only one sintering.

[0046] In some embodiments, the nano hollow silicon material is prepared by the following method...

Embodiment 1

[0057] a): using nano-calcium carbonate particles as a template, using silane to form a silicon layer on the surface of the template by vapor deposition at 400° C., to prepare template-silicon particles;

[0058] b): Removing the template by reacting the template-silicon particles with an acid to prepare a nano-hollow silicon material;

[0059] c) Mix 90 g of asphalt with a softening point of 120° C. and 1000 g of the nano hollow silicon in a mixer at room temperature and low speed, and then heat at a speed of 500 rpm while stirring. When the temperature rises to 100°C, the asphalt becomes viscous and forms a particle mixture with nano-hollow silicon.

[0060] d) Put the particle mixture in a high-temperature furnace for high-temperature carbonization. Before raising the temperature, the high-temperature furnace should be vacuumed and replaced with an inert gas, then the temperature is raised while passing the inert gas, and finally the temperature is lowered. Finally, each n...

Embodiment 2

[0062] Carbon-silicon composite secondary particles were prepared in the same manner as in Example 1, except that the content of pitch in step c) was changed to 120 g.

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Abstract

The present disclosure relates to a carbon-silicon composite secondary particle, characterized in that the carbon-silicon composite secondary particle is a secondary particle formed by nano hollow silicon primary particles and carbon filled between the primary particles. According to the carbon-silicon composite secondary particle disclosed by the invention, silicon-carbon material integration is realized, and after the temperature of the asphalt reaches a softening point, under the condition of high-speed stirring, the asphalt with a relatively small proportion can be sufficiently combined with the nano hollow silicon to form a silicon-carbon fused integrated structure. In addition, the conductivity of the silicon-carbon negative electrode material is remarkably improved by the carbon-silicon composite secondary particles. According to the invention, the asphalt is used as a carbon source and is fused with the hollow silicon and the graphite, and finally non-carbon and non-silicon components are removed through carbonization, so that an excellent electric conductor is obtained. As a negative electrode material, the conductivity is remarkably improved.

Description

technical field [0001] The present disclosure relates to a composite material. Specifically, the present disclosure relates to a carbon-silicon composite secondary particle and a preparation method thereof. Background technique [0002] Silicon, as the negative electrode material of lithium ion battery, has a very high specific capacity (theoretical value is 4200mAh / g, while the specific capacity of negative electrode graphite is only 372mAh / g). However, it has the problems of large volume change during charging and discharging, material disintegration after cycling, and poor cycle performance. For this reason, making silicon into nano hollow particles can solve the problem of material disintegration. [0003] Since the primary particles of nano-hollow silicon are too small and the specific surface is too large, the electrical conductivity is not ideal. Secondary granulation is required to make the particle size distribution and specific surface of the secondary particles ...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/62H01M10/0525C01B32/05C01B33/02B82Y30/00B82Y40/00
CPCH01M4/386H01M4/625H01M10/0525C01B32/05C01B33/02B82Y30/00B82Y40/00Y02E60/10
Inventor 邱新平郑曦张文广李慧玉
Owner BEIJING TU CREATIVE CO LTD