Silicon-carbon composite material with nano micropores and preparation method as well as application thereof

A silicon-carbon composite material, micro-porosity technology, applied in nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc., can solve the problem of silicon expansion that cannot be completely solved, the carbon matrix does not really play a stable structure, etc. problems, to achieve the effect of improving electrochemical performance, improving lithium storage capacity, and suppressing shortcomings

Active Publication Date: 2013-09-18
深圳石墨烯创新中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] After research, the inventor of this patent believes that all silicon-carbon composite materials can not completely solve the problem of silicon expansion during charging and discharging. The key is that the

Method used

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  • Silicon-carbon composite material with nano micropores and preparation method as well as application thereof

Examples

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Example Embodiment

[0029] This embodiment also provides a method for preparing a silicon-carbon composite material with a nanovoid structure, comprising the following steps:

[0030]Step 1: Prepare polyacrylonitrile spinning (PAN) silk solution containing nano-silicon particles and polymer pore-forming agents. The specific steps are as follows: Weigh a certain amount of PAN powder, add it to a certain amount of organic solvent dimethylformamide (DMF), stir and dissolve at 65°C, and prepare a DMF solution of PAN with a mass fraction of 6-15wt%; Taking the quality of PAN as a benchmark, weigh the nano-Si particles that are 1:50-1:1 with the mass ratio of PAN and the polymer pore former ( Polymer-based Pore-Maker, abbreviated as PPM), added to the DMF solution of PAN, continued to stir at 65°C for more than 24 hours, and ultrasonically dispersed for more than 1 hour to obtain a mixture of PAN-Si-PPM in the organic solvent DMF . Among them, the molecular weight M of PAN w It is preferably 100,000...

Example Embodiment

[0056] Example 1

[0057] Compared with Comparative Example 1.

[0058] Step 1: Preparation of polyacrylonitrile spinning solution. Weigh 9g molecular weight M w =150000 PAN powder, added to 96mL of DMF, stirred at 65°C for 24h to dissolve, and prepared a PAN-DMF solution with a mass fraction of 9%; weighed 2.25g of nano-silicon particles with an average particle size of 30-50nm and added them to PAN solution, while adding 4g of PMMA (M w =120000) into the solution, continue stirring at 65°C for 24h, and ultrasonically disperse for 1h to obtain a co-dispersion system of PAN-Si-PMMA in DMF, which will be used for electrospinning.

[0059] The second step: electrospinning to prepare PAN nanofibers doped with Si and PMMA. The electrospinning conditions were the same as the second step in Comparative Example 1 to obtain PAN-Si-PMMA composite nanofibers.

[0060] The third step: oxidation treatment of PAN-Si-PMMA composite nanofibers. The oxidation treatment conditions were t...

Example Embodiment

[0064] Example 2

[0065] Compared with Comparative Example 1.

[0066] Step 1: Preparation of polyacrylonitrile spinning solution. Weigh 9g molecular weight M w =150000 PAN powder, added to 96mL of DMF, stirred at 65°C for 24h to dissolve, and prepared a PAN-DMF solution with a mass fraction of 9%; weighed 2.25g of nano-silicon particles with an average particle size of 30-50nm and added them to PAN solution, while adding 4g of PVC (M w =100000) into the solution, continue stirring at 65°C for 24h, and ultrasonically disperse for 1h to obtain a co-dispersion system of PAN-Si-PVC in DMF, which will be used for electrospinning.

[0067] The second step: electrospinning to prepare PAN nanofibers doped with Si and PVC. The electrospinning conditions were the same as the second step in Comparative Example 1 to obtain PAN-Si-PVC composite nanofibers.

[0068] The third step: oxidation treatment of PAN-Si-PVC composite nanofibers. The oxidation treatment conditions were the sa...

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Abstract

The invention discloses a silicon-carbon composite material with nano micropores and a preparation method as well as application thereof. The composite material comprises nano-silicon (Si) particles and a carbon nanofiber matrix, wherein nano pores and micropore channels communicated with each other are distributed in the carbon nanofiber matrix; the nano-Si particles are distributed in the carbon nanofiber matrix; one part of the nano-Si particles are embedded in the carbon nanofiber matrix; and the other part of the nano-Si particles are positioned in the nano pores. The method comprises the steps of carrying out electrostatic spinning on a polyacrylonitrile (PAN) spinning solution doped with the nano-Si particles and a polymer pore former (PPM) to obtain a PAN-Si-PPM composite nanofiber, and then carrying out oxidation and carbonization to obtain the silicon-carbon composite material. The silicon-carbon composite material is applied to preparation of lithium ion battery cathode materials. Compared with the prior art, the silicon-carbon composite material ensures the overall electron transport capacity of the material while reserving buffer space for expansion of the nano-Si particles.

Description

technical field [0001] The invention relates to a nanocomposite material, in particular to a silicon-carbon composite material with nanometer pores and its preparation method and application. Background technique [0002] Lithium-ion battery anode materials are generally carbon materials, such as graphite, needle coke, mesocarbon microspheres, carbon fibers, nano-carbon fibers, etc. At present, the theoretical reversible lithium storage specific capacity of graphite anode materials that have been commercially applied is 372mAh / g. Improving the capacity of lithium-ion batteries mainly depends on the lithium intercalation ability of negative electrode materials. The research and development of high-capacity negative electrode materials has become the key to improving the performance of lithium-ion batteries. The theoretical lithium storage capacity of silicon (Si) material is 4200mAh / g, which is an ideal material for increasing the negative electrode capacity. However, the vo...

Claims

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Application Information

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IPC IPC(8): H01M4/38B82Y30/00
CPCY02E60/10
Inventor 秦显营李宝华李硕杨全红康飞宇
Owner 深圳石墨烯创新中心有限公司
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