Preparation method for SiO<x>-C-CNT composite material of lithium-ion battery negative electrode

A technology of lithium-ion batteries and composite materials, which is applied in the field of preparation of SiOx-C-CNT composite materials, can solve the problems of rapid capacity decay of negative electrode materials, large volume effect of silicon negative electrode materials, and low cycle life, and achieve improved reversible capacity, The experimental operation is simple and easy, and the cycle performance is stable

Active Publication Date: 2016-05-25
HEBEI UNIV OF TECH +1
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  • Abstract
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Problems solved by technology

[0005] The technical problem to be solved by the present invention is aimed at the disadvantages of large volume effect and poor conductivity of silicon negative electrode materials in the prior art, and the defects of rapid capacity decay, low cycle life and poor rate performance of lithium ion battery negative electrode materials prepared therefrom , proposed an easy-to-operate SiO x -C-CNT composite method

Method used

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  • Preparation method for SiO&lt;x&gt;-C-CNT composite material of lithium-ion battery negative electrode
  • Preparation method for SiO&lt;x&gt;-C-CNT composite material of lithium-ion battery negative electrode
  • Preparation method for SiO&lt;x&gt;-C-CNT composite material of lithium-ion battery negative electrode

Examples

Experimental program
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Embodiment 1

[0032] The first step is to prepare SiO x -C-CNT composite material:

[0033]Weigh 8.33g of tetraethyl orthosilicate and 16.66g of 0.1mol / L hydrochloric acid, dissolve in 24.99g of absolute ethanol, so that the mass ratio of tetraethyl orthosilicate: 0.1mol / L hydrochloric acid: absolute ethanol = 1:2 : 3; Stir at 200r / min for 1h, and use this as the silicon source solution. Weigh 3.8428g of citric acid, 1.9214g of ethylene glycol and 1.9214g of carbon nanotube suspension (carbon nanotube content is 9.0wt%, average diameter of 10nm) dissolved in 10g of deionized water, stirred at 200r / min for 1h, This was used as a carbon source solution. The molar ratio of citric acid: ethyl orthosilicate = 1:2. Pour the carbon source solution into the silicon source solution, and stir at 200 r / min for 30 min to obtain a sol. The sol was poured into a glass petri dish, and the glass petri dish was dried at room temperature for 30 h to form a 0.5mm film. Take the film out of the glass petr...

Embodiment 2

[0040] The first step is to prepare SiO x -C-CNT composite material:

[0041] The preparation of silicon source solution and carbon source solution and the steps of forming a film on a glass petri dish are the same as in Example 1, except that the temperature of the obtained material is raised to 800°C at 5°C / min, kept for 1h, and the temperature drops to room temperature. That is, SiO x - C-CNT composite samples.

[0042] The second step, the preparation of the negative electrode sheet of the battery and the assembly of the half-cell: the same as in Example 1.

[0043] The resulting product is also amorphous SiO x -C-CNT composite material; compared with Example 1, the material obtained in this example has an initial discharge capacity of 1215mAh / g at a rate of 0.1C, and a reversible capacity of 833mAh / g after 20 cycles.

Embodiment 3

[0045] The first step is to prepare SiO x -C-CNT composite material:

[0046] The preparation of silicon source solution and carbon source solution and the steps of forming a film on a glass petri dish are the same as in Example 1, except that the temperature of the obtained material is raised to 1000°C at 5°C / min, kept for 1h, and the temperature drops to room temperature. That is, SiO x - C-CNT composite samples.

[0047] The second step, the preparation of the negative electrode sheet of the battery and the assembly of the half-cell: the same as in Example 1.

[0048] The resulting product is also amorphous SiO x -C-CNT composite material; compared with Example 1, the material obtained in this example has an initial discharge capacity of 1220mAh / g at a rate of 0.1C, and a reversible capacity of 849mAh / g after 20 cycles.

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Abstract

The invention relates to a preparation method for a SiO<x>-C-CNT composite material of a lithium-ion battery negative electrode. According to the method, a new silicon / carbon composite structure is obtained by modes of adding a carbon nanotube conductive network (CNT) and directly pouring the CNT into a culture dish to form a film. The structure comprises a graphite framework material, amorphous SiO<x> and the CNT. With the composite material disclosed by the invention, the agglomeration effect of a nanometer silicon material is solved, and rapid attenuation of specific capacity of the battery is prevented; the amorphous SiO<x> and graphite form a SiO<x>-C structure, a huge stress effect caused by volume expansion / contraction of nanometer silicon can be buffered, and the cycle lifetime of the battery is prolonged; and the carbon nanotube is distributed in the SiO<x>-C structure, silicon and carbon can be connected very well to form a conductive network structure, the conductivity of the composite material is enhanced, and the rate performance of the battery is improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery negative electrode materials, in particular to a SiO used for lithium-ion battery negative electrodes x -The preparation method of C-CNT composite material. Background technique [0002] With the deterioration of the global environment and the continuous consumption of non-renewable energy, we must pay attention to the development and utilization of new energy. In the past 20 years, research on new chemical power sources with long service life, high energy density, safety and pollution-free has always been the focus of research personnel. The development and use of battery technology has played an important role in changing the energy structure. Due to its superior performance, lithium-ion batteries have been used in various mobile devices, such as smartphones, laptops and other fields. With the development of lithium-ion batteries, lithium-ion batteries with high specific energy, l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/587H01M4/62H01M10/0525
CPCH01M4/362H01M4/48H01M4/587H01M4/625H01M10/0525H01M2004/027Y02E60/10
Inventor 张永光刘正军殷福星王新谭台哲
Owner HEBEI UNIV OF TECH
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