Silicon nanosheet-graphene nanosheet composite, preparation and application

A graphene nanosheet, silicon nanosheet technology, applied in nanotechnology, nanotechnology, nanotechnology for materials and surface science, etc., can solve the problem of low cycle stability of composite materials, and achieve fast charge-discharge, cycle The effect of good performance and large lithium storage capacity

Inactive Publication Date: 2018-06-19
SOUTH CHINA AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Studies have shown that when the size of silicon particles is less than 10nm, the volume change during the charging and discharging process can be basically ignored, and the size of the above-mentioned silicon particles is mostly in the range of 50-100nm without considering particle agglomeration, so the prepared composite The cycle stability of the material is still far below the theoretical target, which is greatly limited

Method used

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  • Silicon nanosheet-graphene nanosheet composite, preparation and application
  • Silicon nanosheet-graphene nanosheet composite, preparation and application
  • Silicon nanosheet-graphene nanosheet composite, preparation and application

Examples

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Effect test

Embodiment 1

[0039] A kind of preparation method of silicon nanosheet-graphene nanosheet composite material of the present embodiment, concrete preparation steps are as follows:

[0040] (1) Add 3.0 g of graphite to a mixture of 360 mL of concentrated sulfuric acid and 40 mL of concentrated phosphoric acid, and cool in an ice-water bath. Very slowly 6.0 grams of potassium permanganate was added to the mixture. All operations should be done very slowly. The reaction was then heated to 50 °C and stirred mechanically for 24 h. The reaction was cooled to room temperature and poured slowly into a mixture of ice (400 mL) and 30 mL of 30% hydrogen peroxide. The solution was centrifuged, washed with 500 mL of 5% HCl, and then deionized water to a pH value of about 7, and the obtained product was vacuum-dried at 50° C. to remove water to obtain graphite oxide. Weigh an appropriate amount of graphite oxide and disperse it in deionized water, and ultrasonicate for 30 minutes to prepare a 1.0 mg / mL...

Embodiment 2

[0049] A kind of preparation method of silicon nanosheet-graphene nanosheet composite material of the present embodiment, concrete preparation steps are as follows:

[0050] Steps (1) and (2) are the same as in Example 1.

[0051] (3) Mix 400mL of 1.0mg / mL graphene oxide nanosheet suspension with 200mL of 0.5mg / mL silicon nanosheet suspension, stir evenly, evaporate to dryness at 50°C, and treat at 750°C under vacuum for 2h to obtain silicon nanosheets. sheet-graphene nanosheet composites.

[0052] The cycle performance curve of silicon nanosheet-graphene nanosheet composite material obtained in this example at 0.01~3.0V, 200mA / g current density is as follows Image 6 shown. from Image 6 It can be seen that the first discharge specific capacity of the material reaches 1673.5mAh / g at 0.01-3.0V, 200mA / g current density, and the discharge specific capacity remains at 816mAh / g after 50 cycles, indicating that the material has a good cycle stability.

Embodiment 3

[0054] A kind of preparation method of silicon nanosheet-graphene nanosheet composite material of the present embodiment, concrete preparation steps are as follows:

[0055] Steps (1) and (2) are the same as in Example 1.

[0056] (3) Mix 200mL of 1.0mg / mL graphene oxide nanosheet suspension with 200mL of 0.5mg / mL silicon nanosheet suspension, stir evenly, evaporate to dryness at 50°C, and treat at 750°C under vacuum for 2h to obtain silicon nanosheets. sheet-graphene nanosheet composites.

[0057] The cycle performance curve of silicon nanosheet-graphene nanosheet composite material obtained in this example at 0.01~3.0V, 200mA / g current density is as follows Figure 7 shown. from Figure 7 It can be seen that the first discharge specific capacity of the material reaches 1673.5mAh / g at 0.01-3.0V, 200mA / g current density, and the discharge specific capacity remains at 816mAh / g after 50 cycles, indicating that the material has a good cycle stability. Its cycle performance c...

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Abstract

The invention belongs to the field of materials for lithium-ion batteries and discloses a silicon nanosheet-graphene nanosheet composite, preparation and application. Graphite oxide is prepared with ahummer method and subjected to ultrasonic exfoliation in deionized water, and graphene oxide nanosheet suspension is formed; Li13Si4 granules are added to ethanol, the mixture is stirred at room temperature for a reaction, filtering is performed, silicon granules are obtained and redispersed in ethanol, ultrasonic processing is performed, and silicon nanosheet suspension is obtained; the grapheneoxide nanosheet suspension and the silicon nanosheet suspension are stirred and mixed uniformly, evaporated to be dry and subjected to annealing treatment at 600-1000 DEG C under vacuum condition, and the silicon nanosheet-graphene nanosheet composite is obtained. The obtained silicon nanosheet-graphene nanosheet composite has the advantages that lithium storage capacity is high, cycle performance is good, charge-discharge is fast, and compared with normal charge-discharge rate, capacity of the composite fades little under fast charge-discharge.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a silicon nanosheet-graphene nanosheet composite material and its preparation and application. Background technique [0002] Lithium-ion batteries are currently the most widely used and most promising chemical batteries for energy storage because of their high energy density, high power density, and long service life. Although it has been commercially available since 1990, the energy storage performance of lithium-ion batteries still cannot meet the growing needs of people, especially in power batteries that require higher energy density and power density, such as electric vehicle power supplies. At the same time, as an energy supply device widely used in portable electronic devices, lithium-ion batteries also need to continuously improve their performance to meet the ever-increasing performance requirements and market demand. Therefore, the development o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M10/0525B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00H01M4/364H01M4/386H01M4/583H01M10/0525Y02E60/10
Inventor 方岳平蔡欣周训富何科林
Owner SOUTH CHINA AGRI UNIV
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