A kind of graphene coated silicon composite material and its preparation method and application

A silicon composite material, graphene coating technology, applied in the direction of structural parts, electrical components, battery electrodes, etc., can solve the problems of complex preparation process and high cost, and achieve the effects of wide source, simple method and low price

Active Publication Date: 2020-12-11
广州睿迪新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The graphene / silicon composite material obtained above can show considerable capacity and good cycle stability, especially the performance of the graphene / silicon composite material with coating structure is more superior, but the method for the above-mentioned graphene coated silicon is prepared The process is relatively complicated and the cost is high; further development of efficient and stable graphene-based composite materials is of great significance for improving the energy density of lithium-ion batteries

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  • A kind of graphene coated silicon composite material and its preparation method and application
  • A kind of graphene coated silicon composite material and its preparation method and application
  • A kind of graphene coated silicon composite material and its preparation method and application

Examples

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Embodiment 1

[0038] A preparation method of Si@RGO in this embodiment, the specific preparation steps are as follows:

[0039] (1) Add 3.0 g of graphite to a mixture of 360 mL of 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 are performed very slowly. The reaction was then heated to 50°C and mechanically stirred for 24 hours. 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 until the pH value was around 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 graphene oxide suspension.

[0040] (2) 0.7 g of silicon powde...

Embodiment 2

[0048] A preparation method of Si@RGO in this embodiment, the specific preparation steps are as follows:

[0049] (1) The preparation method of the graphene oxide suspension of 1.0 mg / mL is the same as that of Example 1.

[0050] (2) 0.5 g of silicon powder and 0.5 g of zinc powder are mixed and put into a ball mill jar, and ball milled at 300 rpm for 24 hours to obtain zinc-coated silicon (Si@Zn) particles, which are then ultrasonically dispersed in deionized water to obtain Si@ Zn mixture.

[0051] (3) Mix 700 mL of 1.0 mg / mL graphene oxide suspension with the Si@Zn mixture obtained in step (2), stir and react for 12 hours, and filter to obtain Si@ZnO x The @RGO composite material was soaked in excess 0.1M hydrochloric acid for 12 hours, filtered again, and dried to obtain the Si@RGO composite material.

[0052] The electrochemical performance test method of Si@RGO prepared in this example is the same as that in Example 1. The cycle performance curve of Si@RGO obtained at ...

Embodiment 3

[0055] A preparation method of Si@RGO in this embodiment, the specific preparation steps are as follows:

[0056] (1) The preparation method of the graphene oxide suspension of 1.0 mg / mL is the same as that of Example 1.

[0057] (2) 0.3 g of silicon powder and 0.7 g of zinc powder were mixed and put into a ball mill jar, and ball milled at 300 rpm for 18 hours to obtain zinc-coated silicon (Si@Zn) particles, which were then ultrasonically dispersed in deionized water to obtain Si@ Zn mixture.

[0058] (3) Mix 300 mL of 1.0 mg / mL graphene oxide suspension with the Si@Zn mixture obtained in step (2), stir and react for 12 hours, and filter to obtain Si@ZnO x The @RGO composite material was soaked in excess 0.1M hydrochloric acid for 12 hours, filtered again, and dried to obtain the Si@RGO composite material.

[0059] The electrochemical performance test method of Si@RGO prepared in this example is the same as that in Example 1, and the cycle performance curves of Si@RGO obtai...

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Abstract

The invention belongs to the field of negative electrode materials for lithium ion batteries and discloses a graphene-coated silicon composite material and its preparation method and application. The preparation method includes the following preparation steps: ultrasonic peeling and dispersing graphite oxide in deionized water to form a graphene oxide suspension; mixing Si powder and Zn powder, ball milling and dispersing in deionized water to obtain a Si@Zn particle mixture; The Si@Zn particle mixture is mixed with the graphene oxide suspension, and the reaction is stirred at room temperature to obtain Si@ZnO x @RGO, then soak with acid to remove ZnO x , washed and dried to obtain Si@RGO composite material. The Si@RGO composite material obtained by the present invention can not only suppress the volume change of silicon but also increase the conductivity of the composite material, and has excellent cycle stability and rate discharge performance.

Description

technical field [0001] The invention belongs to the field of negative electrode materials for lithium ion batteries, and in particular relates to a graphene-coated silicon composite material and a preparation method and application thereof. Background technique [0002] In the 21st century, energy shortages and environmental pollution problems are becoming more and more serious, and the development and utilization of various high-energy batteries and fuel cells is imminent. Compared with other secondary batteries, lithium-ion batteries have the advantages of large specific capacity per unit, high working voltage, long cycle life, good safety, and no memory effect. However, the current lithium-ion battery technology cannot meet the continuously increasing demand for energy density, such as pure electric vehicles and hybrid electric vehicles, which urgently requires the development of batteries with higher energy density and higher power to meet current needs. At present, the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 方岳平蔡欣赵忠强周训富
Owner 广州睿迪新材料科技有限公司
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