Graphene and silicon composite and preparation method thereof

A technology of silicon composite materials and composite materials, applied in the direction of nanotechnology for materials and surface science, active material electrodes, electrical components, etc., can solve the problems of high raw material cost, silicon shedding, fast capacity decay, etc., and achieve the preparation process Simple and easy to implement, promote further development, and improve the effect of electrochemical performance

Active Publication Date: 2018-08-10
四川天诺聚能新能源开发有限公司
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

However, traditional mechanical mixing cannot guarantee the uniform recombination of silicon and graphene, and silicon may still fall off during multiple charge and discharge processes, resulting in faster capacity decay
[0006] In view of the above problems, the commonly used solution at present is to nanometerize silicon and compound silicon and carbon. The existing preparation technology cannot meet the needs of production. A silicon-carbon composite negative electrode material and a preparation method thereof. The intermediate product is obtained by mixing and reacting an organic precursor of raw material silicon dioxide, a cationic surfactant, a tin edge solution, and an organic carbon source, and the intermediate product is treated with a treatment liquid, and then washed and dried. The initial product is obtained, and the initial product is heat-treated in an environment with an oxidizing gas content of less than 0.01%, and finally a composite lithium battery negative electrode material is obtained. The preparation process of this material requires high requirements, and the cost of raw materials used is high

Method used

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  • Graphene and silicon composite and preparation method thereof
  • Graphene and silicon composite and preparation method thereof
  • Graphene and silicon composite and preparation method thereof

Examples

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preparation example Construction

[0038] A preparation method of graphene@silicon composite material, comprising the following steps:

[0039] S1: Nano-silicon pretreatment, after nano-silicon is evenly dispersed in the mixture of ethanol and deionized water, hydrofluoric acid is added to bring hydrogen on the surface of nano-silicon; the particle size of nano-silicon is 5-150 nm, and ethanol is 30~40ml, 40~60ml for deionized water, 50~70ml for hydrofluoric acid.

[0040] S2: Electroless deposition of metal nickel, adding the nano-silicon pretreated in step S1 to the chemical plating solution, dip-plating at a constant temperature of 30-100°C for 5-15 minutes, so that it is coated with a layer of metal nickel; wherein, chemical The plating solution is composed of nickel salt, complexing agent, sodium hypophosphite, citric acid and surfactant, and the pH of the solution is adjusted to 8~10 by ammonia water. The nickel salt is one or more of nickel chloride, nickel sulfate, nickel nitrate and nickel acetate. T...

Embodiment 1

[0045] S1: Evenly disperse nano-silicon in a mixture of 35ml ethanol and 50ml water, then add 30 ml hydrofluoric acid to treat the surface of nano-silicon with hydrogen;

[0046] S2: Prepare an electroless plating solution containing 0.1mol / L nickel chloride, 0.56mol / L ammonium chloride, 0.03mol / L citric acid, 0.3mol / L sodium hypophosphite, 0.01mol / L sodium dodecyl sulfate, Adjust the pH to 8 with ammonia water, then add the pretreated nano-silicon into the electroless plating solution, and dip-plat at a constant temperature of 60 °C for 5 min;

[0047] S3: Add the nickel-coated nano-silicon obtained in step S2 into 38 ml of triethylene glycol, stir evenly, and then add 0.25 ml of a 50% sodium hydroxide solution, and continue stirring at 185 ° C for 8 hours. After the obtained product is filtered, washed, and dried, the temperature is raised to 450°C in a quartz tube filled with an inert atmosphere, and calcined for 1 hour to obtain a graphene / nickel / @nano-silicon composite ma...

Embodiment 2

[0050] S1: Evenly disperse nano-silicon in a mixture of 50ml ethanol and 50ml water, then add 50ml hydrofluoric acid to treat the surface of nano-silicon with hydrogen;

[0051] S2: Prepare an electroless plating solution containing 0.15mol / L nickel chloride, 0.56mol / L ammonium chloride, 0.03mol / L citric acid, 0.3mol / L sodium hypophosphite, 0.01mol / L sodium dodecyl sulfate, Adjust the pH to 8.5 with ammonia water, then add the pretreated nano-silicon into the electroless plating solution, and dip-plat for 10 min at a constant temperature of 50°C;

[0052] S3: Add the nickel-coated nano-silicon obtained in step S2 into 60 ml of triethylene glycol, stir evenly, then add 0.25 ml of sodium hydroxide solution with a mass fraction of 50%, and continue stirring at 200 ° C for 8 hours. After the obtained product is filtered, washed and dried, the temperature is raised to 400°C in a quartz tube filled with an inert atmosphere, and calcined for 3 hours to obtain a graphene / nickel / @nano-...

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Abstract

The invention discloses a graphene and silicon composite and a preparation method thereof. According to the preparation method, nano-silicon with hydrogen on its surface is coated with metal nickel through chemical precipitation, graphene grows under in-situ catalysis at a lower temperature after a carbon source is utilized for carburization, the metal nickel is removed, and the graphene and silicon composite, in which the silicon is coated with multiple layers of graphene, is obtained. The preparation process is simple, convenient and easy, and does not need to be done under dangerous or high-temperature conditions, circulation and rate capability of silicon materials are improved by the prepared composite, and further development of silicon-based negative electrode materials is promoted.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium-ion batteries, in particular to a graphene@silicon composite material and a preparation method thereof. Background technique [0002] Lithium-ion battery is a new type of energy storage medium, which has excellent characteristics such as high voltage, long cycle life, high specific capacity, low self-discharge, high safety, environmental protection and pollution-free, and no memory effect. At present, lithium-ion batteries have been widely used in portable electronic devices such as mobile phones, notebook computers and digital products. With the continuous development of human society and the depletion of non-renewable resources, lithium-ion batteries will definitely be used in electric vehicles, hybrid vehicles, etc. The above has a wider application prospect. However, the traditional lithium-ion battery has a small capacity, which cannot meet people's urgent ne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525B82Y30/00
CPCH01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525B82Y30/00H01M2004/021H01M2004/027Y02E60/10
Inventor 王明珊王国良李星
Owner 四川天诺聚能新能源开发有限公司
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