Preparation and application method of graphene-coated porous silicon composite anode material

A graphene-coated, negative electrode material technology, applied in graphene, battery electrodes, electrical components, etc., can solve the problems of limiting the practical application of silicon materials, the capacity decay of silicon electrodes, and the large volume expansion rate, so as to improve the first charge and discharge. Efficiency, prevention of volume expansion, effect of large specific surface area

Inactive Publication Date: 2017-07-04
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

However, the silicon anode material will produce serious volume changes during the cycle, the volume expansion rate is large, and it is easy to fall off from the current collector, which leads to the rapid decay of the capacity of the silicon electrode during the cycle, and eventually makes the electrode invalid, limiting the silicon material. Practical Application on Li-ion Batteries

Method used

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  • Preparation and application method of graphene-coated porous silicon composite anode material

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] (1) Weigh 60g of 2, 4, and 8mm diameter grinding balls, 5g of smelted aluminum-silicon alloy and 3ml of acetone solution in a glove box and add them to a 150ml ball milling tank. The ball milling jar was placed on a planetary ball mill with a rotation speed of 500 rpm for 12 hours. In order to prevent local temperature from being too high, the sample was ball milled for 10 minutes and then suspended for 6 minutes.

[0038] (2) Dissolve the obtained small particles of aluminum-silicon alloy with deionized water, ultrasonically disperse for 20 minutes, then clean it three times, and dry it in an oven for 12 hours at a temperature of 100°C.

[0039] (3) Measure 50ml of 5% dilute nitric acid and 100ml of 10% dilute sulfuric acid respectively, mix well and pour it into a 300ml beaker, and gradually add the aluminum-silicon alloy under vigorous stirring until it is completely dissolved. Then ultrasonic 60min, placed on a magnetic stirrer to stir for 6h. It was washed 5 times with...

Embodiment 2

[0045] (1) Weigh 60g of zirconia balls with a diameter of 4mm, 6g of smelted aluminum-silicon alloy and 5ml of absolute ethanol in a glove box and add them to a 100ml ball mill tank. The ball milling jar was placed on a planetary ball mill with a rotation speed of 200 rpm for 24 hours. In order to prevent local temperature from being too high, the sample was ball milled for 20 minutes and then suspended for 10 minutes.

[0046] (2) Dissolve the obtained small particles of aluminum-silicon alloy with alcohol, ultrasonically disperse for 30 minutes, then clean it three times, and dry it in an oven for 6 hours at a temperature of 60°C.

[0047] (3) Measure 200 ml of 10% hydrofluoric acid and pour it into a 400 ml beaker, and slowly add the aluminum-silicon alloy under vigorous stirring until it is completely dissolved. Then ultrasonic for 30min, put on a magnetic stirrer and stir for 8h. It was cleaned three times with deionization and alcohol, and dried in a vacuum drying oven at 60...

Embodiment 3

[0053] (1) Weigh 50g of zirconia balls (mass ratio 1:1) with diameters of 2 and 4mm respectively, 5g of metallurgical aluminum-silicon alloy and 20ml of n-hexane solution in a glove box and add them to a 100ml ball mill tank. The ball milling jar was placed on a planetary ball mill with a rotation speed of 500 rpm for 12 hours. In order to prevent local temperature from being too high, the sample was ball milled for 15 minutes and then suspended for 8 minutes.

[0054] (2) Dissolve the obtained small particles of aluminum-silicon alloy with deionized water, ultrasonically disperse for 1 hour, and then clean it with deionized water three times, and place it in an oven to dry for 12 hours at a temperature of 120°C.

[0055] (3) Measure 150 ml of 15% hydrochloric acid and pour it into a 400 ml beaker, and slowly add the aluminum-silicon alloy under vigorous stirring until it is completely dissolved. Then ultrasonic for 30min, put on a magnetic stirrer and stir for 4h. It was cleaned ...

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Abstract

Preparation and an application method of a graphene-coated porous silicon composite anode material belong to the field of electrode material preparation. According to the preparation, aluminium-silicon, which is used as a raw material, successively undergoes smelting, mechanical milling and chemical etching to prepare porous silicon; and then the porous silicon, graphene oxide and a carbon source undergo ball milling, spray drying and high-temperature pyrolysis to form a graphene-coated porous silicon composite material. Mass percent of silicon in the prepared porous silicon material is 20-80%; mass percent of metal impurities is 20-80%; particle size distribution is 10 nm- 10 microns; pore size distribution is 1-1000 nm; and porosity is 1-90%. According to the obtained graphene-coated porous silicon composite material, particle size is 1-100 microns, the shape is spherical, particle distribution is uniform, and morphology is consistent. When the material is applied to a lithium ion battery anode material, volume expansion of silicon alloying can be effectively prevented, and initial charge-discharge efficiency, theoretical specific capacity, cycle performance and the like are enhanced. The material of the invention is an ideal anode material in the field of lithium ion battery. The preparation has advantages of simple process, low energy consumption, low cost, good reappearance and high yield.

Description

Technical field [0001] The invention belongs to the field of electrode material preparation, and relates to a preparation method and application of a graphene-coated porous silicon composite negative electrode material, especially in a lithium ion battery. Background technique [0002] In recent years, with the reduction of non-renewable resources, the sustainable development of energy and environment has become the world's top priority, and the development of new energy has become urgent. The performance requirements of chemical energy storage devices continue to increase. Because lithium-ion batteries have the advantages of high energy density, high working voltage, long service life, no memory effect, low self-discharge efficiency, and no environmental pollution, they have become applications in mobile communications and portable computers. High-energy secondary batteries in other aspects. At the same time, the electrode materials of lithium ion batteries require high specifi...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525C01B32/182
CPCH01M4/366H01M4/386H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 李平黄一辉万琦刘志伟曲选辉秦明礼
Owner UNIV OF SCI & TECH BEIJING
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