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Preparation method of porous silicon/graphite/carbon composite negative electrode material for lithium-ion secondary battery

A secondary battery and negative electrode material technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems that cannot meet the actual application requirements, cannot meet the actual application, unfavorable industrial production, etc., and achieve large industrial application value and good cycle Stability, convenient and feasible process conditions

Active Publication Date: 2018-06-22
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Chinese patent CN103730631B discloses a battery material prepared from natural graphite and heat-treated attapulgite. Since the silicon in the natural attapulgite is an oxide, the capacity is extremely low and cannot meet the needs of practical applications.
Although the material has good stability, but the capacity is low, about 400mAhg -1 , cannot meet the practical application
[0007] CN104310404A discloses a method for hydrothermally synthesizing silicon nanopowder with minerals as raw materials, but adding water in the preparation process will react with alkali metals, which has low safety and high requirements for equipment, which is not conducive to industrial application
Although the performance of this material is high, the magnesia thermal reduction temperature is high and the cost is high, which is not conducive to industrial production

Method used

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  • Preparation method of porous silicon/graphite/carbon composite negative electrode material for lithium-ion secondary battery
  • Preparation method of porous silicon/graphite/carbon composite negative electrode material for lithium-ion secondary battery
  • Preparation method of porous silicon/graphite/carbon composite negative electrode material for lithium-ion secondary battery

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Embodiment 1

[0030] The porous silicon of the present invention can be prepared by the following methods:

[0031] (1) Kaolin pretreatment

[0032] (1) Mix kaolin with 1mol / L hydrochloric acid solution according to the mass ratio of 1:20, stir at 30℃ for 5h and then stand for 1h, suck the supernatant, filter and wash, dry at 120℃ for 10h to remove the kaolin Impurities.

[0033] (2) Put the kaolin treated in step (1) into a muffle furnace, heat up to 800°C at a rate of 10°C / min, keep it for 8 hours, and cool to room temperature to remove the hydroxyl groups in the kaolin.

[0034] figure 1 It is the SEM image of natural kaolin. From the figure, it can be seen that natural kaolin is composed of some nanoparticles. These particles are small in size, ranging from tens to hundreds of nanometers in diameter.

[0035] figure 2 It is the XRD pattern of natural kaolin. These diffraction peaks are typical characteristic peaks of kaolin, indicating that the sample is relatively pure.

[0036] (2) Preparation...

Embodiment 2

[0049] (1) Kaolin pretreatment

[0050] (1) Mix kaolin with 1mol / L sulfuric acid solution in a mass ratio of 1:15, stir at 40℃ for 4h, then stand for 1h, suck the supernatant, filter, wash, dry at 120℃ for 10h to remove the kaolin Impurities.

[0051] (2) Put the kaolin treated in step (1) into a muffle furnace at a rate of 10°C / min to raise the temperature to 700°C, keep it for 10 hours, and cool to room temperature to remove the hydroxyl groups in the kaolin.

[0052] (2) Preparation of porous silicon

[0053] (1) Using aluminum-magnesium alloy powder as the reducing agent, the pretreated kaolin and the reducing agent are mixed in a planetary ball mill at a speed of 300 rpm for 3 hours according to a certain mass ratio, and the ball-to-battery ratio is 15:1 to obtain a primary mixture.

[0054] (2) Mix the primary mixture, anhydrous aluminum chloride and anhydrous magnesium chloride according to a certain mass ratio to obtain a mass ratio of kaolin, aluminum-magnesium alloy powder, a...

Embodiment 3

[0065] (1) Kaolin pretreatment

[0066] (1) Mix kaolin with 1mol / L phosphoric acid solution in a mass ratio of 1:10, stir at 100°C for 10 hours and then stand for 1 hour, suck the supernatant, filter, wash, and dry at 120°C for 10 hours to remove the kaolin Impurities.

[0067] (2) Put the kaolin treated in step (1) into a muffle furnace, heat up to 600°C at a rate of 10°C / min, keep it for 6 hours, and cool to room temperature to remove the hydroxyl groups in the kaolin.

[0068] (2) Preparation of porous silicon

[0069] (1) Using aluminum-lithium alloy powder as the reducing agent, the pretreated kaolin and the reducing agent are mixed in a planetary ball mill at a speed of 350 rpm for 8 hours according to a certain mass ratio, and the ball-to-battery ratio is 15:1 to obtain a primary mixture.

[0070] (2) Mix the primary mixture, anhydrous aluminum chloride, and anhydrous lithium chloride uniformly according to a certain mass ratio to obtain kaolin, aluminum-lithium alloy powder, an...

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Abstract

The invention relates to a preparation method of a porous silicon / graphite / carbon composite negative electrode material for a lithium-ion secondary battery. A silicon source of the composite materialis natural mineral soil: namely kaolinite, montmorillonite, mica powder, wollastonite, vermiculite powder, pumice powder and coal gangue. The silicon source is reduced into elemental silicon by usinga metal element or alloy powder and anhydrous metal chloride under a mild condition, and the reduced porous silicon, graphite and an organic carbon source are subjected to high-energy ball mill mixing. The reduction temperature is low, the inherent pore structure of the natural mineral soil is effectively reserved and the prepared silicon material has relatively high specific surface area and abundant pores and has excellent electrochemical properties. Volume expansion can be effectively relieved through the inherent pore characteristic of the natural mineral soil; and the prepared composite material has higher charge-discharge capacity and stability. Especially the kaolinite is wide in source and low in price, so that the preparation cost of the battery material is greatly reduced. The porous silicon / graphite / carbon composite negative electrode material is friendly to environment, simple in preparation method, instrument and equipment and suitable for industrial production.

Description

Technical field [0001] The invention relates to a method for preparing a porous silicon / graphite / carbon composite negative electrode material of a lithium ion secondary battery. Background technique [0002] Lithium-ion batteries have high energy density, long cycle life and low self-discharge rate. They are widely used in smart phones, portable computers, electric vehicles, etc., and have become a hot spot in scientific research. With the development of human society, people have higher requirements for commercial lithium-ion batteries, requiring higher energy density, specific capacity, and service life. At the same time, they need a wide range of materials, cheap, and safe and reliable. At present, the negative electrode materials used in commercial lithium ion secondary batteries are mainly graphite-based carbon materials. However, graphite has a low theoretical capacity (372mAh / g), and is prone to lithium evolution during the rapid lithium insertion process, which has poor ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36
CPCH01M4/362Y02E60/10H01M2004/021H01M4/133H01M4/134H01M4/364H01M4/366H01M10/0525H01M4/583H01M4/1393H01M4/1395H01M4/386H01M4/587H01M10/054H01M2004/027
Inventor 杨化滨杨丹丹
Owner NANKAI UNIV
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