Silicon carbon anode material for lithium ion battery and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, negative electrodes, secondary batteries, etc., can solve problems such as loss of active materials, deterioration of cycle performance, low delithiation potential, etc., achieve high efficiency for the first time, improve ion and Electron transfer rate, effect of high specific capacity

Inactive Publication Date: 2019-10-08
MAANSHAN KEDA PURUI ENERGY TECH CO LTD +1
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

Silicon has an ultra-high theoretical specific capacity (4200mAh / g) and a low delithiation potential (<0.5V), and the voltage platform of silicon is slightly higher than that of graphite. It is difficult to cause lithium precipitation on the surface during charging, and the safety performance is better. However, the volume expansion of silicon is as high as 300% during charging, which causes the powder particles to undergo a large mechanical force and gradually pulverizes and collapses, resulting in the loss of active materials and serious deterioration of cycle performance.

Method used

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  • Silicon carbon anode material for lithium ion battery and preparation method thereof
  • Silicon carbon anode material for lithium ion battery and preparation method thereof

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Embodiment 1

[0043] A method for preparing a silicon-carbon negative electrode material for a lithium-ion battery, comprising the steps of:

[0044] (1) Add artificial graphite and rubidium hydroxide into the reaction kettle according to the mass ratio of 1:0.1. After the solution is stirred evenly, start to heat up to 100°C and keep it warm for 10 hours. During the heating period, stir slowly until the solution is completely dried to obtain porous graphite;

[0045] (2) Add the porous graphite obtained in step (1) into the CVD furnace liner, feed nitrogen to get rid of the air in the CVD furnace until the oxygen content is lower than 100ppm, and then raise the temperature to 700 at a heating rate of 1°C / min. ℃, and then pass through silane for vapor deposition for 5 hours, the silane gas flow rate is 1L / min, so that the nano-silicon particles are uniformly deposited in the pores of the graphite, and the precursor of the negative electrode material is obtained;

[0046] (3) Put the negati...

Embodiment 2

[0048] A method for preparing a silicon-carbon negative electrode material for a lithium-ion battery, comprising the steps of:

[0049] (1) Add artificial graphite and potassium hydroxide into the reaction kettle according to the mass ratio of 1:0.5. After the solution is stirred evenly, start to heat up to 250°C and keep it warm for 5 hours. During the heating period, stir slowly until the solution is completely dried to obtain porous graphite;

[0050] (2) The porous graphite obtained in the step (1) is added into the CVD furnace liner, and helium gas is introduced to get rid of the air in the CVD furnace until the oxygen content is lower than 100ppm, and then at a heating rate of 3°C / min, the temperature is raised to 800°C, then feed dichlorodihydrogen silicon for vapor phase deposition for 3 hours, the gas flow rate of dichloro dihydrogen silicon is 3L / min, so that nano-silicon particles are uniformly deposited in the pores of graphite, and the precursor of the negative el...

Embodiment 3

[0053] A method for preparing a silicon-carbon negative electrode material for a lithium-ion battery, comprising the steps of:

[0054](1) Add artificial graphite and sodium hydroxide into the reaction kettle according to the mass ratio of 1:1. After the solution is stirred evenly, start to heat up to 400°C, keep it warm for 1h, and stir slowly during heating until the solution is completely dried to obtain porous graphite;

[0055] (2) The porous graphite obtained in the step (1) is added into the CVD furnace liner, and argon gas is introduced to get rid of the air in the CVD furnace until the oxygen content is lower than 100ppm, and then at a heating rate of 3° C. / min, the temperature is raised to 800°C, then pass through trichlorosilane for vapor deposition for 1 hour, the gas flow rate of trichlorosilane is 5L / min, so that nano-silicon particles are uniformly deposited in the pores of graphite, and the precursor of the negative electrode material is obtained;

[0056] (3)...

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Abstract

The invention belongs to the technical field of lithium ion batteries and particularly relates to a silicon carbon anode material for a lithium ion battery and a preparation method thereof. The anodematerial is a core-shell structure, wherein the core comprises porous graphite and nano-silicon; the pores of the graphite are formed through strong base erosion; the nano-silicon is deposited in thepores of the graphite by CVD deposition; the shell is an organic cracked carbon layer; the porosity of the porous graphite is 10 to 60%; the median diameter of the nano-silicon is 20-100 nm; and a carbon coating layer has a thickness of 0.1 to 1[mu]m. Compared with the prior art, the silicon carbon anode material for the lithium ion battery prepared by the method uses the porous graphite to reserve a space for the volume expansion of the nano-silicon so as to greatly alleviate the volume expansion of the nano-silicon and increase ion and electron transport rates. The silicon carbon anode material for the lithium ion battery has excellent electrochemical performance and stable structure. The preparation method is simple in process, low in cost, and suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a silicon-carbon negative electrode material for lithium-ion batteries and a preparation method thereof. Background technique [0002] The lithium storage capacity of graphite-based negative electrode materials is low, with a theoretical specific capacity of only 372mAh / g, and it is difficult to have room for improvement. Therefore, the development of new high-performance electrode materials has become a research hotspot. Silicon has an ultra-high theoretical specific capacity (4200mAh / g) and a low delithiation potential (<0.5V), and the voltage platform of silicon is slightly higher than that of graphite. It is difficult to cause lithium precipitation on the surface during charging, and the safety performance is better. However, the volume expansion of silicon is as high as 300% during charging, which causes the powder particles to undergo a large me...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 胡亮张少波王浩方伟
Owner MAANSHAN KEDA PURUI ENERGY TECH CO LTD
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