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A method for surface modification of lithium-ion battery silicon negative electrode material, silicon negative electrode slurry and application

A lithium-ion battery, silicon anode technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as loss of conductive connection of current collectors, pulverization of electrode materials, and lithium consumption.

Active Publication Date: 2018-07-20
江苏载驰科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the application of silicon anode materials has the following problems: First, due to the high theoretical specific capacity of silicon, there is a severe volume effect (volume change of up to 300%) in the process of lithium extraction / intercalation, which will lead to electrode Crushing of material, destruction of conductive network, and loss of conductive connection with current collector
Secondly, due to the repeated shrinkage / expansion of silicon during the electrochemical cycle, the solid electrolyte protective film (SEI film) formed on the surface of the silicon material will always be in a state of dynamic destruction-reconstruction, which will cause continuous Lithium consumption will eventually lead to the attenuation of battery capacity, which is difficult for commercial application and production

Method used

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  • A method for surface modification of lithium-ion battery silicon negative electrode material, silicon negative electrode slurry and application
  • A method for surface modification of lithium-ion battery silicon negative electrode material, silicon negative electrode slurry and application
  • A method for surface modification of lithium-ion battery silicon negative electrode material, silicon negative electrode slurry and application

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Experimental program
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Effect test

Embodiment 1

[0038] (1) Prepare 100g of hydrofluoric acid solution with a mass fraction of 10%, then weigh 20g of commercial silicon powder with a particle size of about 100nm, add it to the hydrofluoric acid solution, and react for 30min under magnetic stirring , completely remove the oxide layer on the silicon surface.

[0039] (2) Then transfer the reacted silicon solution to a centrifuge tube for centrifugation, discard the supernatant, and wash with distilled water 3 times. Then transfer to a vacuum oven and dry at 60 °C for 4 h.

[0040] (3) Transfer the dried silicon powder to a tube furnace, heat it at 500°C for 60 minutes in an air atmosphere, and then take out the porcelain boat to cool down, so that a continuous, dense and uniform silicon oxide layer can be rebuilt on the surface of the silicon powder.

[0041] (4) Weigh 2g of the modified silicon powder and mix it with sodium alginate binder and conductive carbon ink at a mass ratio of 6:2:2, then stir with a high-speed sheare...

Embodiment 2

[0043] (1) Prepare 100g of hydrofluoric acid solution with a mass fraction of 10%, then weigh 20g of commercial silicon powder with a particle size of about 100nm, add it to the hydrofluoric acid solution, and react for 30min under magnetic stirring , completely remove the oxide layer on the silicon surface.

[0044] (2) Then transfer the reacted silicon solution to a centrifuge tube for centrifugation, discard the supernatant, and wash with distilled water 3 times. Then transfer to a vacuum oven and dry at 60 °C for 4 h.

[0045](3) Transfer the dried silicon powder to a tube furnace, heat it at 700°C for 30 minutes in an air atmosphere, and then take out the porcelain boat to cool down, so that a continuous, dense and uniform silicon oxide layer can be rebuilt on the surface of the silicon powder.

[0046] (4) Weigh 2g of silicon powder and mix it with sodium alginate binder and conductive carbon ink at a mass ratio of 6:2:2, then stir with a high-speed shearer at a speed o...

Embodiment 3

[0048] (1) Prepare 100g of a solution with a concentration of 1mol / L, then weigh 20g of commercial silicon powder with a particle size of about 100nm, add it to the hydrofluoric acid solution, and react for 30min under magnetic stirring to completely remove silicon oxide layer on the surface.

[0049] (2) Then transfer the reacted silicon solution to a centrifuge tube for centrifugation, discard the supernatant, and wash with distilled water 3 times. Then transfer to a vacuum oven and dry at 60 °C for 4 h.

[0050] (3) Transfer the dried silicon powder to a tube furnace, heat it at 500°C for 1200 minutes in an air atmosphere, and then take out the porcelain boat to cool down, so that a continuous, dense and uniform silicon oxide layer can be rebuilt on the surface of the silicon powder.

[0051] (4) Weigh 2g of silicon powder and mix it with sodium alginate binder and conductive carbon ink at a mass ratio of 6:2:2, then stir with a high-speed shearer at a speed of 10,000rpm / m...

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Abstract

The invention relates to a method for improving the surface performance of a lithium ion battery silicon negative electrode material. By performing effective surface modification on a silicon negative electrode material, a layer of continuous, uniform and dense silicon oxidizing film can be formed on the surface, so as to form a rich hydroxyl functional group on the surface of the silicon oxidizing film, and by selecting a binder with a specific functional group, the functional group in the binder and the hydroxyl functional group on the surface of the silicon oxidizing film can form a hydrogen bond with relatively strong acting force, so that the binder can be firmly attached to the surfaces of silicon particles, and therefore, on the one hand, the complete conductive network of an electrode can be maintained in the cyclic process, and on the other hand, contact between an electrolyte and the silicon particles can be prevented, thus reducing decomposition of the electrolyte and further improving the electrochemical cyclic stability of the silicon negative electrode.

Description

technical field [0001] The application relates to a method for modifying the surface of a lithium-ion battery silicon negative electrode material, a silicon negative electrode slurry and its application, and belongs to the fields of new energy materials and energy electrochemistry. Background technique [0002] The long-term unrestrained use of traditional non-renewable energy sources (such as coal, oil, natural gas, etc.) has caused a series of environmental pollution to the environment. Therefore, it is imminent to develop green, environment-friendly and pollution-free renewable energy. Rechargeable lithium-ion batteries have attracted people's attention due to their high energy density, high power density, safety, and environmental protection. Lithium-ion batteries have been used with great success in mobile electronics over the past two decades and are considered the best choice for large energy storage devices as well as batteries for electric vehicles. However, large...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/38H01M4/62H01M10/0525
CPCH01M4/386H01M4/621H01M10/0525Y02E60/10
Inventor 张娟
Owner 江苏载驰科技股份有限公司
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