Silicon-based composite material, preparation method thereof, and lithium-ion battery

A technology of silicon-based composite materials and negative active materials, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of poor high-rate charge and discharge performance, low first-cycle coulombic efficiency, and poor material stability. Achieve the effects of improving the first Coulombic efficiency and cycle stability, simple process, and excellent structural stability

Inactive Publication Date: 2019-07-12
SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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Problems solved by technology

[0004] In view of the cumbersome preparation process of silicon-carbon anode materials, poor conductivity, poor material stability, low first-cycle coulombic efficiency when used in lithium-ion batteries, fast capacity decay, poor cycle performance, and poor high-rate charge-discharge performance, etc., The invention provides a silicon-based composite material and a preparation method thereof

Method used

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  • Silicon-based composite material, preparation method thereof, and lithium-ion battery
  • Silicon-based composite material, preparation method thereof, and lithium-ion battery
  • Silicon-based composite material, preparation method thereof, and lithium-ion battery

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preparation example Construction

[0030] The invention provides a method for preparing a silicon-based composite material, comprising the following steps:

[0031] SiO x Mixing treatment with carbon source to obtain SiO x @carbon source mix;

[0032] In an inert atmosphere, the SiO x @Carbon source mixture is solidified and carbonized to obtain SiO x @carbon;

[0033] The SiO x @Carbon is dispersed in a solution with an oxidizing agent, and a conductive polymer monomer and a conductive carbon material are added at the same time to uniformly disperse and in-situ polymerize to obtain a silicon-based composite material;

[0034] The silicon-based composite material is a double-shell core-shell structure material, the outer shell layer is a conductive polymer layer, the inner shell layer is a carbon layer, and a conductive carbon material is embedded on the conductive polymer layer;

[0035] Among them, the SiO x In 0x @Carbon source mix means carbon source coated in SiO x The mixture formed on the surface...

Embodiment 1

[0055] A silicon-based composite material is prepared by the following steps:

[0056] (a) Take a silicon-oxygen material (SiO2) with an average particle size of 15 μm x , 0x @petro asphalt mix.

[0057] (b) SiO x @Petroleum asphalt mixture is placed in a rotary furnace, heated to 250°C at a rate of 10°C / min in a nitrogen atmosphere, and solidified at a constant temperature for 1 hour, then continued to be heated at a rate of 10°C / min to 800°C, kept at a constant temperature for 3 hours, and carbonized to obtain Carbon-coated silicon-oxygen material, SiO x @carbon.

[0058] (c) take the SiO that step (b) obtains x @Carbon 20g is dissolved in an aqueous solution of iron p-toluenesulfonate, and polythiophene monomer (edot) is added, and stirred for 20h at a stirring speed of 800 rpm, so that the polythiophene monomer is polymerized in SiO x @Carbon Surface, among them, polythiophene monomer and SiO x The mass ratio of @ carbon is 0.2:1, and the molar ratio of iron p-toluen...

Embodiment 2

[0061] A silicon-based composite material is prepared by the following steps:

[0062] (a) Take a silicon-oxygen material (SiO2) with an average particle size of 15 μm x , 0x @petro asphalt mix.

[0063] (b) SiO x @Petroleum asphalt mixture is placed in a rotary furnace, heated to 250°C at a heating rate of 10°C / min under a nitrogen atmosphere, and solidified at a constant temperature for 1 hour, then raised to 800°C at a heating rate of 10°C / min, kept at a constant temperature for 3 hours, and carbonized to obtain Carbon-coated silicon-oxygen material, SiO x @carbon.

[0064] (c) take the SiO that step (b) obtains x @Carbon 20g is dissolved in an aqueous solution of ferric p-toluenesulfonate, and polythiophene monomer (edot), conductive carbon black is added, stirred at a stirring speed of 800 rpm for 20h, so that the polythiophene monomer is polymerized in SiO x @Carbon Surface, among them, polythiophene monomer and SiO x The mass ratio of @ carbon is 0.2:1, the molar ...

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Abstract

The invention provides a silicon-based composite material, a preparation method thereof and a lithium-ion battery. The preparation method comprises a step of mixing SiOx and a carbon source to obtaina SiOx@carbon source mixture, a step of curing and carbonizing the SiOx@carbon source mixture under an inert atmosphere to obtain SiOx@carbon, a step of dispersing the SiOx@carbon in a solution with oxidant, simultaneously adding a conductive polymer monomer and a conductive carbon material, uniformly dispersing, and polymerizing in situ to obtain the silicon-based composite material. The silicon-based composite material is a double-shell core-shell structure material, an outer shell layer is a conductive polymer layer, an inner shell layer is a carbon layer, and the conductive carbon materialis embedded into the conductive polymer monomer. The silicon-based composite material obtained by the method can effectively improve the electrochemical performance of the lithium-ion battery when the silicon-based composite material is used as a negative electrode material of the lithium-ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery materials, and in particular relates to a silicon-based composite material, a preparation method thereof, and a lithium-ion battery. Background technique [0002] Because of its high specific capacity (theoretical specific capacity at room temperature is 3580mAh / g), low delithiation potential, and low cost, silicon is considered to be a negative electrode material for the next generation of lithium-ion batteries. However, the large-scale use and industrialization of silicon anode materials are severely constrained by its volume expansion during charge and discharge and the resulting material differentiation and continuous growth of the solid electrolyte layer (SEI). In contrast, silicon-oxygen materials (SiO x ) has a smaller volume change than pure Si while exerting a high specific capacity, so it has a more practical potential in terms of cycle life. Based on SiO x Many researcher...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M4/60H01M10/0525
CPCH01M4/366H01M4/386H01M4/583H01M4/625H01M4/602H01M10/0525Y02E60/10
Inventor 邓永红吴唯郭军坡王曼
Owner SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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