Preparation method of silicon carbon composite material and application thereof used as lithium ion battery negative electrode material

A technology of silicon-carbon composite materials and silicon sources, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of high energy consumption and heavy pollution, and achieve the effects of improving electronic conductance, reducing energy consumption, and simple process

Inactive Publication Date: 2018-03-06
北京博雅合众环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the existing method for preparing porous silicon-carbon composite materials has high energy consumption and relatively large pollution. Therefore, a silicon

Method used

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  • Preparation method of silicon carbon composite material and application thereof used as lithium ion battery negative electrode material
  • Preparation method of silicon carbon composite material and application thereof used as lithium ion battery negative electrode material
  • Preparation method of silicon carbon composite material and application thereof used as lithium ion battery negative electrode material

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Example Embodiment

[0022] The method for preparing the silicon-carbon composite material of the present invention includes the following steps: (1) At room temperature, weigh the silicon source, molten salt, and reducing agent in a specific ratio, and the above-mentioned raw materials and balls according to the ball-to-material ratio of 3:1 -5:1 Put the ball into the ball mill tank, the volume of the ball material does not exceed 2 / 3 of the ball mill tank, mechanically mix for 2-6 hours at a rotating speed of 300-450r / h, and put the resulting mixture in a closed inner liner. After being sealed in a hydrothermal tank, heat treatment for a certain period of time in an oven at 190-280°C to obtain the corresponding silicon-containing precursor; (2), the silicon-containing precursor obtained in step (1) is subjected to acid treatment to remove metal compounds, Silicon dioxide is used to obtain elemental silicon powder; (3), after the elemental silicon powder obtained in step 2) is uniformly mixed with ...

Example Embodiment

[0025] Example 1: Preparation method of silicon-carbon composite material, which includes the following steps: (1) Select molecular sieve as silicon source, select Mg powder as reducing agent, select AlCl3 as low-temperature molten salt; select pitch as carbon source, Mg powder and The molar ratio of molecular sieve is 1:1-2:1, and the molar ratio of Al in the low-temperature molten salt to Si in the molecular sieve is 8:1-12:1. At room temperature, weigh a certain amount of molecular sieve powder, Mg powder and AlCl3 powder, put the above-mentioned raw materials and balls into a ball milling tank at a ratio of 5:1, and mix them mechanically for 5h at a speed of 350r / h, so that the raw materials are fully and uniformly mixed, and the resulting mixture is placed in a closed In the 20ml polytetrafluoroethylene liner, sealed with a stainless steel hydrothermal tank, heat-treated in an oven at 190℃ for 10h to obtain the corresponding silicon-containing precursor; (2), the content ob...

Example Embodiment

[0026] Embodiment 2: The preparation method of silicon-carbon composite material, which includes the following steps: (1) Select molecular sieve as silicon source, select Mg powder as reducing agent, select AlCl3 as low-temperature molten salt; select pitch as carbon source, Mg powder and The molar ratio of molecular sieve is 1.5:1, and the molar ratio of Al in the low-temperature molten salt to Si in the molecular sieve is 10:1. At room temperature, weigh a certain amount of molecular sieve powder, Mg powder and AlCl3 powder, and combine the above raw materials and balls. Put the ball-to-material ratio into a ball mill tank at a ratio of 3:1, and mechanically mix for 2h at a rotating speed of 300r / h to make the raw materials fully and uniformly mixed. The resulting mixture is put into a closed 20ml PTFE liner After sealing with a stainless steel hydrothermal tank, heat treatment in an oven at 230°C for 6 hours to obtain the corresponding silicon-containing precursor; (2) Put th...

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Abstract

The invention discloses a preparation method of a silicon carbon composite material and application thereof used as a lithium ion battery negative electrode material. Porous elemental silicon is prepared by taking a molecular sieve and silicon dioxide aerogel as a silicon source, metal elemental powder as a reducing agent and a low-temperature molten salt as a medium and achieving reduction of metal power on silicon dioxide during thermal processing in a certain temperature, and then the silicon carbon composite material is obtained by mixing the elemental silicon and asphalt and performing high-temperature carbon coating. Due to the porous characteristic of a raw material, the prepared silicon carbon composite material has a good three-dimensional porous structure, a good buffer effect onvolume expansion of a silicon negative electrode during the circulation process is achieved, moreover, the electron conductivity of the material after carbon coating is greatly improved, and long-term circulation stability of a silicon-based negative electrode material is facilitated. The method is low in cost of the raw material and simple in process and is suitable for industrial production ona large scale.

Description

technical field [0001] The invention relates to the technical field of battery material preparation, in particular to a method for preparing a silicon-carbon composite material and its application as a lithium-ion battery negative electrode material. Background technique [0002] Lithium-ion batteries stand out among many energy storage devices due to their advantages such as high energy density, high working voltage, low self-discharge and no memory effect. In recent years, with the development of power vehicles and energy storage industries, traditional lithium-ion batteries have been difficult to meet the needs of practical applications, so the development of high-capacity lithium-ion battery electrode materials has become a top priority. Among many anode materials for lithium-ion batteries, silicon anode materials have become the first choice for next-generation commercial lithium-ion battery anode materials due to their high theoretical specific capacity (3579mAh / g, Li1...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/364H01M4/386H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 沈恋侯喜锋郑允星张雷蔡迅
Owner 北京博雅合众环保科技有限公司
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