Silicon-carbon composite for secondary battery anode material, and method for manufacturing the same.

Abstract

The present invention relates to a silicon-carbon composite for secondary battery anode material and a method for manufacturing the same, and more specifically, to a silicon-carbon composite for secondary battery anode material that minimizes the volume change of silicon particles during the charging and discharging process of a secondary battery, thereby improving the characteristics of the secondary battery when applied as an anode material, and to a method for efficiently manufacturing the same.

Claims

1. A silicon-carbon composite comprising silicon particles and a carbon material, The silicon particles are amorphous, having an average crystallite size of 10 nm or less. The sphericity of the silicon-carbon composite is 0.7 or higher. Silicon-carbon composite.

2. The sphericity of the silicon-carbon composite is 0.9 or higher. The silicon-carbon composite according to claim 1.

3. The silicon-carbon composite has a carbon-based amorphous coating layer formed from a carbon-based coating material on its surface. The silicon-carbon composite according to claim 1.

4. The carbon-based coating material comprises one or more selected from the group consisting of petroleum pitch, ethylene, acetylene, methane, ethane, epoxy resin, polyphenol, polyaniline, polyvinyl alcohol, polyvinyl chloride, and other cross-linked polymers. The silicon-carbon composite according to claim 1.

5. Based on the total weight of the silicon-carbon composite, the silicon particles constitute 55 to 70% by weight, and the carbon material constitutes 30 to 45% by weight. The silicon-carbon composite according to claim 1.

6. A silicon-carbon composite comprising the silicon-carbon composite according to any one of claims 1 to 5, Negative electrode material for secondary batteries.

7. (S1) A step of heating a rotary firing furnace to a temperature of 400°C to 650°C while purging it with an inert gas; and, (S2) A step in which silicon source gas and carbon source gas are simultaneously introduced into the rotary firing furnace, and a homogeneous reaction is carried out under atmospheric pressure conditions to obtain a silicon-carbon composite by co-deposition of silicon and carbon; Includes, The obtained silicon-carbon composite comprises silicon particles and carbon material. The average crystallite size of the silicon particles is 10 nm or less. The silicon-carbon composite D ５０ The values ​​are between 1 μm and 10 μm, and the sphericity is 0.7 or higher. A method for manufacturing silicon-carbon composites.

8. The inert gas includes one or more of nitrogen gas and argon gas. A method for producing a silicon-carbon composite according to claim 7.

9. The rotary firing furnace is a chemical vapor deposition (CVD) reactor equipped with a rotary baffle. A method for producing a silicon-carbon composite according to claim 7.

10. The silicon source gas includes at least one selected from the group consisting of monosilane (SiH ４ ), disilane (Si ２ H ６ ), monochlorosilane (SiHCl ３ ), dichlorosilane (SiHCl ２ Cl ２ ), trichlorosilane (SiHCl ３ ), tetrachlorosilane (SiCl ４ ), and trimethylsilane (SiH(CH ３ )) ３ gas. A method for producing a silicon-carbon composite according to claim 7.

11. The carbon source gas includes one or more gases selected from the group consisting of methane, ethane, propane, butane, ethylene, and acetylene. A method for producing a silicon-carbon composite according to claim 7.

12. The sphericity of the silicon-carbon composite is 0.9 or higher. A method for producing a silicon-carbon composite according to claim 7.

13. The silicon-carbon composite in step (S2) above is cooled to room temperature of 15°C to 25°C to obtain a solid powder. A method for producing a silicon-carbon composite according to claim 7.

14. After the reaction (S2) described above has terminated, (S3) The step of introducing a carbon-based source gas and an inert gas for the coating material to form a carbon-based amorphous coating layer on the result obtained in (S2) to obtain the final silicon-carbon composite is further included. A method for producing a silicon-carbon composite according to claim 7.

15. The above (S3) step is performed by chemical vapor deposition. A method for producing a silicon-carbon composite according to claim 14.

16. The carbon-based source gas is one selected from the group consisting of methane gas, ethane gas, propane gas, butane gas, acetylene gas, ethylene gas, and propylene gas. A method for producing a silicon-carbon composite according to claim 14.

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