Method for producing silicon-based negative electrode active material, negative electrode active material for lithium secondary battery, and lithium secondary battery comprising same
View Patent ↗The present invention relates to a method for preparing a silicon-based negative electrode active material, a negative electrode active material for a lithium secondary battery, and a lithium secondary battery comprising the same. More particularly, the method for preparing the silicon-based negative electrode active material comprises: preparing a porous silica (SiO 2 ) and a thin metal film; coating the porous silica onto the thin metal film; reducing the porous silica to a porous silicon by performing heat-treatment of the thin metal film and the porous silica; and obtaining the porous silicon.
1. A method for preparing a silicon-based negative electrode active material, comprising:
preparing a porous silica (SiO 2 ) and a thin metal film;
coating the porous silica onto the thin metal film;
reducing the porous silica to a porous silicon by performing heat-treatment of the thin metal film and the porous silica; and
obtaining the porous silicon.
2. The method of claim 1 , wherein
the porous silica is derived from diatomite.
3. The method of claim 1 , wherein
the coating the porous silica onto the thin metal film is
coating a water-soluble polymer and the porous silica onto the thin metal film.
4. The method of claim 3 , wherein
the water-soluble polymer is polyethylene oxide, polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, polyethyleneimine, or a combination of thereof.
5. The method of claim 3 , wherein
the coating a water-soluble polymer and the porous silica onto the thin metal film is
coating the water-soluble polymer onto the interface between the thin metal film and the porous silica.
6. The method of claim 1 , wherein
the thin metal film is a thin aluminum film, a thin magnesium film, a thin calcium film, or a combination of thereof.
7. The method of claim 1 , wherein
a pattern is formed on a surface of the thin metal film.
8. The method of claim 7 , wherein
the pattern is formed at intervals of 1 to 100 μm.
9. The method of claim 1 , wherein
the coating the porous silica onto the thin metal film is performed by a roll-to-roll method.
10. The method of claim 1 , wherein
in the coating the porous silica onto the thin metal film,
there are a plurality of units when supposing a thin metal film coated with the porous silica is one unit.
11. The method of claim 1 , wherein
in the reducing the porous silica to a porous silicon by performing heat-treatment of the thin metal film and the porous silica,
the heat-treatment temperature is 750 to 900° C.
12. A negative electrode active material for a lithium secondary battery, comprising the porous silicon obtained according to claim 1 .
13. A lithium secondary battery comprising:
a negative electrode including the negative electrode active material for a lithium secondary battery according to claim 12 ;
a positive electrode including a positive electrode active material; and
an electrolyte.
14. The lithium secondary battery of claim 13 , wherein
the lithium secondary battery further comprises a separator between the positive electrode and the negative electrode.