Negative electrode active material, method of preparing the same, negative electrode and lithium secondary battery employing the electrode including the negative electrode active material
In an aspect, a negative electrode active material, a method of preparing the same, and a lithium secondary battery having the negative electrode including the negative electrode active material is provided. The negative electrode active material may include amorphous silicon oxide, crystalline silicon, carbon, metal silicide, spherical particles and whiskers.
1. A negative electrode active material comprising amorphous silicon oxide, crystalline silicon, carbon, and metal silicide components, wherein the metal silicide component and one or more of silicon oxide, crystalline silicon and carbon is included in spherical particles and whiskers, wherein the negative electrode active material is made by a process comprising:
mixing amorphous silicon oxide, carbon precursor, silicon, metal silicide, and a first solvent together to obtain a negative electrode active material composition; and
spray-drying the negative electrode active material composition to provide the negative electrode active material.
2. The negative electrode active material of claim 1 , wherein the metal silicide is at least one selected from the group consisting of nickel silicide, titanium silicide, titanium silicide, copper silicide, and iron silicide.
3. The negative electrode active material of claim 1 , wherein an amount of the metal silicide is from about 0.5 parts to about 10 parts by weight based on 100 parts by weight of a total weight of the negative electrode active material.
4. The negative electrode active material of claim 1 , wherein the whiskers comprise amorphous silicon oxide, crystalline silicon, and metal silicide.
5. The negative electrode active material of claim 1 , wherein the spherical particles comprise amorphous silicon oxide and crystalline silicon.
6. The negative electrode active material of claim 1 , wherein the spherical particles have an average particle diameter of from about 5 μm to about 15 μm.
7. The negative electrode active material of claim 1 , wherein the whiskers have a length of from about 1 μm to about 5 μm, and a thickness of about from 10 nm to about 20 nm.
8. The negative electrode active material of claim 1 , wherein an amount of the silicon oxide in the negative electrode active material is from about 70 parts to about 90 parts by weight based on 100 parts by weight of a total weight of the negative electrode active material.
9. The negative electrode active material of claim 1 , wherein an amount of the carbon in the negative electrode active material is from about 1 part to about 10 parts by weight based on 100 parts by weight of a total weight of the negative electrode active material.
10. The negative electrode active material of claim 1 , wherein an amount of the silicon in the negative electrode active material is from about 10 parts to about 20 parts by weight based on 100 parts by weight of a total weight of the negative electrode active material.
11. A method of preparing a negative electrode active material, the method comprising:
mixing amorphous silicon oxide, carbon precursor, silicon, metal silicide, and a first solvent together to obtain a negative electrode active material composition; and
spray-drying the negative electrode active material composition,
wherein the electrode active material comprising amorphous silicon oxide, crystalline silicon, carbon, and metal silicide components, wherein one or more of the components is included in spherical particles and whiskers.
12. The method of claim 11 , wherein the spray-drying comprises spraying the negative electrode active material composition at a pressure of from about 300 Pa to about 500 Pa.
13. The method of claim 11 , wherein the carbon precursor is at least one selected from the group consisting of carbon black, pitch, sucrose, carbon nanotube (CNT), and phenol resin.
14. The method of claim 11 , wherein the spray-drying comprises spraying the negative electrode active material composition at a temperature of from about 700° C. to about 1000° C.
15. The method of claim 11 , wherein an amount of the silicon is from about 10 parts to about 200 parts by weight based on 100 parts by weight of the amorphous silicon oxide.
16. The method of claim 11 , wherein an amount of the carbon precursor is from about 5 parts to about 30 parts by weight based on 100 parts by weight of the amorphous silicon oxide.
17. The method of claim 11 , wherein an amount of the metal silicide is from about 1 part to about 10 parts by weight based on 100 parts by weight of the amorphous silicon oxide.
18. A lithium secondary battery comprising a negative electrode including the negative electrode active material of claim 1 .