Composite, electrochemical active material composite using the composite, electrode including the composite or electrochemical active material composite, lithium battery including the electrode, field emission device including the composite, biosensor including the composite, semiconductor device including the composite, and thermoelectric device including the composite

1. An electrochemically active material composite comprising a composite and an electrochemically active material, wherein the composite comprises particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2; and graphene,

wherein the particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2 are completely surrounded by the graphene, and

wherein the particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2 completely surrounded by the graphene are interconnected with each other in a graphene matrix.

2. The electrochemically active material composite of claim 1 , wherein the graphene has a branched structure comprising contacting graphene particles, and wherein the silicon oxide is distributed in the branched structure.

3. The electrochemically active material composite of claim 1 , wherein the graphene has a spherical structure having a size of about 50 nanometers to about 300 nanometers.

4. The electrochemically active material composite of claim 1 , wherein the silicon oxide of the formula SiO 2 or the silicon oxide of the formula SiO x wherein 0<x<2 has an average particle diameter of about 1 nanometers to about 20 nanometers.

5. The electrochemically active material composite of claim 1 ,

wherein an amount of the graphene is greater than 10 parts by weight, based on 100 parts by weight of the composite, and

wherein the graphene extends from the silicon oxide by a distance of about 0.5 nm or less.

6. The electrochemically active material composite of claim 1 , wherein the composite has a major peak having a Bragg angle of about 15 degrees two-theta to about 30 degrees two-theta, and a minor peak in a range of about 40 degrees two-theta to about 50 degrees two-theta, when analyzed using Cu K-alpha X-ray radiation having a wavelength of 1.541 Angstroms.

7. The electrochemically active material composite of claim 1 , wherein there are no silicon oxide or silicon carbide peaks at a chemical shift of about −90 parts per million to about −120 parts per million when the composite is analyzed by 29Si{1H}-cross-polarization/magic-angle spinning nuclear magnetic resonance spectroscopy.

8. The electrochemically active material composite of claim 1 , wherein the composite has a faceted-sphere structure or a crumpled paper ball structure, and the silicon oxide of the formula SiO 2 or the silicon oxide of the formula SiO x wherein 0<x<2 is distributed in the faceted-sphere structure or crumpled paper ball structure.

9. The electrochemically active material composite of claim 1 , wherein the silicon oxide 9 of the formula SO 2 i or the silicon oxide of the formula SiO x wherein 0<x<2 is chemically bound to the graphene via a chemical bond.

10. The electrochemically active material composite of claim 1 , wherein the amount of the graphene is in a range of greater than 10 parts by weight to about 90 parts by weight, based on 100 parts by weight of the composite.

11. The electrochemically active material composite of claim 1 , wherein the graphene extends from the silicon oxide by a distance of about 10 nanometers or less, comprises at least one to 20 graphene layers, and has a total thickness of about 0.6 nanometers to about 12 nanometers.

12. The electrochemically active material of claim 1 , wherein the composite is prepared by a method comprising:

contacting a reaction gas comprising a carbon source gas and silicon dioxide, and thermally treating the reaction gas-contacted silicon dioxide to obtain the composite.

13. The electrochemically active material of claim 1 , wherein in the composite, the silicon oxide of the formula SiOx wherein 0<x<2 is partially or completely formed on the silicon oxide of the formula SiO 2 .

14. An electrode comprising the electrochemically active material composite of claim 1 .

15. The electrode of claim 14 , wherein the electrode is a cathode or an anode.

16. A lithium battery comprising the electrochemically active material composite of claim 1 .

17. A field emission device comprising the electrochemically active material composite of claim 1 .

18. A biosensor comprising the electrochemically active material composite of claim 1 .

19. A semiconductor device comprising the electrochemically active material composite of claim 1 .

20. A thermoelectric device comprising the electrochemically active material composite of claim 1 .

21. An electrochemically active material composite comprising a composite and an electrochemically active material,

wherein the composite comprises particles comprising a silicon oxide of the formula SiOx wherein 0<x<2, and graphene,

wherein the particles comprising a silicon oxide of the formula SiOx wherein 0<x<2 are completely surrounded by the graphene, and

wherein the particles comprising a silicon oxide of the formula SiOx wherein 0<x<2 completely surrounded by the graphene are interconnected with each other in a graphene matrix wherein the particles comprising a silicon oxide of the formula SiO x , wherein 0<x<2 further comprise a silicon oxide of the formula SiO 2 , and wherein, in the composite, the silicon oxide of the formula SiO x wherein 0<x<2 partially or completely surround the silicon oxide of the formula SiO 2 .

22. An electrochemically active material composite comprising a graphene-silicon oxide composite and an electrochemically active material,

wherein the graphene-silicon oxide composite comprises particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2, and graphene,

wherein the particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2 are completely surrounded by the graphene,

wherein the particles comprising a silicon oxide of the formula SiO 2 and a silicon oxide of the formula SiOx wherein 0<x<2 completely surrounded by the graphene are interconnected with each other in a graphene matrix, and

wherein the graphene-silicon oxide composite is coated on surface of the electrochemically active material.