LiF-embedded SiG powder for lithium ion battery

1. A nanographitic composite for use as an anode in a lithium ion battery, comprising:

particles of an electroactive material; and

a coating over each of the electroactive particles comprising a first plurality of graphene nanoplatelets and a solid electrolyte interface (SEI) modifier additive wherein the first plurality of graphene nanoplatelets and one of the electroactive particles have covalent bonding, formation of interdiffusion regions that contain both carbon and electroactive material, or a combination thereof therebetween and the SEI modifier additive is a dry powder that is disposed over at least part of the surface of the electroactive material particles, and a second plurality of graphene nanoplatets each adhered to one of the SEI modifier particles or one of the first plurality of graphene nanoplatelets by van der Waals forces.

2. The nanographitic composite of claim 1 , wherein the coating comprises a mixture of the first plurality of graphene nanoplatelets and the SEI modifier additive.

3. The nanographitic composite of claim 1 , wherein the coating comprises an inner layer of the SEI modifier additive and an outer layer of the first plurality of graphene nanoplatelets, wherein the first plurality of graphene nanoplatelets coat at least a portion of the additive modified electroactive particles to form a layer made up of overlapping graphene nanoplatelets.

4. The nanographitic composite of claim 1 , wherein the first plurality of graphene nanoplatelets forms a contact with at least a portion of the electroactive particle.

5. The nanographitic composite of claim 1 , wherein in the SEI modifier additive is LiF.

6. The nanographitic composite of claim 1 , wherein the first plurality of graphene nanoplatelets have a thickness of 0.34 nm to 50 nm and a lateral dimension of less than 900 nm.

7. The nanographitic composite of claim 1 , wherein the SEI modifier additive results in a discontinuous layer.

8. The nanographitic composite of claim 1 , wherein the SEI modifier additive results in a continuous layer.

9. The nanographitic composite of claim 1 , wherein the first plurality of graphene nanoplatelets-coated nanoscale particles form agglomerates.

10. The nanographitic composite of claim 1 , wherein the first plurality of graphene nanoplatelets have a lateral dimension of less than 500 nm.

11. The nanographitic composite of claim 1 , wherein the first plurality of graphene nanoplatelets have a lateral dimension of 30 nm to 200 nm.

12. The nanographitic composite of claim 1 , wherein the coating comprises multiple layers of graphene nanoplatelets.

13. The nanographitic composite of claim 1 , wherein the electroactive material is one or more material selected from the group consisting of silicon, tin, iron, magnesium, aluminum, lead, gold, silver, titanium, platinum, palladium, ruthenium, copper, nickel, rhodium and nickel and combinations thereof.

14. The nanographitic composite of claim 1 , wherein electroactive material comprises silicon.

15. The nanographitic composite of claim 14 , wherein the silicon is present in a range from 5 wt % to 90 wt % of the composite.

16. The nanographitic composite of claim 14 , wherein the silicon is present in a range from 40 wt % to 70 wt % of the composite.

17. The nanographitic composite of claim 14 , wherein the silicon is present in a range from 30 wt % to 70 wt % of the composite.

18. The nanographitic composite of claim 5 , wherein the LiF is present in a range from 2 wt % to 30 wt % of the composite.

19. The nanographitic composite of claim 1 , wherein graphene is present in a range from 10 wt % to 40 wt % of the composite.

20. The nanographitic composite of claim 1 , wherein the composite further comprises a conductive carbon additive.

21. The nanographitic composite of claim 20 , wherein the conductive carbon additive is selected from the group consisting of carbon black, acetylene black, carbon nanotube, carbon fiber, carbon nanohorn, carbon nanocoil and combinations thereof.

22. The nanographitic composite of claim 1 , wherein the electroactive particle is present in a range from 5 wt % to 90 wt % of the composite.

23. The nanographitic composite of claim 1 , wherein the particles have a surface area is in the range of 50 to 200 m 2/g.

24. An electrode for use as an anode in a lithium ion battery, said electrode comprising:

(a) the nanographitic composite according to claim 1 ; and

(b) a binder.

25. The electrode of claim 24 , further comprising a conductive additive.

26. The electrode of claim 25 , wherein the conductive additive comprises a graphene.

27. The electrode of claim 25 , wherein the conductive additive is 2 to 20 wt % of the total electrode weight.

28. The electrode of claim 25 , wherein the binder is 3 to 20 wt % of the total electrode weight.

29. A lithium ion battery comprising:

an anode according to claim 24 ;

a cathode; and

an electrolyte disposed between and in ionic contact with the anode and the cathode.

30. A nanographitic composite for use as an anode in a lithium ion battery, comprising:

a plurality of composite particles comprising:

an electroactive particle;

a coating layer comprising an inner layer of graphene nanoplatelets that have covalent bonding, formation of interdiffusion regions that contain both carbon and electroactive material, or a combination thereof to the electroactive particle and an outer layer of graphene nanoplatelets that are van der Waal bonded with the inner layer of graphene nanoplatelets, wherein the nanographitic platelets covers at least a portion of the nanoscale particle to form a nanographitic layer; and

a solid electrolyte interface (SEI) modifier additive wherein the SEI modifier additive is a dry powder.

31. The nanographitic composite of claim 30 , wherein the SEI modifier additive is preferentially disposed at the interface of the electroactive particle and the inner layer of graphene nanoplatelets.

32. The nanographitic composite of claim 30 , wherein the SEI modifier additive is disposed in the outer layer of the graphene nanoplatelets surrounding the electroactive particle.

33. The nanographitic composite of claim 30 , wherein the inner layer comprises a mixture of carbon, silicon and LiF.

34. The nanographitic composite of claim 30 , wherein the inner layer is covalently bonded to the electroactive particle.

35. The nanographitic composite of claim 30 , wherein the covalent bond is a pi-bond or a partial pi-bond.

36. The nanographitic composite of claim 30 , wherein the inner layer is bonded to the electroactive particle by van der Waals bond.

37. The nanographitic composite of claim 30 , wherein the graphene nanoplatelets-coated nanoscale particles form agglomerates.

38. The nanographitic composite of claim 30 , wherein the coating layer comprises multiple layers of graphene nanoplatelets.

39. The nanographitic composite of claim 30 , wherein the electroactive particle is one or more selected from the group consisting of silicon, tin, iron, magnesium, aluminum, lead, gold, silver, titanium, platinum, palladium, ruthenium, copper, nickel, rhodium and nickel and combinations thereof.

40. The nanographitic composite of claim 30 , wherein electroactive particle comprises silicon.

41. The nanographitic composite of claim 40 , wherein the silicon is present in a range from 10 wt % to 90 wt % of the composite.

42. The nanographitic composite of claim 40 , wherein the composite further comprises a conductive carbon additive.

43. The nanographitic composite of claim 42 , wherein the conductive carbon additive is selected from the group consisting of carbon black, acetylene black, carbon nanotube, carbon fiber, carbon nanohorn, carbon nanocoil and combinations thereof.

44. An electrode for use as an anode in a lithium ion battery, said electrode comprising:

(a) the nanographitic composite according to claim 30 ; and

(b) a binder.

45. The electrode of claim 44 , further comprising a conductive additive.

46. The electrode of claim 44 , wherein the conductive additive comprises a graphene.

47. The electrode of claim 44 , wherein the conductive additive is 2 to 20 wt % of the total electrode weight.

48. The electrode of claim 44 , wherein the binder is 3 to 20 wt % of the total electrode weight.

49. A lithium ion battery comprising:

an anode according to claim 44 ;

a cathode;

a separator spacing apart the anode and the cathode; and

an electrolyte in contact with the anode and the cathode.