Method of enhanced lithiation of doped silicon carbide via high temperature annealing in an inert atmosphere
A method for enhancing the lithium-ion capacity of a doped silicon carbide is disclosed. The method utilizes heat treating the silicon carbide in an inert atmosphere. Also disclosed are anodes for lithium-ion batteries prepared by the method.
1. A method for increasing the Li-ion capacity of a silicon carbide comprising:
providing a doped silicon carbide; and
heat treating the doped silicon carbide in an inert atmosphere, and electrochemical lithiation of the heat-treated doped silicon carbide, wherein lithiation capacity of the heat-treated doped silicon carbide is greater than lithiation capacity of the doped silicon carbide.
2. A method according to claim 1 wherein the doped silicon carbide is doped 6H-SiC (0001).
3. A method according to claim 2 wherein the doped 6H-SiC (0001) is n-type 6H-SiC (0001).
4. A method according to claim 1 wherein lithiation capacity of the heat-treated doped silicon carbide is up to 57-fold greater than lithiation capacity of the doped silicon carbide.
5. A method according to claim 3 wherein lithiation capacity of the heat-treated n-type 6H-SiC (0001) is up to 57-fold greater than lithiation capacity of the n-type 6H-SiC (0001).
6. A method according to claim 1 wherein the inert atmosphere is argon at atmospheric pressure.
7. A method according to claim 1 wherein the inert atmosphere is argon at less than atmospheric pressure.
8. A method according to claim 1 wherein the inert atmosphere has a pressure below 1×10 −5 Torr.
9. A method according to claim 1 wherein the inert atmosphere has a pressure below 1×10 −9 Torr.
10. A method according to claim 9 wherein the inert atmosphere has a pressure below 1×10 −10 Torr.
11. A method according to claim 1 wherein the doped silicon carbide is heat treated to at least about 1100° C.
12. A method according to claim 1 wherein the heat-treated doped silicon carbide has √3×√3 surface reconstruction.
13. A method according to claim 1 wherein the heat-treated doped silicon carbide has (6√3×6√3)R30° surface reconstruction.
14. A method according to claim 13 wherein the heat-treated doped silicon carbide has the (6√3×6√3)R30° surface reconstruction and graphitic layers on the surface.
15. A method according to claim 14 wherein the graphitic layers are a mixture of single and bilayer graphene.
16. A method according to claim 14 wherein the graphitic layers are multiple layers of graphene.
17. A method according to claim 1 wherein lithiation of the heat-treated doped silicon carbide results in 1:1 Li to Si ratio within at least the top 3 μm of the silicon carbide surface.
18. An anode for a lithium-ion battery, wherein the anode comprises an increased lithium-ion capacity of silicon carbide prepared by a method according to claim 1 .
19. A lithium-ion battery comprising an anode according to claim 18 .
20. A method according to claim 1 wherein the doped silicon carbide is selected from the group consisting of silicon carbide wafer or silicon carbide powder.