Surface-fluorinated silicon-containing electrodes

1. An electrochemical device comprising:

an anode comprising a silicon-dominant electrochemically active material comprising silicon particles;

a coupling reagent; and

a fluorine-containing layer; wherein said layer comprises a metal fluoride compound and wherein said metal fluoride compound comprises LiF, AlF 3 , CuF 2 , FeF 3 , TiF 3 , FeF 2 , NiF 2 , CoF 3 , CoF 2 , MnF 2 , AgCuF 3 , BiF 3 , VF 3 , NbF 5 , or a combination thereof;

a cathode; and

an electrolyte, wherein said electrolyte comprises fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC), or a mixture thereof; and

wherein said coupling reagent couples said fluorine-containing layer to said silicon particles.

2. The electrochemical device of claim 1 , wherein the electrochemically active material comprises silicon at about 70% to about 100% by weight.

3. The electrochemical device of claim 1 , wherein the electrochemically active material comprises silicon particles, and the silicon particles are coated with the fluorine-containing layer.

4. The electrochemical device of claim 3 , wherein the silicon particles have an average particle size between 1 μm and 50 μm.

5. The electrochemical device of claim 1 , wherein the electrochemically active material comprises a film, and the film is coated with the fluorine-containing layer.

6. The electrochemical device of claim 1 , wherein the metal fluoride compound comprises AlF 3 .

7. The electrochemical device of claim 1 , wherein the anode comprises a Si-composite electrochemically active film.

8. The electrochemical device of claim 1 , wherein the anode is a self-supported film.

9. The electrochemical device of claim 1 , wherein said fluorine-containing layer is formed via a chemical reaction with a solid electrolyte interphase (SEI) fluorinating precursor and/or an SEI fluorinating compound.

10. The electrochemical device of claim 1 , wherein electrochemically active material is activated.

11. The electrochemical device of claim 10 , wherein activating the electrochemically active material comprises exposing the electrochemically active material to a coupling reagent.

12. The electrochemical device of claim 11 , wherein the coupling reagent comprises [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEAPTMS).

13. The electrochemical device of claim 10 , wherein the electrochemically active material is activated and is subsequently exposed to a SEI fluorinating precursor.

14. The electrochemical device of claim 10 , wherein the electrochemically active material is activated and is subsequently exposed to a SEI fluorinating compound.

15. The electrochemical device of claim 9 , wherein the SEI fluorinating precursor and/or the SEI fluorinating compound comprises said metal fluoride compound.

16. The electrochemical device of claim 15 , wherein the SEI fluorinating precursor comprises Al(NO 3 ) 3 ·9H 2 O and NH 4 F.

17. The electrochemical device of claim 15 , wherein the metal fluoride compound comprises AlF 3 .

18. The electrochemical device of claim 1 , wherein the cathode comprises lithium.

19. The electrochemical device of claim 1 , wherein the electrolyte comprises greater than or equal to about 10 wt % FEC, EMC, DMC, DEC, PC, or a mixture thereof.

20. The electrochemical device of claim 19 , wherein the electrolyte comprises about 30 wt % FEC and about 70 wt % EMC.

21. The electrochemical device of claim 1 , wherein the electrolyte does not comprise ethylene carbonate (EC).

22. The electrochemical device of claim 1 , wherein the electrolyte comprises LiPF 6 .

23. The electrochemical device of claim 22 , wherein the electrolyte comprises the LiPF 6 at a concentration of about 1 M to about 1.2 M.

24. The electrochemical device of claim 1 , wherein the cathode comprises LiCoO 2 .

25. The electrochemical device of claim 1 , wherein cathode comprises Nickel-Cobalt-Manganese (NCM), Nickel-Cobalt-Aluminum (NCA), or a combination thereof.

26. The electrochemical device of claim 1 , wherein the electrochemical device is a battery.