Additives for high voltage lithium ion batteries

1. An electrolyte composition for a lithium ion battery comprising a lithium salt in a non-aqueous solvent containing an additive comprising a compound of formula R 3 SiOP(O) n F 2 ; wherein each R independently is a hydrocarbyl group; and n is 0 or 1; and wherein the additive is substantially free from (R 3 SiO) 3 P(O) n and (R 3 SiO) 2 P(O) n F.

2. The electrolyte composition of claim 1 , wherein each R independently is a hydrocarbyl moiety selected from the group consisting of alkyl, aryl, aryl-substituted alkyl and alkyl-substituted aryl.

3. The electrolyte composition of claim 1 , wherein each R independently is a hydrocarbyl moiety selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, and phenyl.

4. The electrolyte composition of claim 1 , wherein each R is methyl.

5. The electrolyte composition of claim 1 , wherein the additive is present in the composition at a concentration in the range of about 0.0005 molar (M) to about 0.2 M.

6. The electrolyte composition of claim 1 , wherein the lithium salt comprises lithium hexafluorophosphate (LiPF 6 ).

7. The electrolyte composition of claim 1 , wherein the lithium salt is present in the composition at a concentration in the range of about 0.1 M to about 3 M.

8. The electrolyte composition of claim 1 , wherein the non-aqueous solvent comprises at least one solvent selected from the group consisting of an ether, a carbonate ester, a nitrile, a sulfoxide, a sulfone, a fluoro-substituted linear dialkyl carbonate, a fluoro-substituted cyclic alkylene carbonate, a fluoro-substituted sulfolane, and a fluoro-substituted sulfone.

9. The electrolyte composition of claim 1 , wherein the non-aqueous solvent comprises a combination of an alkylene carbonate and a dialkyl carbonate.

10. An electrolyte composition for a lithium ion battery comprising LiPF 6 at a concentration of about 0.1 M to about 3 M in a non-aqueous solvent containing an additive comprising a compound of formula R 3 SiOP(O) n F 2 at a concentration of about 0.0005 M to about 0.2 M; wherein each R independently is selected from the group consisting of alkyl, aryl, aryl-substituted alkyl and alkyl-substituted aryl; and n is 0 or 1; and wherein the additive is substantially free from (R 3 SiO) 3 P(O) n and (R 3 SiO) 2 P(O) n F.

11. The electrolyte composition of claim 10 , wherein each R independently is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, and phenyl.

12. The electrolyte composition of claim 10 , wherein each R is methyl.

13. The electrolyte composition of claim 10 , wherein the LiPF 6 is present at a concentration of about 1 M to about 1.5 M.

14. The electrolyte composition of claim 10 , wherein the non-aqueous solvent comprises at least one solvent selected from the group consisting of an ether, a carbonate ester, a nitrile, a sulfoxide, a sulfone, a fluoro-substituted linear dialkyl carbonate, a fluoro-substituted cyclic alkylene carbonate, a fluoro-substituted sulfolane, and a fluoro-substituted sulfone.

15. The electrolyte composition of claim 10 , wherein the non-aqueous solvent comprises a combination of an alkylene carbonate and a dialkyl carbonate.

16. The electrolyte composition of claim 10 , wherein the non-aqueous solvent comprises a combination of ethylene carbonate and ethyl methyl carbonate in a respective weight ratio of about 3:7.

17. An electrochemical cell comprising an anode, a cathode, and an electrolyte composition of claim 1 contacting the anode and the cathode.

18. A battery comprising a plurality of electrochemical cells of claim 17 , electrically connected in series, in parallel, or in both series and parallel.

19. An electrochemical cell comprising an anode, a cathode, and an electrolyte composition of claim 10 contacting the anode and the cathode.

20. A battery comprising a plurality of electrochemical cells of claim 19 , electrically connected in series, in parallel, or in both series and parallel.