Eutectic mixtures containing alkali-metal sulfonimide salts, and electrochemical devices utilizing same
Binary and ternary eutectic mixtures and corresponding electrolytes are disclosed. In some embodiments, binary eutectic mixtures and electrolytes each include a first salt, X1 + Y1 − , and a second salt, X2 + Y2 − , wherein each of X1 + and X2 + is an alkali metal cation and X1 + is different from X2 + ; and each of Y1 − and Y2 − is a sulfonimide anion and Y1 − is different from Y2 − . In ternary eutectic mixtures and electrolytes further include a third salt, X3 + Y3 − , wherein X3 + is different from each of X1 + and X2 + . In some embodiments, the eutectic mixtures and electrolytes have melting points in a range of about 5° C. to about 70° C. Electrochemical devices containing such eutectic-mixture electrolytes are also disclosed.
1. An electrolyte, comprising:
a substantially eutectic mixture that includes a first salt, X 1 + Y 1 − , and a second salt, X 2 + Y 2 − , wherein:
each of X 1 + and X 2 + is an alkali metal cation and X 1 + is different from X 2 + ;
each of Y 1 − and Y 2 − is a sulfonimide anion and Y 1 − is different from Y 2 − ; and
the electrolyte has an electrical window from 0V to about 5V.
2. The electrolyte of claim 1 , wherein the substantially eutectic mixture has a melting temperature and a viscosity, and the electrolyte further comprises a fluorine-containing additive that lowers the melting temperature and lowers the viscosity.
3. The electrolyte of claim 2 , wherein the fluorine-containing additive forms from about 1% to about 10% of the electrolyte, by weight.
4. The electrolyte of claim 2 , wherein the electrolyte consists essentially of the first salt, the second salt, and the fluorine-containing additive.
5. The electrolyte of claim 2 , wherein the viscosity is in a range of about 1 cP to about 50 cP.
6. The electrolyte of claim 5 , wherein the viscosity is in a range of about 5 cP to about 20 cP.
7. The electrolyte of claim 1 , wherein the electrolyte consists essentially of the first salt and the second salt.
8. The electrolyte of claim 1 , wherein the substantially eutectic mixture has a melting temperature of about 73° C. or less.
9. The electrolyte of claim 8 , wherein the melting temperature is about 65° C. or less.
10. The electrolyte of claim 9 , wherein the melting temperature is about 50° C. or less.
11. The electrolyte of claim 1 , wherein Y 1 − and Y 2 − are selected from the group consisting of FSO 2 N − SO 2 F (FSI − ) and FSO 2 N − SO 2 CF 3 (FTFSI − ).
12. The electrolyte of claim 11 , wherein X 1 + and X 2 + are selected from the group consisting of Li + , Na + , K + , Rb + , and Cs + .
13. The electrolyte of claim 1 , wherein the substantially eutectic mixture has a melting temperature in a range of about 5° C. to about 70° C.
14. The electrolyte of claim 1 , wherein the substantially eutectic mixture has a melting temperature in a range of about 30° C. to about 70° C.
15. The electrolyte of claim 1 , wherein the substantially eutectic mixture has a melting temperature in a range of about 5° C. to about 30° C.
16. The electrolyte of claim 1 , further comprising a third salt, X 3 + Y 3 − , wherein X 3 + is an alkali-metal cation that is different from each of X 1 + and X 2 + , and Y 3 − is a sulfonimide anion.
17. The electrolyte of claim 16 , wherein the substantially eutectic mixture has a melting temperature and a viscosity, and the electrolyte further comprises a fluorine-containing additive that lowers the melting temperature and lowers the viscosity.
18. The electrolyte of claim 17 , wherein the fluorine-containing additive forms from about 1% to about 10% of the electrolyte, by weight.
19. The electrolyte of claim 17 , wherein the electrolyte consists essentially of the first salt, the second salt, the third salt, and the fluorine-containing additive.
20. The electrolyte of claim 17 , wherein the viscosity is in a range of about 1 cP to about 50 cP.
21. The electrolyte of claim 20 , wherein the viscosity is in a range of about 5 cP to about 20 cP.
22. The electrolyte of claim 16 , wherein the electrolyte consists essentially of the first salt, the second salt, and the third salt.
23. The electrolyte of claim 16 , wherein the substantially eutectic mixture has a melting temperature of about 73° C. or less.
24. The electrolyte of claim 23 , wherein the melting temperature is about 65° C. or less.
25. The electrolyte of claim 24 , wherein the melting temperature is about 50° C. or less.
26. The electrolyte of claim 16 , wherein Y 1 − , Y 2 − , and Y 3 − are selected from the group consisting of FSO 2 N − SO 2 F (FSI − ) and FSO 2 N − SO 2 CF 3 (FTFSI − ).
27. The electrolyte of claim 26 , wherein X 1 + , X 2 + , and X 3 + are selected from the group consisting of Li + , Na + , K + , Rb + , and Cs + .
28. The electrolyte of claim 16 , wherein the substantially eutectic mixture has a melting temperature in a range of about 5° C. to about 70° C.
29. An electrolyte, comprising:
a substantially eutectic mixture that includes a first salt, X 1+ Y 1− , and a second salt, X 2+ Y 2− , wherein:
each of X 1+ and X 2+ is an alkali metal cation and X 1+ is different from X 2+ ;
each of Y 1− and Y 2− is a sulfonimide anion and Y 1− is different from Y 2− ;
the substantially eutectic mixture has a melting temperature and a viscosity, and the electrolyte further comprises a fluorine-containing additive that lowers the melting temperature and lowers the viscosity; and
the viscosity is in a range of about 1 cP to about 50 cP.
30. An electrolyte, comprising:
a substantially eutectic mixture that includes a first salt, X 1+ Y 1− , and a second salt, X 2+ Y 2− , wherein:
each of X 1+ and X 2+ is an alkali metal cation and X 1+ is different from X 2+ ;
each of Y 1− and Y 2− is a sulfonimide anion and Y 1− is different from Y 2− ; and
the substantially eutectic mixture has a melting temperature in a range of about 5° C. to about 30° C.