Lithium ion battery electrolyte including a vitreous eutectic mixture

1. An ionic liquid for an electrolyte of a lithium ion battery, comprising a binary vitreous eutectic mixture represented by the formula A x B y , wherein:

A is a salt chosen from a lithium fluoroalkylsulfonimide or a lithium fluoroarylsulfonimide, wherein the lithium fluoroalkylsulfonimide and the lithium fluoroarylsulfonimide are individually represented by the formula:

wherein R 1 is chosen from F, CF 3 , C 2 F 5 , C 4 F 9 , an aromatic group, or a fluorinated aromatic group and wherein R 2 is chosen from F, C 4 F 9 , an aromatic group, or a fluorinated aromatic group;

B is a solvent chosen from an alkylsulfonamide or an arylsulfonamide;

x and y are the mole fractions of A and B, respectively;

a molar ratio of A to B ranges from 1:0.2 to 1:10; and

the eutectic mixture is a liquid at ambient temperature and has a glass transition temperature of less than −50° C.

2. The ionic liquid as defined in claim 1 wherein the alkylsulfonamide and the arylsulfonamide are individually represented by the formula:

wherein: R 3 is chosen from CH 3 , C 2 H 5 , C 4 H 9 , aryl, fluorinated aryl, (CH 2 ) n CF 3 wherein n is 1 to 5, or (CH 2 ) n OR 6 wherein n is 1 or 2 and R 6 is CH 3 or CF 3 , and R 4 and R 5 are chosen from H, CH 3 , or C 4 H 9 .

3. The ionic liquid as defined in claim 1 wherein A is chosen from lithium bis(fluorosulfonyl)imide, or lithium [(trifluoromethylsulfonyl)(phenylsulfony]imide.

4. The ionic liquid as defined in claim 1 wherein B is chosen from methanesulfonamide, N,N-dimethylmethanesulfonamide, N-methylmethanesulfonamide, ethanesulfonamide, n-butylsulfonamide, alkylethersulfonamide, benzenesulfonamide, or fluorinated benzenesulfonamide.

5. The ionic liquid as defined in claim 1 wherein a molar ratio of A to B ranges from 1:1 to 1:4.

6. The ionic liquid as defined in claim 1 wherein the eutectic mixture has a specific conductivity ranging from about 10 −2 S/cm to about 1×10 −4 S/cm over a temperature range from about +25° C. to about −30° C.

7. The ionic liquid as defined in claim 1 wherein the electrolyte is non-flammable.

8. A lithium ion battery, comprising:

a cathode;

an anode; and

an electrolyte operatively disposed between the cathode and the anode, the electrolyte consisting of a binary eutectic mixture represented by the formula A x B y , wherein:

A is a salt chosen from a lithium fluoroalkylsulfonimide or a lithium fluoroarylsulfonimide, wherein the lithium fluoroalkylsulfonimide and the lithium fluoroarylsulfonimide are individually represented by the formula:

wherein R 1 is chosen from F, CF 3 , C 2 F 5 , C 4 F 9 , an aromatic group, or a fluorinated aromatic group and wherein R 2 is chosen from F, CF 3 , C 2 F 5 , C 4 F 9 , an aromatic group, or a fluorinated aromatic group;

B is a solvent chosen from an alkylsulfonamide or an arylsulfonamide; and

x and y are the mole fractions of A and B, respectively.

9. The battery as defined in claim 8 wherein the alkylsulfonamide and the arylsulfonamide are individually represented by the formula:

wherein: R 3 is chosen from CH 3 , C 2 H 5 , C 4 H 9 , aryl, fluorinated aryl, (CH 2 ) n CF 3 wherein n is 1 to 5, or (CH 2 ) n OR 6 wherein n is 1 or 2 and R 6 is CH 3 or CF 3 , and R 4 and R 5 are chosen from H, CH 3 , or C 4 H 9 .

10. The battery as defined in claim 8 wherein A is chosen from lithium bis(fluorosulfonyl)imide, or lithium [(trifluoromethylsulfonyl)(phenylsulfonyl)]imide.

11. The battery as defined in claim 8 wherein B is chosen from methanesulfonamide, N,N-dimethylmethanesulfonamide, N-methylmethanesulfonamide, ethanesulfonamide, n-butylsulfonamide, alkylethersulfonamide, benzenesulfonamide, or fluorinated benzenesulfonamide.

12. An electrolyte for a lithium ion battery, consisting of a binary vitreous eutectic mixture represented by the formula A x B y , wherein:

A is a salt chosen from a lithium fluoroalkylsulfonimide or a lithium fluoroarylsulfonimide;

B is a solvent chosen from an alkylsulfonamide or an arylsulfonamide;

x and y are the mole fractions of A and B, respectively; and

a molar ratio of A to B ranges from 1:0.2 to 1:10.

13. The electrolyte as defined in claim 12 wherein:

the lithium fluoroalkylsulfonimide and the lithium fluoroarylsulfonimide are individually represented by the formula:

and R 1 and R 2 are individually chosen from F, CF 3 , C 2 F 5 , C 4 F 9 , an aromatic group, or a fluorinated aromatic group; and

the alkylsulfonamide and the arylsulfonamide are individually represented by the formula:

and R 3 is chosen from CH 3 , C 2 H 5 , C 4 H 9 , aryl, fluorinated aryl, (CH 2 ) n CF 3 wherein n is 1 to 5, or (CH 2 ) n OR 6 wherein n is 1 or 2 and R 6 is CH 3 or CF 3 , and R 4 and R 5 are chosen from H, CH 3 , or C 4 H 9 .

14. The electrolyte as defined in claim 12 wherein a molar ratio of A to B ranges from 1:1 to 1:4.