Functionalized ionic liquid electrolytes for lithium ion batteries

1. An electrochemical device comprising:

a cathode;

an anode; and

an electrolyte comprising:

an ionic liquid represented as:

 and

an aprotic gel polymer carrier/solvent and an electrode stabilizing additive, or both an aprotic gel polymer carrier/solvent, an electrode stabilizing additive;

wherein:

R is selected from the group consisting of —CH 2 Si(R″) 2 [OSi(R″) 2 ] m O—Si(R″) 3 , —(R′)—(OCH 2 CH 2 ) n —(OR″), a C 3 -C 5 cyclic carbonate, a sulfolane, an oxalic borate group, a maleic anhydride group, a succinic anhydride group, and a C 1 -C 6 alkyl group substituted with a substituent selected from an isocyanate, sulfone, sulfolane, —OCO 2 R″, C 3 -C 5 cyclic carbonate, or oxalic borate group;

R′ is a C 1-4 alkylene group;

R″ is an alkyl group;

R 1 , R 2 , and R 3 are independently at each occurrence alkyl, cycloalkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl, or any two of R 1 , R 2 , and R 3 join together to form a C 4 -C 5 cycloalkylene group;

R 4 , R 5 , and R 6 are independently at each occurrence H, alkyl, cycloalkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl;

each X − independently comprises boron tetrafluoride, aluminate, bis(oxalato)borate, difluoro(oxalate)borate, phosphorus hexafluoride, alkyl sulfonate, fluoroalkyl sulfonate, aryl sulfonate, bis(alkylsulfonyl)amide, perchlorate, bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide, alkyl fluorophosphate, (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide, nitrate, nitrite, sulfate, hydrogen sulfate, alkyl sulfate, aryl sulfate, carbonate, bicarbonate, perfluoroalkyl group substituted with carboxylate, phosphate, hydrogen phosphate, dihydrogen phosphate, hypochlorite, an anionic site of a cation-exchange resin, or a mixture of any two or more thereof;

n is an integer from 1 to 4; and

m is an integer from 0 to 10.

2. The electrochemical device of claim 1 that is a secondary battery.

3. The electrochemical device of claim 2 wherein the secondary battery is a lithium battery, a lithium-ion battery, a lithium-sulfur battery, a lithium-air battery, a sodium ion battery, or a magnesium battery.

4. The electrochemical device of claim 1 , wherein each R is independently (R′)—(OCH 2 CH 2 ) n —(OR″), —CH 2 Si(R″) 2 [OSi(R″) 2 ] m OSi(R″) 3 , or a C 1-6 alkyl group substituted with a sulfone group.

5. The electrochemical device of claim 1 , wherein R 1 , R 2 , and R 3 are independently at each occurrence C 1 -C 6 alkyl, hydroxyalkyl, or haloalkyl group.

6. The electrochemical device of claim 1 , wherein R 1 is a C 2 -C 6 alkyl.

7. The electrochemical device of claim 1 , wherein R 4 , R 5 , and R 6 are each H.

8. The electrochemical device of claim 1 , wherein X − is [CF 3 CO 2 ] − ; [C 2 F 5 CO 2 ] − ; [ClO 4 ] − ; [BF 4 ] − ; [AsF 6 ] − ; [PF 6 ] − ; [PF 2 (C 2 O 4 ) 2 ] − ; [PF 4 C 2 O 4 ] − ; [CF 3 SO 3 ] − ; [N(CF 3 SO 2 ) 2 ] − ; [C(CF 3 SO 2 ) 3 ] − ; [N(SO 2 C 2 F 5 ) 2 ] − ; an alkyl fluorophosphate; [B(C 2 O 4 ) 2 ] − ; [BF 2 C 2 O 4 ] − ; [B 12 Y 12−k H k ] 2− ; [B 10 Y 10−k′ H k′ ] 2− ; or a mixture of any two or more thereof, wherein Y is independently at each occurrence a halogen, k is an integer from 0 to 12, and k′ is an integer from 1 to 10.

9. The electrochemical device of claim 1 , wherein the ionic liquid has the Formula:

10. The electrochemical device of claim 9 , wherein R is —(CH 2 )—(OCH 2 CH 2 ) n —(OCH 3 ), —CH 2 Si(CH 3 ) 2 [OSi(CH 3 ) 2 ] m OSi(CH 3 ) 3 , or —(CH 2 ) n SO 2 CH 3 .

11. The electrochemical device of claim 1 , wherein the ionic liquid has the Formula:

12. The electrochemical device of claim 11 , wherein R is —(CH 2 )—(OCH 2 CH 2 ) n —(OCH 3 ), —CH 2 Si(CH 3 ) 2 [OSi(CH 3 ) 2 ] m OSi(CH 3 ) 3 , or —(CH 2 ) n SO 2 CH 3 .

13. The electrochemical device of claim 12 , wherein R 1 is a C 2 -C 6 alkyl.

14. The electrochemical device of claim 1 , wherein m is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

15. The electrochemical device of claim 1 , wherein the ionic liquid comprises:

1-ethyl-3-((2-methoxyethoxy)methyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-((2-(2-methoxyethoxyl)ethoxy)methyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

3-2,5,8,11-tetraoxadodecyl-1-ethyl-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-((2-methoxyethoxy)methyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-((2-(2-methoxyethoxyl)ethoxy)methyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

3-2,5,8,11-tetraoxadodecyl-1-ethyl-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-((2-methoxyethoxy)methyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-((2-(2-methoxyethoxyl)ethoxy)methyl)-1H-imidazol-3-ium bis(oxalato)borate;

3-2,5,8,11-tetraoxadodecyl-1-ethyl-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-((2-methoxyethoxy)methyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-((2-(2-methoxyethoxyl)ethoxy)methyl)-1H-imidazol-3-ium hexafluorophosphate;

3-2,5,8,11-tetraoxadodecyl-1-ethyl-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(methylenepentamethyldisiloxane)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(methyleneheptamethyltrisiloxane)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(methyleneoctamethyltetrasiloxane)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(methylenepentamethyldisiloxane)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(methyleneheptamethyltrisiloxane)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(methyleneoctamethyltetrasiloxane)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(methylenepentamethyldisiloxane)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(methyleneheptamethyltrisiloxane)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(methyleneoctamethyltetrasiloxane)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(methylenepentamethyldisiloxane)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(methyleneheptamethyltrisiloxane)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(methyleneoctamethyltetrasiloxane)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(2-(methylsulfonyl)ethyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(2-(ethylsulfonyl)ethyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(2-(propylsulfonyl)ethyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(2-(butylsulfonyl)ethyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-(2-(methylsulfonyl)ethyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(2-(ethylsulfonyl)ethyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(2-(propylsulfonyl)ethyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(2-(butylsulfonyl)ethyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-(2-(methylsulfonyl)ethyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(2-(ethylsulfonyl)ethyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(2-(propylsulfonyl)ethyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(2-(butylsulfonyl)ethyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-(2-(methylsulfonyl)ethyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(2-(ethylsulfonyl)ethyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(2-(propylsulfonyl)ethyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-(2-(butylsulfonyl)ethyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)-1H-imidazol-3-ium bis(oxalato)borate;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)-1H-imidazol-3-ium bis(fluoromethanesulfonyl)imide;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)-1H-imidazol-3-ium hexafluorophosphate;

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)-1H-imidazol-3-ium hexafluorophosphate; or

1-ethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)-1H-imidazol-3-ium hexafluorophosphate.

16. The electrochemical device of claim 1 , wherein the electrolyte further comprises a lithium salt.

17. The electrochemical device of claim 16 , wherein a concentration of the lithium salt in the ionic liquid is from about 0.01 M to about 1.5 M.

18. The electrochemical device of claim 1 , wherein the electrolyte further comprises an aprotic solvent.