Functionalized ionic liquid electrolytes for lithium ion batteries

1. An electrolyte comprising:

a lithium salt; and

an ionic liquid represented as a compound of Formula:

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 3-5 cyclic carbonate, a sulfolane, an oxalic borate group, a maleic anhydride group, a succinic anhydride group, and a C 1-6 alkyl group substituted with a substituent selected from an isocyanate, sulfone, sulfolane, —OCO 2 R″, C 3-5 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 an alkyl, haloalkyl, alkyl substituted with carboxylate, aminoalkyl, cycloalkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl group; or two of R 1 , R 2 and R 3 join together to form a C 4-5 alkylene group;

R 4 , R 5 , R 6 , R 7 , and R 8 are independently at each occurrence H or an alkyl, haloalkyl, hydroxyalkyl, cycloalkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl group;

X − is an anion selected from the group consisting of 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, and 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 electrolyte of claim 1 , wherein the lithium salt is selected from the group consisting of Li[CF 3 CO 2 ]; Li[C 2 F 5 CO 2 ]; Li[ClO 4 ]; Li[BF 4 ]; Li[AsF 6 ]; Li[PF 6 ]; Li[PF 2 (C 2 O 4 ) 2 ]; Li[PF 4 C 2 O 4 ]; Li[CF 3 SO 3 ]; Li[N(CF 3 SO 2 ) 2 ]; Li[C(CF 3 SO 2 ) 3 ]; Li[N(SO 2 C 2 F 5 ) 2 ]; lithium alkyl fluorophosphates; Li[B(C 2 O 4 ) 2 ]; Li[BF 2 C 2 O 4 ]; Li 2 [B 12 Z 12-j H j ]; Li 2 [B 10 Z 10-j′ H j′ ]; and a mixture of any two or more thereof, wherein Z is independently at each occurrence a halogen, j is an integer from 0 to 12 and j′ is an integer from 1 to 10.

3. The electrolyte of claim 2 wherein the concentration of the lithium salt present in the ionic liquid is from about 0.01 M to about 1.5 M.

4. The electrolyte of claim 1 further comprising an aprotic solvent.

5. The electrolyte of claim 1 further comprising an aprotic gel polymer carrier/solvent.

6. The electrolyte of claim 1 further comprising an electrode stabilizing additive.

7. The electrolyte of claim 1 , wherein the ionic liquid has the Formula selected from the group consisting of:

8. The electrolyte of claim 7 , wherein R 4 , R 5 , R 6 , R 7 , and R 8 are independently at each occurrence a hydrogen or a C 1-6 alkyl group.

9. The electrolyte of claim 1 wherein the ionic liquid has the Formula:

10. The electrolyte of claim 9 , wherein R is selected from the group consisting of —(R′)—(OCH 2 CH 2 ) n —(OR″), —CH 2 Si(R″) 2 [OSi(R″) 2 ] m OSi(R″) 3 , and a C 1-6 alkyl group substituted with a sulfone group.

11. The electrolyte 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 .

12. The electrolyte of claim 9 , wherein R 1 , R 2 , and R 3 are independently at each occurrence selected from the group consisting of a C 1-6 alkyl, hydroxyalkyl, and haloalkyl group.

13. The electrolyte 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 ] − ; 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.

14. The electrolyte 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,

3-2,5,8,1-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.

15. An electrochemical device comprising a cathode; an anode; and an electrolyte comprising an ionic liquid of claim 14 .

16. The electrolyte of claim 1 , wherein the ionic liquid comprises:

triethyl((2-methoxyethoxy)methyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl((2-(2-methoxyethoxyl)ethoxy)methyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl((2-(2-(2-methoxyethoxyl)ethoxy)ethoxy)methyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl((2-methoxyethoxy)methyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl((2-(2-methoxyethoxyl)ethoxy)methyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl((2-(2-(2-methoxyethoxyl)ethoxy)ethoxy)methyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl((2-methoxyethoxy)methyl)phosphonium bis(oxalato)borate,

triethyl((2-(2-methoxyethoxyl)ethoxy)methyl)phosphonium bis(oxalato)borate,

triethyl((2-(2-(2-methoxyethoxyl)ethoxy)ethoxy)methyl)phosphonium bis(oxalato)borate,

triethyl((2-methoxyethoxy)methyl)phosphonium hexafluorophosphate,

triethyl((2-(2-methoxyethoxyl)ethoxy)methyl)phosphonium hexafluorophosphate,

triethyl((2-(2-(2-methoxyethoxyl)ethoxy)ethoxy)methyl)phosphonium hexafluorophosphate,

triethyl-(methylenepentamethyldisiloxane)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(methyleneheptamethyltrisiloxane)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(methyleneoctamethyltetrasiloxane)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(methylenepentamethyldisiloxane)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(methyleneheptamethyltrisiloxane)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(methyleneoctamethyltetrasiloxane)phosphonium bis(fluoromethylsulfonyl)imide, triethyl-(methylenepentamethyldisiloxane)phosphonium bis(oxalato)borate,

triethyl-(methyleneheptamethyltrisiloxane)phosphonium bis(oxalato)borate,

triethyl-(methyleneoctamethyltetrasiloxane)phosphonium bis(oxalato)borate,

triethyl-(methylenepentamethyldisiloxane)phosphonium hexafluorophosphate,

triethyl-(methyleneheptamethyltrisiloxane)phosphonium hexafluorophosphate,

triethyl-(methyleneoctamethyltetrasiloxane)phosphonium hexafluorophosphate,

triethyl-(2-(methylsulfonyl)ethyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(2-(ethylsulfonyl)ethyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(2-(propylsulfonyl)ethyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(2-(butylsulfonyl)ethyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-(2-(methylsulfonyl)ethyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(2-(ethylsulfonyl)ethyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(2-(propylsulfonyl)ethyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(2-(butylsulfonyl)ethyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-(2-(methylsulfonyl)ethyl)phosphonium bis(oxalato)borate,

triethyl-(2-(ethylsulfonyl)ethyl)phosphonium bis(oxalato)borate,

triethyl-(2-(propylsulfonyl)ethyl)phosphonium bis(oxalato)borate,

triethyl-(2-(butylsulfonyl)ethyl)phosphonium bis(oxalato)borate,

triethyl-(2-(methylsulfonyl)ethyl)phosphonium hexafluorophosphate,

triethyl-(2-(ethylsulfonyl)ethyl)phosphonium hexafluorophosphate,

triethyl-(2-(propylsulfonyl)ethyl)phosphonium hexafluorophosphate,

triethyl-(2-(butylsulfonyl)ethyl)phosphonium hexafluorophosphate,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)phosphonium bis(trifluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)phosphonium bis(fluoromethylsulfonyl)imide,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)phosphonium bis(oxalato)borate,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)phosphonium bis(oxalato)borate,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)phosphonium bis(oxalato)borate,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)methyl)phosphonium hexafluorophosphate,

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)ethyl)phosphonium hexafluorophosphate, or

triethyl-3-((2-oxo-1,3-dioxolan-4-yl)propyl)phosphonium hexafluorophosphate.

17. An electrochemical device comprising a cathode; an anode; and an electrolyte comprising an ionic liquid of claim 16 .

18. An electrochemical device comprising a cathode; an anode; and an electrolyte comprising an ionic liquid of claim 1 .

19. The electrochemical device of claim 18 that is a lithium secondary battery.

20. The electrochemical device of claim 19 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.