Hydrophobic ionic liquids

• US 5,827,602 A
• Filed: 09/17/1997
• Issued: 10/27/1998
• Est. Priority Date: 06/30/1995
• Status: Expired due to Term

• Current Assignee: Covalent Associates, Inc.
• Original Assignee: Covalent Associates, Inc.
• Inventors: Nanjundiah, Chenniah, Koch, Victor R., Carlin, Richard T.
• Primary Examiner(s): Gorgos, Kathryn L.
• Assistant Examiner(s): Wong, Edna
• Application Number:
  US08/932,931
• Time in Patent Office: 405 Days
• Field of Search: 429/194, 429/198, 429/346, 204/242, 252/622, 361/503, 361/504
• US Class Current: 429/328
• CPC Class Codes: C25D 3/02 from solutions C25D5/34 - C25D5/46 take precedence
• CPC Class Codes: H01G 11/58 Liquid electrolytes
• CPC Class Codes: H01G 11/62 characterised by the solute, e.g. salts, anions or cations therein
• CPC Class Codes: H01M 10/0566 Liquid materials
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

Ionic liquids having improved properties for application in non-aqueous batteries, electrochemical capacitors, electroplating, catalysis and chemical separations are disclosed. Exemplary compounds have one of the following formulas: ##STR1## wherein R₁, R₂, R₃, R₄, R₅, and R₆ are either H; F; separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N; or separate phenyl groups; and wherein the alkyl groups, alkylene radicals or phenyl groups may be substituted with electron withdrawing groups, preferably F--, Cl--, CF₃ --, SF₅ --, CF₃ S--, (CF₃)₂ CHS-- or (CF₃)₃ CS--; and X^- is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 ų.

Claims

1. A hydrophobic ionic liquid comprising a cation and an anion, wherein said cation is selected from the group consisting of:

##STR7## wherein R₁, R₂, R₃, R₄, R₅, and R₆ are either H;

or F;

or separate alkyl groups of from 1 to 4 carbon atoms, respectively;

or two said separate alkyl groups are joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N;

or separate phenyl groups; and

wherein said alkyl groups, unitary alkylene radical or phenyl groups are optionally substituted with electron withdrawing groups; and

wherein said anion is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 Å

³.

2. The hydrophobic ionic liquid of claim 1 wherein, in said cation, said optional electron withdrawing groups are selected from the group consisting of F--, Cl--, CF₃ --, SF₅ --, CF₃ S--, (CF₃)₂ CHS-- and (CF₃)₃ CS--.

3. The hydrophobic ionic liquid of claim 1 wherein said cation has the formula ##STR8## wherein R₁, R₂, R₃, R₄, R₅, and R₆ are either H;

F;

separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N;

or separate phenyl groups; and

wherein the alkyl groups, unitary alkylene radical or phenyl groups are optionally substituted with electron withdrawing groups.

4. The hydrophobic ionic liquid of claim 1 wherein said cation has the formula ##STR9## wherein R₁, R₂, R₃, R₄ and R₅ are either H;

F;

separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N;

or separate phenyl groups; and

wherein the alkyl groups, unitary alkylene radical or phenyl groups are optionally substituted with electron withdrawing groups.

5. The hydrophobic ionic liquid of claim 1 wherein said cation has the formula ##STR10## wherein R₁, R₂, R₃ and R₄ are either H;

F;

separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N;

or separate phenyl groups; and

wherein the alkyl groups, unitary alkylene radical or phenyl groups are optionally substituted with electron withdrawing groups.

6. The hydrophobic ionic liquid of claim 1 wherein said cation has the formula ##STR11## wherein R₁, R₂, R₃ and R₄ are either H;

F;

separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N;

or separate phenyl groups; and

wherein the alkyl groups, unitary alkylene radical or phenyl groups are optionally substituted with electron withdrawing groups.

7. The hydrophobic ionic liquid of claim 1 wherein said anion has the formula ##STR12## wherein each of the moieties Y, Y'"'"', and Y", are --SO₂ -- or --CO--;

the groups R and R'"'"' are separate halogenated alkyl groups of 1-4 carbon atoms, respectively or are joined together to constitute a unitary halogenated alkylene radical of from 2-4 carbon atoms linking Y and Y'"'"' and forming a ring structure which includes R, R'"'"', Y, Y'"'"', and the carbon atom to which Y and Y'"'"' are attached; and

the group R" is an alkyl or haloalkyl radical of 1-4 carbon atoms or a halogenated phenyl group.

8. The hydrophobic ionic liquid of claim 1 wherein said anion has the formula ##STR13## wherein each of the moieties Y and Y'"'"' are --SO₂ -- or --CO--;

the groups R and R'"'"' are separate halogenated alkyl groups of 1-4 carbon atoms, respectively or are joined together to constitute a unitary halogenated alkylene radical of from 2-4 carbon atoms linking Y and Y'"'"' and forming a ring structure which includes R, R'"'"', Y, Y'"'"', and the carbon atom to which Y and Y'"'"' are attached; and

Z is an electron-withdrawing substituent selected from the group consisting of --C(O)H, --NO₂, --CN, --F, and perfluorinated alkyls and aryls containing no more than 8 carbons.

9. The hydrophobic ionic liquid of claim 1 wherein said anion has the formula ##STR14## wherein each of the moieties Y and Y'"'"' are --SO₂ -- or --CO--;

and the groups R and R'"'"' are separate halogenated alkyl groups of 1-4 carbon atoms.

10. The hydrophobic ionic liquid of claim 1 wherein said anion is perfluoro-1,1-dimethylpropyl alkoxide, having the formula CF₃ CF₂ (CF₃)₂ CO--.

11. The hydrophobic ionic liquid of claim 1 wherein said anion is selected from the group consisting of (CF₃)₂ PF₄^-, (CF₃)₃ PF₃^- (CF₃)₄ PF₂^-, (CF₃)₅ PF^- (CF₃)₆ P^-, SF₅ CF₂ SO₃^-, SF₅ CHFCF₂ SO₃^-, (CF₃ SO₂)₂ CH^-, (SF₅)₃ C^- and (O(CF₃)₂ C₂ (CF₃)₂ O)₂ PO^-.

12. The hydrophobic ionic liquid of claim 1 wherein said anion is a mono- or di-perfluorosulfonate.

13. An electrolyte for use in an electrochemical cell comprising

the hydrophobic ionic liquid of claim 1;

and

a polar organic liquid.

14. The electrolyte of claim 13, wherein said polar organic liquid is selected from the group consisting of linear ethers, cyclic ethers, esters, carbonates, lactones, nitriles, amides, sulfones and sulfolanes.

15. The electrolyte of claim 13, wherein said polar organic liquid is selected from the group consisting of diethylether, dimethoxyethane, tetrahydrofuran, dioxane, dioxolane, methyltetrahydrofuran, methyl formate, ethyl formate, methyl propionate, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dibutyl carbonate, butyrolactones, acetonitrile, benzonitrile, nitromethane, nitrobenzene, dimethylformamide, N-methylpyrrolidone, dimethylsulfone, tetramethylene sulfone, sulfolane and thiophene.

16. An electrochemical cell comprising

an anode;

a cathode; and

an electrolyte comprising the hydrophobic ionic liquid of claim 1.

17. An electrochemical cell comprising

an anode;

a cathode; and

an electrolyte comprising the hydrophobic ionic liquid of claim 1 and a lithium salt.

18. The electrochemical cell of claim 16 or claim 17, wherein said electrolyte further comprises a polar organic liquid.

19. The electrochemical cell of claim 18 wherein said electrolyte comprises a solution of 1-ethyl-3-methylimidazolium imide in the polar organic liquid.

20. A capacitor comprising

a first electrode;

a second electrode; and

an electrolyte, said electrolyte comprising the hydrophobic ionic liquid of claim 1.

21. The capacitor of claim 20 wherein said electrolyte further comprises a polar organic liquid.

22. The capacitor of claim 21 wherein said polar organic liquid is selected from the group consisting of linear ethers, cyclic ethers, esters, carbonates, lactones, nitriles, amides, sulfones and sulfolanes.

23. The capacitor of claim 21 wherein said polar organic liquid is selected from the group consisting of diethylether, dimethoxyethane, tetrahydrofuran, dioxane, dioxolane, methyltetrahydrofuran, methyl formate, ethyl formate, methyl propionate, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dibutyl carbonate, butyrolactones, acetonitrile, benzonitrile, nitromethane, nitrobenzene, dimethylformamide, N-methylpyrolidone, dimethylsulfone, tetramethylene sulfone, sulfolane and thiophene.

24. The capacitor of claim 21 wherein said electrolyte comprises a solution of 1-ethyl-3-methylimidazolium imide in the polar organic liquid.

25. A hydrophobic salt comprising a cation and an anion, wherein said cation is a perfluorinated, unsaturated, nitrogen-containing heterocycle and said anion is organic or inorganic.