Non-aqueous electrolytes for lithium electrochemical cells
View Patent ↗A non-aqueous electric current producing electrochemical cell is provided comprising an anode and a cathode, an ionically permeable separator interposed between the anode and the cathode, and a non-aqueous electrolyte, the electrolyte comprising an ionically conducting salt in a non-aqueous medium, the ionically conducting salt corresponding to the formula: M + (Z*(J*) j (X*) x ) − , wherein: M is a lithium atom, Z* is an anion group containing two or more Lewis basic sites and comprising less than 50 atoms not including hydrogen atoms, J* independently each occurance is a Lewis acid coordinated to at least one Lewis basic site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality, X* independently each occurrence is selected from the group consisting of H, C 1 -C 4 alkyl, alkoxide, halide and mixtures thereof, j is an integer from 2 to 12, and x is an integer from 0 to 4.
1. A non-aqueous electric current producing electrochemical cell comprising an anode and a cathode, an ionically permeable separator and a non-aqueous electrolyte comprising an ionically conducting salt in a non-aqueous medium, the ionically conducting salt corresponding to the formula:
M + (Z*(J*) j (X*) x ) − ,
wherein:
M is a lithium atom,
Z* is an anion group containing two or more Lewis basic sites and comprising less than 50 atoms not including hydrogen atoms,
J* independently each occurance is a Lewis acid coordinated to at least one Lewis basic site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality,
X* independently each occurrence is selected from the group consisting of H, C 1 -C 4 alkyl, alkoxide, halide and mixtures thereof,
j is an integer from 2 to 12, and
x is an integer from 0 to 4.
2. A cell according to claim 1 wherein Z* is selected from the group consisting of cyanide, azide, amide, amidinide, substituted amidinide, dicyanamide, imidazolide, substituted imidazolide, imidazolinide, substituted imidazolinide, benzoimidazolide, substituted benzoimidazolide, tricyanomethide, tetracyanoborate, puride, squarate, 1,2,3-triazolide, substituted 1,2,3- triazolide, 1,2,4- triazolide, substituted 1,2,4- triazolide, pyrimidinide, substituted pyrimidinide, tetraimidazoylborate, substituted tetraimidazoylborate, tris(imidazoyl) fluoroborate, substituted tris(imidazoyl) fluoroborate, bis(imidazoyl) difluoroborate, substituted bis(imidazoyl)difluoroborate anions and mixtures thereof, wherein each substituent, if present, is selected from the group consisting of a halo, hydrocarbyl, halohydrocarbyl, silyl, silylhydrocarbyl, a halocarbyl group of up to 20 atoms not counting hydrogen and mixtures thereof, and wherein two substituents, if present, together form a saturated or unsaturated ring system.
3. A cell according to claim 2 wherein Z* is selected from the group consisting of imidazolide, 2-methylimidazolide, 4- methylimidazolide, benzoimidazolide, dimethylamide and mixtures thereof.
4. A cell according to claim 1 wherein J* is a Lewis acid having a formula selected from the group consisting of
as well as mixtures thereof:
wherein:
M* is aluminum or boron;
R 1 independently each occurrence is selected from the group consisting of a halide, alkyl, aryl, alkoxide, aryloxide, dialkylamido, halogenated alkyl, halogenated aryl, halogenated alkoxide, halogenated aryl oxide and mixtures thereof, R 1 having up to twenty carbon atoms, and Ar f1 -Ar f2 in combination is independently, a divalent aromatic group of 6 to 20 carbon atoms.
5. A cell according to claim 4 , wherein J* corresponds to the formula:
BR 1 3 or AlR 1 3 ,
wherein:
R 1 is selected from the group consisting of a halogen, a C 1-20 alkyl, halogenated alkyl, alkoxide, aryloxide, fluorinared alkoxide, fluorinated aryl oxide and mixtures thereof.
6. A cell according to claim 5 wherein R 1 is a halogen.
7. A cell according to claim 5 wherein R 1 is selected from the group consisting of a fluorinated alkyl and fluorinated aryl and mixtures thereof.
8. A cell according to claim 5 wherein R 1 is selected from the group consisting of a fluorinated alkoxide and fluorinated aryl oxide and mixtures thereof.
9. A cell according to claim 8 wherein R 1 is selected from the group consisting of CF 3 CH 2 O, C 3 F 7 CH 2 O, (CF 3 ) 2 CHO, (CF 3 ) 2 (CH 3 )CO, (CF 3 ) 2 (C 6 H 5 )CO, (CF 3 ) 3 CO, FC 6 H 4 O, F 2 C 6 H 3 O, F 3 C 6 H 2 O, F 4 C 6 HO, C 6 F 5 O, (CF 3 ) C 6 H 4 O, or (CF 3 ) 2 C 6 H 3 O and mixtures thereof.
10. A cell according to claim 5 wherein J* is BF 3 .
11. A cell according to claim 5 wherein R 1 is selected from the group consisting of CH 2 CF 3 , C 6 F 5 , (CF 3 ) 2 C 6 H 3 and mixtures thereof.
12. A cell according to claim 1 wherein said ionically conductive salt is a lithium salt selected from the group consisting of lithium bis(trifluoroborane) imidazolide, lithium bis(trifluoroborane)-2-methylimidazolide, lithium bis(trifluoroborane)-4-methylimidazolide, lithium bis(trifluoroborane)-2-isopropylimidazolide, lithium bis(trifluoroborane)benzimidazolide, lithium bis(trifluoroborane)dimethylamide, lithium bis(trifluoroborane)diisopropylamide, lithium bis(trimethoxyborane)imidazolide, lithium bis(trimethoxyborane)-2-methylimidazolide, lithium bis(trimethoxyborane)-4-methylimidazolide, lithium bis(trimethoxyborane)-2-isopropylimidazolide, lithium bis(trimethoxyborane)benzimidazolide, lithium bis(trimethoxyborane)dimethylamide, lithium bis(trimethoxyborane)diisopropylamide, lithium tetrakis(trifluoroborane)tetraimidazoylborate, lithium tris(trifluoroborane)triimidazoylfluoroborate, lithium bis(trifluoroborane)diimidazoyldifluoroborate, lithium tetrakis(trifluoroborane)tetrakis(dimethylamino)borate, lithium tris(trifluoroborane)tris(dimethylamino)fluoroborate, lithium bis(trifluoroborane)bis(dimethylamino)difluoroborate and mixtures thereof.
13. A cell according to claim 1 , wherein the anode is selected from the group consisting of lithium metal, lithium alloys, lithium metal intercalation compounds of carbon and graphite, lithium metal intercalating metal oxides, lithium metal intercalating metal chalcogenides and mixtures thereof.
14. A cell according to claim 1 , wherein the cathode is selected from the group consisting of a transition metal oxide, a transition metal chalcogenide, a poly(carbon disulfide) polymer, an organo-disulfide redox polymer, a polyaniline, an organodisulfide/polyaniline composite and a transition metal oxysulfide and mixtures thereof.
15. A cell according to claim 1 , wherein the non-aqueous medium is selected from the group consisting of non-aqueous liquid polar solvents, solid polymers and polymer gels.
16. A according to claim 15 , wherein the non-aqueous liquid polar solvent is an organic solvent selected from the group consisting of ethers, esters, carbonates, sulfones, nitriles, formats, lactones and mixtures thereof.
17. A cell according to claim 15 , wherein the organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate and dialkyl carbonates of the general formula R 1 OCOOR 2 where R 1 and R 2 are selected independently from a C 1 -C 4 alkyl.
18. A cell according to claim 17 , wherein the organic solvent is selected from the group consisting of dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, ethylene carbonate, propylene carbonate and mixtures thereof.
19. A cell according to claim 17 , wherein the organic solvent is an ether selected from the group consisting of diethyl ether, 1,2- dimethoxy ethane, tetrahydrofuran, dioxolane and mixtures thereof.
20. A cell according to claim 15 wherein the lactone is gama-butyrolactone.
21. A cell according to claim 1 , wherein the separator is a microporous polyethylene film or a porous glass membrane.
22. A non-aqueous electrolyte for an electric current producing electrochemical cell comprising an ionically conducting salt in a non-aqueous medium, the ionically conducting salt corresponding to the formula:
M + (Z*(J*) j (X*) x ) − ,
wherein:
M is a lithium atom,
Z* is an anion group containing two or more Lewis basic sites and comprising less than 50 atoms not including hydrogen atoms,
J* independently each occurance is a Lewis acid coordinated to at least one Lewis basic site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality,
X* independently each occurrence is selected from the group consisting of H, C 1 -C 4 alkyl, alkoxide, halide and mixtures thereof,
j is an integer from 2 to 12, and
x is an integer from 0 to 4.
23. A non-aqueous electrolyte according to claim 22 wherein Z* is selected from the group consisting of cyanide, azide, amide, amidinide, substituted amidinide, dicyanamide, imidazolide, substituted imidazolide, imidazolinide, substituted imidazolinide, benzoimidazolide, substituted benzoimidazolide, tricyanomethide, tetracyanoborate, puride, squarate, 1,2,3-triazolide, substituted 1,2,3- triazolide, 1,2,4- triazolide, substituted 1,2,4- triazolide, pyrimidinide, substituted pyrimidinide, tetraimidazoylborate, substituted tetraimidazoylborate, tris(imidazoyl)fluoroborate, substituted tris(imidazoyl)fluoroborate, bis(imidazoyl)difluoroborate, substituted bis(imidazoyl)difluoroborate anions, and mixtures thereof, wherein each substituent, if present, is selected from the group consisting of a halo, hydrocarbyl, halohydrocarbyl, silyl, silylhydrocarbyl and a halocarbyl group of up to 20 atoms not counting hydrogen, and wherein two substituents, if present, together form a saturated or unsaturated ring system.
24. A non-aqueous electrolyte according to claim 23 wherein Z* is selected from the group consisting of imidazolide, 2-methylimidazolide, 4- methylimidazolide, benzoimidazolide, dimethylamide and mixtures thereof.
25. A non-aqueous electrolyte according to claim 23 wherein said ionically conductive salt is a lithium salt selected from the group consisting of lithium bis(trifluoroborane)imidazolide, lithium bis(trifluoroborane)-2-methylimidazolide, lithium bis(trifluoroborane)-4-methylimidazolide, lithium bis(trifluoroborane)-2-isopropylimidazolide, lithium bis(trifluoroborane)benzimidazolide, lithium bis(trifluoroborane)dimethylamide, lithium bis(trifluoroborane)diisopropylamide, lithium bis(trimethoxyborane)imidazolide, lithium bis(trimethoxyborane)-2-methylimidazolide, lithium bis(trimethoxyborane)-4-methylimidazolide, lithium bis(trimethoxyborane)-2-isopropylimidazolide, lithium bis(trimethoxyborane)benzimidazolide, lithium bis(trimethoxyborane)dimethylamide, lithium bis(trimethoxyborane)diisopropylamide, lithium tetrakis(trifluoroborane)tetraimidazoylborate, lithium tris(trifluoroborane)triimidazoylfluoroborate, lithium bis(trifluoroborane)diimidazoyldifluoroborate, lithiumtetrakis(trifluoroborane)tetrakis(dimethylamino)borate, lithium tris(trifluoroborane)tris(dimethylamino)fluoroborate, lithium bis(trifluoroborane)bis(dimethylamino)difluoroborate and mixtures thereof.
26. A non-aqueous electrolyte according to claim 23 , wherein said non-aqueous medium is selected from the group consisting of non-aqueous liquid polar solvents, solid polymers and polymer gels.
27. A non-aqueous electrolyte according to claim 26 wherein said non-aqueous liquid polar solvent is an organic solvent selected from the group consisting of ethers, esters, carbonates, sulfones, nitriles, formats, lactones and mixtures thereof.
28. A non-aqueous electrolyte according to claim 27 , wherein said organic solvent is selected from the group consisting of ethylene carbonate, propylene carbonate and dialkyl carbonates of the general formula R 1 OCOOR 2 where R 1 and R 2 are selected independently from a C 1 -C 4 alkyl.
29. A non-aqueous electrolyte according to claim 28 , wherein said dialkyl carbonate is selected from the group consisting of dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, ethylene carbonate, propylene carbonate and mixtures thereof.
30. A non-aqueous electrolyte according to claim 28 , wherein said organic solvent is an ether selected from the group consisting of diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, dioxolane and mixtures thereof.
31. A non-aqueous electrolyte according to claim 28 , wherein said lactone is gama-butyrolactone.
32. A non-aqueous electrolyte according to claim 22 wherein J* is a Lewis acid selected from the group consisting of
and mixtures thereof:
wherein:
M* is aluminum or boron;
R 1 independently each occurrence is selected from the group consisting of a halide, alkyl, aryl, alkoxide, aryloxide, dialkylamido, halogenated alkyl, halogenated aryl, halogenated alkoxide, halogenated aryl oxide and mixtures thereof, R 1 having up to twenty carbon atoms, and Ar f1 -Ar f2 in combination is independently, a divalent aromatic group of 6 to 20 carbon atoms.
33. A non-aqueous electrolyte according to claim 32 , wherein J* corresponds to the formula:
BR i 3 or AlR 1 3
wherein:
R 1 is selected from the group consisting of a halogen, a C 1-20 alkyl, halogenated alkyl, alkoxide, aryloxide, fluorinared alkoxide, fluorinated aryl oxide and mixtures thereof.
34. A non-aqueous electrolyte according to claim 33 wherein R 1 is a halogen.
35. A non-aqueous electrolyte according to claim 33 wherein R 1 is selected from the group consisting of a fluorinated alkyl and fluorinated aryl and mixtures thereof.
36. A non-aqueous electrolyte according to claim 33 wherein R 1 is selected from the group consisting of a fluorinated alkoxide and fluorinated aryl oxide and mixtures thereof.
37. A non-aqueous electrolyte according to claim 33 wherein R 1 is selected from the group consisting of CF 3 CH 2 O, C 3 F 7 CH 2 O, (CF 3 ) 2 CHO, (CF 3 ) 2 (CH 3 )CO, (CF 3 ) 2 (C 6 H 5 )CO, (CF 3 ) 2 CO, FC 6 H 4 O, F 2 C 6 H 3 O, F 3 C 6 H 2 O, F 4 C 6 HO, C 6 F 5 O, (CF 3 )C 6 H 4 O, (CF 3 ) 2 C 6 H 3 O and mixtures thereof.
38. A non-aqueous electrolyte according to claim 33 wherein J* is BF 3 .
39. A non-aqueous electrolyte according to claim 33 wherein R 1 is selected from the group consisting of CH 2 CF 3 , C 6 F 5 , (CF 3 ) 2 C 6 H 3 and mixtures thereof.
40. A compound useful as an ionically conducting salt in a non-aqueous electrolyte for a lithium electrochemical cell corresponding to the formula:
M + (Z*(J*) j (X*) x ) − ,
wherein:
M is lithium,
Z* is an anion group containing two or more Lewis basic sites and comprising less than 50 atoms not including hydrogen atoms,
J* independently each occurrence is a Lewis acid coordinated to at least one Lewis basic site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality,
X* is selected from the group consisting of H, C 1 -C 4 alkyl, alkoxide and a halide and mixtures thereof,
j is an integer from 2 to 12, and
x is an integer from 0 to 4.