Electrochemical cell and electrolyte for same
An electrolyte, an electrochemical cell including the electrolyte, and a battery including the electrochemical cell are disclosed. Exemplary electrolytes allow for electrochemical cells and batteries with relatively high efficiency and stability that can be charged to relatively high voltages.
1. An electrolyte comprising:
one or more first solvents, wherein each of the one or more first solvents is selected from the group consisting of a low-coordinating solvent, a non-polar solvent, and a surfactant-type solvent;
one or more second solvents, wherein each of the one or more second solvents is a coordinating solvent; and
one or more lithium salts in an amount of greater than 5 moles per liter of the one or more second solvents,
wherein an amount by volume of the one or more first solvents in the electrolyte is less than or equal to an amount by volume of the one or more second solvents
wherein each of the one or more first solvents is selected from the group consisting of:
a flourine substituted ether;
a non-polar solvent selected from the group consisting of benzene, fluorinated benzene, fluorinated alkane, toluene and fluorinated toluene; and
1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFE-TFPE), tetrafluoroethyl 1,1,2,2-tetrafluoroethyl ether (TFE-TFEE), ethyl 1,1,2,2-tetrafluoroethyl ether (ET-TFEE), Ethyl 1,1,2,3,3,3-hexafluoropropyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether (BTFE), 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (OFP-TFEE), 1,1,1,2,3,3,6,6,7,7-decafluoro-4-oxaheptane, 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether, methoxytridecafluoroheptene and isomers thereof, heptafluoropropyl 1,2,2,2,-tetrafluoroethyl ether, ethyl nonafluorobutyl ether, difluoromethyl 2,2,3,3-tetrafluoropropyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, pentafluoroanisole, 2,3,5,6-tetrafluoroanisole, trifluoromethoxy benzene, 1-fluoro-3-(trifluoromethoxy)benzene, 1,1,2,3,3,3-hexafluoropropyl methyl ether, 1,1,2,2,3,3-hexafluoro-1-(trifluoromethoxy)-3-[(1,2,2-trifluorovinyl)oxy]propane, 1,1,2,2,3,3-hexafluoro-1,3-bis[(1,2,2-trifluorovinyl)oxy]propane, 1,3-bis(1,1,2,2-tetrafluoroethoxy)propane, 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,1,2,3,3-hexafluoro-4-(1,1,2,3,3,3-hexafluoropropoxy-pentane, 2,3,3,4-pentafluorotetrahydro-5-methoxy-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-furan, methyl nonafluorobutyl ether, methyl 2,2,3,3,3-pentafluoropropyl ether, methyl 1,1,2,2-tetrafluoroethyl ether, 1-fluoro-2-(trifluoromethoxy)benzene, 3-(trifluoromethoxy)benzonitrile, hexafluorobenzene, bis(4-fluorophenyl) ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, difluoromethoxy)benzene, 4-(difluoromethoxy)toluene, 2-fluorotoluene, 3-flurotoluene, 4-fluorotoluene, trifluorotoluene, octafluorotoluene, fluorobenzene, difluorobenzene, pentafluorobenzene, hexafluorobenzene, perfluoro-2-methylpentane, perfluoromethylcyclohexane, fluorocyclohexane, perfluoroheptane, 1,2,3,4,5,6-hexafluorocyclohexane, and a cyclohexane; and
wherein each of the one or more second solvents is selected from the group consisting of:
a non-substituted ether; and
dimethoxyethane (DME), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme), butyl diglyme, ethyl diglyme, ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), gamma-butyrolactone (GBL), ethyl acetate (EA), methyl difluoroacetate (MDFA), methyl butyrate (MB), tris[2,2,2-trifluoroethyl]phosphite (TTFP), sulfolane (TMS), a carbonate ester, an acetate, a phosfite, a lactone, and a nitrile.
2. The electrolyte of claim 1 , wherein the fluorine substituted ether is represented by the general formula I or II:
R—{O(CH 2 ) a } b —CH 2 —O—CnF 2n H I
wherein R is —CmF 2 mH or —CmF 2m+1 , n is an integer of 2 or greater, m is an integer of 1 or greater, a is an integer of 1 or 2, and b is 0 or 1;
R—O—R′ II
wherein R and R′ are separately represented by C a F b H c , a is an integer of 2 or greater, b and c are integers >0 with b>c.
3. The electrolyte of claim 1 , wherein the one or more first solvents comprise a less-coordinating solvent selected from the group consisting of BTFE, TFE-TFPE, and TFE-TFEE.
4. The electrolyte of claim 1 , wherein the non-substituted ether is represented by general formula III:
R—O—(CH 2 —CH 2 —O) n —R′ III
wherein R and R′ are hydrocarbon chains C m H 2m+1 where m is an integer of 1 or greater, and n is an integer of 1 or greater.
5. The electrolyte of claim 1 , wherein the electrolyte comprises one or more lithium salts in an amount of about 7 to about 10 moles per liter of the one or more of the second solvents.
6. The electrolyte of claim 1 , wherein the one or more lithium salts are selected from the group consisting of lithium bis(perfluoroalkylsulfonyl)imides, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(perfluoroethylsulfonyl)imide, lithium difluoro(oxalato)borate, lithium tris(oxalato)phosphate, lithium difluorophosphate, lithium difluoro-bis(oxalato)phosphate and lithium tetrafluoro(oxalato)phosphate.
7. The electrolyte of claim 1 , wherein the one or more lithium salts exclude lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium perchlorate.
8. The electrolyte of claim 1 , wherein the one or more lithium salts comprise one or more of LiAsF 6 , LiNO 3 , Lil, LiSCN, LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiC(SO 2 CF 3 ) 3 , LiB(C 2 O 4 ) 2 , wherein a cumulative weight percent of the one or more lithium salts is <10 wt. % percent of the electrolyte.
9. The electrolyte claim 1 , wherein the one or more lithium salts comprise at least a first lithium salt and a second lithium salt, wherein the first lithium salt is selected from the group consisting of lithium bis(perfluoroalkylsulfonyl)imides, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(perfluoroethylsulfonyl)imide, lithium difluoro(oxalato)borate, lithium tris(oxalato)phosphate, lithium difluorophosphate, lithium difluoro-bis(oxalato)phosphate and lithium tetrafluoro(oxalato)phosphate and the second lithium salt is selected from the group consisting of LiAsF 6 , LiNO 3 , Lil, LiSCN, LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiC(SO 2 CF 3 ) 3 , LiB (C 2 O 4 ) 2 .
10. The electrolyte of claim 9 , wherein the electrolyte comprises between about 20 wt. % and 45 wt. % of the first lithium salt and between about 0.1 wt. % and about 10 wt. % of the second lithium salt.
11. The electrolyte of any of claim 1 , wherein one or more salts comprise at least three elements and include two or more of the following: boron, phosphorous, fluorine, carbon, nitrogen, and oxygen.
12. The electrolyte of claim 1 , wherein the one or more lithium salts comprise one or more anions selected from the group consisting of bis(perfluoroalkylsulfonyl)imides, bis(perfluoroalkylsulfonyl)methides, bis(fluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, bis(perfluoroethylsulfonyl)imide, dicyanamide, tricyanomethide, tetracyanoborate, 2,2,2,-trifluoro-N-(trifluoromethylsulfonyl)acetamide, tetrafluoroborate, triflate, bis(oxalato)borate, difluoro(oxalato)borate, perchlorate, hexafluoroarsenate, hexafluoroantimonate, perfluorobutylsulfonate, tris(trifluoromethanesulfonyl)methide, trifluoroacetate, heptafluorobutanoate, thiocyanate, and triflinate.
13. The electrolyte of claim 1 , wherein the electrolyte comprises about 30 to about 65 wt. % of the first solvent.
14. The electrolyte of claim 1 , wherein the electrolyte comprises about 5 to less than 50 v % of the first solvent.
15. The electrolyte of claim 1 , wherein the electrolyte comprises about 10 to less than 50 wt. % of the second solvent.
16. The electrolyte claim 1 , wherein:
the electrolyte consists essentially of the one or more first solvents, the one or more second solvents, and the one or more lithium salts;
the one or more first solvents consists essentially of one or more of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFE-TFPE), tetrafluoroethyl 1,1,2,2-tetrafluoroethyl ether (TFE-TFEE), ethyl 1,1,2,2-tetrafluoroethyl ether (ET-TFEE), ethyl 1,1,2,3,3,3-hexafluoropropyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether (BTFE), 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (OFP-TFEE), 1,1,1,2,3,3,6,6,7,7-decafluoro-4-oxaheptane, 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether, methoxytridecafluoroheptene and isomers thereof, heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether, ethyl nonafluorobutyl ether, difluoromethyl 2,2,3,3-tetrafluoropropyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, pentafluoroanisole, 2,3,5,6-tetrafluoroanisole, trifluoromethoxy benzene, 1-fluoro-3-(trifluoromethoxy)benzene, 1,1,2,3,3,3-hexafluoropropyl methyl ether, 1,1,2,2,3,3-hexafluoro-1-(trifluoromethoxy)-3-[(1,2,2-trifluorovinyl)oxy]propane, 1,1,2,2,3,3-hexafluoro-1,3-bis[(1,2,2- trifluorovinyl)oxy]propane, 1,3-bis(1,1,2,2-tetrafluoroethoxy)propane, 1,2-(1,1,2,2-tetrafluoroethoxy)ethane, 1,1,1,2,3,3-hexafluoro-4-(1,1,2,3,3,3-hexafluoropropoxy-pentane, 2,3,3,4,4-pentafluorotetrahydro-5-methoxy-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-furan, methyl nonafluorobutyl ether, methyl 2,2,3,3,3-pentafluoropropyl ether, methyl 1,1,2,2-tetrafluoroethyl ether, 1-fluoro-2-(trifluoromethoxy)benzene, 3-(trifluoromethoxy)benzonitrile, hexafluorobenzene, bis(4-fluorophenyl) ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, difluoromethoxy)benzene, 4-(difluoromethoxy)toluene, 2-fluorotoluene, 3-flurotoluene, 4-fluorotoluene, trifluorotoluene, octafluorotoluene, fluorobenzene, difluorobenzene, pentafluorobenzene, hexafluorobenzene, perfluoro-2-methylpentane, perfluoromethylcyclohexane, fluorocyclohexane, perfluoroheptane, 1,2,3,4,5,6-hexafluorocyclohexane, and a cyclohexane; and
the second solvent consists of one or more of dimethoxyethane (DME), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme), butyl diglyme, ethyl diglyme, ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), gamma-butyrolactone (GBL), ethyl acetate (EA), methyl difluoroacetate (MDFA), methyl butyrate (MB), tris[2,2,2-trifluoroethyl phosphite (TTFP), sulfolane (TMS), an acetate, a phosphite, a lactone, and a nitrile.
17. The electrolyte of claim 1 , wherein the one or more lithium salts consists essentially of
lithium bis(fluorosulfonyl)imide (LiF 2 NO 4 S 2 ) (LiFSI) salt in an amount of greater than 5 moles per liter of the one or more second solvents.