Polyfluorinated carbonate electrolyte for high-voltage lithium batteries
A non-aqueous solvent composition for a lithium battery comprises a fluorinated solvent mixture that consists essentially of a 1,2-difluoroethylene carbonate and a fluoro-substituted dialkyl carbonate in a respective weight ratio of about 1:3 to about 1:1, and optionally up to about 30 wt % of an additional organic solvent. An electrolyte for a lithium ion battery comprises a lithium salt dissolved in a non-aqueous solvent composition comprising the fluorinated solvent mixture.
1. A non-aqueous electrolyte for a lithium electrochemical cell comprising a lithium salt dissolved in a non-aqueous solvent composition consisting of a 1,2-difluoroethylene carbonate and a fluoro-substituted dialkyl carbonate in a respective weight ratio of about 1:3 to about 1:1; wherein the lithium salt is selected from the group consisting of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium trifluoromethanesulfonate (LiTf), lithium perchlorate (LiClO 4 ), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium thiocyanate (LiSCN), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetracyanoborate (LiB(CN) 4 ), and lithium nitrate.
2. The electrolyte of claim 1 , wherein the 1,2-difluoroethylene carbonate and the fluoro-substituted dialkyl carbonate are present in the composition in a respective weight ratio of about 3:7 to about 1:1.
3. The electrolyte of claim 1 , wherein the 1,2-difluoroethylene carbonate comprises trans-1,2-difluoroethylene carbonate.
4. The electrolyte of claim 1 , wherein the fluoro-substituted dialkyl carbonate comprises one or more compound selected from the group consisting of bis(2,2,2-trifluoroethyl) carbonate and 2-fluoroethyl methyl carbonate.
5. The electrolyte of claim 1 , wherein the lithium salt is LiPF 6 .
6. The electrolyte of claim 1 , wherein the lithium salt is present in the electrolyte at a concentration in the range of about 0.1 M to about 3 M.
7. A non-aqueous electrolyte for a lithium electrochemical cell comprising about 0.5 M to about 2 M solution of an electrolyte salt consisting of LiPF 6 dissolved in a non-aqueous solvent composition consisting of a 1,2-difluoroethylene carbonate and a fluoro-substituted dialkyl carbonate in a respective weight ratio of about 1:3 to about 1:1.
8. The electrolyte of claim 7 , wherein the 1,2-difluoroethylene carbonate comprises trans-1,2-difluoroethylene carbonate.
9. The electrolyte of claim 7 , wherein the fluoro-substituted dialkyl carbonate comprises one or more compound selected from the group consisting of bis(2,2,2-trifluoroethyl) carbonate and 2-fluoroethyl methyl carbonate.
10. An electrochemical cell comprising an anode, a cathode, and a lithium-containing electrolyte of claim 1 contacting the anode and the cathode.
11. The electrochemical cell of claim 10 , wherein the anode comprises metallic lithium or graphite and the cathode comprises a lithium metal oxide.
12. A battery comprising a plurality of electrochemical cells of claim 10 , electrically connected in series, in parallel, or in both series and parallel.
13. An electrochemical cell comprising an anode, a cathode, and a lithium-containing electrolyte of claim 7 contacting the anode and the cathode.
14. The electrochemical cell of claim 13 , wherein the anode comprises metallic lithium or graphite and the cathode comprises a lithium metal oxide.
15. A battery comprising a plurality of electrochemical cells of claim 13 , electrically connected in series, in parallel, or in both series and parallel.