Electrolyte system for high voltage lithium ion battery
A secondary high energy density lithium ion cell includes a cathode comprising a high voltage cathode active material, a lithium metal anode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises an imide salt with a fluorosulfonyl group and a perchlorate salt, wherein the electrolyte is electrochemically stable at operating voltages greater than 4.2V.
1. A secondary high energy density lithium cell, comprising:
a cathode comprising a high voltage cathode active material, wherein the cathode is capable of operating between 3V and 4.5V;
an anode comprising an anode material, wherein the anode material is lithium metal; and
a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises:
an organic solvent selected from the group consisting of cyclic carbonates, glymes, cyclic ethers, ethers and combinations thereof,
an imide salt with a fluorosulfonyl group, wherein the imide salt comprises LiFSI, and a perchlorate salt, wherein the perchlorate salt is selected from the group consisting of LiClO 4 , Ca(ClO 4 ) 2 , Sr(ClO 4 ) 2 , Mg(ClO 4 ) 2 , Ba(ClO 4 ) 2 and any combinations or mixtures thereof and the perchlorate salt has a pre-cycling concentration between 0.05M to 0.50M of the organic solvent, the perchlorate salt provided to form a passivation surface film on at least one of the anode and the cathode,
wherein:
the cathode and the electrolyte are electrochemically stable at operating voltages greater than 4.2V,
the electrolyte has an imide salt concentration between 2 to 10 moles/liter of the organic solvent, and
upon cycling, at least a portion of the perchlorate salt reacts with at least one of the anode and the cathode to form the passivation protective film.
2. The lithium cell of claim 1 , wherein the imide salt consists essentially of LiFSI.
3. The lithium cell of claim 1 , wherein the perchlorate salt comprises LiClO 4 .
4. The lithium cell of claim 1 , wherein the perchlorate salt has a concentration between 0.25M to 0.50M of the organic solvent.
5. The lithium cell of claim 1 , wherein the perchlorate salt has a concentration between 0.35M to 0.45M of the organic solvent.
6. The lithium cell of claim 1 , wherein the perchlorate salt comprises LiClO 4 and one or more perchlorate salts comprising an alkaline earth metal.
7. The lithium cell of claim 1 , wherein the electrolyte comprises a cyclic carbonate selected from the group consisting of ethylene carbonate, propylene carbonate, their derivatives, and any combinations or mixtures thereof, as organic solvent.
8. The lithium cell of claim 1 , wherein the electrolyte comprises a glyme selected from the group consisting of dimethoxyethane, diethoxyethane, triglyme, tetraglyme, their derivatives, and any combinations or mixtures thereof, as organic solvent.
9. The lithium cell of claim 1 , wherein the electrolyte comprises a cyclic ether selected from the group consisting of tetrahydrofuran, tetrahydropyran, their derivatives, and any combinations or mixtures thereof, as organic solvent.
10. The lithium cell of claim 1 , wherein the electrolyte comprises an ether selected from the group consisting of diethylether, methylbutylether, their derivatives, and any combinations or mixtures thereof, as organic solvent.
11. The lithium cell of claim 1 , wherein the anode is a lithium metal foil pressed on a current collector.
12. The lithium cell of claim 1 , wherein the anode is a current collector having a vapor-deposited lithium layer and lithium is subsequently plated on it during the first charge of the battery.
13. The lithium cell of claim 1 , wherein the anode has lithium foil thickness ranging from 0.1 to 100 microns.
14. The lithium cell of claim 1 , wherein the cell comprises at least one surface in contact with the electrolyte, the surface comprising aluminum, aluminum alloy, or stainless steel.
15. The lithium cell of claim 14 , wherein the cell comprises an aluminum containing cathode current collector.
16. The lithium cell of claim 14 , wherein the cell comprises a stainless steel containing form factor.
17. A method of operating a high energy density lithium cell, comprising:
providing the high energy density lithium cell of claim 16 ; and
cycling the cell at least once in a voltage range exceeding 4.2V.
18. The method of claim 17 , wherein the cell is cycled at 0.7 C charge and 0.5 C discharge.
19. The method of claim 17 , wherein cycling comprises cycling the cell to a voltage of 4.5V.
20. The method of claim 17 , wherein the charging voltage is 4.5V.
21. The lithium cell of claim 11 , wherein the current collector comprises a copper foil or mesh.
22. The lithium cell of claim 13 , wherein the lithium foil thickness ranges from 5 to 50 microns.
23. The lithium cell of claim 1 , wherein the high voltage cathode material is a metal oxide material that reversibly intercalates lithium ions at high electrochemical potentials.
24. The lithium cell of claim 23 , wherein the high voltage cathode material has a general formula of Li x M y O z , where M is a transition metal.
25. The lithium cell of claim 24 , wherein the high voltage cathode material active material comprises a layered or a spinel oxide material selected from the group consisting of LiCoO 2 , Li(N 1/3 Mn 1/3 CO 1/3 )O 2 , Li(Ni 0.8 Co 0.15 Al 0.05 )O 2 , LiMn 2 O 4 , Li(Mn 1.5 Ni 0.5 ) 2 O 4 and lithium rich versions thereof.