Electrochemical capacitor having lithium containing electrolyte
A device having a first electrode, a second electrode, a separator positioned between the first electrode and the second electrode, and an electrolyte incorporated throughout the first electrode, the second electrode, and the separator. The electrolyte includes one or more lithium salts and one or more solvents. The first electrode and second electrodes comprise a majority of activated carbon having a microporous pore size distribution.
1. A device comprising:
a first electrode in an opposed relationship to a second electrode;
a separator positioned between the first electrode and the second electrode; and
an electrolyte incorporated throughout the first electrode, the second electrode and the separator, wherein
the electrolyte comprises one or more lithium salts and one or more solvents, and
the first and second electrodes comprise a majority of activated carbon, the activated carbon having a pore size distribution wherein:
pores having a size of ≦1 nm provide a combined pore volume of ≧0.3 cm 3 /g;
pores having a size of from >1 nm to ≦2 nm provide a combined pore volume of ≧0.05 cm 3 /g; and
any pores having a size of >2 nm provide a combined pore volume of <0.15 cm 3 /g, wherein the device has a maximum operable voltage of greater than 2.7 Volts.
2. The device of claim 1 , wherein the lithium salt is selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium perchlorate (LiClO 4 ), lithium triflate (LiCF 3 SO 3 ), lithium bis(trifluoromethanesulfone) imide (LiN(SO 2 CF 3 ) 2 ), lithium bis (perfluoroethylsulfonyl) imide (LiN(SO 2 CF 2 CF 3 ) 2 ), and combinations thereof.
3. The device of claim 1 , wherein the lithium salt is lithium hexafluorophosphate.
4. The device of claim 1 , wherein the solvent is selected from the group consisting of acetonitrile, 1,3-dioxolane, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dimethoxyethane, propylmethyl carbonate, and combinations thereof.
5. The device of claim 1 , wherein the solvent is selected from the group consisting of acetonitrile, ethylene carbonate, propylene carbonate, and combinations thereof.
6. The device of claim 1 , wherein the lithium salt has a concentration in the electrolyte of between about 0.5 and 2 M.
7. The device of claim 1 , wherein at least one of the first and second electrodes comprises a lithium-deposited activated carbon electrode.
8. The device of claim 7 , wherein the deposited lithium comprises from about 0.0001 wt. % to about 6 wt. % of a total weight of the electrode.
9. The device of claim 1 , wherein the device does not include a lithium electrode.
10. An electrochemical capacitor comprising:
a first electrode formed on a first current collector, a second electrode formed on a second current collector, and a separator positioned between the first electrode and the second electrode such that the separator is adjacent to the first and second electrodes; and
an electrolyte incorporated throughout the first electrode, the second electrode and the separator, wherein
the electrolyte comprises one or more lithium salts and one or more solvents, and
the first and second electrodes comprise a majority of activated carbon, the activated carbon having a pore size distribution wherein:
pores having a size of ≦1 nm provide a combined pore volume of ≧0.3 cm 3 /g;
pores having a size of from >1 nm to ≦2 nm provide a combined pore volume of ≧0.05 cm 3 /g; and
any pores having a size of >2 nm provide a combined pore volume of <0.15 cm 3 /g, wherein the capacitor has a maximum operable voltage of greater than 2.7 Volts.
11. The electrochemical capacitor of claim 10 , wherein the lithium salt is selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium perchlorate (LiClO 4 ), lithium triflate (LiCF 3 SO 3 ), lithium bis(trifluoromethanesulfone) imide (LiN(SO 2 CF 3 ) 2 ), lithium bis (perfluoroethylsulfonyl) imide (LiN(SO 2 CF 2 CF 3 ) 2 ), and combinations thereof.
12. The electrochemical capacitor of claim 10 , wherein the solvent is selected from the group consisting of acetonitrile, 1,3-dioxolane, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dimethoxyethane, propylmethyl carbonate, and combinations thereof.
13. The electrochemical capacitor of claim 10 , wherein the lithium salt has a concentration in the electrolyte of between about 0.5 and 2 M.
14. The electrochemical capacitor of claim 10 , wherein at least one of the first and second electrodes comprises a lithium-deposited activated carbon electrode.
15. The electrochemical capacitor of claim 14 , wherein the deposited lithium comprises from about 0.0001 wt. % to about 6 wt. % of a total weight of the electrode.
16. The electrochemical capacitor of claim 10 , further comprising a first sealing member disposed adjacent to the first current collector and around a periphery of the first electrode, and a second sealing member disposed adjacent to the second current collector and around a periphery of the second electrode.
17. The electrochemical capacitor of claim 10 , wherein the capacitor has an energy density of at least about 15 Wh/l.
18. The electrochemical capacitor of claim 10 , where the capacitor has a large cell format having an energy density of at least about 6 Wh/l.
19. An electrochemical capacitor (ECC) pack comprising a plurality of ECC cells, each ECC cell comprising an electrochemical capacitor according to claim 10 where none of the ECC cells include a lithium electrode.
20. An electrochemical capacitor (ECC) pack comprising a plurality of ECC cells, each ECC cell comprising an electrochemical capacitor according to claim 10 where wherein at least one of the first and second electrodes in each of the plurality of ECC cells is a lithium-deposited activated carbon electrode.