SMALL ORGANIC MOLECULE BASED FLOW BATTERY
The invention provides an electrochemical cell based on a new chemistry for a flow battery for large scale, e.g., grid-scale, electrical energy storage. Electrical energy is stored chemically at an electrochemical electrode by the protonation of small organic molecules called quinones to hydroquinones. The proton is provided by a complementary electrochemical reaction at the other electrode. These reactions are reversed to deliver electrical energy. A flow battery based on this concept can operate as a closed system. The flow battery architecture has scaling advantages over solid electrode batteries for large scale energy storage.
1 . A rechargeable battery comprising first and second electrodes, wherein in its charged state, the battery comprises a redox active species in contact with the first electrode and a hydroquinone dissolved or suspended in aqueous solution in contact with the second electrode, wherein during discharge the redox active species is reduced and the hydroquinone is oxidized to a quinone.
2 . The rechargeable battery of claim 1 , wherein the redox active species is dissolved or suspended in aqueous solution.
3 . The rechargeable battery of claim 1 , wherein the redox active species in contact with the first electrode comprises chlorine, bromine, iodine, oxygen, vanadium, chromium, cobalt, iron, manganese, cobalt, nickel, copper, or lead.
4 . The rechargeable battery of claim 1 , wherein the redox active species in contact with the first electrode comprises bromine.
5 . The rechargeable battery of claim 3 , wherein the redox active species in contact with the first electrode comprises a manganese oxide, a cobalt oxide or a lead oxide.
6 . The rechargeable battery of any of claims 1 - 5 , wherein the hydroquinone and quinone in contact with the second electrode have a standard electrochemical potential below 0.4 volts with respect to a standard hydrogen electrode.
7 . The rechargeable battery of claim 6 , wherein the quinone is a water-soluble anthraquinone.
8 . The rechargeable battery of claim 7 , wherein the water-soluble anthraquinone comprises one or more sulfonate groups.
9 . The rechargeable battery of claim 8 , wherein the anthraquinone is 9,10-anthraquinone-2,7-disulfonate.
10 . The rechargeable battery of any of claims 6 - 9 , wherein first and second electrodes are separated by an ion conducting barrier, and the redox active species comprises bromine.
11 . The rechargeable battery of claim 1 , wherein the redox active species is a second quinone dissolved or suspended in aqueous solution.
12 . The rechargeable battery of claim 11 , wherein the first electrode is separated from the second electrode by a barrier that inhibits the passage of the redox-active species and the hydroquinone.
13 . The rechargeable battery of claim 12 , wherein the barrier is a size exclusion barrier.
14 . A rechargeable battery comprising first and second electrodes separated by an ion conducting hydrocarbon barrier or size-exclusion barrier, wherein in its charged state, the battery comprises a quinone at the first electrode and a hydroquinone at the second electrode, wherein during discharge, the quinone is reduced, and the hydroquinone is oxidized.
15 . The rechargeable battery of any of claims 1 - 5 and 11 - 14 , wherein the quinone or hydroquinone in oxidized form is of formula (A)-(D):
wherein each of R 1 -R 10 is independently selected from H, optionally substituted C 1-6 alkyl, halo, hydroxy, optionally substituted C 1-6 alkoxy, SO 3 H, amino, nitro, carboxyl, phosphoryl, phosphonyl, and oxo, or an ion thereof, provided that two of R 1 -R 6 for formula (A) are oxo, two or four of R 1 -R 8 for formula (B) are oxo, and two, four, or six of R 1 -R 10 for formulas (C) and (D) are oxo, wherein the dashed lines indicate that the monocylic ring of formula (A), the bicyclic ring of formula (B), and the tricyclic rings of formulas (C) and (D) are fully conjugated.
16 . The rechargeable battery of any of claims 1 - 5 and 11 - 14 , wherein the quinone or hydroquinone in oxidized form is of formula (I)-(IX):
wherein each of R 1 -R 8 is independently selected from H, optionally substituted C 1-6 alkyl, halo, hydroxy, optionally substituted C 1-6 alkoxy, SO 3 H, amino, nitro, carboxyl, phosphoryl, phosphonyl, and oxo, or an ion thereof.
17 . The rechargeable battery of any of claims 1 - 5 and 11 - 14 , wherein the quinone or hydroquinone in oxidized form is:
9,10-anthraquinone-2,7-disulfonic acid,
9,10-anthraquinone-2,6-disulfonic acid,
9,10-anthraquinone-1,8-disulfonic acid,
9,10-anthraquinone-1,5-disulfonic acid,
9,10-anthraquinone-2-sulfonic acid,
9,10-anthraquinone-2,3-dimethanesulfonic acid,
1,8-dihydroxy-9,10-anthraquinone-2,7-disulfonic acid,
1,5-dihydroxy-9,10-anthraquinone-2,6-disulfonic acid,
1,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid,
1,3,4-trihydroxy-9,10-anthraquinone-2-sulfonic acid,
1,2-naphthoquinone-4-sulfonic acid,
1,4-naphthoquinone-2-sulfonic acid,
2-chloro-1,4-naphthoquinone-3-sulfonic acid,
2-bromo-1,4-naphthoquinone-3-sulfonic acid, or a mixture thereof.
18 . The rechargeable battery of claim 17 , wherein the quinone or hydroquinone in oxidized form is:
9,10-anthraquinone-2,7-disulfonic acid,
9,10-anthraquinone-2,6-disulfonic acid,
9,10-anthraquinone-1,8-disulfonic acid,
9,10-anthraquinone-1,5-disulfonic acid, 9,10-anthraquinone-2-sulfonic acid, or a mixture thereof.
19 . The rechargeable battery of any of claims 1 - 5 and 11 - 14 , wherein the quinone or hydroquinone in oxidized form is:
2-hydroxy-1,4-naphthoquinone-3-sulfonic acid,
1,2,4-trihydroxybenzene-3-sulfonic acid,
2,4,5-trihydroxybenzene-1,3-disulfonic acid
2,3,5-trihydroxybenzene-1,4-disulfonic acid,
2,4,5,6-tetrahydroxybenzene-1,3-disulfonic acid,
2,3,5-trihydroxybenzene-1,4-disulfonic acid,
2,3,5,6-tetrahydroxybenzene-1,4-disulfonic acid, or a mixture thereof.
20 . The rechargeable battery of any of claims 1 - 19 , further comprising a reservoir for quinone and/or hydroquinone dissolved or suspended in aqueous solution and a mechanism to circulate quinone and/or hydroquinone.