Aqueous redox flow batteries featuring improved cell design characteristics
Provided are compositions having the formula M n Ti(L1)(L2)(L3) wherein L1 is a catecholate, and L2 and L3 are each independently selected from catecholates, ascorbate, citrate, glycolates, a polyol, gluconate, glycinate, hydroxyalkanoates, acetate, formate, benzoates, malate, maleate, phthalates, sarcosinate, salicylate, oxalate, a urea, polyamine, aminophenolates, acetylacetone or lactate; each M is independently Na, Li, or K; n is 0 or an integer from 1-6. Also provided are energy storage systems.
1. A composition having the formula M n Ti(L1)(L2)(L3) wherein:
L1 is a catecholate, and L2 and L3 are each independently selected from catecholates, ascorbate, citrate, glycolates, a polyol, gluconate, glycinate, hydroxyalkanoates, acetate, formate, benzoates, malate, maleate, phthalates, sarcosinate, salicylate, oxalate, a urea, polyamine, aminophenolates, acetylacetone or lactate;
each M is independently Na, Li, or K;
n is 0 or an integer from 1-6; and provided that when both L1 and L2 are a catecholate, L3 is not oxalate, urea, catecholate or acetylacetone.
2. The composition of claim 1 , wherein said catecholate comprises 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene, 1,2,4-trihydroxybenzene or a mixture thereof.
3. A flow battery comprising the composition of claim 1 .
4. A composition having the formula M n Ti(catecholate) 2 (hydroxycatecholate);
wherein n is 0 or an integer from 1 to 6.
5. The composition of claim 4 , wherein said hydroxycatecholate comprises 1,2,3-trihydroxybenzene or 1,2,4-trihydroxybenzene.
6. An aqueous solution comprising one or more compositions having the formula M n Ti(L1)(L2)(L3) wherein:
L1, L2, and L3 are each independently selected from catecholates, ascorbate, citrate, glycolates, polyols, gluconate, glycinate, hydroxyalkanoates, acetate, formate, benzoates, malate, maleate, phthalates, sarcosinate, salicylate, oxalate, ureas, a polyamine, aminophenolates, acetylacetone or lactate, provided that at least one of L1, L2, and L3 is a catecholate;
each M is independently Na, Li, or K;
n is 0 or an integer from 1-6; and
wherein the composition is present in a concentration greater than 0.5 M.
7. The aqueous solution of claim 6 , wherein when L1 and L2 are a catecholate, L3 is not oxalate, urea, catecholate or acetylacetone.
8. The aqueous solution of claim 6 , wherein said catecholate comprises 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene, 1,2,4-trihydroxybenzene or a mixture thereof.
9. The aqueous solution of claim 6 , wherein the composition has the formula M n Ti(catecholate) 2 (hydroxycatecholate).
10. The aqueous solution of claim 9 , wherein said hydroxycatecholate comprises 1,2,3-trihydroxybenzene or 1,2,4-trihydroxybenzene.
11. The aqueous solution of claim 6 , wherein the composition is of the formula M n Ti(catecholate) 3 .
12. The aqueous solution of claim 6 , additionally comprising a buffer.
13. The aqueous solution of claim 12 , wherein said buffer is a salt of phosphate, borate, carbonate, silicate, tris(hydroxymethyl)aminomethane (tris), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), piperazine-N,N′-bis(ethanesulfonic acid) (PIPES), and combinations thereof.
14. The aqueous solution of claim 6 having a pH of 1-13.
15. The aqueous solution of claim 6 having a pH of 2-12.
16. The aqueous solution of claim 6 having a pH of 4-10.
17. The aqueous solution of claim 5 , wherein at least one of L1, L2, and L3 is a catecholate bearing a sulfonic acid or a salt thereof.
18. The aqueous solution of claim 17 , wherein at least one of L1, L2, and L3 is a catecholate bearing one sulfonic acid or a salt thereof.
19. The aqueous solution of claim 6 having a pH of about 7 to about 13.
20. The aqueous solution of claim 6 having a pH of about 9 to about 13.