Aqueous redox flow batteries comprising metal ligand coordination compounds

• US 8,753,761 B2
• Filed: 03/12/2013
• Issued: 06/17/2014
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Sun Catalytix Corporation (Martin Marietta Corporation)
• Inventors: Esswein, Arthur J., Goeltz, John, King, Evan R., Reece, Steven Y., Amadeo, Desiree
• Primary Examiner(s): HAN, KWANG S
• Application Number:
  US13/795,878
• Publication Number:
  US 20140030572A1
• Time in Patent Office: 462 Days
• Field of Search: None
• US Class Current: 429/105
• CPC Class Codes: H01M 10/4242 Regeneration of electrolyte or reactants
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

This invention is directed to aqueous redox flow batteries comprising redox-active metal ligand coordination compounds. The compounds and configurations described herein enable flow batteries with performance and cost parameters that represent a significant improvement over that previous known in the art.

Claims

1. A flow battery comprising:

a first aqueous electrolyte comprising a first metal ligand coordination compound;

a second aqueous electrolyte comprising a second metal ligand coordination compound;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte and

a separator disposed between said first aqueous electrolyte and said second aqueous electrolyte;

wherein at least one of the first or second metal ligand coordination compound is of the formula M(L1)<sub>3−

x−

y</sub>(L2)_x(L3)_y^m,

x and y are independently 0, 1, 2, or 3, such that 3−

x−

y is not less than zero;

m is −

5, −

4, −

3, −

2, −

1, 0, +1, +2, +3, +4, or +5; and

M is Al, Cr, Fe, or Ti;

L1, L2, and L3 are each independently ascorbate, a catecholate, a pyrogallate, lactate, gluconate, or citrate; and

wherein

the first and second metal coordination compounds comprise different non-zero valent metals or metalloids.

2. The flow battery of claim 1, with the proviso that if x is 0, y is not 0.

3. The flow battery of claim 1, wherein both of the first and second metal ligand coordination compounds comprise at least one ascorbate, catechol, citrate, gluconate, lactate, or pyrogallol ligand.

4. The flow battery of claim 1, wherein at least one of the metal ligand coordination compounds comprises at least one catecholate or pyrogallate ligand.

5. The flow battery of claim 1, wherein at least one of the metal ligand coordination compounds comprises at least one ascorbate, citrate, gluconate, or lactate ligand.

6. The flow battery claim 1, wherein at least one metal ligand coordination compound comprises Al, Ca , Ce, Co, Cr, Fe, Mg, Mn, Mo, Si, Sn, Ti, U, W, Zn, or Zr.

7. The flow battery of claim 1, wherein one of the metal ligand coordination compounds is a chromium, cobalt, iron, manganese, molybdenum, or ruthenium cyanide compound.

8. The flow battery of claim 1, wherein one of the metal ligand coordination compounds is a chromium, iron, or manganese hexacyanide compound.

9. The flow battery of claim 1, wherein either the first or the second or both the first and second metal ligand coordination compounds is characterized as having a hydrodynamic diameter and the separator is characterized as having a mean pore size, wherein the hydrodynamic diameter of the coordination compound is larger than the mean pore size of the separator.

10. The flow battery of claim 1, wherein either or both of the first or the second metal ligand coordination compounds are present in the first or second electrolyte, respectively, at a concentration of at least 0.75 M.

11. The flow battery of claim 1, wherein the first and second metal ligand coordination compounds each exhibit substantially reversible electrochemical kinetics.

12. The flow battery of claim 1, wherein the flow battery is capable of operating, or is operating, with a current density greater than 50 mA/cm² while exhibiting a round trip voltage efficiency greater than 70%

13. The flow battery of claim 12, wherein the flow battery is capable of operating, or is operating, with a current density greater than 100 mA/cm² while exhibiting a round trip voltage efficiency greater than 70%.

14. The flow battery of claim 13, wherein the flow battery is capable of operating, or is operating, with a current density greater than 200 mA/cm² while exhibiting a round trip voltage efficiency greater than 70%.

15. The flow battery of claim 1, wherein the separator has a thickness of less than 100 μ

m.

16. The flow battery of claim 1, wherein the energy density of the electrolytes is greater than 10 Wh/L.

17. The flow battery of claim 16, wherein the energy density of the electrolytes is greater than 20 Wh/L

18. The flow battery of claim 17, wherein the energy density of the electrolytes is greater than 30 Wh/L.

19. The flow battery of claim 1, wherein the cell retains at least 70% round trip voltage efficiency when subjected to 10 charge/discharge cycles.

20. The flow battery of claim 1, wherein the first and second electrode comprise carbon.

21. The flow battery of claim 1, wherein the separator comprises an ionomer.

22. The flow battery of claim 21, wherein the ionomer comprises a perfluorinated acid functionalized polymer.

23. The flow battery of claim 21, wherein the charge of the first and/or second metal ligand coordination compound is of the same sign as the charge of the ionomer.

24. The flow battery of claim 1, wherein the flow battery exhibits an open circuit potential of at least 0.8 V.

25. The flow battery of claim 24, wherein the flow battery exhibits an open circuit potential of at least 1.0 V.

26. The flow battery of claim 25, wherein the flow battery exhibits an open circuit potential of at least 1.2 V.

27. The flow battery of claim 26, wherein the flow battery exhibits an open circuit potential of at least 1.4 V.