Metal complexes of substituted catecholates and redox flow batteries containing the same

• US 9,837,679 B2
• Filed: 11/25/2015
• Issued: 12/05/2017
• Est. Priority Date: 11/26/2014
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Inventors: Reece, Steven Y.
• Primary Examiner(s): Eoff, Anca
• Application Number:
  US14/952,899
• Publication Number:
  US 20160149251A1
• Time in Patent Office: 741 Days
• CPC Class Codes: C07F 7/28 Titanium compounds
• CPC Class Codes: H01M 2300/0002 Aqueous electrolytes
• 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

Active materials for flow batteries can include various coordination compounds formed from transition metals. Some compositions containing coordination compounds can include a substituted catecholate ligand having a structure of

in a neutral form or a salt form, in which Z is a heteroatom functional group bound to the substituted catecholate ligand at an open aromatic ring position and n is an integer ranging between 1 and 4. When more than one Z is present, each Z can be the same or different. Electrolyte solutions can include such coordination compounds, and such electrolyte solutions can be incorporated within a flow battery.

Claims

1. A composition comprising:

a coordination compound comprising a substituted catecholate ligand, the substituted catecholate ligand having a structure of

2. The composition of claim 1, wherein at least two of L₁, L₂ and L₃ are substituted catecholate ligands.

3. The composition of claim 2, wherein L₁ and L₂ are substituted catecholate ligands and L₃ is an unsubstituted catecholate ligand.

4. The composition of claim 1, wherein L₁ is the substituted catecholate ligand and L₂ and L₃ are unsubstituted catecholate ligands.

5. The composition of claim 1, wherein each of L₁, L₂ and L₃ are substituted catecholate ligands.

6. The composition of claim 1, wherein the transition metal is Ti.

7. The composition of claim 1, wherein any of L₁ to L₃ that are not the unsubstituted catecholate ligand comprises one or more ligands that are independently selected from the group consisting of an unsubstituted catecholate, ascorbate, citrate, glycolate, a polyol, gluconate, a hydroxyalkanoate, acetate, formate, benzoate, malate, maleate, phthalate, sarcosinate, salicylate, oxalate, a urea, a polyamine, aminophenolate, acetylacetonate, and lactate.

8. An electrolyte solution comprising the composition of claim 1.

9. The electrolyte solution of claim 8, wherein the electrolyte solution is an aqueous solution.

10. The electrolyte solution of claim 9, further comprising:

a buffer, a supporting electrolyte, a viscosity modifier, a wetting agent, or any combination thereof.

11. The electrolyte solution of claim 9, wherein the aqueous solution has a pH ranging between about 1 and about 13.

12. The electrolyte solution of claim 9, wherein the transition metal is Ti.

13. The electrolyte solution of claim 9, wherein a concentration of the coordination compound in the aqueous solution ranges between about 0.5 M and about 3 M.

14. A flow battery comprising an electrolyte solution comprising the composition of claim 1.

15. The flow battery of claim 14, wherein the transition metal is Ti.