Coordination compounds having redox non-innocent ligands and flow batteries containing the same

• US 9,938,308 B2
• Filed: 04/07/2016
• Issued: 04/10/2018
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Energy LLC (Martin Marietta Corporation)
• Inventors: Millard, Matthew
• Primary Examiner(s): Fraser, Stewart A
• Application Number:
  US15/093,606
• Publication Number:
  US 20170291916A1
• Time in Patent Office: 733 Days
• CPC Class Codes: C07F 7/28 Titanium compounds
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: H01M 8/20 Indirect fuel cells, e.g. fuel cells with redox couple being irreversible H01M8/18 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Electrolyte solutions for flow batteries and other electrochemical systems can contain an active material capable of transferring more than one electron per oxidation-reduction cycle. Such active materials can include coordination compounds containing a metal center and at least one redox non-innocent ligand. Accordingly, flow batteries can include a first half-cell having a first electrolyte solution therein, where the first electrolyte solution contains a coordination compound having at least one redox non-innocent ligand coordinated to a metal center. Particular redox non-innocent ligands can include those bearing a quinone functional group, such as substituted catecholates bearing a quinone functional group. Some active materials can include compositions containing a coordination compound having at least one redox non-innocent ligand coordinated to a metal center, where the at least one redox non-innocent ligand is a substituted catecholate or a salt thereof bearing a quinone functional group.

Claims

1. A flow battery comprising:

a first half-cell having a first electrolyte solution therein, the first electrolyte solution comprising a coordination compound having at least one redox non-innocent ligand coordinated to a metal center,

wherein the at least one redox non-innocent ligand bears a quinone functional group,

wherein the quinone functional group is part of an aromatic ring bearing a catechol group, fused to the aromatic ring bearing the catechol group, or tethered via a linker to the aromatic ring bearing the catechol group.

2. The flow battery of claim 1, wherein the at least one redox non-innocent ligand comprises a salt of a substituted catecholate bearing the quinone functional group.

3. The flow battery of claim 1, wherein the at least one redox non-innocent ligand is selected from the group consisting of

4. The flow battery of claim 1, wherein the coordination compound has a formula of

D_gM(L₁)(L₂)(L₃);

wherein M is a transition metal;

D is ammonium, tetraalkylammonium, or an alkali metal ion;

g ranges between 0 and 6; and

L₁, L₂ and L₃ are ligands, at least one of L₁, L₂ and L₃ being the at least one redox non-innocent ligand.

5. The flow battery of claim 4, wherein the transition metal comprises titanium.

6. The flow battery of claim 1, wherein the metal center comprises a transition metal.

7. The flow battery of claim 6, wherein the transition metal comprises titanium.

8. The flow battery of claim 1, further comprising:

a second half-cell having a second electrolyte solution therein, the second electrolyte solution comprising an iron hexacyanide complex.

9. A composition comprising:

a coordination compound having at least one redox non-innocent ligand coordinated to a metal center;

wherein the at least one redox non-innocent ligand comprises a substituted catecholate or a salt thereof bearing a quinone functional group;

wherein the quinone functional group is part of an aromatic ring bearing a catechol group, fused to the aromatic ring bearing the catechol group, or tethered via a linker to the aromatic ring bearing the catechol group.

10. The composition of claim 9, wherein the metal center comprises a transition metal.

11. The composition of claim 10, wherein the metal center comprises a transition metal.

12. The composition of claim 9, wherein the coordination compound has a formula of

D_gM(L₁)(L₂)(L₃);

wherein M is a transition metal;

D is ammonium, tetraalkylammonium, or an alkali metal ion;

g ranges between 0 and 6; and

L₁, L₂ and L₃ are ligands, at least one of L₁, L₂ and L₃ being the at least one redox non-innocent ligand.

13. The composition of claim 9, wherein the at least one redox non-innocent ligand is selected from the group consisting of

14. The composition of claim 9, further comprising:

an aqueous solution in which the coordination compound is disposed.

15. The composition of claim 14, wherein the aqueous solution has an alkaline pH.