Electrochemical energy storage systems and methods featuring large negative half-cell potentials

Patent metadata

Field	Value
Publication number	US-2017098850-A1
Application number	US-201615387594-A
Country	US
Kind code	A1
Filing date	Dec 21, 2016
Priority date	Jul 27, 2012
Publication date	Apr 6, 2017
Grant date	—

Abstract

The invention concerns flow batteries comprising: a first half-cell comprising: (i) a first aqueous electrolyte comprising a first redox active material; and a first carbon electrode in contact with the first aqueous electrolyte; (ii) a second half-cell comprising: a second aqueous electrolyte comprising a second redox active material; and a second carbon electrode in contact with the second aqueous electrolyte; and (iii) a separator disposed between the first half-cell and the second half-cell; the first half-cell having a half-cell potential equal to or more negative than about −0.3 V with respect to a reversible hydrogen electrode; and the first aqueous electrolyte having a pH in a range of from about 8 to about 13, wherein the flow battery is capable of operating or is operating at a current density at least about 25 mA/cm 2 .

First claim

What is claimed is the following:

1 . A flow battery comprising:
a first half-cell comprising:
a first aqueous electrolyte comprising a first redox active material, and a first carbon electrode in contact with the first aqueous electrolyte;
a second half-cell comprising:
a second aqueous electrolyte comprising a second redox active material, and a second carbon electrode in contact with the second aqueous electrolyte; and
a separator disposed between the first half-cell and the second half-cell;
wherein the first half-cell has a half-cell potential ranging between −0.3 V and −0.7 V with respect to a reversible hydrogen electrode, and the first redox active material exhibits substantially reversible electrochemical kinetics.

2 . The flow battery of claim 1 , wherein the flow battery is capable of operating at a current density ranging between 25 mA/cm 2 and 500 mA/cm 2 .

3 . The flow battery of claim 2 , wherein the flow battery is capable of operating with a current efficiency of at least 50% at a current density ranging between 50 mA/cm 2 and 500 mA/cm 2 .

4 . The flow battery of claim 2 , wherein the flow battery is capable of operating with a current efficiency of at least 85% at a current density ranging between 50 mA/cm 2 and 500 mA/cm 2 .

5 . The flow battery of claim 1 , wherein the flow battery is capable of operating with a current efficiency of at least 50%.

6 . The flow battery of claim 1 , wherein the flow battery is capable of operating with a current efficiency of at least 85%.

7 . The flow battery of claim 1 , wherein the flow battery has an open circuit voltage ranging between 1.48 V and 1.95 V.

8 . The flow battery of claim 1 , wherein the redox active materials do not plate onto the carbon electrodes during operation of the flow battery.

9 . The flow battery of claim 1 , wherein at least the first redox active material is a metal ligand coordination compound.

10 . The flow battery of claim 9 , wherein both the first redox active material and the second redox active material are metal ligand coordination compounds.

11 . The flow battery of claim 9 , wherein the first redox active material is a metal ligand coordination compound comprising titanium.

12 . The flow battery of claim 11 , wherein the second redox active material is a hexacyanide metal ligand coordination compound.

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

14 . The flow battery of claim 1 , wherein the second half-cell has a potential ranging between +1.10 V and +2.0 V versus a reversible hydrogen electrode.

15 . The flow battery of claim 1 , wherein each redox active material exhibits substantially reversible electrochemical kinetics.

16 . A system comprising the flow battery of claim 1 , and further comprising:
a first chamber containing the first aqueous electrolyte and a second chamber containing the second aqueous electrolyte; at least one electrolyte circulation loop in fluidic communication with each chamber, the at least one electrolyte circulation loop comprising storage tanks and piping for containing and transporting the first and second aqueous electrolytes; and a power conditioning unit.

17 . A flow battery comprising:
a first half-cell comprising:
a first aqueous electrolyte comprising a first redox active material, and a first carbon electrode in contact with the first aqueous electrolyte;
a second half-cell comprising:
a second aqueous electrolyte comprising a second redox active material, and a second carbon electrode in contact with the second aqueous electrolyte; and
a separator disposed between the first half-cell and the second half-cell;
wherein the first half-cell has a half-cell potential ranging between −0.3 V and −0.7 V with respect to a reversible hydrogen electrode, and the flow battery is capable of operating with a current efficiency of at least 50% at a current density ranging between 50 mA/cm 2 and 500 mA/cm 2 .

18 . The flow battery of claim 17 , wherein the flow battery is capable of operating with a current efficiency of at least 85% at a current density ranging between 50 mA/cm 2 and 500 mA/cm 2 .

19 . The flow battery of claim 17 , wherein the first redox active material is a metal ligand coordination compound comprising titanium.

20 . The flow battery of claim 19 , wherein the second redox active material is a hexacyanide metal ligand coordination compound.

Assignees

• Lockheed Martin Advanced Energy Storage Llc

Inventors

• Esswein Arthur J
• Reece Steven Y
• Goeltz John
• King Evan R
• Amadeo Desiree
• Tyagi Nitin
• Jarvi Thomas D

Classifications

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H01M8/04276

  Arrangements for managing the electrolyte stream, e.g. heat exchange · CPC title

• H01M8/188 Primary

  by recharging of redox couples containing fluids; Redox flow type batteries · CPC title

• H01M4/96

  Carbon-based electrodes · CPC title

• H01M8/20

  Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) · CPC title