All-vanadium sulfate acid redox flow battery system

Patent metadata

Field	Value
Publication number	US-11532832-B2
Application number	US-202016859142-A
Country	US
Kind code	B2
Filing date	Apr 27, 2020
Priority date	Oct 6, 2014
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

All-vanadium sulfate redox flow battery systems have a catholyte and an anolyte comprising an aqueous supporting solution including chloride ions and phosphate ions. The aqueous supporting solution stabilizes and increases the solubility of vanadium species in the electrolyte, allowing an increased vanadium concentration over a desired operating temperature range. According to one example, the chloride ions are provided by MgCl2, and the phosphate ions are provided by (NH4)2HPO4.

First claim

We claim:

1. An anolyte and catholyte system for use in an all vanadium sulfate acid redox flow battery system, comprising:
(i) an anolyte comprising
water,
1.0-2.5 M VOSO 4 and H 2 SO 4 to provide 1.0-2.5 M vanadium as V 2+ and V 3+ and 4.5-6 M sulfate ions,
0.025-0.25 M magnesium ions, and
an anolyte dual-component system comprising 0.05-0.5 M chloride ions and 0.05-0.5 M phosphate ions; and

(ii) a catholyte comprising
water,
1.0-2.5 M VOSO 4 and H 2 SO 4 to provide 1.0-2.5 M vanadium as V 4+ and V 5+ and 4.5-6 M sulfate ions,
0.025-0.25 M magnesium ions, and
a catholyte dual-component system comprising 0.05-0.5 M chloride ions and 0.05-0.5 M phosphate ions,

wherein components of the dual-component system do not change a redox reaction potential between V 5+ and V 4+ and do not react with sulfate.

2. The anolyte and catholyte system of claim 1 , wherein the anolyte and the catholyte independently further comprise
0.05-1.5 M ammonium ions.

3. The anolyte and catholyte system of claim 2 , wherein sources of the chloride ions, phosphate ions, magnesium ions, and ammonium ions are selected from MgCl 2 , (NH 4 ) 2 HPO 4 , (NH 4 )H 2 PO 4 , (NH 4 ) 3 PO 4 , Mg(OH) 2 , HCl, NH 4 OH, H 3 PO 4 , NH 4 Cl, MgHPO 4 , Mg(H 2 PO 4 ) 2 , Mg 3 (PO 4 ) 2 , and NH 4 Mg PO 4 .

4. The anolyte and catholyte system of claim 1 , wherein the anolyte and catholyte independently are solutions prepared by combining water, VOSO 4 , H 2 SO 4 , magnesium chloride, and ammonium phosphate.

5. The anolyte and catholyte system of claim 1 , wherein:
(i) the anolyte and the catholyte independently comprise 1.5-2.0 M VOSO 4 and H 2 SO 4 to provide 1.5-2.0 M vanadium and 4.5-6 M sulfate ions; or
(ii) the dual-component systems of the anolyte and the catholyte independently comprise 0.1-0.2 M chloride ions and 0.1-0.2 M phosphate ions; or
(iii) both (i) and (ii).

6. The anolyte and catholyte system of claim 5 , wherein the dual-component systems of the anolyte and the catholyte independently comprise:
an amount of magnesium chloride to provide 0.05-0.1 M magnesium ions and 0.1-0.2 M chloride ions; and
an amount of ammonium phosphate to provide 0.2-0.4 M ammonium ions and 0.1-0.2 M phosphate ions.

7. An all-vanadium sulfate acid redox flow battery system comprising:
a cathode comprising graphite, graphene, or a carbon-based electrode;
an anode comprising graphite, graphene, or a carbon-based electrode;
a separator;
an anolyte comprising 1.0-2.5 M vanadium as V 2+ and V 3+ in an aqueous supporting solution; and
a catholyte comprising 1.0-2.5 M vanadium as V 4+ and V 5+ in an aqueous supporting solution, the anolyte and the catholyte independently comprising:
water,
1.0-2.5 M VOSO 4 and H 2 SO 4 to provide 1.0-2.5 M vanadium and 4.5-6 M sulfate ions,
0.025-0.25 M magnesium ions,
0.05-0.5 M chloride ions, and
0.05-0.5 M phosphate ions,

wherein the system is operable over a temperature range from −5° C. to 50° C.

8. The battery system of claim 7 , wherein the battery system has:
(i) a coulombic efficiency >90% at a current density from 10 mA/cm 2 to 320 mA/cm 2 ; or
(ii) an energy efficiency >75% at a current density from 10 mA/cm 2 to 320 mA/cm 2 ; or
(iii) a voltage efficiency >75% at a current density from 10 mA/cm 2 to 320 mA/cm 2 ; or
(iv) any combination of (i), (ii), and (iii).

9. The battery system of claim 7 , wherein the magnesium ions and chloride ions are provided by magnesium chloride.

10. The battery system of claim 7 , further comprising 0.05-1.5 M ammonium ions.

11. The battery system of claim 7 , wherein the phosphate ions are provided by ammonium phosphate.

12. The battery system of claim 7 , wherein the anolyte and catholyte independently comprise:
water;
1.5-2.0 M VOSO 4 and H 2 SO 4 to provide 1.5-2.0 M vanadium and 4.5-6 M sulfate ions,
0.05-0.1 M magnesium ions,
0.1-0.2 M chloride ions, and
0.1-0.2 M phosphate ions.

13. The battery system of claim 12 , wherein the anolyte and catholyte independently further comprise 0.2-0.4 M ammonium ions.

14. A method of making an electrolyte solution for an all-vanadium sulfate acid redox flow battery system, the method comprising:
dissolving amounts of VOSO 4 and H 2 SO 4 in water to provide a solution comprising 1.0-2.5 M vanadium and 4.5-6 M sulfate ions;
adding an amount of a magnesium ion source to the solution to provide 0.025-0.25 M magnesium ions;
adding an amount of a chloride ion source to the solution to provide 0.05-0.5 M chloride ions;
adding an amount of an ammonium ion source to the solution to provide 0.05-1.5 M ammonium ions; and
adding an amount of a phosphate ion source to the solution to provide 0.05-0.5 M phosphate ions.

15. The method of claim 14 , wherein the magnesium ion source, chloride ion source, ammonium ion source, and phosphate ion source are selected from MgCl 2 , (NH 4 ) 2 HPO 4 , (NH 4 )H 2 PO 4 , (NH 4 ) 3 PO 4 , Mg(OH) 2 , HCl, NH 4 OH, H 3 PO 4 , NH 4 Cl, MgHPO 4 , Mg(H 2 PO 4 ) 2 , Mg 3 (PO 4 ) 2 , and NH 4 MgPO 4 .

16. The method of claim 14 , wherein magnesium chloride is the magnesium ion source and the chloride ion source.

17. The method of claim 14 , wherein ammonium phosphate is the ammonium ion source and the phosphate ion source.

18. The method of claim 14 , wherein:
(i) the amount of the magnesium ion source provides 0.05-0.1 M magnesium ions; or
(ii) the amount of the chloride ion source provides 0.1-0.2 M chloride ions; or
(iii) the amount of the ammonium ion source provides 0.2-0.4 M ammonium ions; or
(iv) the amount of the phosphate ion source provides 0.1-0.2 M phosphate ions; or
(v) any combination of (i), (ii), (iii), and (iv).

19. The method of claim 14 , wherein magnesium chloride is the magnesium ion source and the chloride ion source, the method further comprising adding an amount of magnesium chloride to the solution to provide 0.05-0.1 M magnesium ions and 0.1-0.2 M chloride ions.

20. The method of claim 14 , wherein ammonium phosphate is the ammonium ion source and the phosphate ion source, the method further comprising adding an amount of ammonium phosphate to the solution to provide 0.2-0.4 M ammonium ions and 0.1-0.2 M phosphate ions.

Assignees

• Battelle Memorial Institute

Inventors

• Nie Zimin
• Wang Wei
• Wei Xiaoliang
• Li Bin
• Liu Jun
• Sprenkle Vincent L

Classifications

• H01M8/188 Primary

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

• Y02E60/50

  Fuel cells · CPC title

• H01M8/20 Primary

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