Ionic liquid catholytes and electrochemical devices containing same

Patent metadata

Field	Value
Publication number	US-10424803-B2
Application number	US-201515508032-A
Country	US
Kind code	B2
Filing date	Sep 15, 2015
Priority date	Sep 15, 2014
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

An ionic liquid catholyte includes an ionic liquid, such as 1-ethyl-3-methylimidazolium chloride (EMICl), at least one half of a redox couple, and a sodium salt. The ionic liquid catholyte is suitable for use as a liquid cathode in an electrochemical device including an anode current collector, an anode in contact with the anode current collector, a cathode current collector, a liquid cathode in contact with the cathode current collector, and a solid electrolyte separating the anode and cathode current collectors. The one half of the redox couple includes a metal in a first oxidation state that is oxidized or reduced to yield the metal in a second oxidation state, and the redox couple includes the metal in the first oxidation state and the metal in the second oxidation state. The solid electrolyte is permeable to sodium ions and is in contact with the liquid anode and the liquid cathode.

First claim

What is claimed is:

1. A battery comprising:
an anode current collector;
an anode in contact with the anode current collector;
a cathode current collector;
a liquid cathode in contact with the cathode current collector, wherein the liquid cathode comprises a catholyte solution comprising:
an ionic liquid or ionic liquid mixture, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium chloride (EMICl);
a redox couple or one half of a redox couple; and
a sodium salt,
wherein the one half of the redox couple comprises a metal in a first oxidation state that is oxidized or reduced to yield the metal in a second oxidation state, and the redox couple comprises the metal in the first oxidation state and the metal in the second oxidation state; and

a solid electrolyte separating the anode current collector and the cathode current collector, wherein the solid electrolyte is permeable to sodium ions and is in contact with the anode and the liquid cathode.

2. The battery of claim 1 , wherein the metal in the second oxidation state can be reduced or oxidized to yield the metal in the first oxidation state.

3. The battery of claim 2 , wherein the redox couple comprises Fe(II) and Fe(III).

4. The battery of claim 2 , wherein the redox couple comprises Mn(II) and Mn(III).

5. The battery of claim 2 , wherein the redox couple comprises Cu and Cu(II).

6. The battery of claim 2 , wherein the redox couple comprises Cu and Cu(I).

7. The battery of claim 2 , wherein the redox couple comprises Cu(I) and Cu(II).

8. The battery of claim 2 , wherein the redox couple comprises Cr(III) and Cr(VI).

9. The battery of claim 1 , wherein the ionic liquid is a salt or a combination of salts in the liquid state below 100° C.

10. The battery of claim 1 , wherein the catholyte solution comprises an aluminum salt.

11. The battery of claim 10 , wherein the aluminum salt comprises aluminum chloride.

12. The battery of claim 1 , wherein the sodium salt comprises sodium chloride.

13. The battery of claim 1 , wherein the solid electrolyte comprises a material having the general formula Na 1+x Zr 2 Si x P 3-x O 12 , wherein 0<x<3.

14. The battery of claim 1 , wherein the solid electrolyte is coated with indium tin oxide.

15. The battery of claim 1 , wherein the battery delivers at least 70% of its theoretical energy density.

16. The battery of claim 1 , wherein the energy efficiency (E %) of the battery, calculated as:

Energy
⁢

⁢
efficiency

=

⁢

∫

v
discharge

⁢

i
discharge

⁢
dt

∫

v
charge

⁢

i
charge

⁢
dt

≈

V

mid
-
discharge

⁢

C
discharge

V

mid
-
charge

⁢

C
charge

,

=

⁢

(

voltage
⁢

⁢
efficiency

)

⁢

(

coulombic
⁢

⁢
efficiency

)

is at least 90%.

17. The battery of claim 1 , wherein the Coulombic efficiency of the battery is at least 95%.

18. The battery of claim 1 , wherein the anode comprises liquid sodium or sodium alloy at a temperature in a range between 100° C. and 200° C.

Assignees

• Arizona Board Of Regents For And On Behalf Of Arizona State Univ
• Univ Arizona State

Inventors

• Angell Charles Austen
• Xue Leigang

Classifications

• H01M8/20

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

• H01M4/8652

  as mixture · CPC title

• H01M8/188 Primary

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

• Y02E60/528

  Cross-Sectional Technologies · mapped topic

• Y02E60/50

  Fuel cells · CPC title