Air cell

Patent metadata

Field	Value
Publication number	US-10637116-B2
Application number	US-201514851533-A
Country	US
Kind code	B2
Filing date	Sep 11, 2015
Priority date	Sep 19, 2014
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Disclosed is an air cell with higher energy density than before. An air cell comprises an electrolyte solution containing a potassium hydroxide solution having a pH of 17.3 or more under a temperature condition of 23° C., an anode containing iron, and a cathode.

First claim

The invention claimed is:

1. An air cell comprising:
an electrolyte solution containing a potassium hydroxide solution having a pH of 17.5 or more and 18.4 or less under a temperature condition of 23° C.;
an anode containing iron as an anode active material; and
a cathode,
wherein an average diameter of the anode active material is 0.1 μm or more and 1 mm or less,
wherein the mass ratio of iron in the anode accounts for 10% by mass or more and 100% by mass or less of the mass of the anode, and
wherein the air cell is configured so that a charge-discharge reaction at the anode occurs according to the following formula (2), in which an arrow from the left-sided formula to the right-sided formula indicates a discharge reaction, and an arrow from the right-sided formula to the left-sided formula indicates a charge reaction:
Fe+2OH − ⇄Fe(OH) 2 +2 e − E 0 =−0.975 V.  Formula (2):

2. The air cell according to claim 1 , wherein the anode contains at least one selected from the group consisting of iron metal, iron alloy, and iron compounds, and the cathode comprises a cathode layer containing at least one electroconductive material.

3. The air cell according to claim 1 , wherein the potassium hydroxide solution contains an additive for facilitating a discharge reaction and having a concentration that does not inhibit an electrode reaction and can prevent the formation of a passive film on a surface of the anode.

4. The air cell according to claim 3 , wherein the additive is K 2 S.

5. The air cell according to claim 1 , which comprises a separator between the anode and the cathode.

6. The air cell according to claim 1 , wherein the average diameter of the anode active material is 1 μm or more and 100 μm or less.

7. The air cell according to claim 1 , wherein the average diameter of the anode active material is 10 μm or more and 20 μm or less.

8. An air cell comprising:
an electrolyte solution containing a potassium hydroxide solution having a concentration of 13.0 mol/L or more and 15.1 mol/L or less;
an anode containing iron as an anode active material; and
a cathode,
wherein an average diameter of the anode active material is 0.1 μm or more and 1 mm or less,
wherein the mass ratio of iron in the anode accounts for 10% by mass or more and 100% by mass or less of the mass of the anode, and
wherein the air cell is configured so that a charge-discharge reaction at the anode occurs according to the following formula (2), in which an arrow from the left-sided formula to the right-sided formula indicates a discharge reaction, and an arrow from the right-sided formula to the left-sided formula indicates a charge reaction:
Fe+2OH − ⇄Fe(OH) 2 +2 e − E 0 =−0.975 V.  Formula (2):

9. The air cell according to claim 8 , wherein the anode contains at least one selected from the group consisting of iron metal, iron alloy, and iron compounds, and the cathode comprises a cathode layer containing at least one electroconductive material.

10. The air cell according to claim 8 , wherein the potassium hydroxide solution contains an additive for facilitating a discharge reaction and having a concentration that does not inhibit an electrode reaction and can prevent the formation of a passive film on a surface of the anode.

11. The air cell according to claim 10 , wherein the additive is K 2 S.

12. The air cell according to claim 8 , which comprises a separator between the anode and the cathode.

13. An air cell comprising:
an electrolyte solution containing a potassium hydroxide solution having an iron solubility of 288.6 μg/mL or more and 393.5 μg/mL or less under a temperature condition of 23° C.;
an anode containing iron as an anode active material; and
a cathode,
wherein an average diameter of the anode active material is 0.1 μm or more and 1 mm or less of the mass of the anode,
wherein the mass ratio of iron in the anode accounts for 10% by mass or more and 100% by mass or less, and
wherein the air cell is configured so that a charge-discharge reaction at the anode occurs according to the following formula (2), in which an arrow from the left-sided formula to the right-sided formula indicates a discharge reaction, and an arrow from the right-sided formula to the left-sided formula indicates a charge reaction:
Fe+2OH − ⇄Fe(OH) 2 +2 e − E 0 =−0.975 V.  Formula (2):

14. The air cell according to claim 13 , wherein the anode contains at least one selected from the group consisting of iron metal, iron alloy, and iron compounds, and the cathode comprises a cathode layer containing at least one electroconductive material.

15. The air cell according to claim 13 , wherein the potassium hydroxide solution contains an additive for facilitating a discharge reaction and having a concentration that does not inhibit an electrode reaction and can prevent the formation of a passive film on a surface of the anode.

16. The air cell according to claim 15 , wherein the additive is K 2 S.

17. The air cell according to claim 13 , which comprises a separator between the anode and the cathode.

Assignees

• Toyota Motor Co Ltd

Inventors

• Suyama Hiroshi

Classifications

• H01M4/248

  Iron electrodes · CPC title

• H01M12/08 Primary

  composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type · CPC title

• H01M2300/0014

  Alkaline electrolytes · CPC title

• H01M12/06

  with one metallic and one gaseous electrode · CPC title

• H01M8/083

  Alkaline fuel cells · CPC title