Air cell
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.
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.