Zinc-air secondary battery having inorganic solid electrolyte body

1. A zinc-air secondary battery comprising:

an air electrode functioning as a positive electrode;

an inorganic solid electrolyte body provided in direct contact with one side of the air electrode, the inorganic solid electrolyte body having hydroxide ion conductivity;

a metal negative electrode provided opposite to the air electrode with respect to the inorganic solid electrolyte body, the metal negative electrode comprising zinc or a zinc alloy; and

an electrolyte solution in which the metal negative electrode is immersed, the electrolyte solution being separated from the air electrode by the inorganic solid electrolyte body,

wherein the inorganic solid electrolyte body prevents carbon dioxide from the air from contacting the electrolyte solution.

2. The zinc-air secondary battery according to claim 1 , wherein the inorganic solid electrolyte body has a relative density of 90% or more.

3. The zinc-air secondary battery according to claim 1 , wherein the inorganic solid electrolyte body is densified by hydrothermal solidification method.

4. The zinc-air secondary battery according to claim 1 , wherein the inorganic solid electrolyte body is impermeable to carbon dioxide.

5. The zinc-air secondary battery according to claim 1 , wherein the inorganic solid electrolyte body is formed in a plate shape.

6. The zinc-air secondary battery according to claim 1 , wherein the metal negative electrode is composed of particles made of the zinc or the zinc alloy.

7. The zinc-air secondary battery according to claim 1 , wherein the Electrolyte solution is an alkaline metal hydroxide aqueous solution.

8. The zinc-air secondary battery according to claim 1 , wherein the air electrode is a porous carbon material supporting a catalyst having redox catalytic property.

9. The zinc-air secondary battery according to claim 1 , wherein the air electrode is a porous material composed of inorganic oxide fine particles having redox catalytic property, wherein the inorganic solid electrolyte body is formed in a film shape on the one side of the air electrode.

10. The zinc-air secondary battery according to claim 1 , wherein the inorganic solid electrolyte body is composed of a layered double hydroxide having a basic composition represented by the general formula:

M 2+ 1-x M 3+ x (OH) 2 A n− x/n .mH 2 O

wherein, M 2+ is a bivalent cation, M 3+ is a trivalent cation, and A n− is an n-valent anion, m in any integer denoting mol number of water, n is an integer of 1 or more, x is from 0.1 to 0.4.

11. The zinc-air secondary battery according to claim 10 , wherein M 2+ is Mg 2+ , M 3+ is Al 3+ , and A n− is CO 3 2− .

12. The zinc-air secondary battery according to claim 1 , further comprising a battery cell which has an air hole for allowing the air electrode to be in contact with an outside air and houses the air electrode, the inorganic solid electrolyte body, the metal negative electrode, and the electrolyte solution.

13. The zinc-air secondary battery according to claim 12 , further comprising a current collector having air permeability provided between the battery cell and the air electrode.

14. The zinc-air secondary battery according to claim 12 , wherein the battery cell comprises:

a positive electrode case having the air hole and housing at least the air electrode; and

a negative electrode case fitted to the positive electrode case and housing at Least the metal negative electrode and the electrolyte solution.

15. The zinc-air secondary battery according to claim 14 , wherein the positive electrode case and the negative electrode case are fitted to each other through at least one gasket.