Battery using layered double hydroxide
Provided is a battery including a layered double hydroxide. The battery includes a positive electrode, a negative electrode, an electrolytic solution being an aqueous alkali metal hydroxide solution, and a layered double hydroxide having a fundamental composition represented by the formula: M 2+ 1−x M 3+ x (OH) 2 A n− x/n ·mH 2 O where M 2+ represents a divalent cation, M 3+ represents a trivalent cation, A n− represents an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is any real number, the layered double hydroxide being in contact with the electrolytic solution, wherein a metal compound containing a metal corresponding to M 2+ and/or M 3+ is dissolved in the electrolytic solution such that erosion of the layered double hydroxide by the electrolytic solution is suppressed. The present invention provides a highly reliable battery such that the degradation of a layered double hydroxide (LDH) contained in the battery can be significantly reduced.
1. A battery comprising:
a positive electrode;
a negative electrode;
an electrolytic solution being an aqueous alkali metal hydroxide solution; and
a layered double hydroxide separator exhibiting hydroxide ion conductivity, and having a fundamental composition represented by the formula: M 2+ 1−x M 3+ x (OH) 2 A n− x/n ·mH 2 O where M 2+ where M 2+ represents a divalent cation, M 3+ represents a trivalent cation, A n− represents an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is any real number, the layered double hydroxide separator being in contact with the electrolytic solution and separating the positive electrode from the negative electrode, wherein
a metal compound containing a metal corresponding to M 2+ and/or M 3+ is dissolved in the electrolytic solution such that erosion of the layered double hydroxide by the electrolytic solution is suppressed.
2. The battery according to claim 1 , wherein the aqueous alkali metal hydroxide solution is an aqueous potassium hydroxide solution.
3. The battery according to claim 1 , wherein the metal dissolved in the electrolytic solution is in the form of a metal ion, a hydroxide, and/or a hydroxy complex.
4. The battery according to claim 1 , wherein the metal compound is preliminarily dissolved in the electrolytic solution.
5. The battery according to claim 1 , wherein M 2+ comprises Mg 2+ , M 3+ comprises Al 3+ , and A n− comprises OH − and/or CO 3 2− in the formula.
6. The battery according to claim 1 , wherein the metal compound comprises a metal corresponding to M 3+ .
7. The battery according to claim 1 , wherein the metal compound comprises Al.
8. The battery according to claim 7 , wherein the electrolytic solution has an Al concentration of 0.1 mol/L to 20 mol/L.
9. The battery according to claim 7 , wherein the electrolytic solution has an Al concentration of 2.0 mol/L to 20 mol/L.
10. The battery according to claim 7 , wherein the electrolytic solution has an Al concentration of 0.001 mol/L to 20 mol/L.
11. The battery according to claim 1 , wherein the metal compound is aluminum hydroxide and/or γ-alumina.
12. The battery according to claim 1 , wherein the separator further comprises an additional material.
13. The battery according to claim 12 , wherein the additional material is a polymer.
14. The battery according to claim 1 , wherein the separator is densified to exhibit water impermeability and gas impermeability.
15. The battery according to claim 1 , further comprising a porous substrate disposed on either or both of the surfaces of the separator.
16. The battery according to claim 1 , wherein the negative electrode is coated with the layered double hydroxide.