| abstract |
[Problem] To provide a metal-oxygen battery with which it is possible to reduce overvoltage, and which uses an oxygen storage material including a hexagonal crystalline composite metal oxide represented as general formula A x B ｙ O z as a positive electrode material. Also provided is a method for producing an oxygen storage material used in the metal-oxygen battery. [Solution] A metal-oxygen battery (1) comprising a positive electrode (2) having oxygen as an active substance, a negative electrode (3) having lithium metal as an active substance, and an electrolyte layer (4) sandwiched between the positive electrode (2) and the negative electrode (3), wherein the positive electrode (2) is equipped with an oxygen storage material containing mixed crystals of a hexagonal crystalline composite metal oxide represented by general formula A x B y O z (in the formula, A is a metal selected from the group consisting of Y, Sc, La, Sr, Ba, Zr, Au, Ag, Pt and Pd, B is a metal selected from the group consisting of Mn, Ti, Ru, Zr, Ni and Cr, x = 1, 1 ≦y≦2, and 1≦z≦7. However, A and B must not both be Zr.) and one or more non-hexagonal crystalline composite metal oxides represented by said general formula A x B y O z . |