Metal-air batteries use metals with negative electrode potential such as magnesium, aluminum, zinc, mercury, iron, etc. as the negative electrode, and oxygen or pure oxygen in the air as the positive active material. The electrolyte solution of metal-air batteries generally uses an alkaline electrolyte aqueous solution. If lithium, sodium, calcium, etc. with a more negative electrode potential are used as negative electrodes, because they can react with water, only non-aqueous organic electrolytes such as phenol-resistant solid electrolytes can be used or inorganic electrolyteor.