NOVELTY - Electric energy storage, comprises: providing a metal-air battery comprising a metal-containing negative electrode (2), a porous positive air electrode (3), an oxygen ion conductor electrolyte (1), and optionally, a ceramic layer located between the porous positive air electrode and the oxygen ion conductor electrolyte; and connecting the metal-air battery to an electric energy source so that metal air battery is electrically recharged, where the method excludes the connection of the metal-air battery to a chemical energy source, and the metal-air battery works at 300-1000 degrees C.    USE - The method is useful for electric energy storage. The metal-air battery and a module system are useful as a energy storage device or a power source which are useful for utility applications as well as for automotive and power electronic applications (all claimed).    ADVANTAGE - The method utilizes a metal-air battery: which is low cost, better safety and has higher energy density; has a longer cycle life than conventional lithium-air cells since no lithium dendrite is formed which also avoids short circuits and thermal runaway, thus making the metal-air battery system of the invention safer than conventional lithium-based batteries; and that can be electrically charged and discharged for more than 1000 cycles without any type of fuel or chemical source, thus producing a Coulombic efficiency of approximately 1.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) the metal-air battery comprising the metal-containing negative electrode, the porous positive air electrode, the oxygen ion conductor electrolyte, and optionally, the ceramic layer, where the electrolyte is in contact with the metal-containing negative electrode at one side and with the porous positive air electrode on the other side, or when the ceramic layer is present the solid oxide electrolyte is in contact with the metal-containing negative electrode at one side and with the ceramic layer on the other side, the metal-containing electrode is enclosed in a cover case (4) to isolate the electrode form any gas or any chemical source, and the metal-air battery is only rechargeable by electricity;    (2) a module system comprising at least two stacked metal-air batteries; and    (3) manufacturing the metal-air battery system comprising: providing the oxygen ion conductor electrolyte; placing the porous positive air electrode and the metal-containing negative electrode on each side of the solid oxide electrolyte; and enclosing the metal negative electrode in the tight cover case.    DESCRIPTION OF DRAWING(S) - The figure illustrates a tubular design of a high-temperature metal-air battery.    Electrolyte (1)    Anode (2)    Cathode (3)    Cover case (4)    Current collector (5)