NOVELTY - The method involves creating an oxygen gas-shield on electrolyte side of air electrode in less than 2 seconds at start of charging session. The cell is charged without anodic polarization of air electrode with help of electric conductive material placed between electrolyte side of air-electrode and bulk of electrolyte, and oxygen gas-shield obstructing passage of ions of electrolyte between electrolyte side of air-electrode and bulk of electrolyte. The oxygen gas-shield is removed at start of discharging session.    USE - Method for operating secondary metal-air electrochemical cell and zinc-air cell with metal anode and air cathode for use in electric vehicles and stationary applications.    ADVANTAGE - Since the evolved oxygen is used as a gas-shield insulating the active layer of the air-electrode from the bulk of electrolyte, the current flow in the active layer is effectively prevented. Thus, the electrochemical activity is blocked and degeneration of the active-layer is effectively prevented. The alveoli matrix in front of the active-layer can enhance the insulation effect of the gas-shield during anodic polarization and create a favorable environment for the active-layer during cathodic polarization. Since the anodic and cathodic processes held on the air-electrode can be separated, the air-electrode and the catalysts that are contained during the charging sessions of the cell are effectively protected from degeneration. Thus, the longer service life of the air-electrode is achieved. Since the shield-electrode serves also as anodic current-collector during recharging of the electrochemical cell, the design of the cell is simplified and the cost of the cell is minimized. Since the oxygen gas-shield on electrolyte side of air electrode is provided, the oxygen does not evolve inside the active layer. Thus, the service life of the air-electrode can be prolonged.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a composite bi-functional air-electrode;    (2) a secondary electrochemical metal-air battery; and    (3) a method for manufacturing composite air-electrode.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the composite bi-functional air-electrode.    Gas diffusion layer (21)    Active layer (22)    Conductive layer (24)    Evolved oxygen (40)    Screen (50)