Abstract: A separator which is permeable to hydroxide ion, and which contains at least one Dendrite Stopping Substance such as Ni(OH)2, or its precursor.

Abstract: A separator which is permeable to hydroxide ion contains at least one Dendrite Stopping Substance such as Ni(OH)2, or its precursor.

Abstract: Method of operating a secondary Metal-Air electrochemical cell with a metal anode and an air cathode including the steps of (a) at start of a charging session, creating in less than 2 seconds an oxygen gas-shield on the electrolyte side of the air-electrode obstructing ion passage between the bulk of the electrolyte and the air-electrode; (b) charging the cell without anodic polarization of the air-electrode with the help of (i) electric conductive material placed between the electrolyte side of air-electrode and the bulk of electrolyte, and, (ii) the oxygen gas-shield obstructing passage of ions of the electrolyte between the electrolyte side of air-electrode and the bulk of electrolyte; (c) removing the oxygen gas-shield at start of a discharging session.