Abstract: The present invention is relates in a metal-Air battery, which called coin cell generally, having a cathode in the container wherein anode top filled with electrolyte is placed with gasket in between. In this battery structure, air chamber is provided between the cathode and cathode container, and cathode is being abutted by embossed polarity mark to maximize a gas diffusion passage from a port to peripheries of cathode providing clearance of air chamber between peripheries of cathode container and cathode. This air passage provides sufficient and rapid airflow makes a cell operate at maximum performance and extend cell lifetime.