CATHODE FOR AN AIR SECONDARY BATTERY HAVING A TRAP PORTION CONFIGURED TO CONFINE A METAL OXIDE REACTION PRODUCT

An air secondary battery (10) has a cathode (12) to which an oxygen-containing gas is supplied, an anode (14) containing an active metal material, and an electrolyte (16) interposed between the cathode (12) and the anode (14). In a discharge process, metal ions are generated from the active metal material, transferred through the electrolyte (16), and then reacted and bonded with oxygen molecules in the oxygen-containing gas on the cathode (12). Thus, the oxygen is reduced to generate a metal oxide. The cathode (12) has a trap portion for confining the metal oxide. For example, the cathode (12) has a first cathode layer (20) and a second cathode layer (22) having different average pore diameters. The first cathode layer (20) located adjacent to the electrolyte (16) and having a smaller average pore diameter acts as the trap portion.