Cathode for metal air battery, preparation therefor and use thereof

Disclosed is an air cathode for a metal air battery, comprising a support layer and a catalyst layer which are stacked, wherein the outside surface of the catalyst layer is provrided with a high-molecular polymer layer; the high-molecular polymer layer has a high-molecular polymer with C-H as a main chain, the C-H main chain is bonded with a benzene ring, and the benzene ring is bonded with an amine functional group; or the high-molecular polymer has a main chain only having phenyl groups, and the phenyl group is bonded with an amine functional group; and the amine functional group comprises a first amine functional group and a second amine functional group. By coating a layer of high-molecular polymer on the surface of the catalyst layer of the cathode of the metal air battery, same is made into an air cathode and a metal air battery is prepared; and by controlling the loading capacity of the polymer on the surface of the catalyst layer of the air cathode, the carbonatization problem long-standing in the metal air battery is relieved while maintaining the discharge performance of the battery, and the lifetime of the battery is prolonged from hundreds of hours to thousands of hours, thus promoting the practical progress of the metal air batteries.