Advanced nanomaterials for efficient oxygen electrodes in metal–air batteries

Abstract Recently, metal–air batteries based energy devices have attracted enormous attention due to their high-energy density, easy fabrication, good safety, and environmental friendliness. The oxygen electrodes are the most important components that determine the batteries’ performances. Therefore it is highly important to optimize the oxygen catalytic activities of these loaded nanomaterials in electrodes to achieve high-performance for metal–air batteries. Up to now, diverse kinds of oxygen catalysts have been used for the metal–air batteries, such as noble metals and alloy nanoparticles, transition metal oxides and their composite catalysts, carbon nanotube, graphene, and many other newly emerged heteroatom-doped or hierarchically porous carbon and carbon nanofibers. These developed oxygen catalytic nanomaterials with large surface areas, highly active catalytic centers, and unique nanostructures have offered great opportunities to fabricate more advanced metal–air batteries for different application areas, such as automobile, wearable electronics, and biomedical devices. The aim of this book chapter is to provide an overall introduction of the nanostructures and catalytic performances of these nanomaterials-based oxygen electrodes, and also provide the insights to the researchers for the fabrications of next-generation air cathode in metal–air batteries.