ИСТИНА

An air cathode for a metal-air battery (e.g., a Li-air battery) including reduced graphite oxide (RGO) having a ratio of carbon to oxygen of from about 5 to about 10, is provided. The RGO is prepared by chemical reduction of graphite oxide, e.g., using ascorbic acid as a reducing agent. Li-air battery including such cathode including the RGO is also provided. In some embodiments, the Li-air battery includes an anode including lithium metal, and a solid-state electrolyte disposed between the anode and the cathode.