A rechargeable Li-air battery was studied using various carbon-supported metal-alloy catalysts as an air electrode. Carbon-supported Pt-Pd, Pd-Ir and Pt-Ru catalysts were prepared by an impregnation-reduction method. For comparison, carbon-supported Pt (Pt/C), Pd (Pd/C), Ir (Ir/C), and Ru (Ru/C) catalysts were also prepared by the same method; physicochemical characterizations were carried out using X-ray diffraction and transmission electron microscopy. The prepared catalysts were subsequently cast onto both nickel foam and GDL to be evaluated as air cathodes in Li-air batteries. Charge-discharge tests were carried out using a Swagelok-type cell, with both 1 M LiPF6 in PC:EC:DEC (3:2:5) and 1 M LiPF6 in TEGDME used as an electrolyte. Cycling performance and impedance tests were also conducted. The initial charge-discharge tests showed that alloying two different metals is an effective technique for decreasing the charging voltage. Among all electrodes tested, the Pt-Ru/C electrode was shown to possess a stable cycle performance and the highest round-trip efficiency. (C) 2013 Published by Elsevier B.V.