Synthesis and electrocatalytic properties of various metals supported on carbon for lithium–air battery

• Various metals supported on carbon were synthesized by an impregnation method.
• Alloying two different metals significantly decreased the overpotential for charging.
• Pt–Ru/C catalyst exhibited the lowest charging voltage, and high cyclability for over 40 cycles with the highest round-trip efficiency and lowest cell impedance.

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.

Overpotentials for both charge and discharge can be controlled by catalyst composition.Figure optionsDownload high-quality image (166 K)Download as PowerPoint slide