Ru/ITO: A Carbon-Free Cathode for Nonaqueous Li–O<sub>2</sub> Battery

Ru nanoparticles deposited on a conductive support indium tin oxide (Ru/ITO) were applied as a carbon-free cathode in a nonaqueous Li–O<sub>2</sub> battery. The Li–O<sub>2</sub> battery with Ru/ITO showed much lower charging overpotentials and better cycling performance at 0.15 mA/cm<sup>2</sup> than those with Super P (SP) and SP loaded with Ru nanoparticles (Ru/SP) as the cathodes. The carbon-free cathode Ru/ITO can effectively reduce formation of Li<sub>2</sub>CO<sub>3</sub> or other Li carbonates in a discharging process, which cannot be completely decomposed upon charging, in comparison with the carbon based cathode. The improved performance of Ru/ITO can be attributed to the superior catalytic activity of Ru nanoparticles toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and the absence of carbon that has been reported to react with Li<sub>2</sub>O<sub>2</sub> to form Li<sub>2</sub>CO<sub>3</sub>.