Pd-functionalized MnOx-GeOy nanomembranes as highly efficient cathode materials for Li-O-2 batteries

Li-O-2 batteries have the potential to be the candidate for the power source to drive electric vehicles and portable electronics. Recent studies have been focused on searching for stable electrode materials for rechargeable Li-O-2 batteries with high efficiency and long cycle life. Here Pd-functionalized MnOx-GeOy nanomembranes were fabricated as the cathode materials of Li-O-2 batteries. The incorporation of Pd nanoparticles on the nanomembranes matrix enables the fast transportation of both electrons and lithium ions as well as oxygen-containing species, thus efficiently lowering the charge voltage and greatly prolonging the cycle life of Li-O-2 batteries to 160 cycles without apparent degradation. More importantly, Li-O-2 batteries using such as-prepared Pd-functionalized MnOx-GeOy nanomembranes can be cycled repeatedly with extremely low charge voltage of only 3.14 V. The presence of small amounts of Pd nanoparticles contributes to the formation of toroid-like Li2O2 during the oxygen reduction reaction which is efficiently decomposed afterwards by the oxygen evolution reaction. The encouraging performance suggests that such nanomembrane-based materials are promising cathode architectures for the future Li-O-2 batteries. (C) 2015 Published by Elsevier Ltd.