Urchin-like α-MnO2 decorated with Au and Pd as a bi-functional catalyst for rechargeable lithium–oxygen batteries

Rechargeable lithium–oxygen batteries have attracted considerable attention due to their high energy density. The critical challenges that limit the practical use of this technology include sluggish kinetics of the electrochemical oxygen reactions on the cathode during discharging and charging. Here, urchin-like α-MnO2 materials decorated with Au and Pd nanoparticles are developed for use as a cathode catalyst for rechargeable Li–O2 batteries with hybrid electrolytes. Au and Pd particles as large as 3–8 nm are uniformly dispersed on the vertically aligned nanorods of α-MnO2. The Au/α-MnO2 and Pd/α-MnO2 catalysts show excellent bi-functional activity for both oxygen reduction and evolution. A rechargeable Li–O2 battery with a hybrid electrolyte is constructed using the nanostructured composite catalysts. Charging and discharging experiments of the batteries indicate that the metal-decorated, urchin-like α-MnO2 can be used as an efficient bi-functional catalyst for rechargeable hybrid Li–O2 batteries.

► Nanostructured composite catalysts for rechargeable lithium–oxygen batteries.
► Urchin-like α-MnO2 decorated with Au and Pd nanoparticles.
► The catalysts show high bi-functional activity for oxygen reduction and evolution.
► The catalysts reduce discharge–charge overpotentials of a hybrid Li–O2 battery.