Sea Urchin Shaped α-MnO₂/RuO₂Mixed Oxides Nanostructure as Promising Electrocatalyst for Lithium–Oxygen Battery

α–MnO 2 /RuO 2 mixed oxides in the form of sea urchin shaped nanostructures were synthesized in the weight ratio of 82:18 via a simple hydrothermal method. The synthesized α–MnO 2 /RuO 2 urchin nanostructure was constructed with several straight and radially grown nanorods, and composed of homogeneously distributed MnO 2 and RuO 2 nanoparticles. When the α–MnO 2 /RuO 2 nanostructure was applied for air cathode catalyst, it displayed superior cyclic performances of lithium air battery with stable specific capacity, decreased overpotential and good retention rate. The α–MnO 2 /RuO 2 urchin nanostructure exhibited excellent bifunctional electrocatalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Linear sweep voltammetry study confirmed that the α–MnO 2 /RuO 2 nanostructure possesses catalytic performance comparable to that of commercial Pt/C for the ORR, while it exhibits lower onset potential and higher limiting current than those of commercial Pt/C for the OER.