Oxygen Reduction Reaction Using MnO₂Nanotubes/Nitrogen-Doped Exfoliated Graphene Hybrid Catalyst for Li-O₂Battery Applications

Nitrogen-doped thermally exfoliated graphene (NExG) synthesized by a simple one-step method combined with α-MnO 2 nanotubes (NT) is employed as air cathode materials for lithium oxygen (Li-O 2 ) battery applications. α-MnO 2 NT/NExG composite is shown to demonstrate excellent oxygen reduction reaction (ORR) activity in an aprotic non-aqueous electrolyte Li-O 2 cell resulting in 2.92 V at the current density of 100 mA g −1 , discharge current density of 7.2 A g −1 at 2.2 V, and the maximum power density of 15.8 W g −1 based on carbon mass. This excellent performance of the composite suggests that not only α-MnO 2 NT exhibits a remarkable catalytic activity for ORR, but also NExG with a large surface area and high electrical conductivity is capable of catalyzing ORR, demonstrating an outstanding hybrid effect in an aprotic non-aqueous electrolyte Li-O 2 cell.