Oxygen Reduction Reaction Using MnO2 Nanotubes/Nitrogen-Doped Exfoliated Graphene Hybrid Catalyst for Li-O2 Battery Applications

Nitrogen-doped thermally exfoliated graphene (NExG) synthesized by a simple one-step method combined with alpha-MnO2 nanotubes (NT) is employed as air cathode materials for lithium oxygen (Li-O-2) battery applications. alpha-MnO2 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 alpha-MnO2 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. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.086302jes] All rights reserved.