V₂O₅-NiO composite nanowires: A novel and highly efficient carbon-free electrode for non-aqueous Li-air batteries operated in ambient air

Due to the ultra-high theoretical energy density, the non-aqueous Li-air battery has attracted a lot of attention over the past decade. However, the decomposition of electrode during discharge and charge processes has limited the further development of this technology. Here, we fabricate a novel carbon- and binder-free electrode, V₂O₅-NiO composite nanowires, for non-aqueous Li-air batteries. With this novel electrode, the battery displays an over-potential of as low as 0.56 V and is operated stably for 250 cycles (1000 h) with an energy efficiency of as high as 70% at the current of 250 mA g⁻¹ in pure oxygen. When the current density further increases to 500 and 750 mA g⁻¹, the electrode enables the battery to operate stably for 220 and 200 cycles, indicating the excellent cycling stability and rate capability of the V₂O₅-NiO composite nanowire in pure oxygen. Moreover, in ambient air, the battery with this electrode can be steadily cycled for 200 times (800 h) at the current density of 250 mA g⁻¹ with an energy efficiency of as high as ∼68%. Therefore, the V₂O₅-NiO composite nanowire offers great promise to replace the carbon electrode and further realize the operation of non-aqueous Li-air battery in ambient air.