Ultrafine Ru/RuOx Nanoparticles Uniformly Anchored on Carbon Nanotubes as Cathode Electrocatalyst for Lithium-Oxygen Batteries

The nonaqueous lithium-oxygen (Li-O-2) battery possesses extremely high theoretical energy density which is considered as one of the most fascinating next-generation energy storage systems. However, the sluggish oxygen redox reaction kinetics in the cathode of Li-O-2 battery severely limits its practical application. The incorporation of cathode electrocatalyst with high activity is an effective strategy to address this issue. Herein we report a novel electrocatalyst of ultrafine Ru/RuOx nanoparticles (NPs) decorated on the surface of carbon nanotubes (Ru/RuOx@CNTs) synthesized by a facile modified ethylene glycol reduction method. The as-prepared Ru/RuOx@CNTs electrocatalyst as cathode for Li-O-2 battery delivers high initial discharge specific capacity up to 3795 mAh g(-1), low overpotential and preferable cycle stability of 113 cycles with a limited specific capacity of 500 mAh g(-1) at 0.1 mA cm(-2) compared with CNTs cathode, which is originated from the well-dispersed Ru/RuOx nanoparticles on CNTs, leading to efficient electrocatalytic activities for oxygen reduction and evolution reactions.