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

Abstract 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/RuO x nanoparticles (NPs) decorated on the surface of carbon nanotubes (Ru/RuO x @CNTs) synthesized by a facile modified ethylene glycol reduction method. The as‐prepared Ru/RuO x @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/RuO x nanoparticles on CNTs, leading to efficient electrocatalytic activities for oxygen reduction and evolution reactions.