Preparation And Performance Study Of Transition Metal-based Cathode Catalyst For Lithium-Oxygen Battery

Compared with traditional fuel vehicles,the biggest advantage of new energy vehicles is environmentally friendly which is in line with the concept of sustainable development.It is required to develop novel high specific energy battery systems for the development of electrical vehicles.At present,the lithium ion battery used in electric vehicles on the market has a range of about 300 to 500 kilometers,which is far from meeting people's requirements for long-distance transportation.Among the possible alternatives to lithium-ion batteries,the aprotic lithium-oxygen?Li-O₂?battery is considered as one of the most fascinating next-generation energy storage systems because of its extremely high theoretical energy density.It is expected to be widely used as vehicle power batteries in the future.However,the sluggish oxygen redox reaction kinetics in the cathode of Li-O₂ battery which causes the low discharge capacity,high overpotential and short cycle life severely limits its practical application.The incorporation of cathode catalyst with high activity is an effective strategy to address this issue.The main contents are listed as follows:?1?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-O₂ battery delivers high initial discharge specific capacity up to 3795 mAh/g,low overpotential and preferable cycle stability of 113cycles with a limited specific capacity of 500 mAh/g at 0.1 mA/cm² 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.?2?A facile twice-hydrothermal method is developed for synthesizing NiCo₂S₄porouscore-shellspheres.As-preparedmaterialsascathodecatalystfor Lithium-Oxygen batteries deliver high initial discharge specific capacity up to 2683mAh/g and preferable cycle stability of 80 cycles with a limited specific capacity of500 mAh/g at 0.1 mA/cm² compared with Super P cathode,which is originated from efficient electrocatalytic activities of the NiCo₂S₄ for oxygen reduction and evolution reactions.Moreover,the morphology of porous core-shell spheres could accommodate more discharge products and avoid the performance degradation because of volumetric variation.