Preparation And Characterization Of High-performance Cathode Catalysts For Non-aqueous Lithium-oxygen Battery

The widespread use of portable devices such as mobile electronic devices,electrical vehicles and smart grids requires more better-performanced batteries with higher specific energy.Lithium-oxygen batteries with nearly 10 times the of lithium-ion batteries have become a research hotspot.However,the commercialization process is delayed by the poor rate performance,cycle efficiency and stability.In order to improve the performance of lithium-oxygen batteries,the following studies were carried out by desiging the structure cathode catalysts:1.After two steps of hydrothermal reaction,RuO₂/CoMnOx@CNT was prepared by loading RuO₂ nanoparticles on the nanoflower-structured CoMnOx@CNT's surface.XRD,ICP-AES,BET,SEM,TEM and XPS were taken to characterize the structure of the catalyst.And the lithium-oxygen battery was assembled with RuO₂/CoMnOx@CNT as catalyst has relatively stable cycle performance at low current,and sustained 123 cycles with a capacity limit of 500 mAh·g^-1 at a current density of 100 mA·g^-1.The results of ex-situ SEM,XRD and in-situ EIS confirmed that the dispersion of discharge products is attributed to the the nanollower structure and a large number of contact sites.2.Sol-gel method and high temperature sintering were used to produce the nitrogen doped-carpenterworm-like NiNC catalyst.And RuO₂/NiNC was prepared by loading RuO₂ nanoparticles on NiNC's surface.XRD,ICP-AES,SEM,BET,TEM,XPS and Raman were taken to characterize the structure of the catalyst.The lithium-oxygen battery assembled with RuO₂/NiNC catalyst has relatively stable cycle-performance at low current,and sustained 261 cycles with a capacity limit of 500 mAh·g^-1 at a current density of 200 mA·g^-1.The results of ex-situ SEM,XRD and in-situ EIS can confirm that what is generated on the surface of the cathode is ellipsoidal and small sized Li₂O₂ during discharge,and Li₂O₂ gradually decompose under the action of composite electrocatalysts during charging,which proves that the electrocatalysts have high catalytic activity and can effectively improve the cycle performance of batteries.As a consequence,some innovations were made in terms of the design of electrocatalysts of lithium-oxygen batteries.RuO₂ nanoparticles supported both on nanoflower-structured CoMnOx@CNT and NiNC carriers were designed and prepared.which significantly improved the cycling stability of LOBs.The ex-situ and in-situ analytical methods were used to characterize the electrocatalysts,which confirms that the improvement of cycle performance of LOBs is due to the highly dispersed and decomposed of the discharge products on the three-dimensional electrocatalysts.