Study On Preparation And Application Of Nitride And Oxide In High Specific Surface Area

Because of their energy density comparable to that of fossil fuels,lithium-oxygen batteries have attracted much attention and are thought to be the most likely to become the next generation energy system of electric vehicle whose mileage close to combustion engine vehicles.but there are still many problems hindering the practicality of lithium-oxygen batteries.The most prominent problem is the low efficiency of the cathode catalyst,which leads to a large overpotential during the charge-discharge process.Therefore,it is more and more important to develop efficient and economical catalysts.To solve the above problems,the preparation of transition metal nitrides and oxide nanoparticles was studied from the design of microstructure,and the properties of hollow titanium nitride microspheres in lithium-air batteries were investigated.The research contents were as follows:1)The monodisperse polystyrene microspheres（PS）were synthesized by soap-free emulsion polymerization,the surface was hydrophilic treated by concentrated sulfuric acid,and then the core-shell microspheres of PS@TiO₂ were prepared by sol-gel method.Finally,the PS@TiO₂ core-shell microspheres were calcined in ammonia atmosphere,900℃for 3 hours to obtain hollow titanium nitride microspheres.2)Firstly,the ZIF-7 nanoparticles were prepared,then used this as a template,using hydrated copper nitrate as copper source and hydrated cobalt nitrate as cobalt source,the precursor of copper cobaltate was prepared,and then calcined in air to prepare copper cobaltate nanoparticles.3)Firstly,carbon spheres were prepared by hydrothermal method using sucrose as raw material,and then the hollow cobalt tetroxide microspheres were prepared by calcination in air with cobalt acetate as the template.4)Hollow titanium nitride microspheres were used as cathode catalysts for lithium-oxygen batteries.After static activation,electrochemical tests were carried out to analyze the data of battery capacity,CV curve,charge-discharge table and so on.The results showed that the hollow titanium nitride had higher capacity,better rate capability and more stable cycling performance than the bulk titanium nitride and Ketchin Black.