Structure Design And Doping Modification Of TiO₂as Anode Material For Lithium Ion Batteries

Among the existing various types of batteries, such as zinc/alkaline manganese, plumbic acid, nickelchromium/hydrogen, solar energy storage battery, by contrast, because of the high voltage and energydensity, repeat recharge, almost no self-discharge and memory effect, no pollution to the environment,lithium-ion batteries have been widely used in various types of electronic products. Lithium-ion batterypower supply makes the quality of the products lighter, which is closely related to all walks of people’s life,vary from the gas burner, water heater to plane, submarine and torpedo is littered with the footprint oflithium-ion batteries.To great extent, battery capacity is decided by the performance of the electrode material itself, theimpact factors on anode materials is greater than cathode material. At present, carbon-based materials is themost popular industrialization of lithium battery anode materials, but the production of lithium dendrite isthe unavoidable problem, once the diaphragm punctured consequences, the situation is serious and evencause explosion and fire. In addition, during the first cycle the SEI film makes Li+have larger irreversibleloss, eventually lead to the low coulomb efficiency.Existing commercial anode materials have reached their’s limit, the performance of the carbon anodematerials and the existing shortcomings and inadequacies exist, Based on the disadvantages of carbonmaterials, looking for new alternative materials, is the urgent problem. All kinds of transition metal oxidesin recent years were widely used for lithium battery anode material. Among them, TiO2due to itsenvironmental protection and easy preparation attract more attention. The intercalated-li potential is around1.7V, effectively avoid the lithium dendrite and the formation of SEI film. In recent years, with the rapiddevelopment of nano structure technology, nano materials are widely used as electrode materials. Aslithium storage material, nano materials, the larger specific surface area and shorter diffusion distance,which is very beneficial to Li+embedded and effectively restrain the volume expansion in the process ofcharging and discharging, so as to prolong the cycle life of the battery. Compared to the conventional bodyof material, nano TiO2has big volume percent of interface and high diffusion coefficient, more conduciveto Li+embedded. The method of preparation of nano TiO2is simple and controllable, the application prospect is very good.Due to stable chemical properties, no excitant and sensitization effect, comprehensive advantages ofuv protection, TiO2have been widely used in light catalysis, cosmetic, sewage treatment, air purificationand other fields. but the electrical conductivity of TiO2is poor which limits the electrochemicalperformance. Based on the shortcomings of poor conductivity TiO2, we carry on the doping modification.Because of the close ionic radius of Sn4+(0.069nm), Nb5+(0.0605nm) to Ti4+(0.0605nm), which is easyto implement doping, and to explore the single-phase&three-phase state doping and different valence, thispaper discusses the performance of TiO2nanotube electrodes embedded lithium and stannic chloride andniobium oxide as the precursor of tin (Sn4+) doped and niobium (Nb5+) doped inquiry:1. Sn-doped anatase TiO2nanotubes were synthesized by sol-gel and hydrothermal method. The resultsshow that, nanotubes possess excellent stability, the anatase phase maintained unchanged and theoptimal anneal temperature is400oC. The electrochemical performances of pure and Sn-doped TiO2nanotubes were studied by comparison. It was found that the electrochemical performances ofSn-doped TiO2nanotubes improved and5at.%Sn-doped TiO2nanotube exhibits the bestelectrochemical performances.2. Nb-doped TiO2nanoflowers were synthesized by sol-gel and hydrothermal method. The results showthat the anatase phase maintained unchanged. The electrochemical performances of lithium insertioninto un-doped and Sn-doped TiO2nanotubes were studied by comparison. It was found that theelectrochemical performances of Nb-doped TiO2also improved, but the extent of improved ofSn-doped TiO2nanotubes was better than that of Nb-doped TiO2nanotubes.