| Lithium-ion battery is a best choice for the portable energy storage devices and energy vehicles to date since its light, high power density and stable performance. Especially, the titanium dioxide(TiO2) and lithium titanate(Li4Ti5O12), as a lithium battery anode material, have a good rate performance; while ferroferric oxide(Fe3O4) and silicon-based materials possess high capacity. Due to the special properties of these materials, they had received extensive attentions from many researchers to date. This paper focused on synthesizing different composition and structure of titanium-based anode materials, or preparing various kinds of modified Fe3O4 and silicon-based anode materials. The electrochemical performances of these as-prepared materials applied in lithium-ion batteries were studied. Furthermore, a series of full lithium-ion batteries were assembled successfully using these as-prepared anode materials and the spinel cathode, in which, the assembly conditions of full battery, electrolyte system and additives and lithiation time had been explorative studied. This thesis mainly included the following contents:(1) Using urea as assitance reactant, the carbon and nitrogen co-doped mesoporous TiO2 nanospheres were obtained. With a high electrical conductivity and porous structure, the as-prepared C&N-doped TiO2 nanospheres have a superior performance in lithium-ion battery application;(2) Porous TiO2 nanoribbons and TiO2 nanoribbon/carbon dot composites with excellent performances in lithium-ion batteries were prepared via a simple and efficient hydrothermal method.(3) Porous and uniform structures of rutile TiO2 microspheres were prepared through a simple acid-assisted hydrothermal method. Furthermore, Li4Ti5O12 microspheres were synthesized by using the as-prepared titanium dioxide as precursor. The lithium storage properties of these materials were well evaluated.(4) Using urea as carbon and nitrogen source, the carbon and nitrogen modified Li4Ti5O12 nanoparticles with hierarchical structure were prepared, this anode material has excellent lithium storage properties, the effects of the introduction amount of carbon and nitrogen on the performance of Li4Ti5O12 were studied.(5) A new kind of metal oxide nanoparticle coated with a uniform layer of N-doped carbon(e.g., Fe3O4@CNy, CoOx@CNy) was prepared readily in one-step. The nanoparticles show a high and stable lithium storage ability for lithium-ion battery application. Moreover, using urea as nitrogen source to nitride the surface of Fe3O4, its lithium-ion storage ability could also be improved efficiently. In addition, a series of V2O5 coated LiMn2O4(LiMn2O4@V2O5) samples were prepared and its structure and morphology were well characterized. The LiMn2O4@V2O5 material delivers an excellent cycling ability and rate capability in lithium battery.(6) A new and simple strategy was developed to effectively disperse TiO2 nanocrystals into porous carbon(PC), and a series of hierarchical PC-TiO2 composites with different architectures were synthesized. By varying the amount of TiO2, the lithium-ion storage capacity of PC-TiO2 could be controllably tuned. Additionally, these composites also exhibited very stable cycling performance and rate capability. Based on these results, a new full cell of LiNi0.5Mn1.5O4/PC-TiO2 was successfully assembled and investigated. This full cell not only delivered a high energy density of 413 Wh kg-1(vs. cathode material) but also showed a good rate capability and an energy retention of 90.5% over 100 cycles. Using TiO2-PC composite as anode material in sodium battery, the porous carbon has a positive effect on the electrochemical performance of TiO2 in sodium-ion battery application. The composite of TiO2-PC delivered an excellent rate capability property.(7) A simple surfactant-assisted reflux method was used in this study for the synthesis of cocklebur-shaped Fe2O3 nanoparticles(NPs). With this strategy, a series of nano-structured Fe2O3 NPs with a size distribution ranging from 20 to 120 nm and a tunable surface area were readily controlled by varying re?ux temperature and the type of surfactant. A new composite of Fe3O4@CFx was prepared by coating the primary Fe2O3 NPs with a layer of F-doped carbon(CFx) with a one-step carbonization process. The Fe3O4@CFx composite was utilized as the anode in a lithium ion battery and exhibited a high reversible capacity. In addition, a new LiNi0.5Mn1.5O4/Fe3O4@CFx battery with a high energy density of 371 Wh kg-1(vs. cathode material) was successfully assembled.(8) With silica nanoparticles(SiOx) grinding with carbon nanotubes, the composite of SiOx@CNT was prepared, and its capacity could reach to 900 mA h g-1. Based on this anode material of SiOx@CNT, two new full cells with high capacity were successfully assembled versus the cathode of LiNi0.5Mn1.5O4 or LiMn2O4. |
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