Preparation Of Nanostructured Transition Metal Oxide And Its Application In Negative Electrode Of Lithium Ion Batteries

Nanostructure materials have attracted great research interests due to their unique properties compared with the bulk materials. Among them, transition metal oxides with nanostructures, such as Fe2O3, Co3O4, NiO and ZnO, have numerous advantages and great potential applied value in energy storage and conversion and it becomes of significant importance to control their synthesis and take the advantage of their superiority as energy storage and conversion system. As an energy storage and conversion system, rechargeable lithium ion batteries are of great importance and wide-ranging applications. The new generation rechargeable lithium ion batteries should not only meet the need for consumer electronics nowadays, but more importantly for the energy storage of future hybrid electrical vehicles (HEV). Thus, the breakthrough of new nanomaterials coupled with their structural innovation will dominate the technical development of energy storage and conversion in the future. The synthesis of Nanostructured transition metal oxides and their applications in energy storage and conversion will be discussed in this thesis.We will discuss the effect of different synthetic conditions including the concentration and times of spin-coating of zinc oxide seed, the growth substrate, the concentration and composition of growth solution and also the growth time to the nanostructure morphology of zinc oxide in chapter Ⅱ of the thesis.In the third chapter, we will study the fabrication of nickel oxide, which is also a transition metal oxide and further its performance as the anode for lithium ion battery. The nickel oxide nanosheet with a high theoretical lithium capacity will be directly grown on the current collector copper foil to reduce the charge transfer resistance resulting in effective lithium ion and charge transfer. Furthermore, nickel oxide nanomaterials directly grown on copper substrate is no need to add any conductive or binder accessories for coin cell assembly which simplifies the assembly procedures.In chapter IV of the thesis, we directly grew branched nanowire composite of two high theoretical capacity transition metal oxides CO3O4and Fe2O3on Ti foil and then do the cell assembly for studying the electrochemical performance of the composite. The branched nanocomposite as the anode of lithium ion battery exhibits high capacity and cycling stability due to the stable structure and advatages for charge carriers transfer.In the last chapter, we will synthesize zinc sulfide nanotubes, hollow cuprous sulfide nanocubes and nickel sulfide nanosheets from the corresponding transition metal oxides zinc oxide nanowires, cuprous oxide nanocubes and nickel oxide nanosheets through anion exchange reaction and kirkendall effect. Then, we study the the electrochemical performance of nickel sulfide as lithium ion battery anode. The main advantage of such a synthesis method is that the morphology of nanomaterials can commonly be kept and even we can get hollow materials with larger surface area.