Fabrication Of Transitional Oxide CuO And Mn₂O₃and Their Applications In Lithium-ion Battery

In this thesis, transition metal oxides of CuO microspheres and Mn2O3porous microspheres were prepared and studied as cathode materials in lithium ion batteries. Urchin-like CuO microspheres were firstly synthesized by hydrothermal reaction in low temperature reaction kettle. We also studied the effects such as nanometer size, different morphologies and reaction temperature on the electrochemical performances, In addition, porous MnCO3microspheres as precursors were prepared in the autoclave and synthesized porous Mn2O3microspheres by morphology-controlled decomposition of MnCO3. We also discussed their possible formation mechanism and studied their performance as lithium ion battery, respectively.The main contents of this paper are summarized as follows:1. In this thesis, copper oxide hierarchical microspheres directly grown on copper foil are achieved through a hydrothermal reaction. By changing the reaction temperature from100℃to150℃, the CuO nanostructures respectively present as urchin-like architectures assembled by nanorods and hollow microspheres composed of nanoparticles, which are confirmed by their scanning electron microscopy images. Then the resultant CuO@Cu organizers are directly served in Li-ion batteries without any binders and conductive additives. Hence, the copper foil performs as both the supporter of CuO formation and the current collector of the electrodes. Correspondingly, urchin-like CuO spheres@Cu deliver the combination of good rate and excellent cycle performance, which receive capacity of250mAh·g-1at2A·g-1and maintain a high reversible capacity of600mAh·g-1even after400cycles at100mA·g-1.2. In this thesis, a cheap, scalable and highly reproducible process was introduced for the preparation of porous MH2O3microspheres. Firstly, uniform and micron-sized porous MnC03spheres were synthesized by using widely available MnSO4·H2O and NH4HCO3as raw materials, and ethanol as the solvent. The reaction temperature was maintained at200℃for8h. Secondly, after thermal decomposition of porous MnCO3spheres at600℃for2h in air, porous Mn2O3microspheres were obtained. Subsequently found that porous Mn2O3microspheres show a good rate capability and highly specific capacity of800mAh·g-1at a current density of150mA@g-1after50cycles.