Research On The Controllable Preparation, Microstructure And Lithium Storage Performance Of Metal Oxide Micro/nano Structure

With the rapid development of electronic devices and electric vehicles,lithium ion batteries?LIBs?,as one of green energy storage devices,have attracted great attention.Metal oxides have been widely investigated as negative electrode materials for LIBs due to their high specific capacity,environmental friendliness,and safety.However,the volume expansion and poor cycling performance seriously limit the applications of LIBs during the charge-discharge process.Thus,the construction of high performance metal oxide anode materials has an important influence on LIBs.In this thesis,the preparation,microstructure and electrochemical properties of iron oxides and tin oxides micro-nano structures are systematically investigated.In Chapter 1,the development,working principle and composition of LIBs are reviewed.In addition,the electrochemical properties of metal oxides as anode materials for LIBs are introduced in details.In Chapter 2,the reagents and experimental equipment are introduced.Besides,the characterization methods for the morphology,phase and electrochemical properties of the materials are described in details.In Chapter 3,Fe₂O₃ hexahedrons with different sizes were synthesized through hydrothermal process and the effect of binder and size on electrochemical performance of Fe₂O₃ was studied.Under the same experimental conditions,the Fe₂O₃ nano-hexahedrons with sodium alginate binder exhibits greatly enhanced lithium storage performance.In Chapter 4,SnO₂ nanorods,Fe₂O₃ sub-micro-hexahedrons and Fe₂O₃-SnO₂micro-nano structures were prepared through hydrothermal process and the electrochemical performance of three different anode materials was investigated.The Fe₂O₃-SnO₂ micro-nano structures show high reversible capacity,long cycling life and good stability due to the synergistic effect between SnO₂ and Fe₂O₃.