Study On Electrochemical Properties Of Transition Metal Oxide Thin Film Anode Materials

In the past few decades,the electronic devices have a great development.Especially in recent years,the development of portable electronic devices?laptops,mobile phones,cameras?and new energy vehicles enhance the demands of new energy storage system.Because the commercial graphite anode material cannot meet the needs of electronic devices,it is urgent to exploit new anode materials for the high performance lithium ion batteries.Transition metal oxides are considered to be the most possible anode material for the next generation of commercial lithium ion batteries,which have high specific capacity,small volume changes during charge-discharge process and rich resources.Also,transition metal oxides have disadvantages of capacity decaying while cycling and poor conductivity.Many chemical methods have been tried to improve the decay of capacity.However the traditional chemical composition with different morphology cannot achieve the high energy density,because the densities of prepared materials are too low to achieve the high energy density.Therefore,this thesis focuses on preparing good chemical performance transition metal oxide anode materials with high energy density for lithium ion batteries:Firstly,we prepared the nanosized Fe₂O₃ film to enhance the cyclic performance.Pulsed Laser Deposition was introduced to prepared nanoclusters Fe₂O₃ film.Comparing the electrochemical performance of Fe₂O₃ film prepared at room temperature and 400 ?,respectively.It turns out that the Fe₂O₃ film with nanosized crystal prepared at room temperature had batter cyclic performance than film prepared at 400 ?.So nanosized Fe₂O₃ film prepared by PLD not only solves the problem caused by chemical method,but also possesses superior electrochemical performance.Secondly,we composited the CoO with nanosized Co metal to improve the performance of large charge-discharge current density.We obtained CoO-Co composite by changing the pressure of oxygen.Because of the good electronic conductivity and catalysis of Co,the charge-discharge performance under high current has a great improvement.