The Research Of SnO₂ And CuO Nanowires Anode Materials For Lithium-ion Batteries

All work of this dissertation mainly focuses on the synthesis of SnO₂ nanowires and CuO nanowires and the application of them as anode materials in lithium ion batteries. The storing Li performance and mechanism of them are discussed in detail. The details are as follows. SnO₂ nanowires are synthesized through Carbon-Thermal Reduction method. Their morphology and structure are analyzed through XRD, SEM and TEM experiment, their electrochemical performance are analyzed through CV, discharge-charge test and cycling test. The experiment results shows that single crystal SnO₂ nanowires can reach the theoretical specific capacity of SnO₂. Furthermore, because of the advantage of wire-like structure that is not easily destroyed by volume expansion compared with SnO₂ nanoparticles, the electrode is not easily stripped from copper foil. Therefore, the cycling performance is better than that of SnO₂ nanoparticles. After cycling for 16 times, the specific capacity can remain 550mAh/g. The electrochemical performance of SnO₂ nanoparticles which have the prospect of industrial application and the influence of electric additives on their performance are also studied. The results show that the electric additives can effectively reduce the first irreversible capacity but have little influence of on the cycling performance. Moreover, CuO nanowires are synthesized in large scale through wet-chemical method. From electrochemical test, it is found that the cycling performance and high rate performance is excellent. The capacity can remain above 600mAh/g after 100 cycles and the specific capacity at 1.0C can reach 90% of that at 0.1C. It is thought that for the one hand polycrystalline CuO nanowires can provide much more Li-intercalation sites than bulk CuO, for the other hand the small diameter and the structure defect can improve the Li diffusion in the active material.