| Recently, considerable efforts have been devoted to develop high performance lithium ion batteries(LIBs) for applications ranging from rapidly expanding portable electronics markets, electric vehicles, along with stationary power storage devices. At the current state of LIBs technology, it is well accepted that commercial graphite anodes will not be capable of meeting rapidly increasing energy demands in the near feature. As highly promising candidates for next generation LIBs devices, 3d transition oxides anodes can provide much better electrochemical per formance. Among these transition metal oxides, Cu O provides attractive properties, such as a high specific energy storage capacity, abundant global reserves, economical affordability, environmental compatibility and ease of production. However, Cu O electrodes stuffer from low electrical conductivity, which is unfavorable for charge transfer during LIBs operation, thereby resulting in poor electrochemical performance. Additionally, Cu O electrodes suffer from rapid capacity decay due to the large volume variations and significant structural changes during charge and discharge processes.To overcome these drawbacks, significant research efforts have been devoted to improving the performance of Cu O electrodes. In this thesis, novel structure design and morphology control techniques, hybridization of composite Cu O/r GO or MCNTs have been involved in improvement of Cu O electrodes. On the other hand, novel structured design and morphology control techniques will also help improve the other anode eletrodes.During the fabricating process using the solid phase method, the electrochemical performance of Cu O eletrodes by calcination and grinding method were compared. And the temperature fator and reagent ratio were founded to be crucial to solid phase method. The solid phase method for preparing Cu O powders is scalable.Leaf-like Cu O, oatmeal-like Cu O, Cu O microspheres and bean-like Cu O were fabricated by using the solution-precipitation method, which involved complexing agent and precipitant agent.The element of the Cu O electrode of the first cycle of cyclic voltammetry at different points was studied by XPS, and the relationship between morphology of particles and electrochemical performance was also explored. 3D spherical particles with porous structure were show stable cycling capacity and excellent rate performance.Different copper salt was employed with urea using hydrothermal synthesis method and hollow spherical Cu O, flower-like Cu O, thorn-like Cu O and sphercial Cu O was prepared. The influence of the anion in the salt on morphology was explored, and the influnece of salt ratio, reaction temperature and reaction time were also studied. By employing XPS, the surface of the Cu O electrode was studied, and it was found out the calcination process was detrimefal cycling capacity and rate performance. Combination of all the factors, such as morphology, cycling performance, EIS spectra and Li-ion diffusion coefficient, hollow spherical Cu O show superior cycling performance, cycling life and rate performance.Finally, Cu O/r GO and Cu O/MCNTs composites were prepared by the hydrothermal synthesis method. r GO was prepared by thermal dilation method with fine and thin carbon layer, which was suitable for composite preparation. Through comparison of cycling performance, Cu O/r GO composite electrode showed good electrochemical performance. |
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