| The increasing concerns on energy, environmental and the rapid development of modern science and technology have more demands on batteries. Lithium ion batteries (LIB) are attractive for use with the favorable properties of high voltage, long cycling life, high energy density and pollution-free. In order to improve performance, lower cost, promote industrialization of LIB, the synthesis and properties of cathode materials as well as the fabrication technique of LIB were studied by using various electrochemical methods in combination with modern analytic techniques, e.g., XRD, SEM, and BET. The synthesis and performance of three kinds of typical cathode active materials were mainly studied and a whole process of producing technique of LIB was developed.The influence of synthesis conditions such as heat treatment, atmosphere and raw material on the structure and morphology of LiCoO2 was discussed. At high temperature, LiCoO2 presented anisotropy and layered structure, and tended to appear the phenomena of sinter and microcrystal growth. Increase of oxygen partial pressure could decrease the size of microcrystal and particle. In addition, it also could restrain the agglomeration of particles. The consecutive calcination method was proposed for the synthesis of LiCoO2, which simplified the process and solved the problems of slow reaction rate at low temperature and the uncontrollability of particle size because of the agglomeration at high temperature.Based on the establishment of the relationship between synthesis conditions and physical characteristics, the influence of physical parameters of particle distribution, specific surface area and morphology, which play an important role on the electrochemical behavior of LiCoO2 on the electrode interface state, was examined. The result shows that particle size and specific surface area have a greater effect on the capacity and voltage cycling performance of LiCoO2. The narrow particle size distribution is favorable for the improvement of cycling performance of LiCoO2, while too large specific surface area can sharply deteriorate its performance. With the decrease of the crystal size, the charge/discharge performance in heavy drain was improved. Under the optimum conditions, the synthesized LiCoO2 shows excellent high rate performance, high capacity and stable voltage performance. Assuming a spherical electrode model, the equation of diffusion current density of LiCoO2 electrode was deduced. The test results of diffusion coefficient reveal the intrinsic reason of the different high rate performance of LiCoO2 samples.The LiNi0.5Co0.5O2 was prepared from the corresponding carbonate and hydroxide. The effect of synthesis conditions on structure was discussed. The optimum synthesis condition was at 740 C, in oxygen with hydroxide as precursors. With the introduction of structural factor |Fhkl|2 , the theory explanation for the criterion for the stiochiometry of LiNiO2 was proposed for the first time. The electrochemical tests of LiNi0.5Co0.5O2 show that it may be a low cost substitute for LiCoO2.The electrochemical performance of doped LiMn2O4 was examined. The cycling performance of LiMn2O4 was improved and an increase of lithium ion diffusion coefficient was observed at the expenseof initial capacity. The crystal field theory was applied to explain the mechanism of capacity fading and the electrochemical performance improvement of LiMn2O4 with different doped elements. Capacity fading was caused by the aberrance of d electron arrangement in Mn3+ in the octahedron sites, the doped metal ions raised the stability of LiMn2O4 structure, and consequently its electrochemical performance was improved. The stability of the d electron arrangement was different in various metals, which was the essential reason for the difference of capacity fading.The intercalation/deintercalation mechanism of LIB cathode materials was studied. Under the hypothesis, the equivalent circuit was built, and electrochemical impedance spectroscopy of lithium ion intercalation/ deintercalation...
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