The Investigation of Thermo/Electrochemistry of New Safety Additive in Lithium Ion Battery

• Main Authors: Huei-Jhen Chen, 陳惠貞
• Other Authors: Chorng-Shyan Chern
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/7y8uqc

碩士 === 國立臺灣科技大學 === 化學工程系 === 106 === The copolymerization of uracil and N,N’- bismaleimide-4,4’- diphenylmethane (BMI) was used in this study. For knowing the reactivity for the polymer, the free-model method by non- isothermal kinetics was used to determine the activity energy. In addition, polymerized uracil(UR) and BMI/UR as the additive were used to coat the surface of the LiCo0.95Al0.05O2 cathode particles. Coin-type half cells were assembled with metallic lithium anodes for electrochemical tests such as charge/discharge (C/DC), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and so on. The morphology and element analysis of the surface of the cycled electrodes were examined by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). And the thermal stability of the cathodes was shown by the DSC results. Besides, the influence of the additives upon the cathodes were confirmed by comparing the experiment results of the bare LiCo0.95Al0.05O2 and coated- LiCo0.95Al0.05O2. In this study, the experiment result shows that the optimum concentration of the two additives in the cathodes for improving the capacity fading after charging/discharging at room temperature and high temperature is 0.5wt%. Moreover, the charging/discharging result indicates that the higher amount of uracil or uracil/BMI additive will cause the worse capacity fading. And the electrodes with the additive have the lower heat generation. This result implies that the additives which are used in this study can improve the thermal stability of the electrode materials by heat suppression compared with the bare LiCo0.95Al0.05O2. Furthermore, the electrode with 1.0wt% uracil has the best thermal stability according to the data from the experiment in this study.