【摘要】 研究了随锂离子的脱出,锂离子电池正极材料LixCoO2(0·5<x<1)晶体结构的变化.对高温合成的LiCoO2用强氧化剂NaS2O8化学抽取锂离子,得到几种不同锂含量的脱锂态LixCoO2,并使用X射线衍射和电子衍射进行晶体结构分析.X射线衍射结果表明,在0·5<x<1范围内LixCoO2晶胞参数c发生变化.电子衍射结果表明,脱锂态的LixCoO2(0·5<x<1)中发生了X射线衍射检测不到的锂离子/空位有序排列的相变,从而使晶体结构显著变化,并给出了相应的晶体结构模型.相变在以LiCoO2为电极的电池充放电曲线上表现为电压平台.更多还原

【Abstract】 The crystal structure change of Li_xCoO₂ （0.5<x<1） during delithiating process was studied in order to optimize the electrochemical property of the Li-ion battery cathode material LiCoO₂. Li_xCoO₂ samples with different lithium contents were prepared by chemically extracting lithium from LiCoO₂ with Na₂S₂O₈. The crystal structures of these samples were then analyzed by X-ray diffraction and electron diffraction. From X-ray diffraction, the lattice parameter c of Li_xCoO₂ （0.5<x<1） changes with Li content. The results of electron diffraction indicate that the ordered arrangement of lithium and vacancy in Li_xCoO₂ （0.5<x<1） which cannot be detected by XRD leads to significant change in crystal structure and the corresponding crystal structure model was proposed. Phase transformation exhibits voltage plateau in the charge and discharge curves of a Li-ion battery with LiCoO₂ cathode.更多还原