【作者】 柳宏；

【导师】 谷亦杰；

【作者基本信息】 山东科技大学 ， 材料学， 2008， 硕士

【摘要】 LiFePO₄是当前锂离子电池新一代正极材料的研究热点之一。本文采用高温固相法合成了Fe位和Li位掺杂的样品,采用XRD（X-ray radial diffraction,X射线衍射分析）、SEM（Scanning electron microscope,扫描电子显微镜观察）、充放电试验等测试手段,从合成方法、结构特征、表面形貌、电化学性能等方面进行了研究,确定了不同掺杂元素的最佳配比。结合第一性原理计算方法,对掺杂磁性原子含量为0.25的结构进行了计算,发现掺杂磁性原子后能带结构变得复杂化,而且更密集。总的电子态密度分布基本没有变化,变化主要集中在费米能级附近的磁性原子3d轨道上,掺入的磁性原子对最近邻的Fe原子的电子分布影响比较大。本文还进一步计算了LiFePO₄脱嵌前后的电子结构,结果表明脱嵌前后的能带结构和电子态密度存在差异,为后续对LiFePO₄材料进行系统的结构分析奠定了基础。更多还原

【Abstract】 LiFePO₄ is promising candidates of cathode materials for lithium ion batteries. The Fe-doping and Li-doping LiFePO₄ were prepared by high temperature solid-phase synthesization. A study on the synthesis method, structure and electrochemical performance of LiFePO₄ as cathode materials for lithium ion batteries had been carried out systemically and in detail through test measures such as XRD, SEM, and CV and so on in this dissertation. The test results showed the best doping contents in the samples.An ab initio method with pseudo potentials had been used to calculate the 0.25 doping content in the cathode material LiFePO₄ in Lithium batteries. The results showed that the band structure of doped was more complicated and dense than undoped LiFePO₄. There ware no significant changes in the total DOS. On the contrary, the changes had taken placed in the 3d orbit of the magnetic atoms at the Fermi level. The electron density distrutions of the nearest Fe atom were significantly influenced by the doping magnetic atoms.The first-principles calculations were also performed in the FePO₄. The calculated conclusions were revealed that there were differences in the band structure and electrons density between LiFePO₄ and FePO₄. Therefore, the basis had been prepared for the deep systemic structural analysis in LiFePO₄.更多还原