稀土金属离子掺杂对LiFePO4结构和性能的影响

Effect of Rare Earth Ions Doping on the Structure and Performance of LiFePO4

摘要:

采用稀土金属离子 (Er3+、Y3+、Nd3+)分别对LiFePO4的Li、Fe原子位进行掺杂，通过X射线衍射 (XRD)、恒电流充放电及电化学阻抗(EIS)法系统地研究掺杂对LiFePO4结构和性能的影响。结果表明：掺杂试样的微观结构和性能与掺杂离子半径、取代位置密切相关。LiFe0.99Y0.01PO4试样具有最佳的电化学性能，在15 mA·g-1放电电流密度下首次放电容量达到149.8 mAh·g-1，当电流密度增加到300 mA·g-1时，放电容量为134.3 mAh·g-1，经过50次循环充放电后，放电容量保持率为99.1%

Abstract:

Li and Fe atom sites of LiFePO4 were doped by rare earth ions (Er3+, Y3+, Nd3+), respectively. The change of structure and performance of LiFePO4 was investigated by XRD, galvanostatic charge and discharge experiments and electrochemical impedance tests. The results show that the microstructure and performance of doped samples are interrelated with radii of doping ions and doping site. LiFe0.99Y0.01PO4 displays the excellent electrochemical performance. Its initial discharge capacity is 149.8 mAh·g-1 under the current density of 15 mA·g-1. When 300 mA·g-1 current is applied, its discharge capacity is 134.3 mAh·g-1. Its capacity retention is 99.1% after 50 cycles.