铁位掺杂对磷酸铁锂电化学性能的影响

采用球磨法制备了铁位掺杂的磷酸铁锂（LiFePO4）正极材料。使用X射线衍射（XRD）、环境扫描电子显微镜（ESEM）对制备的材料进行表征，并将材料组装成扣式电池，使用蓝电系统和电化学工作站对其进行电化学性能测试和分析。结果表明，LiM0.05Fe0.95PO4和LiFePO4结构几乎一样，在0.1 C倍率下LiFePO4的首次放电比容量为125 mA·h/g，掺杂M（M=Mg，Cu，Zn）后首次放电比容量为145、141、139 mA·h/g，材料的电化学性能明显提高，其交流阻抗减小，循环50次后容量保持率为87%左右。

Effects on the electrochemical performance of LiFePO4 by doping at Fe site

LiFePO4 anode materials which were doped at the Fe site were prepared by ball milling.The samples were characterized by X-ray diffraction（XRD） and environmental scanning electron microscope（ESEM），and they were made in button-type electrochemical cells for performance testing and analysis by using the Land system and electrochemical working station.Results indicated that the LiM0.05Fe0.95PO4 and LiFePO4 samples had the same crystal structure.At 0.1 C rates，the initial discharge capacity of LiFePO4 was 125 mA·h/g，and the initial discharge capacities were up to 145，141，and 139 mA·h/g after doping by M（M=Mg，Cu，and Zn） at Fe site，respectively.It improved the electrochemical properties of the materials significantly and reduced its alternating-current impedance.The capacity remaining rate was about 87% after 50 cycles.