LiMgxFe1-xPO4/C,LiMnx Fe1-x PO4, LiFe1-x-y Mnx Mgy PO4 /C cathode materials were synthesized for lithium rechargeable batteries by two step ball-milling and high temperature solid-state reaction, using Li2CO3, FeC2O4·2H2O, (NH4)2HPO4, MnCO3, (MgCO3)4·Mg(OH)2·5H2O as raw materials and glucose as carbon source. Effect of doping Mg2+ and Mn2+ on the structure and performance of the samples was discussed, Effect of doping Mg2+ and Mn2+ on crystal structure and surface morphology of LiFePO4/C composite material was investigated by using X-ray diffraction, scanning electron microscope, and X-ray energy dispersive spectroscopy. Electrochemical measurements were used to study effect of doping Mn2+ and Mg2+ on charge/discharge performance and cycle stability of LiFePO4 /C composite material Results indicated that the prepared samples by doping Mn2+ and Mg2+ have single olivine structures and uniform particle sizes, and exhibited an excellent electrochemical performance and enhanced stabilities. Among them, the first specific discharge capacity of LiMg0.1 Fe0. 9 PO4 /C was 128.4mAh/g at 0.1C; the first specific discharge capacity of LiMn0.1 Fe0.9 PO4 /C was 110. 8mAh/g at 0.1C; the fist specific discharge capacity of LiFe0.8 Mg0.1 Mn0.1PO4 /C was 131. 8mAh/g at 0.1C.%以碳酸锂、草酸亚铁、磷酸氢二铵、碳酸镁、碳酸锰为原料,葡萄糖为碳源,采用两步球磨高温固相法合成了锂离子电池正极LiMgx Fe1-xPO4/C、LiMnx Fe1-xPO4/C、LiFe1 -x-yMnxMgyPO4/C复合材料.讨论了镁、锰金属离子对LiFePO4/C结构和性能的影响.利用X射线衍射、扫描电子显微镜、X射线能谱仪等方法研究了镁、锰金属离子掺杂对LiFePO4/C晶体结构和表面形貌的影响；利用电化学方法研究了镁、锰掺杂对LiFePO4/C充放电性能和循环稳定性的影响.结果表明,镁、锰金属离子掺杂合成的LiFePO4/C具有单一的橄榄石结构,颗粒尺寸均匀,具有良好的电化学性能和循环稳定性.掺杂的LiMg0.1 Fe0.9 PO4/C、LiMn0.1 Fe0.9PO4/C、LiFe0.8 Mn0.1 Mg0.1 PO4/C在0.1C下首次放电比容量分别为128.4mAh/g、110.8mAh/g、131.8mAh/g.
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