中文摘要：

用化学沉淀法制备了Mg^2＋、Al^3＋、Ti^4＋、V^5＋和Ni^2＋掺杂的磷酸铁锂，用恒电流充放电方法测量掺杂LiFePO4的充放电性能，用x射线衍射和里特沃尔特方法表征了掺杂LiFePO4的晶体结构。研究表明，少量金属离子掺杂能有效地提高LiFePO4的大电流放电性能，其中Li1-xTixFePO4、Li1-xVxFePO4和Li1-xNixFePO4以2C速率充放电时，放电比容量在120mAh／g以上，循环20次后容量保持率在80％以上。主要原因是掺杂金属离子以固溶体形式存在，并占据锂的位置，改变了晶体中原子间距离和位置，引起晶胞收缩和Li-O原子间平均距离增加，形成了有利于锂离子脱嵌的结构。

英文摘要：

The chemical co-precipitation method was used to synthesize LiFePO4 by doping with Mg^2＋, A1^3＋, Ti^4＋, V^5＋, and Ni^2＋, then the specific charge/discharge capacity of LiFePO4 was measured by stable-current charge/discharge method and the particle structure was examined by X-ray diffraction and Rietveld method. The results indicate that a small amount of metal ion doping can improve the discharge capacity of LiFePO4 to above 120 mAh/g at high current and keeping the capacity over 80% after 20 cycles when the charge/discharge rate is at 2C for Li1-xTixFePO4, Li1-xVxFePO4 and Li1-xNixFePO4, mainly due to the metal ion dopings in the form of solid solution and occupying the position of Lithium. The metal ion dopings change the distance and position between atoms in grains, resulting in the contraction of unit cells, the increase of average distance between Li-O atoms and the disengagement of Lithiumions.