用化学沉淀法制备了Mg2+、Al3+、Ti4+、V5+和Ni2+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-xToxFePO4、Li1-xVxFePO4和Li1-xNixFePO4以2 C速率充放电时,放电比容量在120 mAh/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.
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