| 正极材料Li0.99Nb0.01Fe1-xMgxPO4/C的制备及电化学性能的研究 |
| Synthesis and Electrochemical Performance of Li0.99Nb0.01Fe1-xMgxPO4/C Cathode |
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| 摘要: 采用两步固相反应合成了锂、铁双位掺杂的锂离子电池正极材料Li0.99Nb0.01Fe1-xMgxPO4/C(x=0，0.01，0.02，0.03，0.04)。通过X射线衍射(XRD)、扫描电镜(SEM)以及恒电流充放电测试，研究了复合材料的晶体结构、形貌以及电化学性能。实验结果表明，制备的Li0.99Nb0.01Fe1-xMgxPO4/C(x=0，0.01，0.02，0.03，0.04)为纯相，掺杂适量的Nb5+、Mg2+离子可减小材料的晶粒尺寸，当Nb离子掺杂量为1mol%、Mg离子掺杂量为3mol%时，Li0.99Nb0.01Fe0.97Mg0.03PO4 /C的电化学性能最佳。室温下，0.2C、1C、2C、4C(1C=170 mA·g-1)倍率充放电其首次放电比容量分别为153.7、149.7、144.6、126.4 mAh·g-1，即使在8C倍率下放电其放电比容量也有92.2 mAh·g-1，并表现出良好的循环性能。 |
| 关键词: LiFePO4 碳包覆 掺杂 固相反应 |
| 基金项目: |
| Abstract: The multiple doping Li-ion battery cathode materials Li0.99Nb0.01Fe1-xMgxPO4/C(x=0, 0.01, 0.02, 0.03, 0.04) were synthesized by two-step solid state reaction. The prepared samples were characterized by X-ray diffractometry, SEM and galvanostatic charge-discharge test. The results show that Li0.99Nb0.01Fe1-xMgxPO4/C samples are pure olive phase, and appropriate amount of doping ions of Nb5+ and Mg2+ can reduce the particle size. Li0.99Nb0.01Fe0.97Mg0.03PO4 /C has the best electrochemical performance. At room temperature, The initial discharge capacity of the sample delivers 153.7, 149.7, 144.6 and 126.4 mAh·g-1 at 0.2, 1, 2 and 4C rates (1C=170 mA·g-1), even at 8C rate, the initial discharge capacity of the sample remains 92.2 mAh·g-1. In addition, it shows excellent cycle stability at different rates. |
| Keywords: LiFePO4 carbon coated doping solid state reaction |
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| 杜 柯,刘 艳,胡国荣,彭忠东,曹雁冰,蒋庆来.正极材料Li0.99Nb0.01Fe1-xMgxPO4/C的制备及电化学性能的研究[J].无机化学学报,2010,26(7):1235-1239. |
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