| 钒掺杂对正极材料LiFePO4/C的电化学性能影响 |
| Effect of Vanadium Substitution on Electrochemical Performance of LiFePO4/C for Lithium-Ion Batteries |
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| 摘要: 以LiH2PO4和廉价的Fe2O3为原料，葡萄糖为有机碳源，通过选择高价V5+进行铁位掺杂固相合成碳包覆复合改性的LiFe1-xVxPO4/C（x=0，0.01，0.03，0.05，0.07，0.1）材料。700℃下处理得到结晶性好、电化学性能良好、较高振实密度ρ=1.2g·cm-3的材料。X射线光电子能谱（XPS）测试结果表明掺入的钒为高价态V5+，能产生更多的过剩电子，从而提高了电子电导率，且V5+的掺入没有改变Fe的价态。交流阻抗测试结果进一步证明了V5+的掺入降低了电荷迁移阻抗，提高了材料的电子电导率。其中优化的材料LiFe0.95V0.05PO4显示了不同倍率下良好的充放电比容量，在0.1C、1C、2C和5C倍率的放电比容量分别为155、146.5、135.3和125.9mAh·g-1，5C循环500次后容量为119.5mAh·g-1，容量保持率为94.9%，材料循环性能较好，具有良好的实际应用价值。 |
| 关键词: 锂离子电池 LiFePO4 V掺杂 |
| 基金项目: 中央高校基本科研业务费项目（No.2012QNZT018），中国博士后科学基金项目（No.2012M521546）资助项目。 |
| Abstract: LiFe1-xVxPO4/C(x=0, 0.01, 0.03, 0.05, 0.07, 0.1)composites with Vanadium doped and carbon coated were prepared by solid-state method synthesis route, using LiH2PO4 and low-priced Fe2O3 as starting materials. well-crystallized LiFe1-xVxPO4/C composites with high tap density (ρ=1.2 g·cm-3) were obtained at 700 ℃ for 4 h, which had good electrochemical performance. XPS of V2p and Fe2p for LiFe1-xVxPO4/Csamples indicated that the doped Vanadium was V5+ which produced more excess electrons, and improved the electronic conductivity; and the doped Vanadium would not change Iron valence. The analyses of AC impedance indicated that the doped V5+ reduced the charge migration resistance and improved electronic conductivity of the material. The optimum LiFe0.95V0.05PO4/C cathode displayed 155 mAh·g-1 at 0.1C, 146.5 mAh·g-1 at 1C, 135.3 mAh·g-1 at 2C, 125.9 mAh·g-1 at 5C discharge rate, showing good rate properties. The discharge capacity remained at 119.5 mAh·g-1 after 500 cycles with a capacity maintenance of 94.9%, showing good cycling stability and practical applications. |
| Keywords: lithium ion battery LiFePO4 vanadium doping |
| 投稿时间：2014-03-12 修订日期：2014-04-23 |
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| 罗亮,曹雁冰,杜柯,彭忠东,胡国荣.钒掺杂对正极材料LiFePO4/C的电化学性能影响[J].无机化学学报,2014,30(9):2000-2005. |
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