废旧电池再生磷酸铁锂正极的钛掺杂改性研究

Performance of titanium-doped LiFePO_4 recycled from spent batteries

对废旧锂离子电池再生磷酸铁锂正极材料,采用钛元素进行掺杂改性。用X射线衍射仪和扫描电镜分析不同掺杂量对材料物相结构和形貌的影响。用恒电流充放电、循环伏安和交流阻抗等方法测试材料电化学性能。与未掺杂的再生LiFePO_4/C相比,掺杂5%Ti的LiFePO_4/C(LFT5P/C)材料电荷传递阻抗减小,电化学性能明显提高。掺杂正极在0.1 C下首次放电比容量高达140.6 mAh/g,1 C倍率下循环近400次,每次的容量衰减率仅为0.019 6%。

The regenerated lithium iron phosphate (LiFePO4) from spent lithium ion batteries was modified by Ti doping. X-ray diffraction and scanning electron microscope were used to investigate the effect of doping amounts on the structure and morphology of doped products. Galvanostatic charge/discharge test, cyclic voltammetry, and electrochemical impedance spectrum were employed to study the electrochemical performance of the as-prepared cathodes. Compared with pristine LiFePO4/C, doped cathodes exhibits decreased charge-transfer resistance and evidently enhanced electrochemical performance. Specifically, the doped cathode LFT5P/C delivers a high initial discharge specific capacity of 140.6 mAh/g at 0.1 С, and the capacity decay is only 0.019 6% per cycle when the cathode is cycled at 1С for nearly 400 cycles.