掺钴对富锂磷酸亚铁锂大电流放电性能的影响

摘要

采用固相法制备了具有橄榄石型结构的微米Li1.12Fe0.98C0.02PO4／C样品．通过充放电循环、循环伏安实验、交流阻抗、XRD衍射、红外光谱、扫描电镜等现代技术研究了制备的样品的电化学性能．研究表明，在2C倍率电流下，制备的Li1.12FePO4／C和Li1.12Fe0.98Co0．02PO4／C样品第1循环的放电容量分别为64．8和108．9mAh·g^-1，第30循环的放电容量分别为67．3和110．1mAh·g^-1．因此，掺钴的富锂Li1.12Fe0.98Co0．02PO4／C样品具有明显改善的大电流放电性能．%A Li1.12Fe0.98Co0.02PO4/C composite with the micrometer size was synthesized by a solid state reaction. The as-prepared composite was characterized by charge-discharge tests, cyclic vohammetry, electrochemical impedance spectroscope, XRD patterns, infrared spectroscopy and scanning electron microscope method. The experimental results show that Li1.12Fe0.98Co0.02PO4/C delivers a capacity of 108.9 mAh ·g^-1 in the 1st cycle and 110.1 mAh ·g^-1 in the 30th cycle at 2 C rate,respectively. Cobalt doping obviously improves the discharge performance of lithium iron phosphate at high rate current.