论文部分内容阅读
采用化学氧化法,以吡咯为单体、三氯化铁为氧化剂、苯磺酸钠为掺杂剂在磷酸铁锂颗粒表面进行原位聚合,制备了聚吡咯/磷酸铁锂(PPy/LiFePO4)复合材料。用FTIR、XRD和SEM对PPy/LiFePO4复合材料进行了结构与形貌表征。用电化学工作站和充放电测试系统对复合材料的电化学性能进行了表征。结果表明:PPy/LiFePO4复合材料作锂二次电池正极具有良好的充放电循环性能。当PPy质量分数为17%,充放电电流为0.1mA时,PPy/LiFePO4复合材料最高放电比容量达163mAh.g-1,50次循环之后放电比容量仍为初始时的94.9%;与LiFePO4相比,当PPy的含量适当时,PPy/LiFePO4复合正极材料的放电比容量会有明显提高。PPy的加入提高了LiFePO4的电子电导率,从而提高了活性物质有效利用率,因此PPy/LiFePO4复合材料的比容量和循环性能均得到了提升。
Poly (pyrrole / lithium iron phosphate) (PPy / LiFePO4) was prepared by in situ polymerization on the surface of lithium iron phosphate particles using pyrrole as monomer and ferric chloride as oxidant and sodium benzenesulfonate as dopant. Composites. The structure and morphology of PPy / LiFePO4 composites were characterized by FTIR, XRD and SEM. The electrochemical performance of the composites was characterized by electrochemical workstation and charge-discharge test system. The results show that: PPy / LiFePO4 composite material for lithium secondary battery cathode has a good charge-discharge cycle performance. When the PPy mass fraction is 17% and the charge-discharge current is 0.1mA, the maximum discharge specific capacity of PPy / LiFePO4 composites reaches 163mAh.g-1. After 50 cycles, the specific discharge capacity is still 94.9% When the content of PPy is appropriate, the discharge specific capacity of PPy / LiFePO4 composite cathode material will be significantly improved. The addition of PPy increased the electronic conductivity of LiFePO4, thereby increasing the effective utilization of active materials, PPy / LiFePO4 composite materials have improved the specific capacity and cycle performance.