LiFePO_4/PANI复合材料的制备及电化学性能

Synthesis and electrochemical properties of LiFePO_4/PANI composites

通过原位聚合法,制备一系列的导电聚合物(Polyaniline,PANI)的LiFePO4/PANI复合材料。单用傅里叶红外光谱(FTIR)和高分辨透射电镜(HRTEM)表征PANI与LiFePO4之间的相互作用以及PANI对LiFePO4的包覆状况。采用四探针、电化学阻抗谱及恒电流充放电测试复合材料的电导率及其电化学性能。结果表明:当PANI含量为6.75%(质量分数)时,能在LiFePO4的表面形成均匀的包覆层,试样具有最佳的电化学性能,电荷转移电阻较小,交换电流较大,C/12倍率下首次放电容量为151.97mA·h/g,并具有较好的循环性能及倍率性能。

A series of conductive polymer LiFePO4/polyaniline composites were synthesized through in-situ polymerization.The interaction between PANI and LiFePO4 and the coating situation between PANI and LiFePO4 were characterized by Fourier infrared spectroscopy（FTIR） and high resolution transmission electron microscopy（HRTEM）.The four-probe methods,electrochemical impedance spectroscopy and galvanotactic current charge and discharge methods were used to test the electronic conductivity and electrochemical performance of the composites,respectively.The results show that evenly coated layers are formed when the content of PANI reaches 6.75%（mass fraction） with the best electrochemical performance,lower charge transfer resistance and larger exchange current.The initials discharge capacity is 151.97 mA·h/g at the discharge rate of C/12 with good rate and cycling capability.