【摘要】 以共沉淀法合成的(Ni1/3Co1/3Mn1/3)(OH)2为前驱体,在氧气氛中合成了层状正极材料LiNi1/3Co1/3Mn1/3O2,用F、Si离子复合掺杂的方法对其进行改性。X射线粉末衍射(XRD)分析表明,复合掺杂没有改变晶体的六方单相层状结构。扫描电镜(SEM)观察到产物呈类球形且颗粒均匀,平均粒径在0.1~0.2μm。循环伏安(CV)性能显示,复合掺杂提高了该材料中Li+离子脱-嵌过程的可逆性。电化学阻抗谱(EIS)测试结果表明,复合掺杂降低了该材料的电化学极化,抑制其在循环过程中电化学反应阻抗的增加。复合掺杂后的层状材料首次放电容量为172.8mAh·g-1(0.2C),20次循环后仍有166.4mAh·g-1。更多还原

【Abstract】 A modified cathode material of LiNi1/3Co1/3Mn1/3O2 with the layered structure was prepared by composite doping with F and Si ions under oxygen atmosphere using (Ni1/3Co1/3Mn1/3)(OH)2 as the precursor obtained by co-precipitation method. The results of X-ray diffraction (XRD) analysis show that it remains a well-layered structure with single phase of hexagonal after composite doping. The micrographs of scanning electron microscopy (SEM) indicate that the samples with approximatively spherical shape are with a narrow particle size ranged from 0.1 μm to 0.2 μm. Cyclic voltammograms (CV) measurement suggest that the reversibility of the cathode materials enhances by composite doping during intercalating and de-intercalating. The results of electrochemical impedance spectroscopy (EIS) indicate that the electrode polarization reduces and hence the increase of the electrochemical reaction impedance of cathode is restrained after composite doping during cycling. The doped materials have an initial discharging capacity of 172.8 mAh·g-1 at 0.2C of discharging current, and remain the capacity of 166.4 mAh·g-1 even after 20 cycles.更多还原