采用一步水热法合成Nb_2O_5和Fe(Ⅲ)掺杂的五氧化二铌微纳米球(Fe-Nb_2O_5),并利用X射线衍射(XRD)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)等测试手段分别对其结构和形貌进行了表征。结果发现,所合成的Fe-Nb_2O_5和Nb_2O_5均为正交晶相,Nb_2O_5为尺寸分布在50~300 nm之间的形貌不规则颗粒,而Fe-Nb_2O_5是由约50 nm的一次颗粒自组装而成的直径约为1μm的均匀微纳米球,即具有多级结构,其有利于增大电极材料与电解液的接触界面。电化学测试结果表明,Fe-Nb_2O_5的循环稳定性和倍率性能得到明显改善,在50 m A·g~(-1)电流密度下,100次循环后放电容量仍保持在193.2 m Ah·g~(-1),即使在5 A·g~(-1)的电流密度下,容量仍可达到108.4 m Ah·g~(-1)。并分析了其性能改善的原因。
【英文摘要】
Fe(Ⅲ)-doped niobium oxide(Fe-Nb_2O_5) and Nb_2O_5 were prepared by the one-step hydrothermal route.Both samples were characterized by X-ray diffraction(XRD), electron microscopy(SEM), Transmission electron microscope(TEM) and so on. The results showed that Fe-Nb_2O_5 and Nb_2O_5were orthorhombic phase. Nb_2O_5 was irregular particle with the wider size distribution of 50 ~300 nm, and Fe-Nb_2O_5 was homogeneous micro/nano sphere with the diameter of 1 μm, which assembled from 50 nm sized nano-particles The p...