新型锂离子电池材料FeS_2/VGCF的合成与电性能研究

Synthesis and Electrochemical Characteristics of the Novel FeS_2/VGCF Material for Lithium-Ion Batteries

以草酸亚铁（FeC2042H20）、硫粉（s）、气相生长的碳纤维（VGCF）~原料，通过固相法合成了锂离子电池材料FeS2／VGCF。采用X射线衍射（XRD）、扫描电镜（SEM）、循环伏安（Cv）和恒流充放电循环等方法对合成材料的结构、形貌以及电化学性能进行了表征。结果表明：合成的二硫化亚铁材料呈条块状。在1．0～2．6V（vsLi／Li’）电压范围内，以0．1c（1C=890mA／g）倍率进行恒电流充放电，FeS2与FeS2／VGCF的放电容量分别为692、872mAh／g，在0．5C倍率下，经过50、100、200次循环后纯FeS2的放电比容量分别为268、71、28mAh／g，而FeS2／VGCF的放电比容量可分别保持在469、417、254mAh／g，较之无VGCF修饰的FeS2材料表现出良好的倍率性能和循环性能。

FeSjVGCF battery material was prepared by solid-state method using FeC204＂2H20, S and Vapor-Grown Carbon Fiber （VGCF） as the starting materials. The synthesized material was characterized by means of X-ray diffrac- tion （XRD）, scanning electron microscope （SEM）, cyclic voltammograms （CV） and galvanostatic charge/discharge cycling tests. The result shows that the material of VGCF presents string centers. The discharge specific capacity of the FeS2 and FeS2/VGCF electrodes can reach 692 and 872 mAh/g at 0.1C in the voltage range of 1.0 to 2.6 V （vs Li / Li＋）, respectively. The FeS2/VGCF electrode can sustain 469, 417 and 254 mAh/g after 50, 100 and 200 cycles at 0.5C （1C = 890 mA/g）, much higher than those of FeS2 prepared without VGCF （268, 71 and 28 mAh/g）. Compared with FeS〉 the cyclic capacity and stability of FeS2/VGCF are improved.