硫掺杂纳米Li2FeSiO4/C制备与电化学性能

Preparation and Electrochemical Properties of Sulfur Doped Nanometer Li2FeSiO4/C

摘要:

采用固相反应法制备了 Li2FeSiO4-xSx/C (x=0,0.01,0.02,0.03)纳米正极材料。通过 X 射线 衍射（XRD）、扫描电子显微镜（SEM）、能量色散光谱仪（EDS）、X 射线光电子能谱（XPS）、拉 曼光谱（Raman）、红外吸收光谱（FTIR）及恒流充放电测试研究了材料的微观形貌、晶体结构和 电化学性能。结果表明，Li2FeSiO3.98S0.02/C 形貌呈纳米球状，平均粒径为45.38nm，纳米尺寸的粒径有利于缩短Li+的扩散途径；碳包覆抑制纳米晶粒的生长，可以增强材料的导电性；硫掺杂能扩大材料的隧道间距，加快了Li+的迁移速率。Li2FeSiO3.98S0.02/C 表现出较高的充放电比容量、优异的倍率性能以及循环稳定性，在 0.1C 下首次放电比容量高达 180.1mAhg -1，在 10C 下放电比容量为 85mAhg-1,1C 下循环 100 次后的容量保持率为 91.3%。

Abstract:

Li2FeSiO4-xSx/C (x=0,0.01,0.02,0.03) nano cathode materials were prepared by solid state reaction. The micro morphology, crystal structure and electrochemical properties of the materials were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman), infrared absorption spectroscopy (FTIR) and constant current charge discharge tests. The results show that the Li2FeSiO3.98S0.02/C morphology is nano spherical, and the average particle size is 45.38nm. The nano particle size is conducive to shortening the diffusion path of Li+; Carbon coating can inhibit the growth of nanocrystals and enhance the conductivity of materials; Sulfur doping can expand the tunnel spacing of materials and improve the magnification performance of materials. Li2FeSiO3.98S0.02/C shows high charge discharge specific capacity, excellent rate performance and cycle stability. The specific capacity of the first discharge at 0.1C is up to 180.1mAhg-1, and the capacity retention rate after 100 cycles at 10C is 91.3%.