PEG包覆涂层对含碳纤维导电剂的锂硫正极材料的影响

通过球磨混合及聚乙二醇（PEG）包覆处理制备含有高模量碳纤维（HMCF）的硫基复合材料.采用X射线衍射(XRD)和扫描电子显微镜(SEM)测定材料的结构和形貌，采用X-光电子扫描能谱（XPS）验证了PEG包覆在材料的表面，较系统地研究了PEG含量对含有高模量碳纤维的硫正极比容量、循环稳定性和倍率性能等性能的影响.结果表明：和常用的导电剂乙炔黑(AB)相比，HMCF导电剂具有结晶度高，接触角小，吸液性能好等优点.当PEG涂层量为1.09%时，硫正极初始放电容量为1312.5 mAh·g^-1，在电流密度为200 mA·g^-1充放电时，50次循环以后可逆容量保持为650 mAh·g^-1，和没有PEG涂层相比，循环稳定性提高了39.9%.

Effect of PEG-Coating on Properties of Lithium-Sulfur Battery Cathode Material Containing Carbon Fiber Conductive Agent

The composite materials contained high modulus carbon fiber (HMCF) were successfully prepared by employing a ball-milling process based on the coating treatment of polyethylene glycol (PEG), and their structures and morphologies were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques．The influences of PEG content on sulfur cathode capacity, cycle stability and rate performance were systematically studied. It was found that by the pre-coating of PEG, the cathode exhibited the high initial discharge specific capacity of 1312.5mAh•g^-1 at a current rate of 0.2C, and the reversible discharge capacity of 650 mAh•g^-1 was obtained after 50 cycles at a current rate of 200mA•g^-1, showing the remarkably improved cycling stability.