S/石墨烯复合材料的水热法制备及其电化学性能研究

采用水热法制备了S/石墨烯复合材料,并利用XRD,SEM,TEM等手段考察了其微观结构及形貌特征,发现石墨烯呈现多层状,与硫复合后能将其充分包覆。以复合材料为正极、锂为负极组装成扣式电池进行CV,EIS及充放电等电化学性能测试。结果表明:添加石墨烯后硫正极的可逆性明显改善,多次充放电后电池内阻有所增加,在0.3mA/cm2电流密度下放电,首次放电比容量为1 145mAh/g,经30次充放电循环后仍可稳定在500mAh/g。

Preparation of S/graphene composite by hydrothermal synthesis and study on its electrochemical performance

In this paper, a sulfur/graphene composite was prepared by hydrothermal synthesis, where graphene was regarded as a carrier of sulfur active substance. The surface structure and crystal form of the composite material were characterized by X- ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）. It was found that gra- phene appeared multi-layer and sulfur was fully coated by graphene. Electrochemical tests demonstrated that the reversibility of sulfur active material had improved by adding graphene and internal resistance had increased after a number of cycles. The first discharge specific capacity was up to 1 145 mAh/g at 0.3 mA/emz and the capacity remained about 500 mAh/g after 30 cycles.