聚乙烯吡咯烷酮包覆硫/碳复合材料的制备及其电化学性能

采用液相化学沉积法,并引入聚乙烯吡咯烷酮(PVP)制备得到聚乙烯吡咯烷酮包覆硫/碳复合材料。采用热重分析(TGA)、扫描电子显微镜(SEM)、X射线衍射(XRD)、恒流充放电和循环伏安(CV)表征其物化性能和电化学性能,结果表明,聚乙烯吡咯烷酮可有效提高硫/碳复合材料的电化学性能。0.35 C充放电时,所得聚乙烯吡咯烷酮包覆硫/碳复合材料首次放电比容量达到1 415.3 mAh/g(按单质硫的质量计算),120次后比容量保留为903.3 mAh/g,容量保持率为63.8%;2 C充放电时,首次放电比容量可达到904 mAh/g,200次后比容量仍能保持在486.8 mAh/g。

Polyvinylpyrrolidone Coated Sulfur/Carbon Composite Cathode for High-Rate Lithium-Sulfur Batteries

A novel sulfur/carbon composite was prepared via simple chemical deposition method involving polyvinylpyrrolidone （PVP）. It is confirmed from the scanning electron microscopy （SEM）, X-ray diffraction （XRD）, galvanostatic discharge-charge and cyclic voltammetry （CV） that the polyvinylpyrrolidone coated S/C composite displays better electrochemical features, compared with the S/C composite without polyvinylpyrrolidone. The S/C-PVP electrode delivers an initial discharge specific capacity of 1 415.3 mAh/g （based on the weight of sulfur） and retains 903.3 mAh/g （63.8% of the initial capacity） after 120 cycles at 0.35 C. Furthermore, the S/C-PVP electrode achieves an initial discharge specific capacity of 904 mAh/g and retains 486.8 mAh/g after 200 cycles at high-rate of 2 C.