PEG包覆对锂硫电池正极电化学性能的影响

Effect of PEG Coating on Electrochemical Performance of Cathode for Lithium-Sulfur Battery

通过球磨法和热处理法制备硫/乙炔黑/碳纳米管(S/AB/CNT)复合材料,并用溶剂蒸发法制备聚乙二醇(PEG)包覆的S/AB/CNT复合材料。对制备的PEG包覆S/AB/CNT复合材料进行XRD分析,表明PEG包覆可以减弱硫的晶态结构。对PEG包覆量不同的S/AB/CNT复合材料进行SEM形貌分析,表明PEG包覆使S/AB/CNT复合材料表面更光滑。通过PEG包覆量不同的S/AB/CNT正极的电化学测试表明,含量为4 wt%时的PEG包覆S/AB/CNT复合电极电化学性能最好。在0.1 C电流倍率下,首次放电比容量为907 mAh/g,80次循环后容量仍保持在800 mAh/g,说明PEG包覆能很好地改善复合材料的电化学性能。

Sulfur/acetylene black/carbon nanotube(S/AB/CNT) composites were prepared by ball milling and heat treatment,and S/AB/CNT composites with polyethylene glycol(PEG) coating were prepared via solvent evaporation.XRD of the PEG-coated S/AB/CNT composite showed that PEG coating could weaken the crystalline structure of sulfur.SEM morphology of S/AB/CNT composites with different PEG coating amounts showed that PEG coated the surface and made the surface smoother.Electrochemical tests of S/AB/CNT cathodes with different PEG coating amounts suggested that the PEG-coated S/AB/CNT with the 4 wt% PEG had the best electrochemical performance.At 0.1 C,the initial discharge specific capacity was 907 mAh/g and the capacity remained at 800 mAh/g after 80 cycles.This suggested that PEG coating can improve the electrochemical performance of the composite material.