以荷叶制备多级孔碳硫复合正极材料及性能研究

摘要

The carbon skeleton with high specific surface (572.1 m2/g) and large number of hierarchical pores espe-cially micro-pores (average pore size at 3.2 nm) was obtained from common lotus-leaves by using multistage car-bonization method. Ball milling and melting method were used to synthesize different S contents (48wt%/62wt%/71wt%) carbon/sulfur composite materials. XRD, FESEM, EDS, and TG were employed to analyze struc-ture and morphology of the samples. The result indicated that element sulfur was uniformly accommodated in the skeletons which were composed by graphene-like layered structure and micrometer sticks. Charge/discharge tests at current density of 0.1C in the voltage range of 1.2-2.8 V showed that the initial discharge specific capacity of the carbon/sulfur composite (62wt%) reached 1246 mAh/g, and its capacity still remained 600 mAh/g even after 100 charge/discharge cycles. The results prove that the obtain composites can suppress the“shuttle effect” of polysul-fide species effectively.%以荷叶为原料,采用多阶炭化的方法,得到高比表面积(572.1 m2/g)和存在大量多级孔尤其微孔(平均孔径3.31 nm)结构居多的炭骨架,继而用高能球磨法及熔融法与单质硫进行复合制备出不同含硫量(48wt%,62wt%,71wt%)碳/硫复合材料。通过XRD、FESEM、EDS和TG对材料结构和形貌进行表征,结果表明硫被均匀固定在多孔碳材料的类石墨烯层状结构和类微米棒结构中。充放电测试表明,62wt%含硫量的复合正极材料性能表现最佳,在0.1C,1.2~2.8 V范围内充放电,首次放电比容量达1246 mAh/g,100次循环后依旧保持在600 mAh/g,制备出的复合正极材料对多硫化物的“穿梭效应”起到了抑制作用。