Wang Nan, Peng Sikan, Chen Xiang, Wang Jixian, Wang Chen, Qi Xin, Dai Shenglong, Yan Shaojiu
Beijing Institute of Aeronautical Materials (BIAM) Beijing 100095 P. R. China
RSC Adv. 2019 Feb 21;9(11):6346-6355. doi: 10.1039/c9ra00292h. eCollection 2019 Feb 18.
Lithium-sulfur batteries are attracting significant attention due to their high theoretical specific capacity and low cost. However, their applications are hindered by the poor conductivity of sulfur and capacity fading caused by the shuttle effect. Here, ultrathin manganese dioxide decorated graphene/carbon nanotube nanocomposites are designed as sulfur hosts to suppress the shuttle effect and improve the adsorption efficiency of polysulfides. The graphene/carbon nanotube hybrids, with extraordinary conductivity and large surface area, function as excellent channels for electron transfer and lithium ion diffusion. The ultrathin manganese dioxide nanosheets enable efficient chemical interaction with polysulfides and promote the redox kinetics of polysulfides. As a result, an ultrathin manganese dioxide decorated graphene/carbon nanotube sulfur composite with high sulfur content (81.8 wt%) delivers a high initial specific capacity of 1015.1 mA h g at a current density of 0.1C, high coulombic efficiency approaching 100% and high capacity retention of 84.1% after 100 cycles. The nanocomposites developed in this work have promising applications in high-performance lithium-sulfur batteries.
锂硫电池因其高理论比容量和低成本而备受关注。然而，硫的低导电性和穿梭效应导致的容量衰减阻碍了它们的应用。在此，设计了超薄二氧化锰修饰的石墨烯/碳纳米管纳米复合材料作为硫宿主，以抑制穿梭效应并提高多硫化物的吸附效率。具有非凡导电性和大表面积的石墨烯/碳纳米管杂化物，作为电子转移和锂离子扩散的优良通道。超薄二氧化锰纳米片能够与多硫化物进行有效的化学相互作用，并促进多硫化物的氧化还原动力学。结果，一种具有高硫含量（81.8 wt%）的超薄二氧化锰修饰的石墨烯/碳纳米管硫复合材料在0.1C的电流密度下具有1015.1 mA h g的高初始比容量、接近100%的高库仑效率以及在100次循环后84.1%的高容量保持率。这项工作中开发的纳米复合材料在高性能锂硫电池中具有广阔的应用前景。
