Ma Qingyan, Hu Mengfei, Yuan Yuan, Pan Yankai, Chen Mingqi, Zhang Yayun, Long Donghui
State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
J Colloid Interface Sci. 2020 Apr 15;566:11-20. doi: 10.1016/j.jcis.2020.01.066. Epub 2020 Jan 20.
Functional separator, which bridges anode, electrolyte and cathode together, has the potential to offer a good solution for efficient polysulfide diffusion inhibition and anode protection of Li-S battery. Herein, a novel ultra-thin multifunctional separator is prepared by a facile coating of colloidal dispersion of NbO/reduced graphene oxide nanocomposites (rGO) onto porous polypropylene (PP) matrix. Benefiting from the physical blocking effect of rGO layer and chemisorption of NbO, the shuttle of polysulfides has been greatly suppressed. Meanwhile, the rGO layer functioning as a conductive upper current collector can improve the sulfur utilization, while the NbO with high activity promotes the transformation of sulfur-containing species. With the assistant of NbO-rGO function layer, the sulfur cathode shows significantly improved electrochemical performance with a high specific capacity of 1328 mAh g at 0.2C and 754 mAh g retained after 200 cycles. The sulfur cathode also exhibits excellent rate capability and stable Coulombic efficiency of 91% without the addition of LiNO in the electrolyte. Moreover, the presence of thin NbO-rGO layer also prevents the lithium surface corrosion and the dendrite growth in the lithium anode.
功能隔膜将阳极、电解质和阴极连接在一起，有潜力为抑制锂硫电池中多硫化物的有效扩散和保护阳极提供一个良好的解决方案。在此，通过将铌氧化物/还原氧化石墨烯纳米复合材料（rGO）的胶体分散液轻松涂覆在多孔聚丙烯（PP）基体上，制备了一种新型超薄多功能隔膜。受益于rGO层的物理阻挡作用和铌氧化物的化学吸附作用，多硫化物的穿梭效应得到了极大抑制。同时，作为导电上集流体的rGO层可提高硫的利用率，而具有高活性的铌氧化物则促进含硫物种的转化。在铌氧化物-rGO功能层的辅助下，硫阴极表现出显著改善的电化学性能，在0.2C下比容量高达1328 mAh g，200次循环后仍保留754 mAh g。在电解质中不添加LiNO的情况下，硫阴极还表现出优异的倍率性能和91%的稳定库仑效率。此外，薄铌氧化物-rGO层的存在还可防止锂阳极表面腐蚀和枝晶生长。
