Li Fanqun, Qin Furong, Wang Guanchao, Zhang Kai, Wang Peng, Zhang Zhian, Lai Yanqing
School of Metallurgy and Environment, Central South University Changsha Hunan 410083 China
RSC Adv. 2018 Jan 5;8(3):1632-1637. doi: 10.1039/c7ra10367k. eCollection 2018 Jan 2.
Lithium-sulfur (Li-S) batteries have gained significant attention due to their ultrahigh theoretical specific capacity and energy density. However, their practical commercialization is still facing many intractable problems, of which the most difficult is the shuttle effect of dissolved polysulfides. To restrict the shuttle of polysulfides, herein, a novel double-layer lithium aluminate/nitrogen-doped hollow carbon sphere (LiAlO/NdHCSs)-modified separator was designed. The upper NdHCSs layer on the separator works as the first barrier to physically and chemically adsorb polysulfides, whereas the bottom LiAlO layer acts as the second barrier to physically block the polysulfides without restricting the Li transport due to the high ionic conductivity of LiAlO. Cells with the LiAlO/NdHCSs-modified separator showed an initial discharge capacity of 1500 mA h g at 0.2C, and a discharge capacity of 543.3 mA h g was obtained after 500 cycles at 2C. Especially, when the areal density of the active material was increased to 4.5 mg cm, the cells retained a discharge capacity of 538.6 mA h g after 100 cycles at 0.5C. The outstanding electrochemical performance of Li-S cells with the LiAlO/NdHCSs-modified separators show a new approach for the applications of Li-S batteries.
锂硫（Li-S）电池因其超高的理论比容量和能量密度而备受关注。然而，其实际商业化仍面临许多棘手问题，其中最困难的是溶解多硫化物的穿梭效应。为了限制多硫化物的穿梭，本文设计了一种新型的双层锂铝酸盐/氮掺杂空心碳球（LiAlO/NdHCSs）改性隔膜。隔膜上的上层NdHCSs层作为第一道屏障，物理和化学吸附多硫化物，而底部的LiAlO层作为第二道屏障，物理阻挡多硫化物，同时由于LiAlO的高离子电导率，不限制Li的传输。采用LiAlO/NdHCSs改性隔膜的电池在0.2C下的初始放电容量为1500 mA h g，在2C下循环500次后放电容量为543.3 mA h g。特别是，当活性材料的面密度增加到4.5 mg cm时，电池在0.5C下循环100次后仍保持538.6 mA h g的放电容量。具有LiAlO/NdHCSs改性隔膜的锂硫电池的优异电化学性能为锂硫电池的应用展示了一种新方法。
