Luo Xiang, Lu Xianbo, Zhou Gangyong, Zhao Xingyu, Ouyang Yue, Zhu Xiaobo, Miao Yue-E, Liu Tianxi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Innovation Center for Textile Science and Technology , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China.
R&D Center , Shanghai Kingfa Science & Technology Co., Ltd. , 88 Kangyuan Road , Shanghai 201714 , P. R. China.
ACS Appl Mater Interfaces. 2018 Dec 12;10(49):42198-42206. doi: 10.1021/acsami.8b10795. Epub 2018 Nov 27.
Lithium-sulfur (Li-S) batteries have attracted great attention because of their high energy density and high theoretical capacity. However, the "shuttle effect" caused by the dissolution of polysulfides in liquid electrolytes severely hinders their practical applications. Herein, we originally propose a carboxyl functional polyamide acid (PAA) nanofiber separator with dual functions for inhibiting polysulfide transfer and promoting Li migration via a one-step electrospinning synthesis method. Especially, the functional groups of -COOH in PAA separators provide an electronegative environment, which promotes the transport of Li but suppresses the migration of negative polysulfide anions. Therefore, the PAA nanofiber separator can act as an efficient electrostatic shield to restrict the polysulfide on the cathode side, while efficiently promoting Li transfer across the separator. As a result, an ultralow decay rate of only 0.12% per cycle is achieved for the PAA nanofiber separator after 200 cycles at 0.2 C, which is less than half that (0.26% per cycle) of the commercial Celgard separator.
锂硫（Li-S）电池因其高能量密度和高理论容量而备受关注。然而，多硫化物在液体电解质中的溶解所导致的“穿梭效应”严重阻碍了它们的实际应用。在此，我们首次通过一步电纺合成法提出了一种具有抑制多硫化物转移和促进锂迁移双重功能的羧基官能化聚酰胺酸（PAA）纳米纤维隔膜。特别是，PAA隔膜中的-COOH官能团提供了一个负电环境，这促进了锂的传输，但抑制了多硫化物阴离子的迁移。因此，PAA纳米纤维隔膜可以作为一种高效的静电屏蔽层来限制多硫化物在阴极侧，同时有效地促进锂穿过隔膜的传输。结果，PAA纳米纤维隔膜在0.2 C下循环200次后，实现了仅0.12%/循环的超低衰减率，这不到商业Celgard隔膜（0.26%/循环）的一半。
