Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Science, Wuhan University , Wuhan 430072, China.
College of Chemistry, Central China Normal University , Wuhan 430079, China.
ACS Appl Mater Interfaces. 2017 Apr 5;9(13):11626-11633. doi: 10.1021/acsami.7b00542. Epub 2017 Mar 27.
Great progress has been made on the cyclability and material utilization in recent development of lithium-sulfur (Li-S) batteries; however, most of the sulfur electrodes reported so far have a considerable low loading of sulfur (60%), which causes a substantial decrease in energy density and is therefore difficult for application in batteries. To deal with this issue, we fabricate a novel sulfur composite with a coaxial three-layered structure, in which sulfur is deposited on carbon fibers and coated with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS), thus enabling a high sulfur loading of 70.8 wt % without the expense of its electrochemical performance. Benefiting from the rigid conductive framework of carbon fibers and flexible buffering matrix of the polymer for blocking the diffusion loss of discharge intermediates, the as-fabricated composite electrode exhibits a high initial reversible capacity of 1272 mA h g (based on the total mass of the composite), a stable cyclability with a retained capacity of 807 mA h g after 200 cycles, and a high Coulombic efficiency of ∼99% upon extended cycling, offering a new selection for practical application in Li-S batteries.
在锂硫（Li-S）电池的最新发展中，其循环性能和材料利用率取得了重大进展；然而，迄今为止报道的大多数硫电极的硫负载量（60%）相当低，这导致能量密度显著降低，因此难以应用于电池。为了解决这个问题，我们制备了一种具有同轴三层结构的新型硫复合材料，其中硫沉积在碳纤维上，并涂有聚（3,4-亚乙基二氧噻吩）/聚（苯乙烯磺酸盐）（PEDOT/PSS），从而能够实现高达 70.8wt%的高硫负载量，而不会影响其电化学性能。得益于碳纤维的刚性导电骨架和聚合物的柔性缓冲基质，用于阻止放电中间体的扩散损失，所制备的复合电极表现出高的初始可逆容量 1272 mA h g（基于复合材料的总质量），经过 200 次循环后具有稳定的循环性能，保留容量为 807 mA h g，在扩展循环时具有高的库仑效率（约 99%），为实用化 Li-S 电池提供了新的选择。
