Spider-Web-Inspired NanocompositeModified Separator: Structural and Chemical Cooperativity Inhibiting the Shuttle Effect in Li-S Batteries
Spider-Web-Inspired NanocompositeModified Separator: Structural and Chemical Cooperativity Inhibiting the Shuttle Effect in Li-S Batteries
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DOI：
10.1021/acsnano.8b07491
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发表时间：
2019-02-01
期刊：
影响因子：
17.1
通讯作者：
Zhang, Suojiang
中科院分区：
文献类型：
--
作者：
Fang, Daliang;Wang, Yanlei;Zhang, Suojiang
尽管锂硫电池具有很高的理论容量密度（1675 mAh g（-1）），但多硫化物的穿梭效应严重阻碍了锂硫电池的应用。在这里，灵感来自天然蜘蛛网的工作原理，我们合成了一个蜘蛛网状的纳米复合材料，其中许多中空的介孔二氧化硅（mSiO（2））纳米球/钴纳米粒子通过相互连接的氮掺杂碳纳米管（NCNT）线程。然后通过简单的渗透将纳米复合材料（表示为Co/mSiO（2）NCNT）涂覆在商业隔膜上以减轻上述问题。三维导电网络（NCNT）与丰富的多硫化物吸附位点（SiO2和N）/多硫化物转化催化剂（Co和Co N物种）的紧密结合允许Co/mSiO（2）NCNT涂层不仅通过物理限制和化学键合有效地捕获多硫化物，而且显著地加速多硫化物的氧化还原动力学。此外，非原位实验和理论计算的结合表明，多硫化物在mSiO（2）纳米球上的可逆吸附/脱附有利于Li 2S 2/Li 2S在导电网络上的均匀沉积，有利于长期循环稳定性。结果表明，采用Co/mSiO（2）CNTs包覆隔膜的锂S电池具有优异的循环稳定性和倍率性能。
Despite their high theoretical capacity density (1675 mAh g(-1)), the application of Li S batteries has been seriously hindered by the shuttle effect of polysulfides. Here, inspired by the working principle of natural spider webs, we synthesized a spider-web-like nanocomposite in which many hollow mesoporous silica (mSiO(2)) nanospheres/Co nanoparticles were threaded by interconnected nitrogen-doped carbon nanotubes (NCNTs). Then the nanocomposite (denoted as Co/mSiO(2) NCNTs) was coated on the commercial separator by a simple infiltration to mitigate the above issue. The intimate combination of three-dimensional conductive networks (NCNTs) with abundant polysulfide adsorbent sites (SiO2 and N)/polysulfide conversion catalysts (Co and Co N species) allows the Co/mSiO(2) NCNTs coating layer to not only effectively capture polysulfides via both physical confinement and chemical bonding but also accelerate the redox kinetics of polysulfides significantly. Furthermore, the combination of ex situ experiment and theoretical calculation demonstrates that the reversible adsorption/desorption of polysulfides on mSiO(2) nanospheres benefits uniform deposition of Li2S2/Li2S on the conductive networks, which contributes to long-term cycling stability. As a result, Li S batteries with Co/mSiO(2) NCNTs-coated separators exhibited both excellent cycling stability and rate performance.