The Electrostatic Attraction and Catalytic Effect Enabled by Ionic-Covalent Organic Nanosheets on MXene for Separator Modification of Lithium-Sulfur Batteries
The Electrostatic Attraction and Catalytic Effect Enabled by Ionic-Covalent Organic Nanosheets on MXene for Separator Modification of Lithium-Sulfur Batteries
复制标题
MXene上离子共价有机纳米片的静电吸引和催化作用用于锂硫电池隔膜改性
DOI：
10.1002/adma.202007803
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发表时间：
2021-03-18
影响因子：
29.4
通讯作者：
Li, Xiaoju
中科院分区：
文献类型：
--
作者：
Li, Pengyue;Lv, Haowei;Li, Xiaoju
研究多硫化物的氧化还原动力学和穿梭效应对实现高能量密度和长寿命锂硫电池具有重要意义。本文提出了一种基于多硫化物的静电吸引和催化作用对聚丙烯隔膜进行改性的新策略。Ti 3 C2表面上的胍基离子-共价有机纳米片（iCON）作为PP隔板的涂层。Ti 3C 2和iCON的协同效应为抑制多硫化物的穿梭效应、加快硫物种的氧化还原动力学、促进被拦截的多硫化物的有效转化提供了新的平台。该功能隔膜赋予碳纳米管/硫阴极优异的电化学性能。在2C下2000次循环内，每个循环的平均容量衰减低至0.006%。在硫含量为90wt%、硫负载量为7.6mgcm ~（-2）的情况下，该隔膜仍能保持良好的性能，0.1C时的可逆容量、面积容量和体积容量分别高达1186 mAh·g ~（-1）、9.01mAh·cm ~（-2）和1201 mAh·cm ~（-3）。本工作为高性能锂硫电池的开发提供了一种有前途的隔膜改性方法。
It is of great significance to mediate the redox kinetics and shuttle effect of polysulfides in pursuit of high-energy-density and long-life lithium-sulfur (Li-S) batteries. Herein, a new strategy is proposed based on the electrostatic attraction and catalytic effect of polysulfides for the modification of the polypropylene (PP) separator. Guanidinium-based ionic-covalent organic nanosheets (iCON) on the surface of Ti3C2 is presented as a coating layer for the PP separator. The synergetic effects of Ti3C2 and iCON provide new platforms to suppress the shuttle effect of polysulfides, expedite the redox kinetics of sulfur species, and promote efficient conversion of the intercepted polysulfides. The functional separator endows carbon nanotube/sulfur cathodes with excellent electrochemical performance. The average capacity decay per cycle within 2000 cycles at 2 C is as low as 0.006%. The separator is even effective in the case of sulfur content of 90 wt% and sulfur loading of 7.6 mg cm(-2); the reversible capacity, areal capacity, and volumetric capacity at 0.1 C are as high as 1186 mA h g(-1), 9.01 mA h cm(-2), and 1201 mA h cm(-3), respectively. This work provides a promising approach toward separator modification for the development of high-performance Li-S batteries.