Encapsulating sulfur into mesoporous TiO2 host as a high performance cathode for lithium-sulfur battery
Encapsulating sulfur into mesoporous TiO2 host as a high performance cathode for lithium-sulfur battery
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将硫封装到介孔 TiO2 基质中作为锂硫电池的高性能正极
DOI：
10.1016/j.electacta.2013.06.009
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发表时间：
2013-09-30
影响因子：
6.6
通讯作者：
Zhang, Xiaogang
中科院分区：
文献类型：
--
作者：
Ding, Bing;Shen, Laifa;Zhang, Xiaogang
锂硫（Li-S）电池的商业化一直受到硫阴极电化学利用率低、容量衰减快等问题的阻碍，而硫阴极的电化学利用率低、容量衰减快是由于硫的电导率和离子电导率低、中间多硫化物溶解度高以及硫的体积膨胀引起的。在这里，我们描述了一种现场吸附战略走向上级稳定性的硫电极封装到介孔二氧化钛主机元素硫。Brunauer-Emmett-Teller（BET）、透射电子显微镜（TEM）和扫描透射电子显微镜（STEM）测量明显地表明元素硫（S）占据了TiO 2主体的介孔，形成核-壳状纳米结构。在充放电过程中，TiO 2/S复合材料具有上级的循环稳定性和高的库仑效率。即使在1C的高电流速率下，TiO 2/S复合材料也显示出650 mAh g（-1）的初始比容量和100次循环后89%的比保持率。其优异的电化学性能与TiO 2主体在电化学反应中所起的重要作用密切相关。首先，纳米TiO 2（类似于5 nm）通过化学键相互作用捕获多硫化物，以防止其溶解并最小化“穿梭效应”。更重要的是，原位形成的LixTiO 2作为混合的电/离子导体，促进了Li+/e（-）的传输。二氧化钛的独特功能加上其容易获得，使目前的研究在概念上提供了新的机会，以达到长期的循环稳定性的硫阴极使用无碳主机。(C)2013爱思唯尔有限公司保留所有权利。
The commercialization of lithium-sulfur (Li-S) battery has so far hindered by the low electrochemical utilization and rapid capacity fading of sulfur cathode, which is induced bylaw electric/ionic conductivity, high dissolution of intermediate polysulfides and the volume expansion of sulfur. Herein, we describe an on-site adsorption strategy toward superior stability of sulfur electrode by encapsulating elemental sulfur into mesoporous TiO2 host. Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) measurements obviously indicate that elemental sulfur (S) occupy the mesopores of the TiO2 host, forming a core-shell liked nanostructure. The TiO2/S composite exhibits a superior cycling stability and high Coulombic efficiency during the charge/discharge process. Even at a high current rate of 1 C, the TiO2/S composite shows an initial specific capacity of 650 mAh g(-1) and a specific retention of 89% after 100 cycles. The excellent electrochemical performances are critical related to the significant roles TiO2 host played during the electrochemical reaction. Firstly, the nano-sized TiO2 (similar to 5 nm) traps the polysulfides via chemical bonding interaction to prevent their dissolution and minimize the "shuttle effect". More importantly, the in situ formed LixTiO2, acting as a mixed electric/ionic conductor, facilitates easier Li+/e(-) transport. The unique functions of the TiO2 plus its easy availability make the current study conceptually provides new opportunities to reach long-term cycling stability of sulfur cathode using carbon-free hosts. (C) 2013 Elsevier Ltd. All rights reserved.