Strong Sulfur Binding with Conducting Magn茅li-Phase TinO2n鈥? Nanomaterials for Improving Lithium鈥揝ulfur Batteries

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• 作者：Xinyong Tao ; Jianguo Wang ; Zhuogao Ying ; Qiuxia Cai ; Guangyuan Zheng ; Yongping Gan ; Hui Huang ; Yang Xia ; Chu Liang ; Wenkui Zhang ; Yi Cui
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：September 10, 2014
• 年：2014
• 卷：14
• 期：9
• 页码：5288-5294
• 全文大小：543K
• ISSN：1530-6992

文摘

Lithium鈥搒ulfur batteries show fascinating potential for advanced energy storage systems due to their high specific capacity, low-cost, and environmental benignity. However, the shuttle effect and the uncontrollable deposition of lithium sulfide species result in poor cycling performance and low Coulombic efficiency. Despite the recent success in trapping soluble polysulfides via porous matrix and chemical binding, the important mechanism of such controllable deposition of sulfur species has not been well understood. Herein, we discovered that conductive Magn茅li phase Ti₄O₇ is highly effective matrix to bind with sulfur species. Compared with the TiO₂鈥揝, the Ti₄O₇鈥揝 cathodes exhibit higher reversible capacity and improved cycling performance. It delivers high specific capacities at various C-rates (1342, 1044, and 623 mAh g^鈥? at 0.02, 0.1, and 0.5 C, respectively) and remarkable capacity retention of 99% (100 cycles at 0.1 C). The superior properties of Ti₄O₇鈥揝 are attributed to the strong adsorption of sulfur species on the low-coordinated Ti sites of Ti₄O₇ as revealed by density functional theory calculations and confirmed through experimental characterizations. Our study demonstrates the importance of surface coordination environment for strongly influencing the S-species binding. These findings can be also applicable to numerous other metal oxide materials.

Keywords:

Lithium Sulfur Battery; Magn茅li Phase; Ti₄O₇; Strong Adsorption; Nanoparticles