Mesopore Channel Length Control in Ordered Mesoporous Carbon Hosts for High Performance Lithium-Sulfur Batteries
Mesopore Channel Length Control in Ordered Mesoporous Carbon Hosts for High Performance Lithium-Sulfur Batteries
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DOI：
10.1149/2.0391903jes
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发表时间：
2018-12-28
影响因子：
3.9
通讯作者：
Yu, Jong-Sung
中科院分区：
文献类型：
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作者：
Lee, Byong-June;Park, Hyean-Yeol;Yu, Jong-Sung
以尺寸可调的有序介孔二氧化硅为模板，制备了不同中孔长度的有序介孔碳（OMC），并将其作为硫（S）的载体，研究了中孔长度对锂硫电池（LSB）性能的影响。OMC中发育良好的中孔提供了优异的离子传输路径，增强了质量传输能力，从而表现出更好的循环性能和倍率性能。特别地，具有薄的六棱柱形状和短的中孔长度的片状OMC（pOMC）展示了在168 mA g（-1）的电流密度下1419 mAh g（-1）的高可逆放电容量和优异的循环性能。基于比容量、循环效率和倍率性能，pOMC-S显著优于其介孔碳同行，棒状OMC-S（rOMC-S）和具有较长介孔长度的球形OMC-S（sOMC-S）。这种优异的行为归因于活性硫物质更好地和更多地利用短介孔通道，这诱导更高的硫利用率，并且还得到电化学阻抗谱中的低电化学电阻的支持。改进的电池性能可以根据用于硫负载和多硫化物溶解的中孔通道的利用效率来理解，其随着通道长度的减小而改进。(C)作者（S）2018由ECS发布。
Ordered mesoporous carbons (OMCs) with different mesopore channel length, prepared by using corresponding size-tuned ordered mesoporous silicas as templates, are explored as hosts for sulfur (S) in cathode to investigate the effect of the mesopore length on Li-S battery (LSB) performance. The well-developed mesopores in the OMCs provide an excellent ion transport path, enhancing mass transport capability and thus demonstrating better cycling performance and rate capability. Particularly, platelet OMC (pOMC) with thin hexagonal prism shape and short mesopore length demonstrates the high reversible discharge capacity of 1419 mAh g(-1) at a current density of 168 mA g(-1) and excellent cyclability. Based on the specific capacity, cycle efficiency, and rate capability, the pOMC-S outperforms considerably its mesoporous carbon peers, rod-like OMC-S (rOMC-S) and spherical OMC-S (sOMC-S) with longer mesopore length. This superb behavior is attributed to better and more utilization of short mesopore channels for active sulfur species, which induce higher sulfur utilization, and are also supported by low electrochemical resistances in electrochemical impedance spectroscopy. The improved cell performance can be understood in terms of utilization efficiency of the mesopore channels for sulfur loading and polysulfide dissolution, which improves with decreasing channel length. (C) The Author(s) 2018. Published by ECS.