Creating Effective Nanoreactors on Carbon Nanotubes with Mechanochemical Treatments for High‐Areal‐Capacity Sulfur Cathodes and Lithium Anodes
Creating Effective Nanoreactors on Carbon Nanotubes with Mechanochemical Treatments for High‐Areal‐Capacity Sulfur Cathodes and Lithium Anodes
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DOI：
10.1002/adfm.201800595
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发表时间：
2018-06
影响因子：
19
通讯作者：
Gang Yang;Jian Tan;Ho Jin;Y. H. Kim;Xinyu Yang;D. Son;S. Ahn;Hongcai Zhou;Choongho Yu
中科院分区：
文献类型：
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作者：
Gang Yang;Jian Tan;Ho Jin;Y. H. Kim;Xinyu Yang;D. Son;S. Ahn;Hongcai Zhou;Choongho Yu
锂硫电池可以提供高能量密度和功率，但锂金属阳极上的多硫化物穿梭和锂枝晶形成一直是主要障碍。特别是当活性材料（硫）的面积负载增加以提供高能量密度和充电/放电电流密度升高以提供高功率时，多硫化物穿梭变得严重。这项研究报告了一种新的机械化学方法，在独立的3D多孔CNT海绵中的碳纳米管（CNT）表面上创建沟槽。独特的螺旋沟槽在化学处理过程中通过压力产生，为阴极提供亲多硫化物表面，为阳极提供亲锂表面。使用机械化学处理的电极由制造友好的硫夹层阴极和锂注入阳极制成的Li-S电池表现出高达13.3 mAh cm−2的惊人高面积容量，即使电流密度增加十倍（16 mA cm−2），也仅略微降低，证明了高“电池级”能量密度和功率。其优异的性能可归因于显著改善的反应动力学和来自阴极和阳极处的界面电阻和电荷转移电阻的降低的过电位。沟壁CNT海绵同时解决了Li-S电池阴极和阳极上最关键的问题，这种方法可用于设计用于储能及其他用途的新电极材料。
Li‐S batteries can potentially deliver high energy density and power, but polysulfide shuttle and lithium dendrite formations on Li metal anode have been the major hurdle. The polysulfide shuttle becomes severe particularly when the areal loading of the active material (sulfur) is increased to deliver the high energy density and the charge/discharge current density is raised to deliver high power. This study reports a novel mechanochemical method to create trenches on the surface of carbon nanotubes (CNTs) in free‐standing 3D porous CNT sponges. Unique spiral trenches are created by pressures during the chemical treatment process, providing polysulfide‐philic surfaces for cathode and lithiophilic surfaces for anode. The Li‐S cells made from manufacturing‐friendly sulfur‐sandwiched cathodes and lithium‐infused anodes using the mechanochemically treated electrodes exhibit a strikingly high areal capacity as high as 13.3 mAh cm−2, which is only marginally reduced even with a tenfold increase in current density (16 mA cm−2), demonstrating both high “cell‐level” energy density and power. The outstanding performance can be attributed to the significantly improved reaction kinetics and lowered overpotentials coming from the reduced interfacial resistance and charge transfer resistance at both cathodes and anodes. The trench–wall CNT sponge simultaneously tackles the most critical problems on both the cathodes and anodes of Li‐S batteries, and this method can be utilized in designing new electrode materials for energy storage and beyond.