Laboratory of Living Materials, the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, 430070, Wuhan, China.
Nanoscale. 2018 Jul 5;10(25):11861-11868. doi: 10.1039/c8nr03290d.
Hierarchically porous carbon-supported sulfur material is widely used as a cathode for Li-S batteries because its large surface area and rich porous system provide high sulfur loading, resulting in high specific capacity with stable charge/discharge cycling performance. However, limited attention has been paid to whether the structure of hierarchical porous system affects the final electrochemical performance of Li-S/C batteries. Herein, we present hierarchically structured carbon (WSAC) with varied amounts of mesopores and micropores as a sulfur container for Li-S batteries. It is found that the relationship between electrochemical performance and percentage of microporous volume obeys a volcano distribution, which indicates that the volume percentage of microporous in the meso-microporous structure could be suitably tuned to achieve the desired electrochemical performance. Such S/hierarchically meso-microporous carbon (i.e., WSAC-8) with moderate microporous volume percentage (68.3%) shows high initial specific capacity (1375 mA h g-1) and stable charge/discharge performance (942.6 mA h g-1 after 200 cycles at 0.5C). In particular, WSAC-8 also presented superior capacity behavior at high rate capability, with final capacity as high as 800.1 and 758.7 mA h g-1 for 1C and 2C, respectively.
分层多孔碳负载硫材料因其具有较大的比表面积和丰富的多孔体系，可实现高硫负载量，从而获得高比容量和稳定的充放电循环性能，被广泛用作锂硫电池的正极。然而，人们对分层多孔体系的结构是否会影响最终的锂硫/C 电池电化学性能关注较少。在此，我们提出了一种具有不同中孔和微孔含量的分层结构碳（WSAC）作为锂硫电池的硫容器。研究发现，电化学性能与微孔体积百分比之间的关系呈火山分布，表明中孔-微孔结构中微孔的体积百分比可以适当调谐，以获得所需的电化学性能。具有适度微孔体积百分比（68.3%）的 S/分层中孔-微孔碳（即 WSAC-8）表现出较高的初始比容量（1375 mA h g-1）和稳定的充放电性能（在 0.5C 下循环 200 次后为 942.6 mA h g-1）。特别地，WSAC-8 在高倍率性能下也表现出优异的容量行为，在 1C 和 2C 下的最终容量分别高达 800.1 和 758.7 mA h g-1。
