【作者】 张向倩； 何斌； 李文翠；

【Author】 Xiang-Qian Zhang;Bin He;Wen-Cui Li;School of Chemical Engineering,Dalian University of Technology;

【机构】 大连理工大学化工学院；

【摘要】 锂硫（Li-S）电池具有超高的理论能量密度(2600Wh kg^-1)、环境友好、成本低廉等优点,是目前最具发展前景的二次电池之一。但Li-S电池活性物质硫及充放电产物多硫化物的导电性和Li⁺传导效率低,限制其倍率性能;硫在充放电过程中体积膨胀及形成的多硫化物易溶于电解液,导致循环稳定性差。本文提出一种新型的"化学响应缩孔"制备纤维状炭硫复合材料的新思路,利用壳壁为介孔的大孔容空心管状炭载体装填活性物质硫,然后通过溶液温和缩孔方法将介孔原位收缩为微孔,将活性物质硫限制在炭壁内。该材料的空腔结构和炭载体外侧管壁丰富的微孔孔道可有效缓解多硫化物的溶出。材料展现出高的循环稳定性和优异的倍率性能:4.0 C倍率下比容量达870 mA h g^-1,2.0 C倍率下样品循环200次后的容量为860 mA h g^-1。更多还原

【Abstract】 A fibrous host material with a mesoporous shell and large hollow interior void has been designed, which is capable of storing a payload of sulfur for Li-S batteries. After prefilling the pores and voids with sulfur, the mesopores on the shell is smartly transformed to micropores via a mild solution-based pore shrinking approach. Thus, the sulfur was well confined in the cavity of carbon fiber host（HCFs）. The high aspect ratio fibers form a conductive network and the thin carbon walls allow rapid transport of Li⁺ ions and electrons. Taking advantages of this structure in Li-S batteries, a very high initial discharge capacity of 1638 m Ah g^-1, corresponding to 98% sulfur utilization rate at 0.1 C, was achieved on a sulfur@HCFs composite with a sulfur loading of 61 wt %. Stable capacities-of 854 m A h g1 after 200 cycles at 2.0 C were obtained.更多还原