Trapping sulfur in hierarchically porous, hollow indented carbon spheres: a high-performance cathode for lithium–sulfur batteries
Trapping sulfur in hierarchically porous, hollow indented carbon spheres: a high-performance cathode for lithium–sulfur batteries
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DOI：
10.1039/c6ta03187k
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发表时间：
2016-06
影响因子：
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通讯作者：
Yijun Zhong;Shaofeng Wang;Yujing Sha;Meilin Liu;R. Cai;Li Li-Li;Zongping Shao
中科院分区：
文献类型：
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作者：
Yijun Zhong;Shaofeng Wang;Yujing Sha;Meilin Liu;R. Cai;Li Li-Li;Zongping Shao
具有锯齿状空隙结构的多级多孔空心碳球被设计为高性能锂硫电池正极材料的主体。直径约为100 nm，孔体积为3.72 cm 3 g-1，主体可以将硫保留在多孔结构中，包括外部锥形空腔，多孔碳壳和内衬。精致的锯齿状结构提供了良好的电子和锂离子通道，而对称的锯齿状空隙均匀地减轻了循环过程中体积变化引起的应力。氧官能团进一步缓解了多硫化物的穿梭效应。具有52%硫负载的复合电极在1/10 C（1C = 1675 mA g− 1）下表现出1478 mA h g−1的显著初始放电容量，对应于88%的硫利用率。即使当复合材料的硫/碳（S/C）比从1：1增加到3：1（75%硫负载）时，仍然保持非常高的容量保持率，实现超低容量衰减速率，在1/2C下在1200次循环中每循环约0.047%。
Hierarchically porous hollow carbon spheres with an indented void structure have been designed as hosts for high-performance cathode materials for lithium–sulfur batteries. With a diameter of approximately 100 nm and a pore volume of 3.72 cm3 g−1, the hosts can retain sulfur within the porous structures, including the external cone-like cavities, the porous carbon shells, and the inner linings. The exquisite indented structure provides excellent electron and Li-ion pathways while the symmetrically indented voids evenly alleviate the stress induced by the volume change during cycling. The oxygen functional groups further relieve the shuttle effect of polysulfide. A composite electrode with 52% sulfur loading demonstrates a remarkable initial discharge capacity of 1478 mA h g−1 at 1/10C (1C = 1675 mA g−1), corresponding to 88% sulfur utilization. Even when the sulfur/carbon (S/C) ratio of the composite is increased threefold from 1 : 1 to 3 : 1 (75% sulfur loading), a very high capacity retention is still maintained, achieving an ultraslow rate of capacity fading, ∼0.047% per cycle over 1200 cycles at 1/2C.