Sulfuric acid-adjuvant sulfonated graphene as efficient polysulfides tamer for high-energy-density Li-S batteries
Sulfuric acid-adjuvant sulfonated graphene as efficient polysulfides tamer for high-energy-density Li-S batteries
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硫酸助剂磺化石墨烯作为高能量密度锂硫电池的高效多硫化物驯化剂
DOI：
10.1016/j.jpowsour.2018.11.045
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发表时间：
2019
影响因子：
9.2
通讯作者：
Gong Daoxin
中科院分区：
文献类型：
--
作者：
Zhong Mei-e;Sun Jingchun;Guan Jindiao;Liang Ce;Yu Shuang;Xiao Zhubing;Zhou Nan;Gong Daoxin
锂硫电池具有理论能量密度高、成本低的优点，在大规模储能领域具有广阔的应用前景。然而，硫的绝缘特性和多硫化物的穿梭效应导致硫利用率低，容量衰减快。本研究采用低成本稀硫酸作为磺化试剂制备磺化石墨烯，用于构建独立硫阴极。证实了接枝在石墨烯上的亚砜基团作为介质与长链多硫化物反应，形成硫代硫酸盐/聚硫酸盐中间体，促进了长链多硫化物向短链产物和固体排放产物的转化。重要的是，含硫量为8.2 mg cm−2的独立阴极的面容量为7.57 mA h cm−2，在0.1 C下稳定循环超过100次。
Lithium-sulfur batteries hold great promise for large-scale energy storage owing to their high theoretical energy density and low cost. However, the insulating nature of sulfur and shuttle effect of polysulfides result in low sulfur utilization and rapid capacity decay. Here, sulfonated graphene is fabricated using the low-cost diluted sulfuric acid as sulfonated reagent, for constructing the freestanding sulfur cathode. It is confirmed that the sulfo groups grafted on graphene serve as mediators to react with long-chain polysulfides by forming the thiosulfate/polythionate intermediates, and facilitate the conversion of long-chain polysulfides into short-chain species and solid discharge products. Crucially, the freestanding cathode with sulfur loading of 8.2 mg cm−2exhibits an areal capacity of 7.57 mA h cm−2and stable cycling over 100 cycles at 0.1 C.