State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China.
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China.
Nat Commun. 2019 Mar 4;10(1):1021. doi: 10.1038/s41467-019-08818-6.
Sulfurized polyacrylonitrile is suggested to contain S (n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of LiS (n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g at 0.2 A g), 84% active material utilization and high rate (capacity up to 900 mA h g at 10 A g). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate LiS (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.
含硫聚丙烯腈被认为含有 S（n≤4），在用于锂硫电池的碳酸盐电解液中表现出良好的电化学性能。然而，在醚电解液中的较差结果表明，LiS（n≤4）的高溶解度超过了有限的氧化还原转化，导致溶解和穿梭。在这里，我们在硫代聚丙烯腈中引入少量硒来加速氧化还原转化，在碳酸盐和醚电解液中均表现出优异的性能，包括高可逆容量（在 0.2 A g 下为 1300 mA h g）、84%的活性材料利用率和高倍率（在 10 A g 下高达 900 mA h g）。这些正极在 800 次循环中具有近 100%的库仑效率和超低的 0.029%/循环的容量衰减。通过增强反应动力学成功抑制了多硫化物的溶解。这项工作展示了一种与醚兼容的含中间 LiS（n≤4）的硫正极，具有吸引人的倍率和循环性能，为可应用的锂硫电池提供了有前景的解决方案。
