Wang Ke, Zhao Teng, Zhang Nanxiang, Feng Tao, Li Li, Wu Feng, Chen Renjie
Beijing Key Laboratory of Environmental Science and Engineering, School of Material Science & Engineering, Beijing Institute of Technology, Beijing 100081, China.
Institute of Advanced Technology, Beijing Institute of Technology, Jinan 250300, China.
Nanoscale. 2021 Oct 14;13(39):16690-16695. doi: 10.1039/d1nr04825b.
Sulfurized polyacrylonitrile (SPAN) is a promising cathode material for stable lithium-sulfur (Li-S) batteries due to its shuttle-free redox mechanism. However, the redox kinetics of SPAN needs to be enhanced to improve Li-S batteries. Herein, a salt-templating method is proposed for the fabrication of ultrathin SPAN nanosheets, which can afford a large contact area with the electrolyte and shorten the transport paths of electrons/ions involved in the reaction. Raman analysis confirms the reversible breaking and formation of C-S/S-S bonds in SPAN nanosheets during cycling while SEM reveals the formation of lithium sulfide particles on the surface of SPAN nanosheets at the end of discharge. At a high current density of 2 A g, coin cells based on a SPAN nanosheet cathode can deliver a reversible capacity of 408 mA h g over 100 cycles with a capacity retention rate of 95%. Meanwhile, pouch cells using a SPAN nanosheet cathode exhibit a capacity retention rate close to 100% after 100 cycles at the same current density. These results herald a new approach for powering Li-S batteries by the nanoscale design of the SPAN cathode.
硫化聚丙烯腈（SPAN）因其无穿梭氧化还原机制，是一种用于稳定锂硫（Li-S）电池的有前景的正极材料。然而，需要增强SPAN的氧化还原动力学以改进锂硫电池。在此，提出一种盐模板法来制备超薄SPAN纳米片，其能提供与电解质的大接触面积并缩短反应中电子/离子的传输路径。拉曼分析证实了循环过程中SPAN纳米片中C-S/S-S键的可逆断裂和形成，而扫描电子显微镜揭示了放电结束时SPAN纳米片表面硫化锂颗粒的形成。在2 A g的高电流密度下，基于SPAN纳米片正极的硬币电池在100次循环中可提供408 mA h g的可逆容量，容量保持率为95%。同时，使用SPAN纳米片正极的软包电池在相同电流密度下100次循环后容量保持率接近100%。这些结果预示了一种通过SPAN正极的纳米级设计为锂硫电池供电的新方法。
