Ether-compatible sulfurized polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping

• DOI: 10.1038/s41467-019-08818-6
• Publication Date: 2019-03-04T11:03:46Z
• Authors: Xin Chen; Linfeng Peng; Lihui Wang; Jiaqiang Yang; Zhangxiang Hao; Jingwei Xiang; Kai Yuan; Yunhui Huang; Bin Shan; Lixia Yuan; Jia Xie
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; 7. Clean energy; Article; 3. Good health

AbstractSulfurized polyacrylonitrile is suggested to contain Sn (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 Li2Sn (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−1 at 0.2 A g−1), 84% active material utilization and high rate (capacity up to 900 mA h g−1 at 10 A g−1). 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 Li2Sn (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.