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

ABSTRACT: Sulfurized 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.

SUBMITTER: Chen X 

PROVIDER: S-EPMC6399341 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature