Ether-compatible sulfurized polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30833552.
- Also identified by DOI 10.1038/s41467-019-08818-6 and PMC identifier 6399341.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Sulfurized polyacrylonitrile is suggested to contain S<sub>n</sub> (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 Li<sub>2</sub>S<sub>n</sub> (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<sup>-1</sup> at 0.2 A g<sup>-1</sup>), 84% active material utilization and high rate (capacity up to 900 mA h g<sup>-1</sup> at 10 A g<sup>-1</sup>). 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 Li<sub>2</sub>S<sub>n</sub> (n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.