Chitosan as a functional additive for high-performance lithium-sulfur batteries

摘要

Chitosan with abundant hydroxyl and amine groups as an additive for cathodes and separators has been proven to be an effective polysulfide trapping agent in lithium-sulfur batteries. Compared with common sulfur cathodes, the cathode with chitosan shows an enhanced initial discharge capacity from 950 to 1145 mA h g(-1) at C/10. The reversible specific capacity after 100 cycles increases from 508 mA h g(-1) to 680 mA h g(-1) and 473 to 646 mA h g(-1) at rates of C/2 and 1 C, respectively. In addition, batteries with separators that are coated with a carbon/chitosan layer can exhibit a high discharge capacity of 830 mA h g(-1) at C/2 after 100 cycles and 675 mA h g(-1) at 1 C after 200 cycles with the capacity fading to as low as 0.11% per cycle. This study demonstrates the benefits of using chitosan for not only lithium-sulfur batteries but also potentially other sulfur-based battery applications.