High-performance lithium-sulfur batteries with a carbonized bacterial cellulose/TiO2 modified separator

Lithium-sulfur (Li S) batteries have been considering as a very promising energy storage system since their high theoretical specific capacity and energy density . Nevertheless, the practical commercialization of Li S batteries is hindered by their poor cycle stability and fast capacity fading. Herein, a carbonized bacterial cellulose/titania (CBC/TiO 2 ) modified separator is designed to restrain the shuttle effect of Li S cells with its strong physical and chemical adsorption of polysulfides . Cells with CBC/TiO 2 modified separator show an initial discharge capacity of 1314   mAh   g −   1 at 0.2C, and the capacity retention is 1048.5   mAh   g −   1 after 50   cycles. A discharge capacity of 475   mAh   g −   1 is obtained after 250   cycles at 2C. And during the rate test, Li S cells can deliver a discharge capacity of 537.1   mAh   g −   1 at 2C. The outstanding electrochemical performance of Li S cells with CBC/TiO 2 modified separator shows a new approach for the application of Li S batteries.