High-performance lithium-sulfur batteries with a carbonized bacterial cellulosei/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/TiO2) 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/TiO2 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/TiO2 modified separator shows a new approach for the application of Li-S batteries. (C) 2016 Published by Elsevier B.V.