Ionic polymer-functionalized separator for high performance Li-S battery

With the rapid development of commercialization, the progress of lithium-sulfur (Li-S) batteries has also encountered some severe issues, including low electrical conductivity, shuttle effect of LiPSs, volume changes during charge and discharge, which lead to serious battery capacity attenuation, poor cycle stability and other problems. In order to overcome these problems, a new barrier layer based on multifunctional covalent triazine frameworks (CTFs) is designed as a separator for Li-S battery. This barrier layer can alleviate the shuttle effect by means of the electrostatic interaction between the frameworks and Li + and S x 2− . Therefore, the Li-S battery with ionic polymer-functionalized separators has shown remarkably improvements in electrochemical performances. A high initial capacity of 816.4 mAh g −1 is observed at 1C. Furthermore, after 500 cycles, its capacity retention rate reached 66%. This study emphasizes that the multifunctional constraints between the separator and polysulfides can suppress the shuttle, thus providing a promising strategy for the construction of Li-S batteries.