Enhanced performance of lithium-sulfur batteries with high sulfur loading utilizing ion selective MWCNT/SPANI modified separator

摘要

Graphical abstractDisplay OmittedHighlights?A MWCNT/SPANI-coated separator is designed to improve the properties of Li-S cells.?The modified separator with rich SO3?groups is permeable to Li+but rejects Sn2?.?The Li-S cells employ the cathodes with high sulfur loading of 5mgcm?2.?The modified separator has greatly improved the properties of the Li-S cells.AbstractLithium-sulfur (Li-S) battery has attracted remarkable attention owing to its high theoretical energy density. However, its commercialization is still hampered by the rapid capacity degradation which mainly originates from the polysulfides shuttle between the anode and cathode. In this paper, a functional multiwall carbon nanotube/sulfonated polyaniline (MWCNT/SPANI) modified separator is designed to enhance the electrochemical performance of the Li-S batteries with high sulfur loading. The MWCNT/SPANI-coated separator is highly permselective to Li+but rejects the transportation of polysulfide anions. Besides, the MWCNT/SPANI coating can also work as an upper current collector and provides channels for electron and ion transport to enhance the sulfur utilization and ensure the reactivation of trapped active materials. With the ion selective MWCNT/SPANI-coated separator, the electrochemical performance of the Li-S batteries based on cathodes with high sulfur loading (5mgcm?2) and high sulfur content (72wt%) has been significantly improved. It delivers a reversible capacity of 913mAhg?1at the current density of 100mAg?1after 100 cycles, much higher than that of the cells with pristine Celgard separator. Hence, the ion selective MWCNT/SPANI modified separator is promising for developing high-performance Li-S batteries employing cathodes with high sulfur loading and high sulfur content.]]>