Enhanced cyclability using a polyindole modified cathode material for lithium sulphur batteries

Abstract

Here we report a novel multiwall carbon nanotube/sulphur/polyindole (MWCNT/S/PIN) nanocomposite as a cathode material for lithium–sulphur (Li–S) batteries to alleviate capacity decay. The nanocomposite cathode material is synthesized by chemical precipitation of sulphur onto functionalized MWCNTs followed by in situ polymerization of indole. The MWCNT/S/PIN nanocomposite exhibits an initial specific capacity of 1490 mA h g⁻¹ and enhanced cycling stability compared to the binary nanocomposite (MWCNT/S). The MWCNT/S/PIN composite cathode displays a specific capacity of 1043 mA h g⁻¹ after 100 cycles at 0.1C rate with 70% capacity retention. The better electrochemical performance of the ternary nanocomposite cathode material is attributed to the synergistic effect of the functionalized MWCNTs and polyindole which provides an improved conductivity and effective fencing of intermediate polysulphides.