Ultra-lightweight PANiNF/MWCNT-functionalized separators with synergistic suppression of polysulfide migration for Li–S batteries with pure sulfur cathodes

Abstract

A custom separator with an ultra-lightweight polyaniline nanofiber/multiwall carbon nanotube (PANiNF/MWCNT) coating has been utilized in lithium–sulfur (Li–S) batteries for investigating the electrochemical performance of the hybrid conductive-polymer/carbon coating. The cells employing the PANiNF/MWCNT-functionalized separators facilitate high reversible capacities of 709, 641, and 612 mA h g⁻¹ at, respectively, C/5, C/2, and 1C rates after 100 cycles. High charge-storage capacity retention was also found in the cell with the PANiNF/MWCNT-functionalized separator after a resting time of 12 h. Such dynamic and static electrochemical stability could be ascribed to the synergistic physical adsorption and chemical immobilization of the polysulfides by the ultra-lightweight PANiNF/MWCNT coating (only 0.01 mg cm⁻²). This demonstrates that the design of hybrid polymer/carbon-coated-separators has the potential to become a viable approach for successfully developing practical Li–S batteries.