Boosting the polysulfides adsorption-catalysis process on carbon nanotube interlayer via a simple polyelectrolyte-assisted strategy for high-performance lithium sulfur batteries

●A multifunctional CNT/PDDA-TFSI interlayer was fabricated through a simple polyelectrolyte-assisted strategy.●The continuous CNT skeleton facilitates electron transport.●The interlayer ensures the effective polysulfides adsorption by electrostatic interaction.●The interlayer accelerates the lithium polysulfides conversion. [Display omitted] The introduction of conductive interlayer is an effective strategy to improve the sulfur utilization and restrict the migration of polysulfides for high-performance Li-S battery. Herein, a multifunctional CNT based interlayer was obtained by a simple polyelectrolyte (PDDA-TFSI) modified method. Due to the electro-positivity of PDDA-TFSI and the electronic coupling between CNT and PDDA-TFSI, the CNT/PDDA-TFSI interlayer exhibits a strong adsorption and effective catalysis towards polysulfides. Furthermore, the continuous CNT network ensures the successful electron transport during the charge-discharge process. As expected, the electrochemical properties of Li-S battery can be promoted significantly with the assistance of CNT/PDDA-TFSI interlayer. Even after 300 cycles, the CNT/PDDA-TFSI interlayer-based Li-S battery also delivers a higher capacity retention of 79.2%, proceeding Li-S batteries with and without CNT interlayer. This work proves that CNT/PDDA-TFSI film as a multifunctional interlayer has a promising application in advanced Li-S battery.