Improving the performance of PEDOT-PSS coated sulfur@activated porous graphene composite cathodes for lithium–sulfur batteries

Abstract

A novel PEDOT-PSS coated sulfur@activated porous graphene composite (PEDOT/S@aPG) is prepared by the impregnation of sulfur with aPG and encapsulation with PEDOT-PSS as the cathode material for lithium–sulfur batteries. The abundant nanopores and large surface area of aPG can provide an intimate contact and strong interaction with S species. Furthermore, the conductive PEDOT-PSS layer can facilitate the charge transportation and prevent the dissolution of polysulfides. As a result, the as-prepared PEDOT/S@aPG composite cathode with a sulfur content of about 60.1% shows a higher specific discharge capacity (1198 mA h g⁻¹ at 0.1 C) in the first cycle and good cycling stability, retaining a reversible capacity of 845 mA h g⁻¹ after 200 cycles. Moreover, the PEDOT/S@aPG cathode also exhibits excellent rate capability, showing a high reversible capacity of 718 mA h g⁻¹ at 2 C.