Self-assembled reduced graphene oxide/sulfur composite encapsulated by polyaniline for enhanced electrochemistry performance

Reduced graphene oxide/sulfur/polyaniline (referred to RGO/S/PANI) composite was self-assembled through in situ synthesis and used to investigate the electrochemical properties of lithium/sulfur cells. The RGO/S/PANI composite possessed 809.3/801.9 mAh g(-1) of initial charge/discharge capacities, higher than 588.3/588.2 mAh g(-1) for reduced graphene oxide/sulfur (referred to RGO/S) and 681.4/669.9 mAh g(-1) for sulfur/polyaniline (referred to S/PANI) at similar conditions. The RGO/S/PANI composite obtained 400 mAh g(-1) at 2 C and good reversible capacities of 605.5 and 600.8 mAh g(-1) at 100th charge/discharge cycle at 0.1 C, in comparison with low electrochemical performance of RGO/S and S/PANI. The improved properties could be attributed to the collaboration of RGO and PANI. Co-generation of RGO and sulfur acted as seeds for their depositions, stimulated their uniform distributions, and restricted the agglomeration of sulfur particles in situ synthesis. Polyaniline coated RGO/S and stabilized the nanostructure of RGO/S/PANI in repeated charge/discharge cycles. In addition, RGO and PANI provided many electron channels to enhance sulfur conductivity and sufficient void space for sulfur swelling during charge/discharge cycles.